title: EFFECTS OF NUTRIENT ENRICHMENT ON PRIMARY PRODUCTION AND BIOMASS OF SEDIMENT MICROALGAE IN A SUBTROPICAL SEAGRASS BED(1).
abstract: Eutrophication of coastal waters often leads to excessive growth of microalgal epiphytes attached to seagrass leaves; however, the effect of increased nutrient levels on sediment microalgae has not been studied within seagrass communities. A slow-release NPK Osmocote fertilizer was added to sediments within and outside beds of the shoal grass Halodule wrightii, in Big Lagoon, Perdido Key, Florida. Gross primary production (GPP) and biomass (HPLC photopigments) of sediment microalgae within and adjacent to fertilized and control H. wrightii beds were measured following two 4-week enrichment periods during June and July 2004. There was no effect of position on sediment microalgal GPP or biomass in control and enriched plots. However, nutrient enrichment significantly increased GPP in both June and July. These results suggest that sediment microalgae could fill some of the void in primary production where seagrass beds disappear due to excessive nutrient enrichment. Sedimentary chl a (proxy of total microalgal biomass) significantly increased only during the June enrichment period, whereas fucoxanthin (proxy of total diatom biomass) was not increased by nutrient enrichment even though its concentration doubled in the enriched plots in June.
authors.affiliation: University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, Alabama 35294, USASt. Andrew's North Campus, 370 Old Agency Rd., Ridgeland, Mississippi 39157, USACatfish Genetics Research Unit, USDA/ARS/MSA, PO Box 38,141 Experimental Station Road, Stoneville, Mississippi 38776, USA.
authors.forename: Philip
authors.initials: P
authors.lastname: Bucolo
authors.affiliation: University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, Alabama 35294, USASt. Andrew's North Campus, 370 Old Agency Rd., Ridgeland, Mississippi 39157, USACatfish Genetics Research Unit, USDA/ARS/MSA, PO Box 38,141 Experimental Station Road, Stoneville, Mississippi 38776, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Sullivan
authors.affiliation: University of Alabama at Birmingham, 1300 University Boulevard, Birmingham, Alabama 35294, USASt. Andrew's North Campus, 370 Old Agency Rd., Ridgeland, Mississippi 39157, USACatfish Genetics Research Unit, USDA/ARS/MSA, PO Box 38,141 Experimental Station Road, Stoneville, Mississippi 38776, USA.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Zimba
keywords: Halodule wrightii; eutrophication; fucoxanthin; gross primary production; seagrass; sediment microalgae