Effects of elevated CO2 and nutrients on the community metabolism of a Cymodocea nodosa bed

Authors : Faisal KHAN, Ana ALEXANDRE, Hadayet ULLAH, Rui SANTOS

Pages : 250-257

View : 17 | Download : 8

Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :We assessed the combined effects of elevated CO2 and nutrients on the metabolism of a benthic community dominated by the seagrass Cymodocea nodosa insert ignore into journalissuearticles values(Ucria); Ascherson in a mesocosm experiment. C. Nodosa plants and their associated community were exposed to two CO2 levels simulating future insert ignore into journalissuearticles values(700 ppm, pH 7.84); and current insert ignore into journalissuearticles values(360 ppm, pH 8.12); conditions, and two nutrient levels insert ignore into journalissuearticles values(enriched and ambient concentration); in a total of four treatments insert ignore into journalissuearticles values(-C-N, -C+N, +C-N, +C+N);. Net community production insert ignore into journalissuearticles values(NCP); was estimated from changes in the concentration of dissolved inorganic carbon in the seawater in light incubations using benthic chambers. The variation pattern of NCP with the ordinance was consistent for all treatments. Although differences among treatments were not statistically significant, average NCP values were lowest under CO2 enrichment conditions. NCP was lower at a high CO2 level and ambient nitrogen concentration compared to when nutrient availability was higher, suggesting that the low nutrient availability may modulate the community response to CO2 enrichment. The results obtained suggest that the stimulation of the net community production of C. Nodosa by elevated CO2 concentrations may be curtailed by low nutrient availability.
Keywords : CO2 enrichment, net community production, nutrients, seagrass