Ecological consequences of climatic forcing in the Arctic marine benthos

• Main Author: Williams, Tom
• Format: Thesis
• Language: English
• Published: University of Southampton 2023
• Subjects: Arctic; Climate change
• Online Access: https://eprints.soton.ac.uk/482362/; https://eprints.soton.ac.uk/482362/1/TWilliams_UoS_Thesis_fullres_postviva_amendments_PDFA.pdf; https://eprints.soton.ac.uk/482362/2/Final_thesis_submission_Examination_Mr_Thomas_Williams.pdf

Climate change is causing unprecedented changes in high-latitude environments, which have widespread implications for the underlying ecology and global climate and ocean systems. Of particular concern is the Arctic seafloor, an integral component of sympagic-pelagic-benthic food-webs, biogeochemical cycling and a variety of ecosystem services. Arctic climate change studies often overlook changes in the physiological, behavioural, and life-history traits of organisms, instead focusing on observable, macro-level responses such as range shifts and biomass turnovers. However, alterations of trait expression are crucial in determining an organism's capacity to adapt and influence the environment, preceding population and community-level responses. Substantial variability of trait expression is already observed across different spatiotemporal scales, between co-existing species and within conspecifics. As a result of these complexities, accurately assessing the impact of climate change on Arctic benthic biodiversity and ecosystem functioning is challenging. Here, I use laboratory-based mesocosm experiments, geochemical tracer analyses and simulative ecological extinction scenarios of Arctic benthic model systems to evaluate the consequences of organism responses to climate-driven environmental changes for benthic ecosystem functioning. Overall, my results demonstrate that organism responses are not generic, and can fundamentally alter their ability to persist and mediate aspects of ecosystem functioning. Specifically, I find that the capacity of species to endure climate-induced environmental change does not always equate to sustained contributions towards functional processes such as nutrient cycling and incurs inter- and intra-specific shifts in behaviour and physiological costs within metabolic pathways. Diverse responses to climate change are also reflected in the paleorecords, where intra-specific variability within long-lived cold-water corals influences their reliability in reconstructing deep-water temperature ...