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Seagrass productivity and associated bacterial communities change under increased temperatures

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posted on 2022-10-18, 06:21 authored by Luke Walker

Current rates of ocean warming are predicted to further exacerbate ongoing declines in seagrass populations. Responses of seagrass to increasing temperatures have been studied from a direct physiological perspective while indirect effects, including below ground processes such as those provided by microbial mediation, remain poorly understood. This study recorded differences in seagrass productivity, detrital decomposition rates, and above and below ground bacterial communities between ambient temperatures and temperatures in a warm plume (3 °C above natural) created by a power station discharge channel in Lake Macquarie, Australia that are analogous to conditions predicted by 2100 under current rates of ocean warming. Above ground biomass and seagrass growth rates were both greater at warm sites while below ground biomass and detrital decomposition rates showed a similar, but non-significant trend. The microbial community composition for both sediments and leaf tissues varied significantly between warm and ambient conditions. These findings suggest a 3 °C rise in temperate regions is unlikely to induce mortality in seagrass but may change nutrient cycling in seagrass beds. This has implications for successful seagrass restoration under future warming conditions. Further manipulative experiments are needed to determine temperature effects on particular microbes and the implications for seagrass productivity.  


Table of Contents

1. Introduction -- 2. Methods -- 3. Results -- 4. Discussion -- 5. Conclusions -- 6. References -- Supplementary Materials


A thesis submitted to Macquarie University for the degree of Master of Research ADDITIONAL SUPERVISOR 3: Tim Glasby

Awarding Institution

Macquarie University

Degree Type

Thesis MRes


Thesis (MRes), Macquarie University, Department of Earth and Environmental Sciences, 2021

Department, Centre or School

Department of Earth and Environmental Sciences

Year of Award


Principal Supervisor

Katherine Dafforn

Additional Supervisor 1

Paul Gribben

Additional Supervisor 2

Ezequiel Marzinelli


Copyright: The Author Copyright disclaimer:




64 pages

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