0000000000958058
AUTHOR
R. H. Michener
The role and contribution of the seagrass Posidonia oceanica (L.) Delile organic matter for secondary consumers as revealed by carbon and nitrogen stable isotope analysis
The δ13C and δ15N values of primary producers and consumers were studied to obtain information on the trophic role of Posidonia oceanica L. Delile, the dominant primary producer, in a Mediterranean shallow environment (the Stagnone di Marsala, western Sicily). δ13C strongly discriminated between pelagic and benthic pathways, with the former based on phytoplankton and the latter on a mixed pool of seagrass detritus, epiphytes and benthic algae as carbon sources. A particularly important trophic role appears to be performed by the vegetal epiphytic community on seagrass leaves (δ13C = -14.9 ± 0.1‰), which supports most of the faunal seagrass community (i.e. Amphipoda, Isopoda, Tanaidacea; δ13…
The Use of Carbon Stable Isotopes to Investigate the Origin and Distribution of Suspended and Sedimentary Organic Matter in a Semi-enclosed Mediterranean Marine System
The natural stable isotope values of different primary sources have been used to trace the fate of organic carbon that enters in the marine food webs of Stagnone di Marsala (Italy). Water and sediment samples were collected monthly (March 1996 – February 1997) at 3 stations, characterized by different amounts of vegetal cover and analysed to determine total organic matter (OM), phytopigments, biopolymeric organic carbon (BPC) and stable carbon isotopic composition (δ13C), the latter measured also in main primary producers. Sedimentary OM accumulated in summer, while total suspended organic matter reached highest concentrations in May and December. The concentration of chlorophyll-a carbon i…
The trophic role of the macrophyte Cymodocea nodosa (Ucria) Asch. in a Mediterranean saltworks: Evidence from carbon and nitrogen stable isotope ratios
A multiple stable isotope analysis (δ13C and δ15N) was used to determine the trophic role of the seagrass Cymodocea nodosa (Ucria) Asch. for consumers in a Mediterranean saltworks. Stable carbon and nitrogen isotope ratios performed on primary producers and consumers in February and July 1999 showed that C. nodosa is not a direct dietary source via grazing. No animal presented carbon values as enriched as the seagrass (-7.8‰). The trophic role of Cymodocea occurs through the detritus route via SOM. Sedimentary organic matter (SOM) (δ13C = -16.5‰) seems to be a mixture of particulate organic matter (δ13C = -19.0‰), algae (δ13C = -18.6‰) and seagrass detritus (δ13C = -7.7‰). The results of a …