Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates

Algae-derived dissolved organic matter has been hypothesized to induce mortality of reef building corals. One proposed killing mechanism is a zone of hypoxia created by rapidly growing microbes. To investigate this hypothesis, biological oxygen demand (BOD) optodes were used to quantify the change i...

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Main Authors: AK Gregg, M Hatay, AF Haas, NL Robinett, K Barott, MJA Vermeij, KL Marhaver, P Meirelles, F Thompson, F Rohwer
Format: Article
Language:English
Published: PeerJ Inc. 2013-07-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/107.pdf
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author AK Gregg
M Hatay
AF Haas
NL Robinett
K Barott
MJA Vermeij
KL Marhaver
P Meirelles
F Thompson
F Rohwer
author_facet AK Gregg
M Hatay
AF Haas
NL Robinett
K Barott
MJA Vermeij
KL Marhaver
P Meirelles
F Thompson
F Rohwer
author_sort AK Gregg
collection DOAJ
description Algae-derived dissolved organic matter has been hypothesized to induce mortality of reef building corals. One proposed killing mechanism is a zone of hypoxia created by rapidly growing microbes. To investigate this hypothesis, biological oxygen demand (BOD) optodes were used to quantify the change in oxygen concentrations of microbial communities following exposure to exudates generated by turf algae and crustose coralline algae (CCA). BOD optodes were embedded with microbial communities cultured from Montastraea annularis and Mussismilia hispida, and respiration was measured during exposure to turf and CCA exudates. The oxygen concentrations along the optodes were visualized with a low-cost Submersible Oxygen Optode Recorder (SOOpR) system. With this system we observed that exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria than CCA exudates or seawater controls. Furthermore, in both turf and CCA exudate treatments, all microbial communities (coral-, algae-associated and pelagic) contributed significantly to the observed oxygen drawdown. This suggests that the driving factor for elevated oxygen consumption rates is the source of exudates rather than the initially introduced microbial community. Our results demonstrate that exudates from turf algae may contribute to hypoxia-induced coral stress in two different coral genera as a result of increased biological oxygen demand of the local microbial community. Additionally, the SOOpR system developed here can be applied to measure the BOD of any culturable microbe or microbial community.
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spelling doaj.art-5a9b7742a0b2477f8936691bb191b6412023-12-03T11:05:51ZengPeerJ Inc.PeerJ2167-83592013-07-011e10710.7717/peerj.107107Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudatesAK Gregg0M Hatay1AF Haas2NL Robinett3K Barott4MJA Vermeij5KL Marhaver6P Meirelles7F Thompson8F Rohwer9Department of Biology, San Diego State University, San Diego, CA, USADepartment of Physics, San Diego State University, San Diego, CA, USADepartment of Biology, San Diego State University, San Diego, CA, USADepartment of Biology, San Diego State University, San Diego, CA, USAScripps Institution of Oceanography, University of California at San Diego, La Jolla, CA, USACaribbean Research and Management of Biodiversity (CARMABI), Willemstad, CuraçaoCaribbean Research and Management of Biodiversity (CARMABI), Willemstad, CuraçaoLaboratory of Microbiology, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, BrasilLaboratory of Microbiology, Institute of Biology, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, BrasilDepartment of Biology, San Diego State University, San Diego, CA, USAAlgae-derived dissolved organic matter has been hypothesized to induce mortality of reef building corals. One proposed killing mechanism is a zone of hypoxia created by rapidly growing microbes. To investigate this hypothesis, biological oxygen demand (BOD) optodes were used to quantify the change in oxygen concentrations of microbial communities following exposure to exudates generated by turf algae and crustose coralline algae (CCA). BOD optodes were embedded with microbial communities cultured from Montastraea annularis and Mussismilia hispida, and respiration was measured during exposure to turf and CCA exudates. The oxygen concentrations along the optodes were visualized with a low-cost Submersible Oxygen Optode Recorder (SOOpR) system. With this system we observed that exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria than CCA exudates or seawater controls. Furthermore, in both turf and CCA exudate treatments, all microbial communities (coral-, algae-associated and pelagic) contributed significantly to the observed oxygen drawdown. This suggests that the driving factor for elevated oxygen consumption rates is the source of exudates rather than the initially introduced microbial community. Our results demonstrate that exudates from turf algae may contribute to hypoxia-induced coral stress in two different coral genera as a result of increased biological oxygen demand of the local microbial community. Additionally, the SOOpR system developed here can be applied to measure the BOD of any culturable microbe or microbial community.https://peerj.com/articles/107.pdfOptodeBiological oxygen demandCoralDOCCoral-algal interactionBacteria
spellingShingle AK Gregg
M Hatay
AF Haas
NL Robinett
K Barott
MJA Vermeij
KL Marhaver
P Meirelles
F Thompson
F Rohwer
Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
PeerJ
Optode
Biological oxygen demand
Coral
DOC
Coral-algal interaction
Bacteria
title Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
title_full Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
title_fullStr Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
title_full_unstemmed Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
title_short Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
title_sort biological oxygen demand optode analysis of coral reef associated microbial communities exposed to algal exudates
topic Optode
Biological oxygen demand
Coral
DOC
Coral-algal interaction
Bacteria
url https://peerj.com/articles/107.pdf
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