Document Type

Honors Thesis

Major

Wildlife Ecology

Advisor(s)

Hannah Mittelstaedt, Amanda Klemmer

Committee Members

Jose Eduardo Meireles, Jordan LaBouff, Jasmine Saros

Graduation Year

May 2021

Publication Date

Spring 5-2021

Abstract

Some coastal ecosystems are defined as being carbon sinks for their ability to absorb more carbon than they release as a result of their high primary productivity. There has been support for the claim that macroalgal communities can act as carbon sinks and reduce levels of CO2in seawater through photosynthesis and potentially mitigate some local effects of climate change (Chung et al., 2011; Chung et al., 2013; Hill et al., 2015; Sondak et al., 2017). Within the state of Maine, rocky intertidal zones are coastal ecosystems that are particularly vulnerable to climate change and dominated by Ascophyllum nodosum (rockweed) communities (Fong 2008; Letcher 2015). The objective of this study was to evaluate the ability of rockweed to act as a carbon sink in the Gulf of Maine and mitigate local effects of climate change. The hypothesis for this experiment was photosynthesis, not respiration, would be the dominant process observed in treatments with rockweed present. Productivity was estimated through calculating the departure from oxygen saturation of each treatment.Three habitat complexity treatments were observed: a control with only salt water, rockweed submerged in salt water, and rockweed and invertebrates submerged in salt water. It was predicted the rockweed treatment would have the highest productivity, seconded by the invertebrate and rockweed treatment, and the control treatment would experience neither productivity nor respiration. Results showed little to no oxygen was produced during either trial in any treatment, suggesting that respiration was the dominant process in the experiment. This experiment does not support the claim that rockweed has the ability to act as a carbon sink. Other literature contradicts these findings which suggests this experiment would benefit from replication or further expansion.

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