Monday Astrid defended her Masters thesis on the trophic structure of the mesopelagic community in the Northeastern Atlantic using isotope methods. Supervisors were Eva Garcia Seoane (Institute of Marine Research) who also provided the data and lab guidance, and
Tom J. Langbehn.
Professor Stein Kaartvedt of the University of Oslo was external examiner and led an enjoyable discussion with Astrid.
Her thesis bears the title Trophic structure of mesopelagic species in the Northeast Atlantic Ocean based on stable isotopes of carbon and nitrogen and a link will be provided here as soon as it is available online.
Tom, Astrid, and Eva cool down in the refreshing Bergen rain after a good discussion about Astrid’s thesis work with the examiners. (CC0).
Are you interested in developing your dream project on the ecology and evolution of macroalgae? The project is a collaboration between the research group in Marine Biodiversity and TEG where we wish to work on the adaptations of macroalgae to their seasonal environment as well as the seasonal dynamics of these prominent primary producers and foundation species.
The position is a three to four year postdoc opportunity in coastal ecology and part of a large pool of openings at the University of Bergen within the programme Shaping European Research Leaders for Marine Sustainability (SEAS). Application deadline is 31 October, but please get in touch with professor Kjersti Sjøtun and professor Øystein Varpe to discuss your ideas before that. SEAS is part of an EU mobility programme for international candidates moving to Norway.
Links to further information:
Plentiful fieldwork opportunities for the project such as at the Marine Biological Station Espegrend. (Photo: Øystein Varpe).
Our new project asking how fisheries can contribute more to a sustainable future is hiring new people to investigate the contribution of fisheries to sustainable food systems, refine estimates of primary production and trophic efficiencies, and to map peoples’ values towards nature and food production across sea and land.
The project is funded by the Research Council of Norway, as a Collaborative Project to Meet Societal and Industry-related Challenges within the thematic area Sustainable Food Systems. The project is interdisciplinary across biological oceanography, marine ecology, and psychology, with strong involvement of the seafood industry (Fiskebåt), a conservationist NGO (Nature and Youth), and Norway’s government agency advising and implementing management of marine living resources (Directorate of Fisheries). The project duration is four years starting from November 2021. We are now recruiting four early career researchers, two PhD-candidates and two postdocs. You can read more about the project at the home page. DEADLINE for applications is 3 October 2021, and here are links to the application portal:
This week, the
ASLO 2021 Aquatic Sciences Meeting
is taking place in virtual Mallorca. Anne Deininger (NIVA), Anders F. Opdal (TEG), Dag O. Hessen (UiO), and Helene Frigstad (NIVA) chaired session SS47 Freshwater browning and coastal darkening.
Das Wasser einiger Fjorde an der Westküste Norwegens wird immer brauner (Credit: picture alliance / zb | Andreas Franke)
Prior to the conference, Anne and Anders were interviewed by the German radio braodcaster Deutsclandfunk, and their daily science program Forschung aktuell. Finally, we made it to German radio! Dubbed to German, natürlich. Listen to the whole interview here.
Seit einigen Jahren werden die Seen und Flüsse in Skandinavien immer dunkler. Inzwischen sind auch die Küstengewässer betroffen. Grund dafür ist nicht Umweltverschmutzung, sondern im Gegenteil: Ein Faktor ist sauberere Luft. Die dunkle Farbe bringt jedoch ganze Ökosysteme durcheinander.
Rachael (left) and Andrea (right) have just settled at the University of Bergen and are very excited about getting started with the project and to sharing the experience with all of you.
Internationally, Timothy D. Clark (Deakin University, Australia) will be sparring partner on fish physiology and fieldwork, while Adriana Humanes (Newcastle University, UK) and Julia Strahl (Carl von Ossietzky University of Oldenburg & Helmholtz-Institute for Functional Marine Biodiversity, Oldenburg, Germany) have invaluable expertise and experience with corals. Adriana and Julia are both associated with the CoralAssist Lab at Newcastle University.
Today Anna Ejsmond defended her PhD degree on reproductive timing in eider ducks, online in Zoom. Anna was a student at UNIS on Svalbard and co-supervised from TEG in Bergen.
The discussions between Anna (top left) and her opponents Silke Bauer (bottom left) Swiss Institute of Ornithology) and Sveinn Are Hanssen (top right, NINA, Tromsø) were lively and thoughtful. Jarl Giske (bottom right) was the internal leader of the evaluation committee and Sigrunn Eliassen (centre, top) chaired the dissertation ceremony.
Anna’s PhD thesis consisted of two chapters using a state-dependent models to analyse reproductive timing in eider ducks on Svalbard, an empirical chapter of observations of eiders, and a theoretical paper on strategies for growth and reproduction in freshwater crustaceans. Superviser at UNIS was Mads Forchhammer and Christian Jørgensen from TEG was supervisor from UiB.
Gabriella Ljungström and Katja Enberg in the digital course headquarter at Alrek, Bergen. (Photo: Eivind Senneset/UiB.)
Bergen Summer Research School is an annual event and normally students from all over the world gather in Bergen to participate. This year and last, the school has been a fully digital event, which has worked out surprisingly well considering the different time zones and varying quality of internet connection of the 127 participating students. This year the overarching theme of the summer research school is “Science and Society towards the Sustainable Development Goals” and it offers six courses that focus on key global challenges. In 2021, Katja is the scientific director for the summer school.
The course Sustainable development of life below water sets focus on the UN Sustainable Development Goal 14: Life below water, which aims at “conserving and sustainably using the oceans, seas and marine resources for sustainable development”, and has 10 specified targets related to marine pollution and conservation, sustainable fisheries, and global change. In the course, built on active learning methods, the students acquire knowledge and skills related to science, policy, and society necessary for contributing towards sustainable development of life below water.
More about the Bergen Summer Research School can be found here:
Bergen Summer Research School web pages
UiB news: Gathering PhD candidates from 45 countries around the SDGs
Species distribution models rely heavily on temperature but will get it wrong in boreal and Arctic regions if they ignore seasonality in light. This is the conclusion in a recent article by postdocs Gabriella Ljungström and Tom J. Langbehn, published in Nature Climate Change.
Gabriella and Tom each had a model for bioenergetics in seasonal environments developed during their PhDs, and combined these to investigate the influence of seasons.
Gabriella’s model focused on Atlantic herring and found that overwintering was the main energetic hurdle, and that warming would make energy stores burn faster during the dark and food-free winter.
Tom’s model was for mesopelagic fishes that inhabit the ocean twilight zone, and they struggle during the midnight sun when zooplankton remain near the surface where predators are abundant. With ocean warming, the mesopelagic fish would need more food, but neither predators nor light would disappear. Again, warming would enhance the latitudinal barrier.
This video explains their main findings:
And you can read the full paper here:
Marc Mangel has together with the Johns Hopkins University Applied Physics Laboratory written a report on how to look beyond test results to estimate actual incidence rate and public health risk of various group sizes.
The report is written for individuals tasked with providing analytical advice to policymakers.
Marc Mangel has been a collaborator of TEG since the 1990s, first with Jarl and then with almost everyone, and adjunct professor in our group for the last ten years. Today he is turning 70 - congratulations!
This picture shows Marc in his favourite activity: discussion and conceptualization. (Photo: Phil Levin.)
Jarl Giske struggled with modelling animal behaviour from life history theory in his PhD and discovered state-dependent optimization just before he finished. A month after the defence in 1990 he met Marc who taught him Dynamic Programming and it all fell into place. The two of them have been close research allies and friends ever since, and the relationship has grown so Marc is now a dear friend to many in TEG and a valued mentor to all of us. Over the years Marc has hosted research visits not only by Jarl but also Rune Rosland, Øyvind Fiksen, Sigrunn Eliassen, Christian Jørgensen, Katja Enberg, and Fabian Zimmermann. As adjunct professor the last ten years Marc has visited our group annually to engage with everyone, which has been particularly motivating for our PhD students and postdocs. Yesterday, we celebrated with him in Zoom and with bubbles as he turns 70 today, congratulations!
Although Marc is retiring, at least as a formality, he shows few signs of slowing down his research activities. We are proud that Marc chooses to be closely associated with us also in the next phase and will use Professor Emeritus at University of Bergen as his active title. And we are patiently waiting for the post-covid times when we finally can meet in person again for discussions and brainstorming!
Hakai Magazine published a feature article on coastal water darkening by Doug Johnson: The environmental threat you’ve never heard of.
Brown freshwater draining from rivers to the coastal waters.( Photo: LWM/NASA/LANDSAT/Alamy Stock Photo.)
The article features interviews with Anders F. Opdal from the Theoretical Ecolgoy Group, in addition to Maren Striebel and Oliver Zielinski in The Coastal Water Darkening Project, and Amanda Poste from NINA. The story revolves around findings from a recent paper by Poste, Maeve McGovern, and colleagues at NIVA and University of Oslo. The magazine article is a bit doom-and-gloom, but the researchers did manage to get through a few moderating points.
All in all, it’s difficult to pin down any specific consequences of coastal darkening, says Opdal. [...] It’s a tricky thing to study, with many moving parts.
You can read the whole article here:
Hakai Magazine: The environmental threat you’ve never heard of
All of TEG is proud of Sigrunn Eliassen, who will receive the Thon Foundation's National Teaching Prize for her outstanding contributions to higher education within science and technology.
