Relative impact of a seagrass bed and its adjacent epilithic algal community in consumer diets

Marine Pollution Bulletin

Vangeluwe

Eisinger

et al. 2004

A 15 N tracer study was performed during an experimental transplantation trial of natural Posidonia oceanica cuttings. The experiment was done in situ at 17 m depth in the Revellata Bay (Calvi, NW Corsica, France). Despite high survival rates of transplants (>90%) after one year, the weight and the N content of transplants are significantly lower than those of reference plants. In absence of roots, the transplants are not able to meet their N requirement because, leaf uptake is insufficient to replenish the N lost during the natural leaf decay. This could constitute a major cause of long-term failure for transplantation experiments or natural re-colonisation processes. The increase of the 15 N content in the roots shows that the plant re-allocates the nitrogen of one organ (i.e. leaves, rhizomes) to ensure the growth of another (i.e. roots).

Section: Discussionmentioning

confidence: 99%

“…In the Revellata Bay, the natural 15 N abundance in P. oceanica leaves is 0.36 ± 0.005% 15 N (i.e. +2.6‰ in δ 15 N notation) and does not show a clear seasonal pattern (Lepoint et al, 2000). We calculate the 15 N content in excess (µg 15 N excess shoot -1 ) using the 15 N abundance in excess and N content.…”

Section: Methodsmentioning

confidence: 99%

Nitrogen dynamics in Posidonia oceanica cuttings: implications for transplantation experiments

Marine Pollution Bulletin

Vangeluwe

Eisinger

et al. 2004

“…Kharlamenko et al, 2001;Stephenson et al, 1986), in Mediterranean meadows (e.g. Dauby, 1989;Jennings et al, 1997;Lepoint et al, 2000;Pinnegar and Polunin, 2000;, and in subtropical and tropical meadows (e.g. Fry, 1984;Kitting et al, 1984;Loneragan et al, 1997;Marguillier et al, 1998;Melville and Connolly, 2003;Moncrieff and Sullivan, 2001).…”

Section: Food Web Integratorsmentioning

confidence: 99%

Applications of C and N stable isotopes to ecological and environmental studies in seagrass ecosystems

Marine Pollution Bulletin

Dauby

Gobert

2004

101

Stable isotopes of carbon and nitrogen are increasingly used in marine ecosystems, for ecological and environmental studies. Here, we examine some applications of stable isotopes as ecological integrators or tracers in seagrass ecosystem studies. We focus on both the use of natural isotope abundance as food web integrators or environmental tracers and on the use of stable isotopes as experimental tools. As ecosystem integrators, stable isotopes have helped to elucidate the general structure of trophic webs in temperate, Mediterranean and tropical seagrass ecosystems. As environmental tracers, stable isotopes have proven their utility in sewage impact measuring and mapping. However, to make such environmental studies more comprehensible, future works on understanding of basic reasons for variations of N and C stable isotopes in seagrasses should be encouraged. At least, as experimental tracers, stable isotopes allow the study of many aspects of N and C cycles at the scale of a plant or at the scale of the seagrass ecosystem.

“…In some habitats, studies were made and clear associations between detritus and meiofauna assemblages were established, such as in mangrove leaf litter (Gee and Somerfield, 1997;Gwyther, 2003;Torres-Pratts and Schizas, 2007) or in terrestrial forest (Dumont and Maas, 1988;Fiers and Ghenne, 2000). In seagrass ecosystems, food webs are mainly seen as detrital (Duarte and Cebrian, 1996;Mateo and Romero, 1997;, but many potential food sources coexist (Lepoint et al, 2000). No study, to our current knowledge, was ever performed on the harpacticoid copepod assemblage associated with seagrass macrophytodetritus.…”

Section: Introductionmentioning

confidence: 99%

Seasonal variability of meiofauna, especially harpacticoid copepods, in Posidonia oceanica macrophytodetritus accumulations

Mascart

Journal of Sea Research

Deschoemaeker

et al. 2015

The overall aim of this study was (1) to assess the diversity and density of meiofauna taxa, especially harpacticoid copepod species, present within accumulated seagrass macrophytodetritus on unvegetated sand patches and (2) to elucidate the community structure of detritus-associated harpacticoid copepods in relation to natural temporal variability of physico-chemical characteristics of accumulations. This was investigated in a Posidonia oceanica (L.) Delile seagrass ecosystem in the northwest Mediterranean Sea (Bay of Calvi, Corsica, 42°35′N, 8°43′E) using a triplicate macrophytodetritus core field sampling in two contrasting sites over the four seasons of 2011. Meiofauna higher taxa consisted of 50% Copepoda, of which 87% belonged to the Harpacticoida order. Nematoda was the second most abundant taxa. The copepod community displayed a wide variety of morphologically similar and ecologically different species (i.e. mesopsammic, phytal, phytal-swimmers, planktonic and parasitic). The harpacticoid copepod community followed a strong seasonal pattern with highest abundances and species diversity in May-August, revealing a link with the leaf litter epiphyte primary production cycle. Aside from the important role in sheltering, housing and feeding potential of macrophytodetritus, a harpacticoid community BEST analysis demonstrated a positive correlation with habitat complexity and a negative correlation with water movements and P. oceanica leaf litter accumulation.