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Current and future trophic interactions in tropical shallow-reef lagoon habitats

Citation

Wolfe, K and Deaker, DJ and Graba-Landry, A and Champion, C and Dove, S and Lee, R and Byrne, M, Current and future trophic interactions in tropical shallow-reef lagoon habitats, Coral Reefs, 40 pp. 83-96. ISSN 0722-4028 (2021) [Refereed Article]

Copyright Statement

Copyright Springer-Verlag GmbH Germany, part of Springer Nature 2020

DOI: doi:10.1007/s00338-020-02017-2

Abstract

Calcium carbonate (CaCO3) sediments are the dominant form of CaCO3 on coral reefs accumulating in lagoon and inter-reefal areas. Owing to their mineralogy and a range of physical parameters, tropical CaCO3 sediments are predicted to be more sensitive to dissolution driven by ocean acidification than the skeleton of living reef organisms. How this scales up to impact infaunal organisms, which are an important food source for higher trophic levels, and thereby ecosystem functioning, is not well explored. We combined seasonal field surveys in a shallow-reef lagoon ecosystem on the Great Barrier Reef, Australia, with stable isotope analyses and a tank-based experiment to examine the potential top-down influence of the deposit-feeding sea cucumber, Stichopus herrmanni, on this infaunal community under current and future ocean pH. Densities of surface-sediment meiofauna were lowest in winter and spring, with harpacticoid copepods (38%) and nematodes (27%) the dominant taxa. Stable isotope analyses showed that S. herrmanni had a top-down influence on meiofauna and microphytes with a distinct δ13C and δ15N trophic position that was homogenous across seasons and locations. Tanks that mimicked sandy shallow-reef lagoon habitats were used to examine the effects of ocean acidification (elevated pCO2) on this trophic interaction. We used outdoor control (sediment only) and experimental (sediment plus S. herrmanni) tanks maintained at present-day and near-future pCO2 (+ 570 µatm) for 24 days, which fluctuated with the diel pCO2 cycle. In sediment-only tanks, copepods were > twofold more abundant at elevated pCO2, with no negative effects documented for any meiofauna group. When included in the community, top-down control by S. herrmanni counteracted the positive effects of low pH on meiofaunal abundance. We highlight a novel perspective in coral reef trophodynamics between surface-sediment meiofauna and deposit-feeding sea cucumbers, and posit that community shifts may occur in shallow-reef lagoon habitats in a future ocean with implications for the functioning of coral reefs from the bottom up.

Item Details

Item Type:Refereed Article
Keywords:Great Barrier Reef, meiofauna, ocean acidification, sea cucumber, sediment
Research Division:Environmental Sciences
Research Group:Climate change impacts and adaptation
Research Field:Ecological impacts of climate change and ecological adaptation
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Australia (excl. social impacts)
UTAS Author:Graba-Landry, A (Dr Alexia Graba-Landry)
ID Code:147569
Year Published:2021
Web of Science® Times Cited:1
Deposited By:Sustainable Marine Research Collaboration
Deposited On:2021-11-08
Last Modified:2021-12-06
Downloads:0

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