When Olav Thon donated his fortune to a charity, one of the aims was to promote teaching within science, technology, and medicine in Norway because it cleverly benefits young poeple in education as well as the country as a whole. A main pillar is therefore the Thon Foundation National Teaching Award, and this year Sigrunn Eliassen will be one of three people to receive it.
You can read more about it here:
Khrono - Milliondryss fra Thon til fremragende undervisere [In Norwegian]
Olav Thon Stiftelsen - Årets vinnere 2021 [In Norwegian]
Our colleagues at NIVA recently published a national review on coastal darkening research:
Increased light attenuation in Norwegian coastal waters - A literature review.
The report, lead authored by Helene Frigstad, was also transformed into a research article published in Frontiers in Marine Science:
Influence of Riverine Input on Norwegian Coastal Systems.
The report and article concludes that human induced changes on land are the primary driver of coastal darkening.
From the report cover. (Photo: Anne Deininger, NIVA)
The Norwegian national broadcasting company (NRK) wrote a short news story about our project Nytt miljøproblem i Norge: Klimaendringer gjør havet mørkere [In Norwegian]. Anders F. Opdal and Anders F. Opdal at TEG were interviewed.
Heavily brown coloured freshwater in a Swedish river.(Photo: Øyvind Fiksen.)
Despite the title, neither Opdal nor Aksnes stated that coastal darkening was an environmental problem.
Mørkere hav kan få konsekvenser for småfisken, ifølge professor. Nå skal forskere bruke de neste fire årene på å finne ut om det er en krise for økosystemet.
The article was followed up by a radio interview on the local news program Hordaland i dag. (Scroll to the header Kvifor blir sjøen mørkare or 1:09:45 into the timeline.)
Digital Life Norway features on their web pages the modelling done by Camilla Jensen and Jacqueline Weidnerin during their PhDs.
The full story can be read here:
Jacqueline Weidner defended her thesis successfully 29 June 2020.
Her first paper was a model of the hormone system involved in appetite, feeding, and growth in juvenile fish, with a focus on how the hormone system could control the organism with maximum juvenile survival probability as a goal function.
Her second paper was how this control can work in stochastic food environments, where the fitness value of future-anticipatory control mechanisms by the hormone system emerge from the model.
The third paper is an application of the model to understand the Pace-of-life syndrome (POLS).
Dag O. Hessen of University of Oslo and Dag L. Aksnes from TEG appear on the Norwegian radio program Ekko discussing the causes and consequences of darker coastal waters.
The full radio program [In Norwegian] is available here:
(select the header Havet blir mørkere or scroll to 27:02 on the timeline).
Hva i all verden er det som skjer, undrer jeg. Hva er det som slukker lyset i fjordene og havet? [...]. Det viser seg at Dag Hessen er på saken.
After a successful and fully digital trial lecture, Camilla was already experienced in the art of online presentations when it was time to defend her PhD thesis. And of course, it went smooth. Congratulations as PhD, Dr Jensen!
While the discussion with opponents took place in Zoom, the audience had to follow the defence livestreamed to YouTube. Opponents Jane Behrens from DTU Aqua in Copenhagen and Knut Wiik Vollset at NORCE in Bergen led an exciting and interesting discussion with Camilla as she defended her thesis Hormone strategies as a key for understanding life history tradeoffs in fish.
It was bizarrely ironic that Camilla, who has such a warm heart for parasites, had to cancel her PhD party because of a pathogen, and that her thesis work on digital fish had to be defended digitally. But true to how we have learned to know Camilla, she of course took the whole challenge with a big smile!
Gabriella Ljungström defended her PhD thesis online on YouTube the first day Norway’s universities were closed down because of the Corona pandemic.
With a bit of planning, even unforeseen events at Friday 13th can eventually have a positive outcome. Congratulations, Dr. Ljungström!
First it became clear that the opponents were prevented from travelling to Bergen because of COVID-19 restrictions. Then local regulations were announced that prohibited crowds, so the defence could take place with only the committee, supervisors, and a few more present. The night before the defence all university buildings in Norway were shut down, at the University of Bergen with eight minutes notice. The defence was all the time planned for Friday 13th, but when even the social afterparty had to be cancelled, wasn’t this too much?
Luckily there are tools for electronic communication. The opponents, Elvira Poloczanska (Alfred-Wegener-Institut, Bremerhaven, Germany) and Asbjørn Vøllestad (University of Oslo) were sporty enough to complete their job online with live-streaming. So while Gabriella and her opponents discussed on Skype, the audience could view the whole thing on YouTube from home.
Supervisor Christian Jørgensen had frantically packed away Lego to convert a children’s room into an academic TV-studio, but his son convincingly suggested one Luke Skywalker mini-figure should remain in the background to help with the force should Gabbi need it.
The defence went well, and judging from the series of incoming telephone calls afterwards family and friends had indeed taken part and could share her happiness.
And the scientific topic? It was about bioenergetics, climate, and life history evolution in planktivore fishes.
The opponents Elvira Poloczanska and Asbjørn Vøllestad challenged the candidate with many thoughtful questions. After some time the conversation took on a life of its own, and intensity and focus was indistinguishable from a regular PhD defence as it would have been if everyone were together in the same room.
Being the first digital PhD defence in Norway during the COVID-19, the local UiB newspaper wrote a story that was republished by Khrono, the national university newspaper. You can read them (in Norwegian) here:
Tom J. Langbehn is chairing a session on Biomass, biodiversity, and ecosystem services in the mesopelagic zone at the ICES Annual Science Conference in Copenhagen in September. Submission deadline is 11 March 2020.
Here is the theme session description:
Biomass, biodiversity, and ecosystem services in the mesopelagic zone
Recent acoustic estimates suggest that the mesopelagic zone might harbour 10,000 metric tonnes of unexploited fish biomass, far exceeding global fisheries catches in the epipelagic zone. This has attracted renewed attention to the utilisation of mesopelagic resources. With the global demand for food projected to increase by 60% by 2050, the sustainable exploitation of mesopelagic resources represents a potential game changer.
The fundamental biological knowledge needed for sustainable resource management and an understanding of the vital role of mesopelagic communities in global processes, e.g. biogeochemical cycling, is however lacking. Therefore, renewed research efforts on this largely unexplored and unexplained ocean realm are timely.
This theme session provides an opportunity to review and report on the extensive ongoing international activities in mesopelagic research. Empiricists, modelers, experimentalists, and theoreticians are invited to present studies, share findings from recent cruises, and exchange ideas on the structure, function, and change of mesopelagic ecosystems and interactions with other ocean realms.
Contributions are invited that relate to the mesopelagic zone and:
Specific examples of interest include:
View the session at the ICES webpages:
We currently have an open PhD position in evolutionary parasitology here in Bergen, within the project Anthropogenic Parasite Evolution (ParAnthropE) funded by the Research Council of Norway.
The PhD will be supervised by Adèle Mennerat. Application deadline was 22 December 2019.
The full advertisement can be found here:
Steinar Trengereid started his Master project this autumn in the salmon lice lab with supervisor Adèle Mennerat.
Steinar in the lab.
Steinar is experimentally investigating the links between sex ratio and mating behaviour in the ectoparasitic salmon louse, Lepeiophteirus salmonis.
A phytoplankton bloom in the North Sea in spring 2018. (Photo: NASA.)
Read the story at forskning.no here:
forskning.no: Mørkere vann forsinker algenes årlige vårfest i Nordsjøen
The magazine article, by Øystein Rygg Haanes, focuses on the potential effect of darkening on the annual phytoplankton spring bloom.
Påstår bestefaren din at vannet langs kysten var klarere da han var ung? Det trenger slett ikke være gubbete glorifisering av gode, gamle dager. Ny forskning viser at Nordsjøen var klarere for hundre år siden. En av årsakene til formørkningen er økt plantevekst på land, som fører til at mer fargestoff – nedbrutt organisk materiale – finner veien ut i havet.
The interview is based on this recent paper:
In their accepted paper in Estuarine Coastal and Shelf Science, Dag L. Aksnes, Jan Aure, Per-Otto Johansen, Geir H. Johnsen, and Anne Gro Vea Salvanes provide evidence that ocean warming has caused a multi-decadal oxygen decline in Norwegian fjords.
Observed and simulated oxygen content of the Masfjorden basin.
The open ocean and many coastal waters around the world have lost oxygen over the past 50 years. Eutrophication, involving human-induced discharges of nutrients and organic material, is a major cause for oxygen declines in coastal waters. For the ocean interior, reduced ventilation is likely the main cause. However, this has been difficult to verify because the processes involved in ocean overturning are slow. Ventilation of deep fjord basins is much faster, and the authors show how reduced vertical water exchange has caused long-term oxygen decline.
The study demonstrates that the oxygen content of a deep fjord, Masfjorden, has dropped over the last four decades. In the same period, the temperature of the oxygen-rich North Atlantic Water (NAW), which ventilates Masfjorden as well as other fjords, has increased with about 1ºC. Because of this warming, NAW has become less dense, and therefore less able to sink and thereby bring new oxygen into the basin of Masfjorden. This suggests that deep Norwegian fjords are prone to a warming-induced decrease in ventilation and associated deoxygenation - similar to the hypothesis for oxygen decline of the ocean interior. The authors expect further oxygen decline if NAW becomes less dense because of warming, but an oxygen increase if density should increase. Potential implications of fjord deoxygenation is altered biodiversity involving shift from mesopelagic fishes to jellyfish. As demonstrated in the study, deoxygenation reduces the holding capacity for fish farming. This might have socioeconomic implications as fjords and coastal areas are currently a main asset in Norwegian fish farming.
