Mechanistic understanding of the role of diatoms in the success of the Arctic Calanus complex and implications for a warmer Arctic

Lead Research Organisation: Plymouth Marine Laboratory
Department Name: Plymouth Marine Lab

Abstract

Copepod species of the genus Calanus (Calanus hereafter) are rice grain-sized crustaceans, distant relatives of crabs and lobsters, that occur throughout the Arctic Ocean consuming enormous quantities of microscopic algae (phytoplankton). These tiny animals represent the primary food source for many Arctic fish, seabirds and whales. During early spring they gorge on extensive seasonal blooms of diatoms, fat-rich phytoplankton that proliferate both beneath the sea ice and in the open ocean. This allows Calanus to rapidly obtain sufficient fat to survive during the many months of food scarcity during the Arctic winter. Diatoms also produce one of the main marine omega-3 polyunsaturated fatty acids that Calanus require to successfully survive and reproduce in the frozen Arctic waters. Calanus seasonally migrate into deeper waters to save energy and reduce their losses to predation in an overwintering process called diapause that is fuelled entirely by carbon-rich fat (lipids). This vertical 'lipid pump' transfers vast quantities of carbon into the ocean's interior and ultimately represents the draw-down of atmospheric carbon dioxide (CO2), an important process within the global carbon cycle. Continued global warming throughout the 21st century is expected to exert a strong influence on the timing, magnitude and spatial distribution of diatom productivity in the Arctic Ocean. Little is known about how Calanus will respond to these changes, making it difficult to understand how the wider Arctic ecosystem and its biogeochemistry will be affected by climate change.
The overarching goal of this proposal is to develop a predictive understanding of how Calanus in the Arctic will be affected by future climate change. We will achieve this goal through five main areas of research:
We will synthesise past datasets of Calanus in the Arctic alongside satellite-derived data on primary production. This undertaking will examine whether smaller, more temperate species have been increasingly colonising of Arctic. Furthermore, it will consider how the timing of life-cycle events may have changed over past decades and between different Arctic regions. The resulting data will be used to validate modelling efforts.
We will conduct field based experiments to examine how climate-driven changes in the quantity and omega-3 content of phytoplankton will affect crucial features of the Calanus life-cycle, including reproduction and lipid storage for diapause. Cutting-edge techniques will investigate how and why Calanus use stored fats to reproduce in the absence of food. The new understanding gained will be used to produce numerical models of Calanus' life cycle for future forecasting.
The research programme will develop life-cycle models of Calanus and simulate present day distribution patterns, the timing of life-cycle events, and the quantities of stored lipid (body condition), over large areas of the Arctic. These projections will be compared to historical data.
We will investigate how the omega-3 fatty acid content of Calanus is affected by the food environment and in turn dictates patterns of their diapause- and reproductive success. Reproductive strategies differ between the different species of Calanus and this approach provides a powerful means by which to predict how each species will be impacted, allowing us to identify the winners and losers under various scenarios of future environmental changes.
The project synthesis will draw upon previous all elements of the proposal to generate new numerical models of Calanus and how the food environment influences their reproductive strategy and hence capacity for survival in a changing Arctic Ocean. This will allow us to explore how the productivity and biogeochemistry of the Arctic Ocean will change in the future. These models will be interfaced with the UK's Earth System Model that directly feeds into international efforts to understand global feedbacks to climate change.

