VARIATIONS IN CARBON AND NITROGEN CONTENTS DURING DECOMPOSITION OF THREE MACROALGAE INHABITING SANDSPIT BACKWATER, KARACHI

Abstract

Macroalgae constitute a diverse group of photoautotroph contributing to the primary production in the area. It provides food and habitats (directly or indirectly) to many other inhabitants of the marine and coastal communities and hence forms the foundation for food chain prevailing mangrove environment. Variations in carbon and nitrogen content during decomposition of three macroalgal species, viz. Enteromorpha intestinalis, E. clathrata and Ulva reticulata occurring commonly in mangrove environment, were estimated in laboratory using litter bag technique. Known amount of each macroalgal species was decomposed in separate nylon net bags (1 mm2 mesh) incubated in well aerated seawater tanks. Significant increases in organic nitrogen and decreases in total organic carbon content were recorded during decomposition (p-value < .001) for all algal species studied. Macroalgae appear to be a key component in mangrove environment taking part in the release of particulate and dissolved nutrients and hence play very important role in nutrient dynamics and food web.