The faunal role in the degradation of the common intertidal salt marsh plant Scirpus maritimus

Abstract

The aim of this work was to evaluate the role of different environmental conditions (oxic and anoxic), and the presence of macrofauna and/or meiofauna during the different steps of Scirpus maritimus L. decomposition/mineralization under controlled laboratory conditions. The results showed no significant differences between the anaerobic and the aerobic degradation of plant material, under the presence of bacteria or meiofauna. Nevertheless, under anoxic conditions sediment mineralization was enhanced, with an increase concentration of phosphorus and ammonium in the water phase. Concerning the presence of fauna, results show that, although bacterial activity was responsible for 70% of the S. maritimus leaves degradation, the presence of macrofauna together with meiofauna enhanced the leaves mineralization up to 90%. Moreover, the presence of macrofauna together with meiofauna significantly affected the decomposition of phosphorus and of nitrogen, as well as the leaves lesser labile structural parts, by increasing the mineralization of plant carbon, and raised the nutrient turnover within the system.The present study reinforces the functional link between fauna levels on the nutrient dynamics in salt marshes ecosystems, namely at the vegetation detritus/water column interface.

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

“…The macrophytodetritus host many organisms which can participate in the degradation of this organic material, such as bacteria, fungi, diatom microalgae and invertebrates (Danovaro, 1996;Danovaro et al, 2002;Gallmetzer et al, 2005;Graca, 2001;Mancinelli and Rossi, 2002). Especially motile macro-(N 1 mm) and meiofauna (38 μm-1 mm) invertebrates were revealed to be important in the shredding, degrading and decomposing of the organic wrack (Hyndes and Lavery, 2005;Lillebo et al, 2007;Mancinelli and Rossi, 2002;Vetter, 1995;Wittman et al, 1981).…”

“…Meiofauna are said to play an important role in the degradation of leaf litter (Hyndes and Lavery, 2005;Lillebo et al, 2007). 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).…”

Mercury mobility in a salt marsh colonised by Halimione portulacoides

“…Biological productivity, hydrologic flux regulation, biogeochemical cycling of metals and nutrients and habitat for fish and wildlife, are among the several essential ecological functions supported by these ecosystems. (Richardson, 1999;Mitsch and Gosselink, 2000;Caçador et al, 2007;Lillebø et al, 2007;Reboreda and Caçador, 2007). Due to strategic and economical reasons, most of the large cities around the world are located along or nearby estuaries and, as a consequence, and until recently, salt marshes have become subjected to large inputs of contaminants, namely metals derived from urban and industrial effluents which contribute to their vulnerability.…”

Phytoremediation of cadmium by the facultative halophyte plant Bolboschoenus maritimus (L.) Palla, at different salinities

“…The environmental conditions given for the development of B. maritimus, in the greenhouse experiment, allowed also the growth of microorganisms in the water. The presence of microorganisms and meiofauna may be responsible for B. maritimus leaves degradation and mineralization (Lillebø et al 2007). Furthermore, there were probably microorganisms symbiotically associated with the plants, despite their careful cleaning both at the collection site and in the laboratory.…”