Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska
Thesis (M.S.) University of Alaska Fairbanks, 2022 Estuaries are among the most productive ecosystems on Earth, yet are especially at risk in high-latitude regions due to climate-driven effects on the connected terrestrial and marine realms. Warming in these regions exceeds the global average and is...
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ftunivalaska:oai:scholarworks.alaska.edu:11122/13098 2023-05-15T16:22:37+02:00 Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska Schloemer, James W. Iken, Katrin Konar, Brenda Munk, LeeAnn 2022-08 http://hdl.handle.net/11122/13098 en_US eng http://hdl.handle.net/11122/13098 Department of Marine Biology Food chains Ecology Gulf of Alaska Estuarine ecology Intertidal ecology Land-water ecotones Marine productivity Primary productivity Carbon isotopes Stable isotopes in ecological research Watershed ecology Master of Science in Marine Biology Thesis ms 2022 ftunivalaska 2023-02-23T21:38:03Z Thesis (M.S.) University of Alaska Fairbanks, 2022 Estuaries are among the most productive ecosystems on Earth, yet are especially at risk in high-latitude regions due to climate-driven effects on the connected terrestrial and marine realms. Warming in these regions exceeds the global average and is a major cause of the rapid melting of glaciers. As a result, the timing and magnitude of freshwater discharge into estuaries are subject to increase during the peak in glacial meltwater, ultimately affecting the riverine flux of nutrients and organic matter (OM) from the land to coastal environments. Intertidal communities near the outflow of rivers often rely on supplementing local (marine) food sources with allochthonous (terrestrial) subsidies, despite the fact that terrestrial OM can be problematic for marine consumers to assimilate. We investigated if terrestrial matter subsidizes nearshore food webs in northern Gulf of Alaska watersheds, and if the relative proportion of terrestrial versus marine OM supporting these food webs differed with watershed glaciation characteristics and with seasonal glacial discharge regimes. We employed a Bayesian stable isotope mixing model to determine the contribution of marine (phytoplankton, particulate OM, macroalgae) and terrestrial (vascular plant) sources to the diets of grazing/detritivore and filter/suspension-feeding coastal invertebrates at the outflows of watersheds of varying glacial influence and across various discharge periods. Additionally, we conducted a distance-based redundancy analysis to investigate the effects of watershed-characteristic sourcing and transport of terrestrial OM on nearshore consumer diets. The diets of both feeding groups were predominantly marine (>90%) and varied little among sites or glacial discharge periods. However, consumers were depleted in ¹³C isotopes with increasing glaciation; the significant watershed descriptors suggest that this change was more associated with discharge effects on marine primary production rather than ... Thesis glaciers Alaska University of Alaska: ScholarWorks@UA Fairbanks Gulf of Alaska |
institution |
Open Polar |
collection |
University of Alaska: ScholarWorks@UA |
op_collection_id |
ftunivalaska |
language |
English |
topic |
Food chains Ecology Gulf of Alaska Estuarine ecology Intertidal ecology Land-water ecotones Marine productivity Primary productivity Carbon isotopes Stable isotopes in ecological research Watershed ecology Master of Science in Marine Biology |
spellingShingle |
Food chains Ecology Gulf of Alaska Estuarine ecology Intertidal ecology Land-water ecotones Marine productivity Primary productivity Carbon isotopes Stable isotopes in ecological research Watershed ecology Master of Science in Marine Biology Schloemer, James W. Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
topic_facet |
Food chains Ecology Gulf of Alaska Estuarine ecology Intertidal ecology Land-water ecotones Marine productivity Primary productivity Carbon isotopes Stable isotopes in ecological research Watershed ecology Master of Science in Marine Biology |
description |
Thesis (M.S.) University of Alaska Fairbanks, 2022 Estuaries are among the most productive ecosystems on Earth, yet are especially at risk in high-latitude regions due to climate-driven effects on the connected terrestrial and marine realms. Warming in these regions exceeds the global average and is a major cause of the rapid melting of glaciers. As a result, the timing and magnitude of freshwater discharge into estuaries are subject to increase during the peak in glacial meltwater, ultimately affecting the riverine flux of nutrients and organic matter (OM) from the land to coastal environments. Intertidal communities near the outflow of rivers often rely on supplementing local (marine) food sources with allochthonous (terrestrial) subsidies, despite the fact that terrestrial OM can be problematic for marine consumers to assimilate. We investigated if terrestrial matter subsidizes nearshore food webs in northern Gulf of Alaska watersheds, and if the relative proportion of terrestrial versus marine OM supporting these food webs differed with watershed glaciation characteristics and with seasonal glacial discharge regimes. We employed a Bayesian stable isotope mixing model to determine the contribution of marine (phytoplankton, particulate OM, macroalgae) and terrestrial (vascular plant) sources to the diets of grazing/detritivore and filter/suspension-feeding coastal invertebrates at the outflows of watersheds of varying glacial influence and across various discharge periods. Additionally, we conducted a distance-based redundancy analysis to investigate the effects of watershed-characteristic sourcing and transport of terrestrial OM on nearshore consumer diets. The diets of both feeding groups were predominantly marine (>90%) and varied little among sites or glacial discharge periods. However, consumers were depleted in ¹³C isotopes with increasing glaciation; the significant watershed descriptors suggest that this change was more associated with discharge effects on marine primary production rather than ... |
author2 |
Iken, Katrin Konar, Brenda Munk, LeeAnn |
format |
Thesis |
author |
Schloemer, James W. |
author_facet |
Schloemer, James W. |
author_sort |
Schloemer, James W. |
title |
Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
title_short |
Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
title_full |
Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
title_fullStr |
Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
title_full_unstemmed |
Marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern Gulf of Alaska |
title_sort |
marine and not terrestrial resources support nearshore food webs across a gradient of glacial watersheds in the northern gulf of alaska |
publishDate |
2022 |
url |
http://hdl.handle.net/11122/13098 |
geographic |
Fairbanks Gulf of Alaska |
geographic_facet |
Fairbanks Gulf of Alaska |
genre |
glaciers Alaska |
genre_facet |
glaciers Alaska |
op_relation |
http://hdl.handle.net/11122/13098 Department of Marine Biology |
_version_ |
1766010618645577728 |