A recently accepted article in Marine Ecology progress Series by Stein Kaartvedt, Anders Røstad, Anders F. Opdal, and Dag L. Aksnes shows how a diving ROV with an attached light source trigger dichotomous responses in the mesopelagic fish assemblage.
A diving ROV equipped with LED lamps was herding mesopelagic fish down to the bottom, but nearby fish were attracted to the light.
The authors show how a diving ROV equipped with LED lamps was herding mesopelagic fish down to the bottom at 700 m. The event was monitored by shipborne and bottom-mounted echosounders as well as video footage from the ROV, and indicated that the fish' responses to light included both repulsion and attraction. By constructing an individual-based model, the authors were able to reproduce the herding event by assuming a dichotomous response to light, where fish close to the light source were attracted while fish further away were repulsed. They hypothesize that attraction is associated with the artificial light acting as a point source (beam light), while the repulsion is associated with the artificial light acting as diffuse light.
In their newly accepted paper in Global Change Biology), Anders F. Opdal, Christian Lindemann, and Dag L. Aksnes provide evidence suggesting that the centennial decrease in North sea water clarity may have delayed the phytoplankton spring bloom by up to 3 weeks compared to the early 1900s. This delay stands in contrast to the earlier bloom onset typically expected from global warming.
Predicted phytoplankton response to increased non-chlorophyll light attenuation.
The study utilized a 100-year time series of Secchi disk depth along with various proxies for phytoplankton concentrations. The authors conclude that factors other than phytoplankton, such as increased dissolved organic matter of terrestrial origin, also known as browning, has caused the observed reduction in North Sea water clarity. Through several numerical simulations of water columns, the authors find that the observed coastal water darkening would have delayed the spring bloom by up to three weeks since the early 1900s. In the future, climate warming is expected to further increase browning in lakes and rivers due to increases in terrestrial greening, ultimately reducing water clarity in coastal areas where freshwater drains. However, increased ocean temperature is also suggested to advance the spring phytoplankton bloom due to earlier shoaling of the mixed layer. These contrasting responses highlight the importance of including water transparency in analyses of phytoplankton phenology and primary production.
In a new paper in Frontiers in Ecology and Evolution, Sergey Budaev, Jarl Giske, and colleagues in TEG argue that an animal is a prediction machine that uses its brain and nervous system to model how one or several potential choices will be felt by the body before the decision is made.
The fundamental state to consider is therefore not stomach contents, fat reserves, or body mass per se, but a state of its mind: the global organismic state. The animal's subjective internal model can, via control of the nervous system, set the animal in a mental state that will dominate many aspects of its cognition and behavior, including decision-making.
Today Tom J. Langbehn defended his PhD Thesis with the title Light and visual foraging in the pelagic: Opportunities and constraints along gradients of seasonality. His focus has been how the increasing seasonality at higher latitudes enforce ever stricter constraints on annual cycles of marine organisms.
From left to right: supervisor Christian Jørgensen, opponent Michael T. Burrows, internal committee leader Anne Gro Vea Salvanes, supervisor Øystein Varpe, a happy and smiling candidate, opponent Xabier Irigoien, and supervisor Øyvind Fiksen.
Tom has had a particular focus on how seasonality in light affects visual foragers. At high latitudes, the polar night and midnight sun are challenging for the many marine organisms that perform diel vertical migrations, migrating up and down in the water column on a daily basis to balance foraging opportunities and predation risk. For mesopelagic fish, the main bottleneck is midnight sun, as they then are prevented from migrating to the productive surface layers in the protection of darkness, over time causing depleted energy reserves and risky behaviours. Were the sea ice to disappear in a warming climate, then visual feeders such as planktivorous fish will have much higher expected foraging success.
Do jellyfish matter? A new study recently published in Scientific Reports suggests perhaps not as much as we thought.
An overview of the hypotheses tested.
Long-standing hypotheses regarding the negative effects of jellyfish on small pelagic fish recruitment or as an important competitor for their crustacean zooplankton prey are difficult to test against data. Authors Anders F. Opdal and Dag L. Aksnes at UiB have, together with colleagues in the US, Bulgaria, and South Africa, collected historic and recent data from the Bering Sea, the California Current, the Black Sea, and the Benguela to test a series of jellyfish-related hypotheses at the ecosystem level. By calculating the energy requirements of both fish and jellyfish, they find that although jellyfish in many areas exceed the biomass of fish, their energy requirements are low, and their energetic footprint moderate. In addition, they find little signs of fish biomass, or their crustacean zooplankton prey, being influenced by jellyfish biomass. They conclude that the best available time-series data do not suggest that jellyfish are outcompeting, or have replaced, small pelagic fish on a regional scale in any of the four investigated ecosystems.
From left: UiB representative in the committee professor Mikko Heino, a very happy Nadia Fouzai, and external opponents Irja Ratikainen (NTNU, Norway) and Peter Grønkjær (Aarhus University, Denmark).
The opponents Peter Grønkjær (Aarhus University, Denmark) and Irja Ratikainen (NTNU, Trondheim, Norway) provided stimulating and thoughtful discussions. Supervisors have been Øyvind Fiksen, Anders F. Opdal, and Christian Jørgensen.
Nadia was part of the NorMER network funded by the Nordic countries through Nordforsk.
In December 2018, Marc Mangel was awarded the Outstanding Achievement Award from the American Institute of Fishery Research Biologists (AIFRB).
AIRFB is an association to establish and maintain high professional standards of recognition of achievement and competence. The President of AIRFR emphasizes that the scientific merit and broad-reaching impacts of Marc’s research exemplify the fishery science that AIFRB promotes and recognizes.
Congratulations Marc! We are very pleased to have you as adjunct professor, and we see that you play an important role in the formation of young researchers in the Theoretical Ecology Group!
Large zooplankton avoid predation from fish by sinking into deep and dark depths of the ocean. However, over sea summits and banks they are blocked from sinking very deep by the bottom already at depths that are quite illuminated during daytime. This gives visual foragers such as fish an advantage, and they are more likely to find food over banks than over deep trenches.
In a new study published in Limnology and Oceanography, Johanna Aarflot, Øyvind Fiksen, Anders F. Opdal, Dag L. Aksnes, and others show that large zooplankton in the Barents Sea are generally distributed much closer to the surface in shallower areas. The consequence of this is that large zooplankton are exposed to several orders of magnitude more light during daytime over the 100 m deep banks compared to where the bottom depth is 300 meter or more. A planktivore fish therefore encounters 400 times more prey above the bank, even if prey abundance is the same!
News articles (in Norwegian):
As part of the Theme session D on the Nordic Seas and the Arctic, he highlighted published work (see reference below))quantifying how more light as sea ice declines will boost visual search in pelagic fish. His second talk, in Theme session A on mesopelagic ecosystems, quantified how seasons, in particular in light, may limit the poleward distribution of mesopelagic fish. It was for this talk he received the Best Presentation Award. Congratulations!
Johanna Myrseth Aarflot is participating in Researcher Grand Prix, with a popularized version of her research on tiny copepods and their enormous role in the oceans.
The Institute of Marine Research has interviewed her about her research and her way towards becoming a biologist. You can read the full interview here [in Norwegian]:
Julianne Netteland defended her MSc thesis on 31 August. In her thesis work, she studied the physics of light and vision in relation to dawn song.
Julianne, supervisors, and examiners. From left: Sigrunn Eliassen (supervisor), Irja Ratikainen (examiner, NTNU), Julianne Netteland, Svein Rune Erga (internal examiner, BIO), Christian Jørgensen (supervisor).
In her thesis, entitled Predation risk at dawn: How changing light and birds' traits affect the temporal risk landscape during sunrise, she goes on to identify numerous trade-offs that affect vision, foraging efficiency, and risk of being encountered by predators throughout the dynamic light environment around sunrise.
The Digital Life Norway network is fostering cross-disciplinary studies based in biotechnology, and interviewed several of their projects related to aquaculture, among them our Aha project which aims to model cognition in fish.
The interview can be read here: Bli med på en digital fisketur (https://www.nmbu.no/fakultet/vet/aktuelt/node/34795).
Researcher Adèle Mennerat of the Theoretical Ecology Group is sharing her views on the future of parasitology at the University of Bergen website.
I am frustrated that we know so little, says Adèle Mennerat. We know that the global human impact on ecosystems is enormous, and is not limited to climate change. For parasites perhaps the biggest change lies in how we humans are modifying the availability of their hosts, she continues.
You can read the full interview here:
The future of parasitology (http://www.uib.no/en/matnat/116317/future-parasitology).
How can the essential properties of community structure and ecosystem functioning be captured from a limited number of traits in organisms? 120 researchers from 31 nations met over four days at Solstrand to answer this question.
Ecosystems are complex machineries and our ability to predict how changing drivers and environmental forcing influence them are limited. One way to represent and understand organisms, communities and ecosystems is to think in terms of specific traits, not species, and how the dominant traits appear in an evolutionary or ecological process from fundamental trade-offs between alternative traits. If we can identify the trade-offs between traits, and the trade-offs with the environment, we may have a tool for predicting trait distributions in nature or from given environmental perturbations.
