Benthic community metabolism in a coastal lagoon ecosystem

Abstract

Measurements of benthic oxygen production and consumption at 3 stations over a n annual cycle in a shallow (mean depth = 0.7 m) coastal lagoon on the Rhode Island (USA) coast provide evidence that shallow benthic communities may consume more organic matter than can b e provided by impressive rates of in situ epifloral production. While sandy sediment areas in Potter Pond lagoon showed a net daytime production of about 140 g C m-* y r l , the more extensive areas of fine-grained sediment did not show any significant amount of net benthic daytime production annually. Moreover when nighttime respiratory costs were included, the lagoon benthos a s a whole showed a net organic consumption of 30 g C m-2 y r l in spite of a net annual daytime production rate of 50 g C mS y r l . Rates of in situ oxygen uptake by fine-grained lagoon sediments in the dark were not separable from those of similar sediments in much deeper (mean = 8.6 m) Narragansett Bay. For the lagoon a s a whole, the benthos consumed about 40 to 5 0 % of the combined primary production by phytoplankton, macrophytes and benthic epiflora. This partitioning is slmilar to that found in deeper, plankton-based systems with completely heterotrophic bottom communities.

Composition of biofouling communities on suspended oyster cultures: an in situ study of their interactions with the water column

“…The oxygen fluxes correspond to those presented by Zuburg & Smaal (1993) for mussels with epifauna, and by Dankers et al (1989), whereas the phosphate fluxes are similar to those measured in the intertidal zone by Prins & Smaal (1994). Conversely, the ammonium fluxes recorded in our study are higher than those in the literature (Nowicki & Nixon 1985, Boucher & Boucher-Rodoni 1988. Furthermore, the high nitrate-nitrite flux we recorded could arise not only from animal excretion but also from nitrification processes.…”

Sulfate reduction, acetate turnover and carbon metabolism in sediments of the Ao Nam Bor mangrove, Phuket, Thailand

“…The upward diffusive flux of 02, driven by benthic primary production, is on a daily basis (assuming a 12 h light period) equivalent to the downward diffusive flux and about half of the core flux in darkness. Studies from other tidal flat areas have reported that the benthic community is largely supported by benthic microalgal primary production (Colijn & de Jonge 1984, Nowicki & Nixon 1985, Kristensen 1993. The role of benthic microalgae is less pronounced in the vegetated mid-and high-intertidal zones based on both chlorophyll a content and the upward diffusive O2 flux (3 to 15 % of diurnal uptake).…”

Inter-annual variations of macrobenthic communities over three decades in a land-locked coastal lagoon (Santo André, SW Portugal)

“…Coastal lagoons are particularly vulnerable to eutrophication, due to the restricted exchange with the adjacent sea and the consequent accumulation of nutrients exported by the river basin (Nowicki and Nixon, 1985;Taylor et al, 1995Taylor et al, , 1999. They are also small systems and are therefore easily disturbed both by natural processes and by pollution or adjacent urban and industrial development (Colombo, 1977;Serpa et al, 2007 and references therein).…”