Pan-Arctic Acoustic Archives: Quantifying zooplankton behaviours in a changing Arctic

Lead Research Organisation: Scottish Association For Marine Science
Department Name: Contracts Office


The Arctic is changing rapidly. One of the clearest changes is a reduction in the extent and thickness of summer sea ice. The loss of ice is predicted to increase in the coming years as a consequence of climatic warming. There may be no summer sea ice in the Arctic by 2030. Critically, the ice acts as a shade to sunlight and as it retreats it exposes open water to illumination causing a rapid increase in the growth of marine plants (phytoplankton). These plants use up carbon dioxide (CO2) from the atmosphere and are therefore an important component of Earth's climate system. Once formed, the phytoplankton become food for herbivorous zooplankton who are able to transport this source of carbon to deeper waters where it is excreted and buried in the sediments. This process, called the 'biological pump', transfers carbon from the atmosphere and locks it away. It is important that we understand the relationships between ice, phytoplankton, zooplankton and carbon and these relationships can be simulated in models of biogeochemical cycles. The critical link in this chain is the herbivorous zooplankton. They have a particular behaviour called 'diel vertical migration' (DVM) which is a prominent feature of many marine ecosystems. The animals move quickly tens to hundreds of meters vertically around dawn and dusk in migrations that comprise the most massive periodic shifts in biomass on Earth. The classical view is that DVM occurs as a trade off by individuals between food acquisition and predator avoidance. Zooplankton move upwards to feed at night into the nearsurface where primary production occurs. Here, under the cover of darkness, the risk from visual predators is minimised. This upward/downward migration redistributes carbon fixed by photosynthesis near the surface to deeper waters, and may remove larger quantities of CO2 from the atmosphere than would otherwise be the case, reducing the rate of CO2 accumulation in the atmosphere. Studying zooplankton in the Arctic year round is difficult because of access and ice cover. One successful technique for recording DVM behaviour uses an instrument called an acoustic Doppler current profiler (ADCP). Many ADCPs have been deployed in the Arctic over the last decade to measure currents but the acoustic signals also record zooplankton migrations. Usually these data are only analysed to understand the ocean currents within the localised region where the instrument was deployed. We are at a critical time in Arctic research where we must take a wider, 'pan-Arctic' view of marine processes. We propose to work with international groups to collate, process and archive the ADCP data, creating a unique resource for studying DVM. The regular, rhythmic behaviour means that we can use numerical techniques (circadian rhythm analysis) to quantify how strong and regular the migration behaviour is and relate this to the biological communities that are present, the level of illumination and the amount of sea ice cover. We will use this knowledge to improve models of how zooplankton transport carbon, through their faecal material, to depth. Understanding zooplankton DVM is important for many reasons. Quantifying DVM behaviour will allow us to improve our ability to predict how changes in sea ice might alter changes in the way carbon is captured and stored in the productive Arctic seas. It will give us a greater insight into how and why animals undertake such regular migrations and how the timing of these migrations is controlled. By relating the acoustic data with species data we will be able to understand the role of zooplankton in Arctic ecosystems and this is of particular importance if predictions on the effect of plankton-dependent fish species are to be made.
Title Dawn of the Copepod CHASERS 
Description 3.5 min film describing the main aim of the NERC CHASE project. Copepods are the most abundant and fastest multi-cellular species on the planet, but they face an uncertain future, especially in the Arctic, because of climate change. Jump aboard with SAMS scientists from the NERC funded CHASE project as they go in search of these tiny superheroes of the oceans. 
Type Of Art Film/Video/Animation 
Year Produced 2019 
Impact ~1000 views on Youtube 
Description The overall objective of this research project was fully exploit the numerous and widespread acoustic data sets that exist in the Arctic to attain the first pan-Arctic perspective on zooplankton diel vertical migration (DVM) behaviours. It involved collaboration with international partners to assemble a large and complex database of acoustic data from across the Arctic, which is now a unique and rich resource for pelagic ecological studies to be sustained and grow beyond the lifetime of the project.
Exploitation Route Through international collaboration on exisiting projects
Sectors Environment

Description Arctic marine ecosystems - Applied technology, Biological interactions and Consequences in an era of abrupt climate change
Amount £284,000 (GBP)
Organisation Research Council of Norway 
Sector Public
Country Norway
Start 05/2015 
End 04/2019
Description CIRCA
Amount kr 2,700,000 (NOK)
Funding ID 214271/F20 
Organisation Research Council of Norway 
Sector Public
Country Norway
Start 05/2012 
End 04/2015
Description Changing Arctic Ocean
Amount £2,700,000 (GBP)
Funding ID NE/P006302/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 02/2017 
End 01/2021
Description Chronobiology of changing Arctic Sea Ecosystems (CHASE)
Amount £272,053 (GBP)
Funding ID NE/R012733/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 07/2018 
End 06/2021
Title Acoustic and fluorescence data from: A marine zooplankton community vertically structured by light across diel to interannual timescales 
Description The predation risk of many aquatic taxa is dominated by visually searching predators, commonly a function of ambient light. Several studies propose that changes in visual predation will become a major climate-change impact on polar marine ecosystems. The high Arctic experiences extreme seasonality in the light environment, from 24-h light to 24-h darkness, and therefore provides a natural laboratory for studying light and predation risk over diel to seasonal timescales. Here, we show that zooplankton (observed using acoustics) in an Arctic fjord position themselves vertically in relation to light. A single isolume (depth-varying line of constant light intensity, the value of which is set at the lower limit of photobehaviour reponses of Calanus spp. and krill.) forms a ceiling on zooplankton distribution. The vertical distribution is structured by light across timescales, from the deepening of zooplankton populations at midday as the sun rises in spring, to the depth to which zooplankton ascend to feed during diel vertical migration. These results suggest that zooplankton might already follow a foraging strategy that will keep visual predation risk roughly constant under changing light conditions, such as those caused by the reduction of sea ice, but likely with energetic costs such as lost feeding opportunities due to altered habitat use. 
Type Of Material Database/Collection of data 
Year Produced 2021 
Provided To Others? Yes  
Description St Andrews, PERG 
Organisation University of St Andrews
Country United Kingdom 
Sector Academic/University 
PI Contribution Access to data, access to research infrastructure
Collaborator Contribution Contribution of expertise on bioacoustics
Impact Papers Share PhD studentship
Start Year 2008
Description Presentation to Scottish International Marine Conference 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presented at a workshop titled "International Ocean Governance " within the Scottish International Marine COnference . Title of my contribution was "Scotland's contribution to the international Arctic research community: why should we care and what can we achieve?"
Year(s) Of Engagement Activity 2019