{"id":223,"date":"2010-01-01T23:26:24","date_gmt":"2010-01-01T23:26:24","guid":{"rendered":"http:\/\/www.reefrelieffounders.com\/science\/?p=223"},"modified":"2010-01-14T23:27:01","modified_gmt":"2010-01-14T23:27:01","slug":"bulletin-of-marine-science-eutrophication-and-trophic-state-classification-of-seagrasses-in-the-florida-keys-by-b-e-lapointe-et-al","status":"publish","type":"post","link":"https:\/\/www.reefrelieffounders.com\/science\/2010\/01\/01\/bulletin-of-marine-science-eutrophication-and-trophic-state-classification-of-seagrasses-in-the-florida-keys-by-b-e-lapointe-et-al\/","title":{"rendered":"Bulletin of Marine Science: Eutrophication and Trophic State Classification of Seagrasses in the Florida Keys by B.E. Lapointe, et. al."},"content":{"rendered":"

Eutrophication<\/a><\/span><\/p>\n

Brian E. Lapointe, David A. Tomasko, and William R. Matzie
\nBulletin of Marine Science, 54(3) 696-717, 1994
\n<\/span>ABSTRACT<\/p>\n

“Cultural eutrophication is the most frequently cited factor correlating with the marked global decline in areal extent and vigor of seagrass communities over the past two decades.” — (Larkum, 1976; Kemp et al.;1983; Cambridge and McComb, 1984; Orth and Moore, 1984; Bourcier, 1986; Siberstein et al., 1986; Valiela et al., 1990; Green et al., 1990, Tomasko and LaPointe, 1991).<\/p>\n

Seagrass communities in the Florida Keys are receiving increased nutrient loadings from a variety of land-based human activities that are accelerating coastal eutrophication.<\/p>\n

We assessed relationships among total nitrogen and total phosphorus concentrations of the water column and the productivity, biomass, and epiphyte levels of the seagrasses,Thalassia testudinum and Halodule wrightii, along three onshore-offshore transects (Key West, Big Pine Key, and Long Key) stratified a priori into hypereutrophic, eutrophic, mesotrophic and oligotrophic communities with increasing distance from shore.<\/p>\n

Macroalgal biomass and alkaline phosphate activity (APA) of macroalgae and attached seagrass epiphytes were also determined along the eutrophication gradients.<\/p>\n

H. Wrightii was the dominant seagrass within inshore hypereutrophic strata whereas T. testudinium was dominant in eutrophic, mesotrophic, and oligotrophic strata.<\/p>\n

Seagrasses at the hypereutrophic and eutrophic strata had low shoot densities, low production rates, low area biomass values, low areal production rates, but high levels of attached epiphytes and mat-forming macroalgae.<\/p>\n

Seagrasses at the oligotrophic strata had the highest shoot densities, highest areal biomass values, highest areal production rates, and typically the lowest or second lowest epiphyte levels of all strata and typically the lowest or second lowest epiphyte levels of all strata.<\/p>\n

Alkaline phosphatase activity was lowest for macroalgae at the offshore oligotrophic strata, and highest at the nutrient-enriched hypereutrophic strata where extensive populations of mat-forming macroalgae occurred.<\/p>\n

Microcosm studies showed that both nitrogen and phosphate enrichment alone increased epiphyte levels and reduced rhizome growth rates in T. Testudinum whereas phosphate enrichment alone in increased epiphyte levels and reduced rhizome growth rates of H. wrightii.<\/p>\n

Higher alkaline photphosphatase activity in macroalgae and attached blade epiphytes in hypereutrophic and eutrophic strata reflected increased phosphate-limitation in these dystrophic environments resulting from high concentrations of total nitrogen relative to total phosphate.<\/p>\n

Sustained nutrient enrichment from land-based activities results in increased biomass of attached epiphytes and macroalgae, which attenuate light, reduce dissolved oxygen, and lead to the decline of T. testudinum and a gradient of damage from nearshore to offshore waters.<\/p>\n","protected":false},"excerpt":{"rendered":"

Eutrophication Brian E. Lapointe, David A. Tomasko, and William R. Matzie Bulletin of Marine Science, 54(3) 696-717, 1994 ABSTRACT “Cultural eutrophication is the most frequently cited factor correlating with the marked global decline in areal extent and vigor of seagrass communities over the past two decades.” — (Larkum, 1976; Kemp et al.;1983; Cambridge and McComb, … Continue reading Bulletin of Marine Science: Eutrophication and Trophic State Classification of Seagrasses in the Florida Keys by B.E. Lapointe, et. al.<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":"","_links_to":"","_links_to_target":""},"categories":[1],"tags":[],"class_list":["post-223","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t