Macroalgae reveal nitrogen enrichment and elevated N:P ratios on the Belize Barrier Reef

MARINE POLLUTION BULLETIN

卷:171

Article

Lapointe, Brian E.¹  Tewfik, Alexander²  Phillips, Myles² 

[1] Florida Atlantic Univ, Oceanog Inst, Harbor Branch, 5600 US 1 North, Ft Pierce, FL 34946 USA

[2] Wildlife Conservat Soc, Belize Program, POB 768,1755 Coney Dr,2nd Floor, Belize City, Belize

关键词: Eutrophication;    Coral reefs;    Macroalgae;    Nitrogen;    Phosphorus;    Stable isotopes;   

DOI  :  10.1016/j.marpolbul.2021.112686

来源: Elsevier

【 摘 要 】

Macroalgal blooms are increasing on the Belize Barrier Reef (BBR) as scleractinian coral cover declines. Although some have attributed this to reduced grazing, the role of land-based nutrient pollution has not been assessed. Nutrient enrichment was quantified through macroalgal tissue analysis from Belize City to the offshore fore reef and at several central BBR lagoon sites. These recent data were compared to baseline data from the 1980s. Significant nearshore-to-offshore gradients of %N, %P and delta C-13 in macroalgae all indicated land-based sources of these nutrients. Macroalgal delta N-15 values were generally enriched in nearshore waters where values matched those reported for human sewage. Notably, the N:P ratios of recent macmalgae measurements were elevated at all sites, more than two-fold higher than values from the 1980s (similar to 30: 1 to 70:1). These results support the hypothesis that nitrogen enrichment from land-based sources has increased phosphorus limitation driving macroalgal blooms and coral stress on the BBR.

【 授权许可】

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