Marine ecologists and oceanographers have over the last decade turned to trait-based approaches to develop models and to understand ocean communities. The third workshop on trait-based approaches to ocean life was held in Solstrand, outside Bergen, Norway during 20-23rd of August. The earlier meetings in 2013 (Copenhagen) and 2015 (New Hampshire) set the stage for this arena as a key meeting place for researchers working in this direction. This year, 120 researchers attended the workshop, covering a wide range of ecosystems from reefs to pelagic microbes.
The trait-based approach has deeper roots in terrestrial ecology, and the workshops have always focused on bringing in perspectives from general ecology. The first keynote this year was Oswald Schmitz, from Yale University. His talk was on the evolutionary ecology of ecosystem functioning - with examples on how behavioural plasticity in grazers in response to fear from specific predators can shift grazing pressure, plant communities and nutrient budgets in the soil. The couplings between ecology and evolutionary or adaptive responses are fundamental and cannot be ignored.
Helmut Hillebrand followed up the next day with a keynote on how trait variability and environmental heterogeneity constrain community composition and ecosystem processes. The keynote gave an overview of biodiversity-ecosystem functioning themes, and showed how trait-based perspectives are useful in this debate. Zoe Finkel's keynote brought us to the unicellular domain, focusing on macromolecular and elemental composition of microalgae. The size and content of phytoplankton cells, their element-ratios and carbon content are key traits and state variables which feed back on ecosystem functioning. Frede Thingstad took us even further into the microbial world, to the interactions between viruses and bacteria, to the competition between algae and bacteria and the mixture of drivers shaping structure of microbial communities.
The workshop included 20 contributed talks, 80 posters and a set of break-out sessions, round-table group discussions and plenary discussions with prepared comments. The programme was relaxed with one afternoon session walk-and-talk to the Borgafjell, combining opportunities for individual communication with some exercise and a view over the Bjørnafjord and the Folgefonna glacier.
Next meeting in 2019 will be organized by Ben Ward - in the UK.
Solstrand Hotel provided a relaxed and social atmosphere for scientific discussion. (Photo: Øyvind Fiksen)
Considerable time was set aside for discussion and interaction. In these groups, a host was given a specific topic, but the participants were shifting groups every 15 minutes. In this way, multiple viewpoints and perspectives were heard. (Photo: Øyvind Fiksen)
Another way participants had time to discuss was during the walk-and-talk to Borgarfjellet, in stunning weather. (Photo: Øyvind Fiksen)
All participants (almost) of the Third Workshop on Trait-Based Approaches to Ocean Life.
The Arctic sea-ice cover is rapidly shrinking and light increasingly reaches the previously darkened waters. In a new paper in Global Change Biology, Tom J. Langbehn and co-author Øystein Varpe predict that increased visibility helps fish that hunt by sight to detect their prey.
Under rising temperatures and given the more favourable feeding conditions, southerly-distributed species are likely to expand their distribution poleward. However, the foraging gains will be limited to the summer months, as the polar nigh remains dark regardless of sea-ice loss, a seasonality favouring migratory fish. Changes to the fish community will have multiple consequences for the polar marine ecosystem, particularly for the prey of fish.
The article was picked up by Frontiers in Ecology, which wrote a news story about it.
Fish farming is one of the fastest growing food production sectors in the world, but is also increasingly burdened by infections caused by bacteria, viruses, and parasites. Now, emerging research suggests that diseases of farmed fish may be evolving to become even more harmful to the animals.
In a recent study published in Journal of Evolutionary Biology, Adèle Mennerat and coauthors report that salmon lice seem to have evolved higher levels of virulence (i.e. parasite-induced damage to the host) on salmon farms, as compared to lice coming from areas unaffected by farming. Another study by Sundberg et al. (Proceedings B, 2017), reports similar findings in Flavobacterium columnare, a bacterial pathogen of salmonids. This study remains correlative, and now calls for further research to decipher the causes and mechanisms of such evolution. All of this, and more, explained in The Scientist: Does farming drive fish disease?
Together with Sue Lowerre-Barbieri, Ignacio Catalán, and Ross Boucek, Anders F. Opdal and Christian Jørgensen are convening a
Theme Session on Movement Ecology at the ICES Annual Science Conference
in Florida 18-22 September 2017; Linkages between spatial ecology and sustainable fisheries.
Key-note speakers for the session are are Mike Sinclair (Bedford Institute of Oceanography, Canada), Patricia Reglero (Instituto Español de Oceanografia, Mallorca, Spain) and David Secor (University of Maryland, USA).
Abstracts can be submitted at the conference website (deadline Sunday 30 April). A Themed Article Set in the ICES Journal of Marine Science is planned as follow-up from the session.
Anders F. Opdal, postdoc in the Theoretical Ecology group, contributed a chapter to the Bergen University Musem Year Book on the evolution and dynamics of the Northeast Arctic cod spawning migrations from the late 1800s to modern times.
The cover photo for the 2016 Year Book of the Bergen University Museum is related to Anders Opdal's chapter.
Although the Northeast Arctic cod has its main spawning grounds around the Lofoten archipelago, a mere 700 km swim from their feeding areas in the Barents Sea, historical records show that the Northeast Arctic cod has spawned as far south as Bergen and Lindesnes (1700-1900 km). Anders asks, what could be the evolutionary drivers for such strenuous migrations, and why don't we find theses southern spawners today? The chapter is in Norwegian.
The 3rd International Workshop in Trait-based Approaches to Ocean Life will be arranged at Solstrand Hotel 20-23 August 2017, and the
Hjort Centre and the
Theoretical Ecology Group will be involved in organizing and planning the event.
Anyone interested in or curious about this approach in ecology and contemporary oceanography should reserve the dates and be there! Updated information can always be found at the workshop's website: https://traitbased.b.uib.no
Tom Langbehn, PhD student in the Theoretical Ecology Group as part of the EU-training network MARmaED has recently been awarded two prizes for his poster on the effects of photoperiod and sea ice decline on pelagic foraging interactions.
As light seasonality increases by latitude, so does its biological relevance. At high latitudes all life is adapted to the change of seasons. The general perception of the Arctic Ocean is that of an ecosystem driven by pulses of autotrophic production. However, climate-driven decline in sea ice is fundamentally bound to change the Arctic lightscape. With less sea ice, more light will reach the water. This will change both levels of primary productivity and foraging interactions of higher trophic level visual predators and their zooplankton prey. In his work, Tom demonstrates that dwindling sea ice will seasonally boost foraging of pelagic fish and that the role of light merits consideration in determining species distribution patterns and community composition beyond phytoplankton.
His poster Photoperiodic implications on visual foraging in polar marine ecosystems got awarded the student choice and special mention award at the ClimEco5 IMBER summer school and the best poster award at the YOUMARES7 conference for young marine researchers in Germany. The poster can be downloaded here.
Randi Elisabeth Åsly defended her MSc thesis Tuesday 28 June on the link between extra-pair paternity and cooperation in bird neighbourhoods.
Elisabeth with her two thesis examiners: Odd Jacobsen (external, to the left) and Arill Engås (internal, right).
Extra-pair paternity is common in socially monogamous species, but explaining the adaptive benefit of this mating behaviour has proven difficult from a female point of view. In her MSc thesis, Elisabeth focused on the potential benefit of male cooperation in anti-predator behaviour, and used evolutionary modelling to explore how the number of breeding neighbours may influence cooperative benefits and mating patterns.
She found that extra-pair paternity increased male cooperative investment under most conditions, but that the best male strategy varied for different types of anti-predator behaviours. High extra-pair paternity levels were predicted to be more common in small than in large neighbourhoods, when extra-pair mating is controlled by females. This is contraty to several empirical observations, and raises interesting questions of which additional ecological factors are at play in nature, or, conversely, which factors are missing from the models.
On Friday 17 June Thomas Njerve Olsen defended his Masters Thesis A Killing the Winner study of
visual and tactile organisms in the Black Sea.
Thomas Njerve Olsen during the presentation of his thesis work.
Killing the Winner is a theoretical framework originally developed within
the field of microbial ecology to explain the coexistence of two organisms competing for a shared
resource in a homogeneous environment. The premise being that one organism is specializing in
defence and the other in growth (competition). In his thesis, Thomas has shown that the
The answer to life, the universe, and everything is not 42 - when it comes to reproduction it is another number that matters.
Does predation risk affect extra-pair mating behaviour? And is there a difference in how male and female blue tits respond to approaching predators? These are among the questions that researchers from the FRIMEDBIO project on bird mating behaviour set out to investigate this spring. The researchers were running play-back experiments and doing behavioural observations on blue tits in a population near Montpellier in southern France.
The blue tit lays clutches of 6-12 eggs, which hatch after ca. 2 weeks and the chicks fledge ca. 3 weeks later. During this period they rely on food and protection provided by both parents. (Photo: Sigrunn Eliassen)
The weasel Mustela nivalis and the common genet Genetta genetta are major brood predators in this area. When blue tit parents perceive a potential risk to their nest, they typically emit loud alarm calls and move around the trees to chase the predator away. In the experiments the researchers were interested in knowing to what extent males and females participated in the anti-predator behaviour and whether distance from the nest influenced the intensity of alarm calling.
