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Microbial communities of subtidal shallow sandy sediments change with depth and wave disturbance, but nutrient exchanges remain similar

2010; Inter-Research; Volume: 414; Linguagem: Inglês

10.3354/meps08734

1616-1599

Hugh Forehead, Peter A. Thompson,

Microbial Community Ecology and Physiology

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 414:11-26 (2010) - DOI: https://doi.org/10.3354/meps08734 Microbial communities of subtidal shallow sandy sediments change with depth and wave disturbance, but nutrient exchanges remain similar Hugh I. Forehead1,2,3,*, Peter A. Thompson1 1CSIRO Division of Marine and Atmospheric Research, GPO Box 1538, Hobart, Tasmania 7001, Australia 2School of Plant Biology, 35 Stirling Highway, Crawley, Western Australia 6009, Australia 3Present address: Cellana LLC, 73-4460 Queen Kaahumanu Highway, Kailua-Kona, Hawaii 97640, USA *Email: hforehead8@gmail.com ABSTRACT: Along 3 replicate transects, sediments were sampled from a subtidal sandbank in Cockburn Sound, Western Australia, at 4 depths: 1.5, 4 and 8 m and at 14 m on the flat at the base of the bank. Pulse amplitude modulated (PAM) fluorescence, fluxes of oxygen and inorganic nutrients, N2 fixation and denitrification were measured and sediments analysed for granulometry, pigments, fatty acids, neutral lipids, organic C and total N. There were 2 functional depth zones: 1.5 ~ <4, and ≥4 m. At 1.5 m, chl a concentration was 42.3 mg m–2 (1.83 SE, n = 12), sediments were net heterotrophic, and there were effluxes of inorganic nutrients in the light and uptake in the dark. The 2 intermediate depths had benthic microalgal (BMA) biomass around 88 mg m–2 chl a, and mean gross primary productivity of 2.23 mmol O2 m–2 h–1. At 14 m, chl a concentration was 75 mg m–2, and sediments were net autotrophic. Sediment–water exchanges of inorganic nutrients were dominated by NH4, with maximum efflux from the sediment (1044 µmol m–2 d–1) at 8 m and maximum uptake (539 µmol m–2 d–1) at 4 m. At 1.5 m depth, there was a marked discontinuity in most parameters as the microbial community metabolism and cycling of nutrients between the sediment and water column were altered in conditions of more frequent wave disturbance. At depths ≥4 m, we observed greater amounts of biomass and more primary productivity, but net exchanges of inorganic nutrients were remarkably consistent at all depths from 1.5 to 14 m. KEY WORDS: Microphytobenthos · Benthic microalgae · Biomarkers · Lipids · Pigments · Biogeochemistry · Resuspension Full text in pdf format Supplementary material PreviousNextCite this article as: Forehead HI, Thompson PA (2010) Microbial communities of subtidal shallow sandy sediments change with depth and wave disturbance, but nutrient exchanges remain similar. Mar Ecol Prog Ser 414:11-26. https://doi.org/10.3354/meps08734Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 414. Online publication date: September 13, 2010 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2010 Inter-Research.