Chronobiology of changing Arctic Sea Ecosystems (CHASE)

Lead Research Organisation: British Antarctic Survey


Rational: The CHASE programme will address the core objective of the NERC Changing Arctic Ocean Program by seeking to understand and predict how ecologically important species will respond to climate change. As the Arctic Ocean is warming, zooplankton such as copepods and krill are undergoing habitat range extensions polewards. This will result in exposure to new and more extreme day-length (photoperiodic) climates of the higher latitudes - known in many terrestrial species to have negative consequences on fitness. We will therefore aim to investigate the behaviour, physiology and genetic responses of copepods and krill to their natural and new photoperiodic environments. We will focus on the circadian biological clock, central in day-length measurement and in orchestrating key seasonal life-cycle events.

Approach: To understand large scale ecosystem responses to climate change we need to mechanistically understand small scale individual responses of key organisms driving marine ecosystems and their functional biodiversity. High variability between individuals is an indicator for high adaptive capacity of the population to changing conditions. Due to the ecological relevance of key species their individual variability can give an indication of future ecosystem shifts.
Our approach focusses on the two Arctic key zooplankton groups Calanus finmarchicus / Calanus glacialis (calanoid copepod) and Thysanoessa inermis (krill). We will: 1) characterize the Arctic light climate (spectrum, irradiance) with latitude and season; 2) determine individual copepod and krill behavioural phenotypes with latitude and season; 3) investigate photoperiod as a diapause trigger in copepods; 4) determine the metabolic status of behavioural phenotypes (identified above); 5) provide seasonal characterization of gene expression with a focus on clock mechanisms and the influence of light and; 6) provide indicator genes characteristic for specific life-cycle events, metabolic processes and environmental conditions as well as genetic timekeeping; 7) investigate the effects of light and genetic clock mechanisms on seasonal timing and how the factors may synergistically interact with other environmental and physiological factors and; 8) incorporate these data into life-cycle models to provide a wider, predictive framework for this work.
We will combine a novel, but tested, approach to large scale behavioural screening of activity in copepods and krill with classical physiological investigations on fitness. Activity screening methodology adopted from Drosophila clock research will reveal diel behavioural cycles and rhythms as well as the change of these cycles/rhythms with different photoperiods. We will also use state-of-the-art genetic analyses to characterise the genetic traits of seasonal physiological changes and how light modulates circadian clock and clock related genes. Finally we will incorporate the behaviour, environment and physiological state into existing well-tested individual-based models and dynamic optimisation models to determine the predicted fitness costs of future Arctic climate change scenarios.

Application and benefits: The balanced functioning of the Arctic ecosystem is reliant on the success of key zooplankton primary consumers which influence all higher trophic levels, from fish to whales. CHASE aims to understand how such key organisms function in this extreme environment and will develop the predictive tools necessary to assess how climate change will impact their populations in the future. This will be achieved through a combined sampling/experimental/modelling programme, thereby informing future scientific directions, critical in helping manage areas which are rapidly becoming more accessible to increasing resource exploitation. The project is embedded within international Arctic science networks based in the UK, Norway and Germany and will have a legacy of cooperation beyond the lifetime of the funding.

Planned Impact

Scientific community - CHASE aims to provide the scientific community with a new perspective of zooplankton population ecology which is of particular value to the Polar ecosystem modelling community already embedded in the NERCs changing Arctic Ocean programme. Our findings will be disseminated via high impact publications and presentations at major international meetings, principally Arctic Frontiers and Arctic Change Conferences. In addition there is increasing interest in clocks in non-model systems, particularly those under environmental extremes, to improve our understanding of the evolution of the circadian clock. We will therefore focus CHASE disseminations at various chronobiological meetings such as the UK Clock Club, Society of Biological Rhythms and the Chronobiology Gordon Research Conference.

Policy community - CHASE addresses many international Arctic research priorities as outlined in the EU PolarNEt and the 2015 ICARP III reports. These call for better understanding of Arctic ecosystems and specifically their responses and resilience to anthropogenic impacts whilst encouraging cross-cutting science and international collaboration. Our focal species are of high ecological importance to the North Atlantic and Arctic ecosystems and therefore of broad interest to Arctic fisheries biologists specifically our Nordic partners such as the Norwegian Institute of Marine Research. Further, the German Ministry of Education and Research for marine and Polar research MARE:N has identified "variability, acclimation and adaptability of key organisms to environmental change" as a target research area which should be supported by robust predictive models. Closer to home we will make available our findings to the UK Arctic Office thereby informing UK Arctic science towards future policy development, important at this time with the rapid expansion of Arctic open water for increased commercial exploitation. CHASE partners will be presenting our science during the Arctic Frontiers Tromso meetings which includes focused sessions addressing the opportunities and challenges to achieve viable economic growth with societal and environmental sustainability in the Arctic. We are also conscientious of our duty to IPCC on relevant issues.

