Departamento de Hidrobiología, IRD, Universidad Autonoma Metropolitana Iztapalapa, DCBS, Av San Rafael Atlixco 186, Col Vicentina CP 09340, Iztapalapa, México DF, Mexico.
Mar Pollut Bull. 2010;61(7-12):309-22. doi: 10.1016/j.marpolbul.2010.06.021. Epub 2010 Aug 17.
Considering the growing concern about the impact of anthropogenic inputs on coral reefs and coral reef lagoons, surprisingly little attention has been given to the relationship between those inputs and the trophic status of lagoon waters. The present paper describes the distribution of biogeochemical parameters in the coral reef lagoon of New Caledonia where environmental conditions allegedly range from pristine oligotrophic to anthropogenically influenced. The study objectives were to: (i) identify terrigeneous and anthropogenic inputs and propose a typology of lagoon waters, (ii) determine temporal variability of water biogeochemical parameters at time-scales ranging from hours to seasons. Combined ACP-cluster analyses revealed that over the 2000 km(2) lagoon area around the city of Nouméa, "natural" terrigeneous versus oceanic influences affecting all stations only accounted for less than 20% of the spatial variability whereas 60% of that spatial variability could be attributed to significant eutrophication of a limited number of inshore stations. ACP analysis allowed to unambiguously discriminating between the natural trophic enrichment along the offshore-inshore gradient and anthropogenically induced eutrophication. High temporal variability in dissolved inorganic nutrients concentrations strongly hindered their use as indicators of environmental status. Due to longer turn over time, particulate organic material and more specifically chlorophyll a appeared as more reliable nonconservative tracer of trophic status. Results further provided evidence that ENSO occurrences might temporarily lower the trophic status of the New Caledonia lagoon. It is concluded that, due to such high frequency temporal variability, the use of biogeochemical parameters in environmental surveys require adapted sampling strategies, data management and environmental alert methods.
考虑到人们对人为输入物对珊瑚礁和珊瑚礁泻湖的影响越来越关注，但令人惊讶的是，人们对这些输入物与泻湖水质营养状态之间的关系关注甚少。本文描述了新喀里多尼亚珊瑚礁泻湖的生物地球化学参数分布情况，据称那里的环境条件从原始贫营养到人为影响的范围都有。本研究的目的是：(i) 确定陆源和人为输入物，并提出泻湖水质的分类法，(ii) 确定从小时到季节时间尺度的水生物地球化学参数的时间可变性。联合 ACP-聚类分析表明，在努美阿市周围 2000 平方公里的泻湖区域，“自然”陆源和海洋影响所有站点的影响仅占空间变异性的不到 20%，而 60%的空间变异性可归因于少数近岸站点的严重富营养化。ACP 分析能够明确区分沿离岸-近岸梯度的自然营养富集和人为引起的富营养化。溶解无机养分浓度的高时间可变性强烈阻碍了它们作为环境状况指标的使用。由于周转时间较长，颗粒有机物质，特别是叶绿素 a，似乎是营养状态的更可靠的非保守示踪剂。结果进一步证明，ENSO 事件可能会暂时降低新喀里多尼亚泻湖的营养状态。因此得出结论，由于这种高频时间可变性，在环境调查中使用生物地球化学参数需要采用适应性采样策略、数据管理和环境警报方法。
