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Assessing the Down-Fjord Mechanistic Relationships of Biodiversity and Abundance of Antarctic Benthic Macrofauna of Andvord Bay

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Title:Assessing the Down-Fjord Mechanistic Relationships of Biodiversity and Abundance of Antarctic Benthic Macrofauna of Andvord Bay
Authors:Lewis, McKenna
Contributors:Smith, Craig (advisor)
Oceanography (department)
Global Environmental Science (department)
ice shelves
sea ice
primary production
show 1 moremarine ecology
show less
Date Issued:2018
Publisher:University of Hawaiʻi at Mānoa
Place of Publication:Honolulu
Abstract:Glaciomarine fjords exhibit substantially different ecosystem forcing than adjacent
continental shelves and can be highly sensitive to climate warming. Extensive research
indicates that subpolar Arctic fjords are heavily influenced by glacial meltwater and
sediment inputs, resulting in high turbidity and seafloor burial rates. These physical
disturbances yield macrofaunal communities with low abundance and diversity. In
contrast, poorly-studied sub-polar fjords along the Western Antarctic Peninsula (WAP)
sustain weak meltwater influences, resulting in low turbidity and seafloor burial rates.
Thus, benthic communities in WAP fjords may not currently be limited by turbidity and
burial disturbance and may have the potential to harbor abundant and diverse
macrobenthic communities. Here we characterize the benthic macrofaunal community of
Andvord Bay, a subpolar fjord along the warming WAP. We compare down-fjord
changes in macrobenthic abundance, diversity, and functional-group structure (groups of
organisms with different ecosystem roles) to a variety of potential ecological drivers.
These ecological drivers include sediment burial rate, sediment Chl-a concentration (an
indicator of labile detritus availability), and sediment-community respiration (an indicator
of seafloor detrital carbon flux). Sediment disturbance likely only limits the abundance
of benthic communities of the inner fjord regions, but is too weak in the middle fjord to
open shelf to limit the communities. The trend in abundance outside of the disturbed
inner fjord sites is likely driven by POM flux to the seafloor. In areas of high abundance,
the large food flux to the seafloor promotes richness, but the sedimentation disturbance is
not enough to promote evenness. As global sea and air temperatures continue to rise,
glacial melt and sedimentation in WAP fjords will increase, resulting in low benthic
abundance and diversity, resembling present-day Arctic fjords.
Pages/Duration:57 pages
Rights:All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Rights Holder:Lewis, McKenna
Appears in Collections: Global Environmental Science Theses

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