Measuring, weighing, blood sampling and ringing are part of the standard monitoring protocol for this blue tit population near Montpellier, France. (Photo: Sigrunn Eliassen)
The study site is situated in a beautiful deciduous forest and contains a network of nest-boxes that has been monitored as part of a long-term, multi-site study initiated more than 40 years ago by Jacques Blondel, and now led by Anne Charmantier at CNRS in Montpellier. From the time when nests are occupied until the chicks fledge, several hundred boxes are checked at regular intervals. Chicks are ringed and measured, and blood samples of young and adults are collected to determine parentage. Master student Marie Danielsen and postdoc Adèle Mennerat at BIO will analyse these data focusing on the link between extra-pair paternity and anti-predator behaviours.
Adèle Mennerat holding a 15-day old blue tit chick during routine measurements and ringing. (Photo: Sigrunn Eliassen)
Adèle Mennerat spends part her time at the Centre for Women's and Gender Research, and by contrasting her experiences from bird mating systems with social scientists focussing on human gender studies, a common ground is now emerging and being picked up by the national science news forskning.no.
Researcher Claus Halberg at Department of Philosophy, UiB, draws perspectives from the work of Robert Trivers in the 1970s to new developments in evolutionary ecology, and finds an interesting change of focus towards understanding the female as being more active in mate choice with consequences for construction of social interactions.
You can read the whole story here [in Norwegian]:
forskning.no: Parer seg med flere hanner for å sikre ungene.
The Theoretical Ecology Group welcomes Gabriella Ljungström and Tom Langbehn, two new PhD candidates within the EU-training network MARmaED.
Gabriella and Tom will model climate change effects in marine fish stocks with a focus on fish life histories. Their work is part of the EU training network MARmaED (Marine Management and Ecosystem Dynamics under Climate Change), with 8 partner institutions across Europe. The common goal is to investigate how sustainable exploitation of marine living resources and the maintenance of biodiversity can be achieved in the face of overexploitation, climate change, and other anthropogenic stressors.
Gabriella Ljungström has a broad background in science with a BSc majoring in Climate Science from Macquarie University in Sydney, Australia, and a Master of Atmospheric Science with orientation towards Environmental Sciences from the University of Gothenburg, Sweden. This broad background stems from a profound interest in how human activities lead to changes in our atmosphere and oceans, and how these changes are altering biological systems. Gabriella's PhD work within the Theoretical Ecology Group will focus on optimal harvesting under multiple human stressors by modelling how fishing and climate warming jointly determine new optima for behavioural and life history traits.
Tom J. Langbehn recently graduated from the international and interdisciplinary MSc program Marine Biology at the University of Bremen. Prior to this he took an international BSc in Environmental and Industrial Biology from the University of Applied Science Bremen, Germany. Tom is a cold water-enthusiast and therefore he choose to spend extended study and research periods abroad in Iceland, Norway, and Arctic Svalbard. Throughout his graduate and postgraduate training the focus of his work has been on (polar) marine ecology, fisheries, and fish biology, with particular emphasis on the effects that ocean climate and human activities have on the biology and adaptive strategies of fish populations. Within the Theoretical Ecology Group he will work on limits to northwards range shifts of fish stocks under climate warming.
The annual retreat for the extended Theoretical Ecology Group took place in Myrkdalen in early January. We went to a skiing resort as we often do, where some time was reserved for various skiing activities in the slopes, mountains or in the groomed tracks nearby.
The group has increased in numbers recently, with the new PhD students Tom Langbehn and Gabriella Ljungström in the MARmaED project and Johanna Fall and Johanna Aarfloth from Institute of Marine Research as our associated members, and Ryan Dillon as a visiting PhD from University of Tromsø. Also, this was the first annual retreat for a number of people who arrived last year - exciting times for all of us!
At the retreat we focussed on getting to know each other, our research interests and we discussed how to structure group activities to the benefit all of us. The first day we discussed modelling and theory as a scientific method, and then we all gave short presentations on our main research agenda, and at last we developed our structure as a group. We certainly are a diverse group in terms of research themes and questions, but at the same time we share many common approaches and methods.
The Theoretical Ecology Group has grown the last year. From left to right: Sergey Buadev, Anders Opdal, Camilla H. Jensen, Christian Jørgensen, Jaqueline Weidner (partly hidden), Elisabeth Åsly, Johanna Fall, Sigrunn Eliassen, Ryan Dillon, Adèle Mennerat, Dag Aksnes, Øyvind Fiksen, Tom Langbehn, Gabriella Ljungström, Chris Lindemann, and Johanna Aarfloth.
Sigrunn Eliassen talked [in Norwegian] about female birds and sexual infidelity on the popular science radio show Ekko, aired by the NRK, Norway's national public broadcasting service.
Most bird species live in socially monogamous pair relationships, but paternity tests have shown that the offpsring often belong to another father than the male who provides care at the nest. It is easy to understand why extra-pair mating is advantageous to a male, who then can sire offspring without costly and time-consuming investments in care. It is harder to explain why extra-pair mating can be advantageous to the females. Eliassen discusses how female birds can use extra-pair matings to promote cooperation between the males in the neighbourhood. The theory provides new perspective on how cooperation may arise and be maintained, and explains observed patterns of the sexual division of labour.
Norwegian text: De fleste fugler lever i sosialt monogame parforhold, men farskapstester viser at ungene ofte har en annen far enn han som bidrar med foreldreomsorgen i reiret. Fordelen med sideparinger er lett å se for hanner som slipper kostbar investering i avkom, men det er vanskeligere å forklare hvordan hunnene kan dra fordeler av dette. I følge teorier foreslått av Eliassen og Jørgensen kan hunfugler bruke sideparinger til å fremme samarbeid mellom hanner i et nabolag. Teorien gir nye perspektiver på hvordan samarbeid oppstår og forklarer mønstre i arbeidsdeling mellom kjønn.
You can listen to the podcasts here:
Short version, Saturday 9 January 2016:
Longer version, Wednesday 13 January 2016:
And the theory is presented in this paper:
The first Hjort Summer school was a held at Espegrend field station in early September, with about 30 participants from all over the world and from a broad range of disciplines.
The topic was Fishing and physics as drivers of marine ecosystem dynamics, with Ken Frank, Anna Gårdmark, and Hjalmar Hatun as invited teachers and lecturers. They gave an overview over current state-of-the-art in the science of how marine ecosystems are functioning, with core examples from continental shelf areas, the Baltic, and the Fareoe Islands. In addition, several of the Hjort Centre scientists contributed lectures on microbial food webs, fish-jellies, the Barents Sea, and fisheries management.
The students also presented their own research and participated actively in discussions, computer- and group exercises, and even some field work (beach seining).
As usual in Bergen, the weather was warm and sunny, and allowed for barbecue on the beach and swimming in the sea. We also made an excursion to Bergen to see the town and to do some of the touristic hikes to the surrounding mountains.
This summer school was a great success, and will be continued next year if funding is secured. Hopefully it will be a tradition, and an opportunity to bring together marine scientists in a range of disciplines to learn from the leading scientists in the field.
The 2015 Hjort Summer School had about 30 participants from all over the world.
Ken Frank, Anna Gårdmark, and Hjalmar Hatun were the main teachers, and the students also presented their own research to each other.
The topic was Fishing and physics as drivers of marine ecosystem dynamics and there was also time for socializing in nice weather and beautiful surroundings at Espegrend. The bravest ones even went for a (cold) swim.
We are currently seeking two PhDs (3 years each) to model effects of climate change on fish life histories. The positions are part of the EU training network MARmaED. Application deadline is 18 October 2015.
PhD project A: How may climate-driven evolution of fish life histories and behaviours interact with effects of fishing?
PhD project B: With climate warming, species are expected to move northwards, but what happens when they approach high latitudes with increasing seasonality and even a long polar night?
The PhD students will be taking part in the activities of the Theoretical Ecology Group. The PhD positions will be part of the EU training network MARmaED, with 8 partner institutions across Europe. Because the positions are EU-funded, special mobility requirements apply: You cannot have been resident in Norway (the host country) for more than 12 months in total during the last 36 months (counted from starting date of the PhD position), and you are ineligible if your research experience (beyond the MSc degree) exceeds 4 years.
PhD supervisors will be Christian Jørgensen (email: firstname.lastname@example.org) and Øyvind Fiksen (email: email@example.com). The workplace will be the Theoretical Ecology Group at the University of Bergen. Application deadline is 18 October 2015 and we hope the candidate can start by January 2016.
You can read the whole advertisement here:
On Friday 21 August Rebecca Holt defended her PhD thesis entitled Climate-induced evolution of the behaviour and life-history strategies of Atlantic cod (Gadus morhua).
Two of the chapters have already been published:
Public outreach is part of the PhD education at the University of Bergen, and hopefully a blog can lead to more feedback than more classical, printed outlets. Stay tuned to her blog for more...
On Thursday 30 October Daniel Sellæg defended his Masters thesis Inferring female extra-pair mating behaviour from observed patterns of extra-pair paternity with a process-based model.
A proud Daniel with his thesis. (Photo: Bjørn Snorre Andersen.)
Using numerical models, Daniel showed that many more female birds can have extra-pair mating behaviour than end up having extra-pair young in their nest. Particularly, the difference between the female behaviour and the quantifiable output, extra-pair chicks, is large when the rate of extra-pair paternity is low or clutch size small. Supervisors were Sigrunn Eliassen and Christian Jørgensen.
