Benthic oxygen exchange in a live coralline algal bed and an adjacent sandy habitat: an eddy covariance study

Attard, K. M., Stahl, H., Kamenos, N. A. , Turner, G., Burdett, H. L. and Glud, R. N. (2015) Benthic oxygen exchange in a live coralline algal bed and an adjacent sandy habitat: an eddy covariance study. Marine Ecology Progress Series, 535, pp. 99-115. (doi:10.3354/meps11413)

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Abstract

Coralline algal (maerl) beds are widespread, slow-growing, structurally complex perennial habitats that support high biodiversity, yet are significantly understudied compared to seagrass beds or kelp forests. We present the first eddy covariance (EC) study on a live maerl bed, assessing the community benthic gross primary productivity (GPP), respiration (R), and net ecosystem metabolism (NEM) derived from diel EC time series collected during 5 seasonal measurement campaigns in temperate Loch Sween, Scotland. Measurements were also carried out at an adjacent (~20 m distant) permeable sandy habitat. The O2 exchange rate was highly dynamic, driven by light availability and the ambient tidally-driven flow velocity. Linear relationships between the EC O2 fluxes and available light indicate that the benthic phototrophic communities were lightlimited. Compensation irradiance (Ec) varied seasonally and was typically ~1.8-fold lower at the maerl bed compared to the sand. Substantial GPP was evident at both sites; however, the maerl bed and the sand habitat were net heterotrophic during each sampling campaign. Additional inputs of ~4 and ~7 mol m-2 yr-1 of carbon at the maerl bed and sand site, respectively, were required to sustain the benthic O2 demand. Thus, the 2 benthic habitats efficiently entrap organic carbon and are sinks of organic material in the coastal zone. Parallel deployment of 0.1 m2 benthic chambers during nighttime revealed O2 uptake rates that varied by up to ~8-fold between replicate chambers (from -0.4 to -3.0 mmol O2 m-2 h-1; n = 4). However, despite extensive O2 flux variability on meter horizontal scales, mean rates of O2 uptake as resolved in parallel by chambers and EC were typically within 20% of one another.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Kamenos, Dr Nicholas and Burdett, Miss Heidi
Authors: Attard, K. M., Stahl, H., Kamenos, N. A., Turner, G., Burdett, H. L., and Glud, R. N.
College/School:College of Science and Engineering > School of Geographical and Earth Sciences
Journal Name:Marine Ecology Progress Series
Publisher:Inter-Research
ISSN:0171-8630
ISSN (Online):1616-1599
Copyright Holders:Copyright © 2015 The Authors
First Published:First published n Marine Ecology Progress Series 535:99-115
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
522851Doctoral Training GrantSusan WaldronNatural Environment Research Council (NERC)NE/H525303/1SCHOOL OF GEOGRAPHICAL & EARTH SCIENCES