IAP-24-043

Impact of environment and climate change on shallow-water foodwebs in polar ecosystems

Polar marine environments are amongst some of the least researched biodiversity systems on Earth. This is especially the case for life on the seabed, the benthos. Data describing interactions between species on polar benthos are very rare. This project aims to generate a better understanding of how species interactions affect biodiversity in polar regions in the southern and northern hemisphere. Polar marine habitats hold some of the most unusual biologies globally. Growth rates are slower than anywhere else, as are embryo development rates (Peck, 2018). Activity rates, including food processing times, are also slow. These factors affect how predators and prey interact and the flow of energy from primary consumers to top predators. Because food supply is often limited to short summer seasons in these environments the foodweb here is assumed to be dominated by omnivores. Yet, except for some model organisms, little is known about the actual biology of most dominant taxa here, impeding predictions about the ecosystem response to climate change.

Foodwebs are descriptions of the interactions between species and the energy, or carbon flow between species from the primary producers to top consumers. Knowledge on their structure and how they function varies substantially from place to place. In the Southern Ocean some pelagic food webs are well documented, especially those around krill, fisheries and whales. However, the benthic foodweb is poorly understood, and it is in the benthos that over 90% of the ca 20,000 species living in Antarctica exist. There is also strong evidence that climate change is impacting benthic habitats and driving distribution changes in the benthos (Griffiths et al. 2024). Similarly, environment and climate change are having equally significant impacts on the Arctic environment (Renaud et al. 2015). Yet, while Antarctic taxa have evolved in isolation over millions of years, Arctic ecosystems are heavily influenced by propagule pressure from the Pacific and Atlantic Ocean. Thus, Arctic ecosystems may be expected to change more rapidly because of range expansion from temperate regions owing to a lack of a geographical boundary.

Stable isotope analysis is widely used in confirming foodweb dynamics. Although there is numerous stable isotope studies conducted in polar environments these studies often only represent: (1) a snapshot in time (i.e., one field season); (2) cover a limited geographical range; and/or (3) focus on specific aspects or taxa of the foodweb. This study will aim to cover at least two summer field seasons in the Arctic, at Svalbard and Greenland. Fieldwork to Antarctica (i.e., Rothera station, on the Antarctic Peninsula) will not be possible. Sampling in the Arctic will focus on producing a holistic foodweb, including all known dominant consumers. Samples will include organisms from the base of the food chain, and throughout the invertebrate (and possibly vertebrate) ecology of the tidal and sub-tidal environments. The isotopic foodweb will be produced using traditional stable measurements in the first instance, carbon, nitrogen and sulfur, but other geochemical analyses may be undertaken. BAS has already conducted a preliminary benthic foodweb analysis at Rothera by one of the previous station-based marine biologists (Dr Nadescha Zwerschke – see her other work on Antarctic blue carbon (Zwerschke et al. 2022)). She has unpublished stable isotope data on 26 prevalent benthic consumers for two summer and one winter season from Rothera, as well as monthly samples for source material, such as macroalgae, phytoplankton and biofilm. These data and additional analyses of samples collected by BAS will be available to the student. This project would therefore start from a stronger base than most projects of its type.

Ecological samples will be collected in the Arctic, at Svalbard, Longyearbyen and sub-arctic at Nuuk, Greenland, to conduct stable isotope analysis in the UK. Selected living specimens that are likely to be more vulnerable to environment and climatic change will be transported back to BAS for aquarium experiments to be conducted in their Controlled Environment Facility. This may involve changing the salinity and temperature, but it may also involve introducing new organisms to experiments that are observed or predicted to migrate north as a result to climate change. Responses on how the organisms respond will be investigated through video monitoring (i.e., behaviour) and feeding ecology (through observation and stable isotope labelling). Ecological samples from Rothera will be collected by BAS divers and scientists to conduct comparable experimental work to be carried out. This may be undertaken on the following: the starfish Odontaster validus, the urchin Sterechinus neumayeri, the amphipod Prostebingia gracilis, the snail Margarella antarctica, the anemone Isotaelia antarctica and the holothurian Heterocucumis steineni.

Prof Gröcke has many contacts in Svalbard and is already conducting macroalgae research in that region, and thus adding a foodweb element will be viable and easier to organise compared with most polar research. In addition, Dr Zwerschke is based at the Greenland Institute of Natural Resources and will be able to host the student to conduct fieldwork. All polar aspects of this project will be designed in collaboration between the prospective student and collaborators, and it will be encouraged from the outset that the student apply for additional financial support from other sources to support such activities, such as the Greenland-UK bursary scheme.

Marine ecology, data collection and analysis. Food web dynamics and modelling. Marine experimentation tanks. Stable isotope geochemistry. Standard techniques and training will be undertaken by the student. Analytical methods will be done under the supervision of each expert supervisor in their respective laboratories. Data analysis will consist of advanced statistical analysis and modelling.

Year 1

A detailed literature review and dataset compilation will be conducted by the student in the first 3 months of the PhD. Fieldwork will be investigated in polar systems (Longyearbyen, Svalbard and Nuup Kangerlua, Greenland). This will involve an ecological foodweb analysis of the inter-tidal and sub-tidal environments. Samples will be returned to BAS for further analysis and experimentation. The student will visit Durham University for training and undertaking stable isotope analysis. The presentation of project aims and outlines at suitable conference outlets will be investigated.

Year 2

Experimental studies will be conducted at BAS and Newcastle University to develop a greater understanding of environment (marine chemistry) and climatic change (i.e., temperature, light) responses on specific organisms from Antarctica and the Arctic. This will involve researching, designing and implementing experimental projects on living organisms. Fieldwork in Svalbard and Greenland is also planned. Analysis of data from first round of experiments. First international conference will be attended.

Year 3

All laboratory work and experimentations will be completed by the end of this year. Continuation of data analysis. Write first papers from the experimental work conducted. Present research results at suitable conference outlets (either national or international).

Year 3.5

Complete data analysis. Produce thesis.

BAS and NU will provide training marine ecology and biodiversity, and aquatic experimentation. Should the opportunity arise for Antarctic fieldwork via further support from a CASS grant the student will be trained in polar fieldwork. Newcastle University will provide training in marine community and biodiversity analysis, Greenland Institute of Natural Resources will provide local expertise, previously collected data, laboratory facilities, for sample preparation and desk space. Durham University will provide training in stable isotope ratio mass spectrometry (IRMS). The student will benefit from being part of a NU DTP cohort where the student will acquire data analysis skills through existing ecological modelling and related post-graduate modules at NU, as well as being a part of the BAS DTP cohort with dedicated training courses and wider training opportunities within the Cambridge area. Other cross-disciplinary skills (e.g. project planning and management; scientific writing and critical analysis; data analysis and statistics) will be gained through specialist modules at NU. The student will also learn many practical and transferrable skills such as:
– Laboratory techniques for sample preparation
– State-of-the-art analytical techniques (IRMS)
– Project management
– Teamwork in remote polar regions (i.e., Svalbard, Greenland)