Recently, Theoretical Ecology Group researchers Eliassen and Jørgensen showed in PLoSONE how female-driven extra-pair mating creates powerful incentives for male cooperation among neighbours. This week, a News & Views article in Nature by Ben Sheldon and Marc Mangel argues that the new model represents an important shift in focus for empirical studies of extra-pair mating, and that it also has broad implications for our understanding of the evolution of cooperation among unrelated individuals.
Our understanding of avian mating systems was completely overturned by the invention of molecular techniques and paternity analysis, revealing that the majority of bird species, once thought to be monogamous, were instead genetically polyandrous. Since then, hundreds of studies have shown that extra-pair paternity is widespread, and sometimes as many as half of the young in a nest can be sired by a male other than the putative father. The benefits of extra-pair paternity to males are quite obvious, whereas the adaptive explanations for female-driven extra-pair mating have revolved around 'good genes' effects. Despite an extensive, and, according to Sheldon and Mangel, "rather fruitless effort," the evidence for 'good gene' benefits is weak at best.
According to the new model by Sigrunn Eliassen and Christian Jørgensen, the key evolutionary driver in the evolution of extra-pair mating lies in the distribution of a male's potential paternity across nests. When a male gains interests in several neighbouring families, this creates incentives for him to cooperate with other male neighbours and produce public goods that in turn benefit females. Sheldon and Mangel further extend this perspective, claiming that the use of adaptive dynamic modelling lays "the groundwork for investigating the broader goal of understanding the emergence of societies as complex adaptive systems."
Although data are yet not available for testing the model's predictions in ways that exclude other hypotheses, the new theory may spark a shift in empirical focus from genetic effects to the ecological costs and benefits of extra-pair mating. In conclusion, Sheldon and Mangel argue that this perspective also "has broad consequences for our understanding of the evolution of cooperation among interacting, but non-related, individuals."
I think, therefore I am, said the French philosopher Rene Descartes almost 400 years ago. Wrong, said Antonio Damasio and several others: I feel, therefore I am. While the rational mind is pretty young on this planet, feelings and their evolutionary precursors are ancient.
When psychologists use the word "feeling", they mean that there is a conscious recognition of the phenomenon in the person who feels. This does not apply to emotions. The emotions are evolutionarily much older than feelings, from a time when no living being was aware its own existence.
Two emotions in a simple fish brain. (Illustration: Bjørn Snorre Andersen.)
The first study (Giske et al. 2013), which was published in The American Naturalist in December 2013, showed that "emotional" fish are more limited in their behaviour than "rational" fish, and that this restriction leads to the possible coexistence of several different "personalities" in a population. It also showed that emotions enable individuals to make good behavioural choices also in situations they have never before experienced, even if the individuals are unable to judge whether the choice was good or bad.
The second study (Giske et al. 2014), published in Proceedings of the Royal Society of London Series B, Biological Sciences in August 2014, shows that populations consisting of individuals with emotions have greater genetic variation than is necessary in relation to the environment they live in, and that this variation makes the population more adaptable to environmental changes. It therefore seems that emotions, and feelings which came much later, both led to individuals being better able to meet a wide range of challenges in a fairly good way, and to populations which are better equipped to evolve when environmental conditions so dictate.
When molecular paternity testing became available, ornithologists were shocked to reveal that birds, generally thought to be monogamous, commonly had mixed broods where some of the offspring were sired by the social male while the rest, often a substantial proportion, originated from matings with an extra-pair male. Later studies have revealed that extra-pair mating is often initiated by females, but the adaptive significance has remained elusive. In PLoS One today, Eliassen and Jørgensen argue that one of its key benefits is that it promotes neighbourhood cooperation.
For males the advantages of extra-pair mating are clear: they may sire extra offspring without having to provide costly care. It is less clear why females seem to accept, or even solicit, matings outside the pair-bond. Why would a female mate with extra-pair males when it normally entails a risk that her social male will reduce on his contribution to offspring care, on which she relies?
Researchers have long looked into so-called 'good gene' effects, investigating whether extra-pair mates have better genes. One of the main predictions from the 'good genes' hypothesis is that in a brood, those offspring with an extra-pair sire should have better survival, faster growth, or otherwise higher fitness than siblings sired by the social male. Despite vast effort across several decades, few such advantages to extra-pair offspring have been found and there is emerging consensus that something else than a desire for good genes must explain the adaptive benefits to females.
In the new study, Sigrunn Eliassen and Christian Jørgensen use evolutionary models to turn the question around. A consequence of extra-pair mating is that males may have offspring in several nests. Males should therefore not aggressively monopolize a territory because that makes resources unavailable to their extra-pair offspring, by sharing they would increase their fitness. And if males face a trade-off between protecting the neighbourhood and protecting their own nest, then it may pay to cooperate over shared vigilance and defence because that safeguards all their potential offspring. Through extra-pair mating, females thus incentivize males to collectively contribute to a secure and productive neighbourhood. The advantage of extra-pair mating to females is thus a cooperative benefit produced by males.
The models further predict sex-specific division of labour, that whole nests and neighbourhoods benefit from extra-pair mating (not only the extra-pair half-siblings), and integrates with existing theory with the prediction that extra-pair mating should be more common in short-lived species.
And does it apply beyond birds? There are two key premises: paternity uncertainty, which is present also in fish, particularly those with internal fertilization, and in mammals; and paternal care interpreted in a broad sense. Within mammals, it might be rodents and primates that best fulfil the requirements.
For more details, please see the paper:
Snorre Andersen has handed in his Masters Thesis, supervised by Jarl Giske.
Title: Effects of genetic complexity and time resolution in an individual-based model of mesopelagic fish with hunger and fear.
Supervisor: Jarl Giske.
Defence: Wednesday 25 June at 9:15 in K1. External examiner will be Geir Huse from IMR.
The thesis is a sensitivity analysis of the temporal resolution in a mathematical model for planktivorous mesopelagic fish. In addition, the genetic complexity of the model was increased by adding more genes, allowing more complex neuronal responses with better precision.
The increased temporal resolution of each diel cycle gave higher population egg production, the only evolutionary measure of quality in the model. Individuals changed also more frequently between the two states 'Hungry' and 'Afraid' when allowed to do so by the increased resolution. However, the overall level of fear did not stabilize or converge between simulations with higher genetic complexity, higher temporal resolution or more generations. It was found that for almost all stages of life, the increased genetic complexity was not needed and it did not yield higher population egg production. Simulation time can be shortened by a factor of 10 by reducing number of generations and diel cycles even when increasing the number of time steps in each cycle.
Scientists from the Marine Microbiology Group and the Theoretical Ecology Group at the University of Bergen recently described in PNAS how the world's most abundant organism may result from an evolutionary arms race between viruses and bacteria.
The existence of the world's presumably most abundant organism was unknown to science until its appearance in DNA samples from the Sargasso Sea in 1990, which gave this organism the somewhat obscure name SAR11. This is a small bacteria whose number has been estimated to make up one quarter of all marine bacteria, implying that there are probably more than 1028 SAR11 bacteria on Earth (for comparison, the estimated number of stars in the universe is roughly 1023, i.e. there are 100 000 SAR11 bacteria for each star).
The question of what lies behind this success has fascinated microbiologists, not the least because SAR11 is a simple organism with a small genome and hence few genes. Why is such a minimalistic strategy apparently key to success? The debate has first and foremost been guided by the ideas that SAR11 either is so successful due to its ability to defend itself against viruses and predators, or due to its ability to compete with other bacteria for limiting resources. In the last issue of the prestigious American science journal PNAS (Proceedings of the National Academy of Sciences), scientists from the Department of Biology at the University of Bergen have analysed the following trade-off: If the cost of viral defence is high in terms of reduced growth and reproductive ability (and vice versa), then those individuals investing too much into competition will be eaten or get infected, and those who invest too much into defence will starve. A logical consequence is that the key to success appears not to lay in either of the two extremes, but rather in using a level of defence where the price in terms of reduced competitive ability is minimal. Instead of considering SAR11 as a species composed of similar individuals, the scientists show how an evolutionary arms-race between SAR11 bacteria and their viruses leads to a number of different clones within the SAR11 bacteria, where some clones are strong competitors for limiting resources and others have strong defence against viruses, while most of the clones lie between these two extremes.
The work is part of the recently completed PhD thesis by Selina Våge and was conducted as part of the ERC Advanced Grant project MINOS to professor Frede Thingstad. The work gives a theoretical framework that can link genetic information from molecular analyses to marine ecosystem properties.
Read more in the original article, which was published in PNAS online on 13 May 2014:
Friday 4 April at 10:15 Selina Våge is defending her thesis entitled Pelagic microbial food web organization: Extending the theory for structure and diversity generating mechanisms based on life strategy trade-offs .
Opponents are Mick Follows (Massachusetts Institute of Technology, USA) and Andy Visser (Technical University of Denmark), and the defence will take place in Stort auditorium, Høyteknologisenteret, Thormøhlensgate 55.
For more info see the UiB press release (in Norwegian).
We had a wonderful day with seminars and discussions as
the Theoretical Population Ecology and Evolution Group from
Lund University, Sweden, visited us in Bergen.
They were on a week-long Nordic road-trip, and arrived from the University of Oslo by train and, despite the stormy weather, continued to NTNU in Trondheim with the coastal ferry Hurtigruten.