General public - People are naturally fascinated by Polar Regions and it is therefore relatively easy to engage the public in Arctic science, particularly with images of polar bears. The challenge is to entertain and educate about more enigmatic subject matters such as zooplankton. However, our groups have been extremely successful in promoting our science, reaching a very wide audience via effective communications teams and understanding the needs of the media. A recent video abstract and press release centred on zooplankton behaviour dubbed "Arctic Werewolves" (for more information just google it) resulted in the top 1% of publically cited papers for the high impact journal Current Biology. The increasing use of institutional websites linked to social media, especially twitter, has expanded our scientific 'reach', demonstrated by the 6.5K and 22K followers of the SAMS and BAS twitter feeds respectively. We will display our science in the SAMS Ocean Explorer Centre and provide educational material to local schools and nurseries in Argyll. We will also provide outreach material for the Glasgow Science Centre under the 'EnviroScience' theme to illustrate the effects of Arctic warming on ecosystems and link to a website at the University of Delaware focusing on using zooplankton for inquiry-based teaching and learning of biological concepts.

Finally CHASE is committed to training future Arctic scientists and our PDRAs will be encouraged to become part of the Association of Polar Early Career Scientists (APECS) to facilitate appropriate career development and networking and will be encouraged to take part in any SAMS/UHI transferrable skill development and science communication training programmes
Description AArctic zooplankton species live in an extremely complex 3D environment where tradeoffs are required to balance growth with the risk of predation at both daily and seasonal time scales. As species move north into new light environments, these tradeoffs have potential to change. A state dynamic model has been developed which predicts the optimal vertical habitat for individual CV Calanus finmarchicus copepods throughout their growing season, with energetic cost and gain functions for each choice parameterised on empirical observations (irradiance, food availability, and predation rate). The model has been parameterised for the East Norwegian Sea and replicates seasonal behaviour well with differences in vertical migration and diapause initiation with body condition.

We have also collaborated with colleagues as SAMS in which we determined individual copepod swimming activity using onboard experiments during the CAO cruise JR18007. By relating swimming behaviour results to other diapause indicators such as collection depth, respiration rate and morphometric analysis, our findings suggest that this behavioural assay could be a novel tool in discriminating between active and dormant copepods, and thus will help assess the putative endogenous and exogenous factors involved in diapause onset. This work has been published in a special issue of Frontiers in Marine Science (The Physiology, Ecology and Biogeochemistry of Marine Zooplankton in a Changing Arctic Ocean).
Exploitation Route Chronobiology is an important aspect of animal adaptation to environmental change. Our results will inform modellers and policy makers of the direct and indirect consequences of environmental change to marine communities.
Sectors Environment

Description We have published two articles for young readers. The first (Mayor et al "Marine copepods, the Wildebeest of the Oceans") reveals how important copepods are to foodwebs in teh world's oceans, particularly the polar regions. The second (Freer and Hobbs "The World's Biggest Game of Hide-and-Seek") looks at the behaviour of pelagic organisms in what is the biggest daily migration on Earth. Both articles are reviewed by the young readers themselves nad have an international distribution.
First Year Of Impact 2020
Sector Education,Environment
Impact Types Societal

Title Range-wide occurrence records of the subarctic copepod Calanus finmarchicus and associated environmental predictor variables 
Description This dataset contains occurrence records and associated metadata for the zooplankton species Calanus finmarchicus that were compiled from multiple open access databases. A file containing the corresponding background points is provided, along with gridded environmental variables for each season (Jan-Feb-Mar, Apr-May-Jun, Jul-Aug-Sep, Oct-Nov-Dec) and era (1955-1984, 1985-2017) that were assessed in this study. Together these data were used as input files for the MaxEnt ecological niche model within the peer reviewed article: Freer JJ, Daase, M, Tarling GA, (2021) Modelling the biogeographic boundary shift of Calanus finmarchicus reveals drivers of Arctic Atlantification by subarctic zooplankton, Global Change Biology. Finally, an R Markdown document is provided to enable data users to replicate the model optimisation and prediction steps using the input data files within this repository. Funding was provided by: UKRI Natural Environment Research Council (NERC): DIAPOD (NE/P006213/1) NERC and the German Federal Ministry of Education and Research (BMBF): CHASE (NE/R012687/1) Norwegian Research Council: Deep Impact project (300333). 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Impact Not applicable