ISSN:
1573-2932
Keywords:
Ruppia cirrhosa
;
epiphyte slime
;
oxygen
;
sulphide
;
disturbance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Energy, Environment Protection, Nuclear Power Engineering
Notes:
Abstract The relationship between macrophyte cover and benthic fluxes of oxygen, nutrients and sulphide has been examined in a shallow fishpond with a nearly homogeneous meadow of Ruppia cirrhosa (Petagna) Grande (Bassin d'Arcachon, western France). In 1993 and 1994, benthic fluxes were measured in early and late summer. These periods were selected to represent the production and decay phases of Ruppia in order to determine the effect on benthic processes. Benthic fluxes of elements were measured by means of multiple dark and light benthic chambers in the presence or absence of community components. In summer 1994, at the end of the incubation period, profiles of acid volatile sulphide (AVS) and chromium reducible sulphur (CRS) were measured also in the 0-5 cm sediment horizon in cores withdrawn from the dark benthic chambers and from the sediment outside the chambers. Oxygen production and consumption were closely related to macrophyte cover, whilst the contributions of plankton and microphytobenthic communities were less significant. In the water column, dissolved inorganic nutrients were almost totally depleted, while dissolved organic nitrogen attained concentrations up to 200 µM. In late summer, Ruppia biomass underwent a significant decay due to the build up of a thick epiphyte layer, mostly around floating leaves. The epiphyte slime was rich in labile organic matter, the decomposition of which led to a significant oxygen uptake as well as to sulphide production. Therefore, we postulate that epiphyte growth can cause disturbance in the aquatic system keeping dissolved sulphide at very high levels. Biogeochemical reactions, such as precipitation of iron sulphide, can exert a control lowering the amplitude of such disturbances.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1018312127829
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