Per Lundberg led the group to the Department of Biology with astonishing temporal and spatial precision. He talked about the utility, or lack thereof, associated with theoretical modelling. Jacob Johansson presented a model for phenology in migrating birds, with a follow-up talk by Nadiah Kristensen. Mikael Pontarp and Jörgen Ripa were also visiting. After lunch it was time for seminars given by Bergen researchers.
Norway's Prime Minister Erna Solberg officially opened the Hjort Centre for Marine Ecosystem Dynamics on 18 February, Hjort's 145th birthday.
Present were also the Fisheries Minister Elisabeth Aspaker and the City Mayor of Bergen Trude Drevland. The Hjort Centre is a collaboration between University of Bergen, Uni Research, Institute of Marine Research, and Nansen Environmental and Remote Sensing Center, and several researchers from the Theoretical Ecology group have been central in developing the concept and drafting the Science Plan.
You can read more about the Hjort Centre opening (in Norwegian) at:
Here are some further background news stories:
The Norwegian Public Broadcaster NRK has picked up the article by Dag L. Aksnes and colleagues in Nature Communications, which claims that about ten billion tonnes of mesopelagic fish remain unexploited in the deep oceans.
- We might need to start fishing further down in the food chain to provide the world's growing population with enough nutrients. The vast abundance of mesopelagic fish represents an obvious opportunity, Dag says.
The article itself can be found here:
Selina will give her trial lecture Friday 14 February 12:15.
Title: Mechanisms for and population diversity consequences of parasite defense throughout the tree of life.
Evaluation Committee: Professor Arne Skorping, Researcher Sigrunn Eliassen, Professor Ruth-Anne Sandaa.
Time and place: Friday 14 February 12:15, Seminar room K3, Biologen (Thormøhlensgate 53B).
Everyone is welcome.
Selina will defend her thesis Friday 4 April.
Opponents: Mick Follows (MIT), Andy Visser (DTU), and Lise Øvreås (UiB).
Thesis title: Pelagic microbial food web organization. Extending the theory for structure and diversity generating mechanisms based on life strategy trade-offs.
Mesopelagic fishes dominate the global fish biomass, yet there exist major uncertainties regarding their real abundance. In Nature Communications today, Dag L. Aksnes is co-author on a paper arguing that the commonly accepted biomass estimate of mesopelagic fishes of one billion tonnes should be raised by an order of magnitude.
The new estimate is based on analysis of nine months of acoustic data collected during a circum-global scientific cruise.
This finding is consistent with a recent paper (Kaartvedt et al. 2012, see link below) which suggested that mesopelagic fish have been drastically underestimated because of their efficient avoidance of traditional sampling gear. The contribution of the mesopelagic fishes to e.g. ocean biogeochemical cycling was deemed insignificant based on previous estimates of their biomass, but this thinking may have to be revised. Furthermore, it appears that the trophic efficiency in the open ocean is much higher than previously assumed.
Why do females engage in extra-pair copulation (mating with other males than their own partner) - and what are the resulting selective pressures on male behaviour (how should males respond to this)? The (scientific) temptation was too big: Adèle Mennerat has joined TEG for four years to work with Sigrunn Eliassen and Christian Jørgensen on an ongoing project studying promiscuity and the evolution of cooperative neighbourhoods, and funded by the Research Council of Norway. She is also holding an Associate Professorship at the University of Amiens (France), from which she could take a temporary leave for the duration of the project.
Adèle with two blue tits.
Her research interests lie at the interface of evolution, ecology, and behaviour. She has background in both Molecular Biology (ENS Lyon, France) and Evolution & Ecology (University of Montpellier, France) and a PhD in Population Biology and Ecology (CEFE / University of Montpellier, France). Her PhD thesis focused on the adaptive value of animal self-medication behaviours. She has previously worked at UiB as a researcher (2008-2010) in the Evolutionary Ecology Group, working on life history and virulence evolution of parasites with Arne Skorping. She then spent two years as a Marie Curie fellow at the Edward Grey Institute at the Department of Zoology of Oxford University, studying the links between disease transmission and social behaviour. In Amiens she is exploring life history evolution and terminal investment, invasion ecology, and epidemiological consequences of climate variability. She has addressed those questions using various model species from bacteria to fish although birds remain her favourite group.
In Bergen she will use empirical data from the "real world" to test assumptions and predictions from models developed by Sigrunn & Christian, starting with birds and later on expanding the scope to other groups (including primates).
Kristina Kvile is a visiting PhD student through the
Nordic Centre of Excellence network NorMER.
She will stay in Bergen for almost two months, and the focus of the stay is
to investigate zooplankton survey data from the Barents Sea in the light
of a hydrodynamic model of the area and an individual based model of
Calanus finmarchicus. With this, she hopes to shed light on the spatial
dynamics of C. finmarchicus in the Barents Sea.
Kristina is normally based at the Centre for Ecological and Evolutionary
Synthesis (CEES) at the University of Oslo.
You can read more about her project here:
The small city of Bergen already produces so many peer-reviewed publications
within marine science that it is on the top 10 list worldwide, but a challenge
has been to convert mass into momentum. In an attempt to raise ambitions and put
the big questions on the agenda, four institutions in Bergen have now agreed to
collaborate in a Hjort Centre for Marine Ecosystem Dynamics.
The partners are:
The centre's ambition is to become an international point of gravity in marine ecosystem research worldwide.
The Centre is named after Johan Hjort, often referred to as the founder of modern fisheries science due to his contributions and particularly the book Fluctuations in the great fisheries of Northern Europe (1914). Most of his groundbreaking research was done in Bergen, where Hjort became Norwegian Fisheries Director and simultaneously the first director of the Institute of Marine Research.
The Hjort Centre will have its official opening on Tuesday 18 February 2014, and there is currently hectic activity on developing the Science Plan with heavy involvement from the Theoretical Ecology Group.
By the end of August all members of the Theoretical Ecology Group will have moved to their new offices within the main building of the Department of Biology.
Since the Department of Biology became co-located in its new buildings roughly three years ago, the Theoretical Ecology Group has been living a life in isolation in the building next door. Although the distance has not been more than a few meters, we have missed the daily joy of bumping into colleagues in the corridors. Not so any more. By the end of August all members of the Theoretical Ecology Group will have moved to their new offices within the main building of the Department of Biology. From then on you find us in Thormøhlensgate 53B, floor 3, with postdocs on floor 2. Further good news is that we now will share corridor with Evofish and the Evolutionary Ecology Research Group. We are looking forward to new interactions!
PhD student Selina Våge, together with PhD student Julia E. Storesund and professor Frede Thingstad, extend the ongoing discussion of why SAR11, an abundant bacterial group in the pelagic ocean, is so successful.
A figure from the article, illustrating two possible scenarios (clustered (A) and interspersed (B)) of how strains of bacterial species may be distributed along the growth rate axis. The interspersed scenario (B) supports the highest total virus abundance according to our model, and allows for a dominance of defensive SAR11 strains despite a high SAR11 virus abundance.
Our paper on fishing-induced evolution of growth was listed first among the most accessed papers in Marine Ecology in 2012.
The journal's list is here:
We have a new PhD student in the group - Nadia Fouzai started late last year and is already developing her first paper on how temperature operates to influence physiology, behaviour and eventually growth and survival in larval cod.
Nadia's PhD project is connected to the Nordic Centre of Excellence NorMER (The Nordic Centre for Research on Marine Ecosystems and Resources under Climate Change). Her thesis will be on how temperature and other climate-related environmental factors can affect the survival of larval cod. Supervisors will be Øyvind Fiksen, Anders F. Opdal, and Christian Jørgensen.
Nadia did her undergraduate at National Institute of Agronomy of Tunisia (INAT), then she went to Spain to take a Masters of Science degree within the field of Fisheries economics and management, at University of Barcelona. Her Masters thesis was entitled Management of the Adriatic Sea Exploited Marine Ecosystem by means of the Application of Ecopath Modelling and the Simulation Tool Ecospace, taken at Institute of Marine Science (ICM-CSIC), Barcelona, Spain. Her thesis was later published in Journal of Marine Systems, see below. She speaks Arabic, French, Spanish and English - and has just started on a Norwegian course.
According to her own words she is not deterred by the climate in Bergen. We hope she will adapt to the local climate, just as her cod larvae!
In a feature article in the Norwegian national newspaper VG, researcher Anders F. Opdal commented on the ongoing research in the Theoretical Ecology Group on how a modern trawl fishery has altered both demography and spawning distribution of the Northeast Arctic cod stock.
The Norwegian national newspaper VG recently published an article focusing on the negative effects of trawling, directed towards the ongoing debate concerning future oil production in Lofoten, an important spawning area for the Northeast Arctic cod. Journalist Inga R. Holst argued that not only the oil industry, but also the fishing industry faces serious environmental challenges. Researcher Anders F. Opdal commented on the ongoing research in the Theoretical Ecology Group regarding the negative consequences trawling, and how a modern trawl fishery has altered the both demography and spawning distribution of the Northeast Arctic cod stock. You can read the whole story here.
The program for the annual Darwin Day, on Tuesday 12 February, is now out. Professor Andrew Read from Pennsylvania State University will talk about drug resistance, evolving pathogens, and evolutionary medicine.
At 12:00 he will give a talk at Haukeland University Hospital, and at 18:00 a lecture at the Student Centre. The evening lecture is arranged in collaboration with the Horizons seminar series by the Faculty of Mathematics and Natural Sciences at UiB, and the lunch lecture in collaboration with Centre for International Health and Haukeland University Hospital.
