Post-Grant Reports

Title

Student-Faculty Collaborative Research Grant Report

Document Type

Report

Publication Date

2-13-2015

Disciplines

Biology | Marine Biology | Terrestrial and Aquatic Ecology

Abstract

Marine sponges are known to host large and diverse microbial communities, with the composition of these communities remaining fairly stable across large spatial and temporal scales. Sponges inhabiting the coast of Oregon, USA host bacteria capable of numerous nitrogen transformations, so it is hypothesized that the bacterial community would change as ambient nutrient conditions change. To test this hypothesis, we placed nutrient addition devices (NAD) at Netarts Bay, Oregon for six weeks to increase the nutrient load. We assessed bacterial abundance and diversity within individuals of Haliclona sp. A, the dominant sponge at the site, using scanning electron microscopy (SEM), denaturant gradient gel electrophoresis (DGGE), and microbiome analysis using illumina sequencing. We also collected ambient and exhalent water samples to assess the nutrient fluxes through the sponge. SEM results suggest that treated individuals had significant declines in their bacterial loads. DGGE and microbiome analysis confirm these decreases in bacterial load and show decreases in bacterial diversity. In addition, we found significant changes in nitrate and total nitrogen fluxes between control and NAD treated sponges, suggesting that bacterially-mediated nitrogen cycling was significantly modified by the nutrient addition. Thus, increased nutrient loads appear to detrimentally affect sponges and their associated microbial communities.

Comments

This research was conducted as part of a Linfield College Student-Faculty Collaborative Research Grant in 2014, funded by the Office of Academic Affairs.

Student collaborators were Mariah Denhart and Kathryn Van Dyk.

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