Temporal changes in the biochemical composition and nutritional value of the particulate organic matter available to surface deposit-feeders:a two year study

Abstract

Gross sedimentation rates (GSR) were monitored together with the main characteristics of the collected matenal (i.e. organic content, C, N, total proteins, lipids, carbohydrates, available proteins and amino acids) over a 2 yr cycle at a shallow station (18 m) of the bay of Banyuls, France. In addition, sediment pigment concentrations and meiofaunal densit~es were recorded monthly during a 1 yr period. GSR ranged between 0.6 and 317.8 g DW m ' cl'' Spring and summer were characterized by relatively low and constant GSR whereas fall and wlnter were characterized by relat~vely high and hlghly variable GSR. There was a negatlve relationship between GSR and the organic content of material collected within the sediment traps, suggesting the importance of resuspension in controlling GSR. Growth rates of the deposit-feeding bivalve Abra ovata fed sediment trap material collected on 6 sampling dates were also measured. Significant changes in important nutrient components (e.g. available proteins) of sedimenting materials from these different sampling dates correlated with growth differences and confirmed the existence of temporal changes in the quality of the material collected in the sediment traps. The highest growth rate was obtained for the material collected during May 1993, which coincided with maximal meiofauna densities and maximal pigment concentrations at the surface of the sediment. The best descript.ion of growth was obtained when using available proteins and total lipids as the independent variables of simple linear regression models. This supports the use of these parameters as descriptors of food quality. The consequences of our results on the parameterization of changes in food quality within models of continental shelf food webs are discussed. It is suggested that such changes should be simulated through control functions based on available protein contents.

Core sediment biogeochemistry in specific zones of Cochin Estuarine System (CES)

“…Earlier report suggests the dominance of carbohydrate and lower PRT:CHO ratio is a typical feature of detrital heterotrophic environments (Danovaro 1996). Lipid-carbohydrate ratio (LPD:CHO) showed an average value of 3.3, 2.4, 4.2 and 1.1 in SS 1 , MS 1 , MS 2 and NS 1 cores, respectively, which in turn reflects energetic (food) quality of the organic contents in the study area and well supports the earlier literatures (Gremare et al 1997(Gremare et al , 2002Fabiano and Pusceddu 1998). Elevated value (15.758) was found in MS 2 core at a depth of 21 cm.…”

“…Besides, they are consumed by microheterotops in both fresh water and marine ecosystems and contribute essentially to the bacterial production (Rich et al 1996). Its concentrations have been associated with the most labile fraction of sedimentary organics and it is considered the best descriptor of meiofauna abundance and biomass, over enzymatically hydrolysable aminoacids or protein contents (Gremare et al 1997;Fabiano et al 1995;Gremare et al 2002). Elevated levels of lipid concentration found at three cores (SS 1 , MS 1 and MS 2 ) indicates the biological activity associated with the productive nature of the environment (figure 2).…”

Effects of sediment organic matter quality on bioaccumulation, degradation, and distribution of pyrene in two macrofaunal species and their surrounding sediment

“…Since sedimenting organic matter constitutes an important food source and substrate for benthic macro -and microorganisms, seasonal variations in its quantity and quality affects organism growth, production, metabolism and activity (Smetacek, 1980, Christensen & Kanneworff, 1985, Graf, 1992, Gremare, Amouroux, Charles, Dinet, RiauxGobin, Baudart et al, 1997, Granberg, Hansen & Selck, 2005. Such physiological response due to changes in food value is likely also to affect the absorption, metabolism and general fate of sediment associated contaminants.…”

Temporal Variations of Shallow Subtidal Meiofauna in Los Cristianos Bay (Tenerife, Canary Islands, Ne Atlantic Ocean)

“…Shallow marine meiobenthos are known to vary seasonally with physico-chemical regimes and environmental trophic dynamics (GUIDI-GUILVARD AND BUSCAIL, 1995;DANOVARO, 1996;GRÉMARE ET AL, 1997;ÓLAFSSON AND ELMGREN, 1997). However, one of the main drawbacks in the field is to know how to separate the effects of the different parameters, e.g.…”