The funding of our new project on the evolution of mating systems was highlighted by the Norwegian national newspaper Aftenposten as the type of innovative science the Research Council of Norway would like to support more strongly in the coming years.
Project leader Sigrunn Eliassen and researcher Christian Jørgensen recently received news that a new four-year project on the evolution of mating systems received funding by the Research Council of Norway. The Norwegian national newspaper Aftenposten highlighted this as the type of innovative science that the national funding body would like to support more strongly in the coming years. A post-doc will be recruited to the project, and work in collaboration with the University of Bergen's Center for Women's and Gender Research.
Trait-based ecosystem models are becoming more popular and taken into use in a wide range of applications and questions in oceanography. Read more about what they think about the future for Trait-based ecosystem models here:
Dag L. Aksnes is coauthor of the Featured Article in the current issue of Marine Ecology Progress Series. The paper shows how internal waves vary the thickness of a turbid surface layer, causes a fluctuation in light intensity of 3 to 4 orders of magnitude, leading fish to migrate vertically, but now with a period of 30 min instead of 1 day.
A figure from the article, illustrating the effect of the internal wave on fish distributions. Each wace cycle is about 30 minutes. (Illustration by Hege Vestheim.)
The major upwelling systems of the oceans sustain a large part of the world fisheries. The high productivity of these systems has been attributed to high primary production, short food chains, and high trophic transfer efficiency. The study Internal wave-mediated shading causes frequent vertical migrations in fishes suggests that frequent vertical migration (FVM) in fish might contribute to increased prey encounters and the time available for safe visual foraging, thus improving fish growth and survival and trophic transfer efficiency in the Benguela upwelling system. The observed FVM appears to be facilitated by the periodic shading of downwelling irradiance due to the action of internal waves. The thickness of a turbid surface layer varies with the wave and causes a fluctuation in light intensity of 3 to 4 orders of magnitude. Like diel vertical migration, the fish respond by vertical migration, but now with a period of 30 min instead of 1 day. Thus it is hypothesized that fish feeding is enhanced due to an increase in the daily number of antipredation windows for feeding in the water column.
Effects of interactions between fish populations on ecosystem dynamics in the Norwegian Sea - results of the INFERNO project is the title of a special issue of Marine Biology Research published today.
Geir Huse, Jens Christian Holst, Kjell Rong Utne, Leif Nøttestad, Webjørn Melle, Aril Slotte, and Geir Ottersen are guest editors. The volume includes several articles using the Norwecom end-to-end model, with contributions from Geir Huse, Solfrid Hjøllo, Morten Skogen, and Kjell Rong Utne, among others. The Special Issue is found online at http://www.tandfonline.com/toc/smar20/8/5-6.
Starting April 2012, the Theoretical Ecology Group arranges a weekly seminar series on marine ecological modelling, with a special focus on issues of relevance for development of the NORWECOM end-to-end ecosystem model.
Starting April 2012, the Theoretical Ecology Group arranges a weekly seminar series on marine ecological modelling, with a special focus on issues of relevance for development of the NORWECOM end-to-end ecosystem model. Talks may include a wide variety of topics in quantitative ecology. The seminar series is a meeting point for ecologists, geophysicists, mathematicians, and computer scientists from UiB (Dept. of Biology, Geophysical Institute, Dept. of Mathematics), Uni Research, Institute of Marine Research, and other research institutes, and is open to all interested.
We received a total of 45 applications for the 3-year PhD position connected to the Nordic Centre of Excellence NorMER.
A total of 45 applications was received for the 3-year PhD position connected to the Nordic Centre of Excellence NorMER. The successful candidate will model responses in cod larvae to climate change, and work with Øyvind Fiksen, Christian Jørgensen, and Anders F. Opdal.
A 3-year PhD position connected to the Nordic Centre of Excellence NorMER is now announced.
The successful applicant will perform theoretical modelling studies on larval cod growth and survival in scenarios of future oceanographic conditions. The research question is how recruitment success of larval cod will depend on changes in environmental and ecological conditions such as ocean temperature, acidity, primary production, optics and prey availability. The candidate will apply optimality modelling and individual-based models to integrate from physiological processes to ecological and evolutionary mechanisms involved in long-term changes of the environment.
We are seeking a highly motivated candidate with background in one or more of the following disciplines: biological oceanography, ecology, evolution, behavioural ecology, larval fish biology, life history theory, physiology and theoretical biology. Candidates with backgrounds from related disciplines will also be considered. Good communication and writing skills in English and a desire to engage in collaborative research are essential.
For further information and to apply, please visit
(you may need to click 'English' in the top menu to change language). The application deadline is 30 March 2012.
Perdana Karim Prihartato is an Indonesian PhD student of professor Stein Kaartvedt at the Red Sea Research Center at KAUST in Saudi Arabia.
He visits TEG in October 2011 to learn Dynamic Programming and to start modeling the life history and behavior of Red Sea mesopelagic fish by this method. He is cooperating here with Rune Rosland (who studied Norwegian mesopelagic fish by the same modeling tools in his PhD) and Jarl Giske, who is also his co-supervisor at KAUST.
The Theoretical Ecology Group met for two days at Herdlevågen Gjestehus. The hotel used to be the marine biological
station of Bergen, but was abandoned to avoid noise and pollution as the city's airport was planned at Herdla. As
the institute moved to Espegrend, so did the airport plans, and Espegrend is ironically now the closest neighbour to Flesland.
Jarl blended in perfectly as he gave a talk on modelling proximate mechanisms for decision-making in fish.
In addition to members from the Department of Biology, researchers from Institute of Marine Research (IMR) and Uni Research (Uni) were also present. Part of the discussions revolved around plans for how to establish a research centre with all three research institutions involved.
Two new faces also joined the meeting and presented their science. Rebecca Holt is beginnig a PhD on cod and climate change in September. Leo Zijerveld is a long-term visitor from the Sottish Agricultural College in Edinburgh, and is completing a PhD on the dynamics of disease outbreaks.
The extended Theoretical Ecology Group at Herdla. Back row (from left): Jarl Giske, Nicolas Dupont, Rune Rosland, Rebecca Holt, Frode Vikebø (IMR), Geir Huse (IMR), Kjell Utne (IMR), Christian Jørgensen (Uni). Front row: Agurtzane Urtizberea, Dag Aksnes, Sigrunn Eliassen, Øyvind Fiksen, Anders Frugård Opdal (Uni), Leo Zijerveld (visitor). In front: Marco Castellani.
Rebecca Holt from Plymouth, United Kingdom, has been offered the position as PhD Student in connection
with the Nordic Centre of Excellence NorMER (The
Nordic Centre for Research on Marine Ecosystems and Resources under Climate Change).
There were a total of 52 applicants, ten were interviewed, and Rebecca was ranked first by the committee.
Leo Zijerveld is a visiting PhD Student from Biomathematics & Statistics Scotland, Sottish
His interests are stochastic models for the spread of disease in heterogeneous wildlife populations. To derive parameter estimates for such models, he uses time series data and Markov Chain Monte Carlo inference techniques.
A stunning fifty-two applications were received for the recently announced PhD position as part of the Nordic
Centre of Excellence NorMER (The Nordic Centre for Research on Marine Ecosystems and
Resources under Climate Change).
Several of the candidates are excellent, and interviewing will begin soon. But first one has to get throughly through the nearly 2000 pages of letters and documentation to make sure everyone has been evaluated fairly.
We currently have a four-year PhD scholarship open. The position is part of
The Nordic Centre for Research on Marine Ecosystems and
Resources under Climate Change, and will involve evolutionary modelling of adaptations to
climate change in the Atlantic cod.
The application deadline is 30 March 2011. Follow this link to find out more.
Anders F. Opdal defended his PhD thesis in November 2010 and has now been hired as researcher
in Uni Computing.
His focus will be to combine models of fish larval survival and drift from oceanography models, with life history models for the adult phase in a fish's life. The aim is to close the life cycle in a broad perspective by coupling these modelling tools. The research is funded by the Research Council of Norway through the Havet and Kysten thematic programme.
Professor Marc Mangel at
University of California Santa Cruz
joined TEC in November 2010 as Adjunct Professor at Department of Biology.
His relationships with TEC date back to the early 1990s. He has been guest lecturer on several UiB PhD courses, co-supervisor for UiB PhD students, host for TEC researchers at sabbaticals, and co-authors in several of our journal articles. In his adjunct professorship he will participate in three TEC core activities, namely Evolution of mating systems, Evolution in Fisheries Science, and Animal Decision Making.
More information about Marc can be found at his web page: http://users.soe.ucsc.edu/~msmangel/.
The Nordic Center of Excellence NorMER (The Nordic Centre for Research
on Marine Ecosystems and Resources under Climate Change) was granted funding November 2010
and is now launching its activities.
The center is led from the Univesity of Oslo (chaired by Professor Nils Christian Stenseth) in conjunction with the Stockholm Resilience Center (Professor Carl Folke is co-chair). Department of Biology, University of Bergen, is one of nine nodes across the Nordic countries.
The network will research climate change effects on Atlantic cod, a species with a wide distribution in Nordic waters and of great regional economic importance. The main activity of the centre will be to fund 16 PhD students and 4 postdocs that will visit several of the nodes. The first positions will be announced 18 February 2011 with application deadline 30 March 2011.