Date of Award

Summer 8-23-2019

Level of Access

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Rhian Waller

Second Committee Member

Peter Auster

Third Committee Member

Damian Brady

Additional Committee Members

Brenda Hall

Abstract

Glacier Bay National Park and Preserve in Southeast Alaska is a system of fjords that presents an ideal natural laboratory to study terrestrial, aquatic and marine patterns of succession due to its unique and recent history of deglaciation. The patterns of deep benthic community assemblages in the fjords of Glacier Bay were investigated by quantitative assessment of underwater photo-quadrats collected using a remotely operated vehicle. The percent cover and diversity of species were lowest near the glaciated heads of the fjords and highest in the Central Channel and at the mouths of the fjords of Glacier Bay, where oceanographic conditions of low sedimentation and increased tidal currents are favorable. The diverse communities at the mouths of the fjords and in the Central Channel consisted of large colonies of the Red Tree Coral, Primnoa pacifica, as well as sponges, brachiopods, multiple species of cnidarians, echinoderms, molluscs and arthropods. The communities at the heads of the fjords were heavily dominated by pioneering species such as brachiopoda, hydrozoan turf, the encrusting stoloniferan coral Sarcodyction incrustans, and smaller colonies of Primnoa pacifica. This research demonstrates a gradient of species dominance from the Central Channel to the heads of the glaciated fjords of Glacier Bay, which is likely driven by a combination of physical and biological factors such as sedimentation, nutrient availability, larval dispersal, and competition.

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