Sediment features, macrozoobenthic assemblages and trophic relationships (δ13C and δ15N analysis) following a dystrophic event with anoxia and sulphide development in the Santa Giusta lagoon (western Sardinia, Italy)

6533b7d4fe1ef96bd12633ea

RESEARCH PRODUCT

Sediment features, macrozoobenthic assemblages and trophic relationships (δ13C and δ15N analysis) following a dystrophic event with anoxia and sulphide development in the Santa Giusta lagoon (western Sardinia, Italy)

Antonio Mazzola Gianmarco Giordani G.a. Fenzi G. Van Der Velde G. Van Der Velde Salvatrice Vizzini Sanjeevi Rajagopal J. Kassenberg Paolo Magni

subject

Geologic Sediments Food Chain Animal Ecology and Physiology Oceans and Seas stable isotopes Sulfides Aquatic Science Biology Oceanography Benthos Animals Sedimentary organic matter Seawater Organic matter Anaerobiosis Isotope analysis Trophic level Population Density chemistry.chemical_classification Carbon Isotopes Nitrogen Isotopes Ecology Temperature Detritivore Biodiversity pollution impact Invertebrates Pollution Food web Oxygen Italy chemistry macrofauna benthic communities food webs stable isotopes eutrophication transitional waters food webs organic enrichment Fish kill

description

Macrozoobenthic assemblages and stable carbon (delta C-13) and nitrogen (delta N-15) isotope values of various primary producers (macroalgae and angiosperms) and consumers (macroinvertebrate filter/suspension feeders, deposit feeders, detritivores/omnivores and carnivores and fishes) were studied in the Santa Giusta lagoon (Sardinia, Italy) before (spring) and after (autumn) a dystrophic event which occurred in the summer of 2004. A few days after the dystrophy, the physico-chemical characteristics of sediments and macrozoobenthic assemblages were also investigated. In the latter occasion, high total organic carbon (3.9%) and organic matter (15.9%) contents of surface sediments went together with peaks in Licid-volatile sulphide concentrations. Certain immediate effects were quite extreme, such as the drastic reduction in macrozoobenthos and the massive fish kill in August 2004. Among the macrozoobenthos, there were few individuals or chironomid larvae and Capitella cf. capitata left. However, by October, chironomid larvae were numerous, indicating a lack of predators (e.g. fish) and competitors. In addition, some bivalve species and polychaetes which were absent, or present in small numbers before the event, became relatively numerous. The results are discussed based on a knowledge of the sulphide tolerance of these species. Stable isotope analysis clearly showed that the basal level of the food web for most consumers consisted mainly of macroalgae and sedimentary organic matter, and that the values before and after the dystrophic event were not significantly different from one another. This indicates that the relations among different trophic levels were quickly restored following the dystrophic event. (c) 2007 Elsevier Ltd. All rights reserved.

year	journal	country	edition	language
2007-12-21	Marine Pollution Bulletin

https://doi.org/10.1016/j.marpolbul.2007.10.015