Seasonal responses of a fringing reef community to eutrophication (Reunion Island, Western Indian Ocean)
Seasonal responses of a fringing reef community to eutrophication (Reunion Island, Western Indian Ocean)
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岸礁群落对富营养化的季节性反应（留尼汪岛，西印度洋）
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发表时间：
1993
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通讯作者：
O. Nairn
中科院分区：
文献类型：
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作者：
O. Nairn
研究了受富营养化海底地下水排放影响的退化边缘礁底栖生物群落组成的季节变化。从12月到2月(旺季)，藻类主导着底栖、过度生长的硬珊瑚：19%的硬珊瑚在研究区域死亡，其中16%被藻类覆盖(草皮主要由Ceramiales、Dictyosphaeria setchellii和结壳珊瑚藻类组成)，3%被漂白并随后死亡。在定性评估中，粗江江豚似乎是礁滩上珊瑚过度生长和死亡的一个主要因素。藻类组成在丰度和优势度上表现出很强的季节性变化。藻类群落的变化与两个环境因素高度相关：(1)3月份出现间歇性信风，与大型肉质藻相被岩生藻相取代相关；(2)11月平静，与水域变暖有关，与大型肉质藻类的增加有关，能够过度生长许多底质。因此，在炎热的季节，水文条件造成富营养化条件，促进藻类生长，同时降低珊瑚的活力。因此，这是珊瑚群落在富营养化条件下生长的最关键时期。
Seasonal changes in benthic community composition were investigated on a degraded fringing reef subject to nutrient-enriched submarine groundwater discharge. From December to February (hot season), algae dominate the benthic commuruty, overgrowing scleractinians: 19 % of hard corals died in the studied area, of which 16 % were overgrown by algae (turfs mostly composed of Ceramiales, Dictyosphaeria setchellii and encrusting coralline algae) and 3 % were bleached and subsequently died. In a qualitative assessment, the rhodophyte Gracilaria crassa appeared to be a major factor in the overgrowth and mortality of corals on the reef flat. Algal components displayed strong seasonal variation in abundance and dominance. Changes in the algal community are highly correlated with 2 environmental factors : (1) early onset of intermittent trade winds in March, correlated with replacement of large fleshy algal facies by lithophytic algal facies and (2) calm conditions in November, associated with warming of the waters, correlated with an increase in large fleshy algae capable of overgrowing many substrata. Thus, during the hot season, hydrological conditions cause eutrophic conditions and enhance algal growth while reducing coral vitality. Therefore, this is the most critical period for a coral community growing in eutrophic conditions.