Date of Award
5-17-2024
Document Type
Thesis
Abstract
Mucus-net feeders are under-appreciated organisms that can have large impacts on how organic matter moves through food webs. In the Northern Gulf of Alaska and Prince William Sound they are represented primarily by pelagic tunicates (larvaceans, doliolids, salps) and pelagic snails (pteropods). Over a 20-year time-series (2001-2021) there was strong seasonality of larvacean abundance and species composition. Spring was dominated by Oikopleura labradoriensis and Fritillaria borealis, with higher diversity during autumn, due largely to the periodic presence of warm-water species. There was a distinct cross-shelf gradient with Oikopleura dioica, spreading across the lower salinity shelf during the autumn, and Fritillaria species becoming more prominent at offshore stations. Up to 45% of individual species and 19% to 28% of the tunicate community variation could be explained by physical variables (Temperature, Salinity, Chlorophyll α) and climate indices (ENSO, PDO, NPGO) during the spring and autumn, respectively. There were pronounced shifts in species composition and abundance during marine heatwaves. Limacina helicina showed a negative relationship to climate indices, with strongest correlation to the North Pacific Gyre Oscillation during spring. These long-term species-level records in subarctic waters provide improved understanding of how the mucus-net feeding community may continue to shift in a changing ocean climate.
Recommended Citation
Stidham, Emily, "Climate influences emerge within two decades of observations for pelagic tunicates and pelagic snails in the northern Gulf of Alaska" (2024). Oceanography . 39.
https://ualaska.researchcommons.org/uaf_grad_oceanography/39
Handle
http://hdl.handle.net/11122/15191