Date of Award

5-2014

Level of Access

Campus-Only Thesis

Degree Name

Master of Science (MS)

Department

Marine Biology

Advisor

Robert Steneck

Second Committee Member

Teresa Johnson

Third Committee Member

Joseph Kelley

Abstract

Planning how to accommodate growing coastal populations is the impetus for ocean planning (OP), which has become a goal for many countries including the United States. One big challenge for OP will be describing vast marine ecosystems using limited resources. We sought to develop abiotic proxies that characterize megafaunal communities and tested this approach over nearly 300km of coast in the Gulf of Maine (GOM) using stratified-random remotely operated vehicle surveys. Together, depth, substrate and oceanographic processes explained a significant portion of variance in models for the species structure, biomass and diversity of benthic assemblages (these variables explained 36.2%-54.7%). According to canonical correlation analysis, depth and substrate were the strongest determinants of community structure. While cumulative biomass and biodiversity related to the oceanographic gradient of the GOM coastal current system, according to generalized additive modeling. Our results suggest abiotic factors can be strong forcing functions for the assembly of marine communities. Locally, substrate heterogeneity interacts with traits of benthic species to create fme-scale differences in species structure. At a coastal scale, depth regulates available primary and secondary production. Lastly, at a regional scale, thermography creates biogeographic patterns in benthic assemblages, which may be most vulnerable to climate change. Our approach allows localized studies to be scaled up for large marine ecosystems and could become a template for considering the multi-scale spatial extent of assemblages in the context of ocean activities. Using abiotic proxies as templates for marine assemblages could allow managers and policy-makers to conduct OP without depending on costly and time-consuming surveys of entire large marine ecosystems.

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