Planned Impact

The major beneficiaries will be fisheries policy makers, biogeochemical modellers, climate scientists and political bodies concerned with the health and management of the Arctic ecosystem. Improved understanding of Arctic fisheries is important for understanding the food security and provision of protein and nutrition for many nations, including the UK. Our work will also be of benefit to academics interested in understanding trophic interactions and the biogeochemistry of marine ecosystems. The involvement of PhD students and early career scientists will ensure that we contribute to training the next generation of research scientists.
Understanding how the abundance and lipid content of Calanus is likely to change is central to understanding how the productivity of fish and higher trophic levels will be affected by future environmental change. This understanding is therefore of central importance to fisheries and ecosystem managers throughout the Arctic. Knowledge of zooplankton mediated carbon sequestration is required for accurate model parameterisation and validation, and thus of benefit to biogeochemical and climate modellers: New parameterisation of the spatio-temporal distribution of copepod abundance will ready for coupling to MEDUSA, the biogeochemical model adopted by NERC and the UK Met Office to provide marine biogeochemistry in UKESM1, the UK community Earth System Model being used in phase 6 of the Coupled Model Intercomparison Project (CMIP6) that will feed into IPCC Assessment Report 6. More accurate predictions of Calanus distributions will provide more detailed insight into the knock-on effects for the composition and abundance of Arctic fish communities. In turn, this will provide more realistic assessments of food security and the provisioning of marine protein and essential omega-3 polyunsaturated fatty acids.
We will maximize the visibility and accessibility of our research to Arctic policy makers and fisheries scientists by presenting our program and its findings at Arctic Frontiers conferences (http://www.arcticfrontiers.com/), the annual gathering of academics, politicians and business with interests in the Arctic. Our program has been designed with the involvement of ecosystem and biogeochemical modelers from the outset. On-going, 2-way dialogue between the observational/experimental and modeling components of our work will enable the effective uptake of our data products. Involvement of NEMO-MEDUSA in CMIP6 will ensure that our work contributes to the broader political process via the reports of the IPCC. We are also working directly with US and Norwegian modelling groups that are developing seasonal and multidecadal forecasts for the benefit of management and policy regarding high-value fisheries like Alaska pollock and marine mammal conservation. This simultaneous integration of multiple, well-tested copepod models into three internationally prominent oceanographic models will, to our knowledge, constitute the most complete ensemble experiment in understanding and predicting the future of Arctic zooplankton to date.

Publications

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Mayor D (2020) Marine Copepods, The Wildebeest of the Ocean in Frontiers for Young Minds

 
Description The sequence data from the high throughput sequencing shows the community structure (relative to biomass) including Calanus species present. For cruise JR17005 the results generated by amplifying the DNA with the 18S primers generated a total of over 1.5 million sequences that were clustered in to 28 OTUs (Operational Taxonomic Units). At the majority of stations Calanus dominated the community structure, with 16S results revealing that Calanus finmarchicus was the most prevalent species at all bar three of the stations. For cruise JR18007 the results generated by amplifying the DNA with the 18S primers generated a total of over 1 million sequences that were clustered in to 18 OTUs that contain 95% of the sequence data returned. Calanus also dominated the community structure at all stations sampled. The 16S results revealed that Calanus finmarchicus was the most prevalent species at all stations with the exception of station D10 that was dominated by Calanus glacialis.
Exploitation Route Knowledge of species present, essential for other collaborators.
Sectors Environment

 
Title Molecular community analysis of the whole zooplankton assemblage 
Description Copepods of the genus Calanus are key zooplankton species in the North Atlantic and Arctic marine ecosystems. Despite their high abundance and ecological importance unambiguous identification to species level remains challenging without the use of molecular techniques. Zooplankton samples were collected with Bongo nets at multiple stations during the two DIAPOD cruises JR17005 and JR18007. The samples were processed for molecular community analysis of the whole zooplankton assemblage, including Calanus congeners. This was achieved by metabarcoding using two regions of DNA. First the more 'standard' metabarcode; the highly variable V9 region of the 18S SSU rRNA gene for whole community analysis and secondly a region of the mitochondrial 16S rRNA gene, which allows identification of the Calanus to species level. High throughput sequencing was undertaken on an Illumina sequencer. Data from the HTS were analysed by processing through the Qiime pipeline to determine the community structure (relative to biomass) including Calanus species present. All Calanus used in the Egg Production Rate (EPR) experiments on JR17005 and JR18007 have been identified to species level using the Restriction Fragment Length Polymorphism (RFLP) technique developed by Lindeque, 1999. In summary, Calanus from the EPR of both cruises were dominated by Calanus finmarchicus. 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? No  
Impact None yet 
 
Description Convened a session for the ICES Annual Science Meeting 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Convened a session "Molecules and morphology; integrative taxonomic analysis of marine planktonic assemblages" at the ICES Annual Science Conference as part of the Working Group on integrated molecular and morphological taxonomy.
Year(s) Of Engagement Activity 2018
URL https://www.ices.dk/news-and-events/asc/asc2018/Pages/default.aspx
 
Description Interactive workshop for Key Stage II pupils at All-Saints-Primary School, Thurlestone, and Modbury Primary School as part of the schools environmental awareness week. 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Gave presentations and ran an interactive workshop on changing oceans for Key Stage II pupils at All-Saints-Primary School, Thurlestone, and Modbury Primary School as part of the schools' environmental awareness week. The pupils expressed an increased interest in science. Pupils and teachers changed their attitude towards using single-use plastic and school environmental group started to discourage use of plastic in packed lunches and started presenting awards to those with no plastic in their lunch box.
Year(s) Of Engagement Activity 2018
 
Description KCC Marine Warriors Team 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Presented to the Marine Warriors Team at Kingsbridge Community College on the threats faced by our oceans, including climate change, the Arctic and plastic pollution in the marine environment.

The students reported an interest in this area and have set up action groups to promote recycling in school, reduce single-use plastic and fund-raise to lay a mooring buoy to prevent anchoring in fragile estuary areas.
Year(s) Of Engagement Activity 2018
 
Description MetaZooGene 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited member of a new SCOR Working Group for 2019-2022 entitled MetaZooGene: Toward a new global view of marine zooplankton biodiversity based on DNA metabarcoding and reference DNA sequence databases.
Year(s) Of Engagement Activity 2019
URL http://scor-int.org/Annual%20Meetings/2018_SCOR_Meeting/MetaZooGene.pdf
 
Description Outreach activity sheet 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Produced an activity sheet based on "Copepods; the mini-beasts of the ocean". Circulated to a number of Educational centers and tourist attracts from The Glasgow Science Center to The Eden Project.
Year(s) Of Engagement Activity 2019
 
Description STEM Ambassador 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Helen Parry, in her role as a STEM Ambassador at Plymouth Marine Laboratory, visited Devonport High School for Girls (Plymouth) to give a presentation to year 12 students about "Careers in Science" and answer questions. The talk aimed to present the nature and scope of careers within science, focusing on marine science and open the eyes of the girls to the opportunities available beyond the traditional options of medicine, dentistry and veterinary science. Examples were given of fieldwork undertaken in the Arctic, November 2019.
Year(s) Of Engagement Activity 2019
 
Description STEM Ambassador visit to Devonport High School for Girls (Plymouth) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Helen Parry, in her role as a STEM Ambassador, visited Devonport High School for Girls (Plymouth) to give a presentation to year 12 students about "Careers in Science" and answer questions. The talk aimed to present the nature and scope of careers within science, focusing on marine science and open the eyes of the girls to the opportunities available beyond the traditional options of medicine, dentistry and veterinary science. Examples were given of fieldwork undertaken in the Arctic.
Year(s) Of Engagement Activity 2017
 
Description Talk and workshop at Eden Project laboratory summer program 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Pennie Lindeque ran the first day of the Eden project lab summer programme. Giving talks and a workshop on the importance of zooplankton and Microplastics in the marine environment from problems to solutions.
Year(s) Of Engagement Activity 2019
 
Description Westcountry Wonderwoman Event 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Schools
Results and Impact Motivational talk as a guest speaker at the Westcountry Wonderwoman event for International Woman's day.
Over 100 pupils aged 11-18 attended a 3 hour evening session with the strapline #PressForProgress.
Many pupils provided feedback that they were inspired to work hard, follow their dreams and were motivated to pursue STEM careers.
Year(s) Of Engagement Activity 2018