Recent Eutrophication in the Southern Basin of Lake Petén Itzá, Guatemala: Human Impact on a Large Tropical Lake
Recent Eutrophication in the Southern Basin of Lake Petén Itzá, Guatemala: Human Impact on a Large Tropical Lake
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危地马拉佩滕伊察湖南部盆地最近的富营养化：人类对大型热带湖泊的影响
DOI：
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发表时间：
2004
期刊：
影响因子：
2.6
通讯作者：
Christine A. M. Taylor
中科院分区：
文献类型：
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作者：
M. Rosenmeier;M. Brenner;W. Kenney;T. J. Whitmore;Christine A. M. Taylor
一个来自危地马拉Petén Itzá湖南部盆地一个小海湾的210Pb年代沉积物岩心记录了最近的文化富营养化。泥沙堆积增加始于公元1930年的∼，与集水区人口增长相吻合，是分水岭砍伐森林和增加地表径流的结果。与此同时，Petén Itzá沉积物岩心的地球化学记录表明，磷负荷和有机质积累增加。公元1965年后的高营养盐浓度与较低的沉积物C/N比相吻合，表明浮游植物对有机质池的相对贡献增加。富营养化和富营养化硅藻种类的优势度证实了这一结论。有机质δ13C值在公元1965年后下降，似乎与佩特恩伊塔湖南部盆地近期富营养化的其他指标相矛盾。然而，最近沉积物中相对贫化的δ13C值可能反映了13C耗尽的污水流出物的贡献。1965年后有机质δ15N的增加表明输送到湖泊中的溶解无机氮发生了变化。相对较小的δ15N(∼0.6‰)的增加小于污水和土壤中硝酸盐负荷的预期，并可能被低δ15N值的固氮蓝藻的存在所抵消。
A 210Pb-dated sediment core from a small bay in the southern basin of Lake Petén Itzá, Guatemala documents recent cultural eutrophication. Increased sediment accumulation beginning ∼1930 A.D. coincided with catchment population growth and was a consequence of watershed deforestation and increased surface run-off. At the same time, geochemical records from the Lake Petén Itzá sediment core indicate increased phosphorus loading and organic matter accumulation. High nutrient concentrations after 1965 A.D. coincided with lower sediment C/N ratios, suggesting an increase in the relative contribution of phytoplankton to the organic matter pool. This inference is confirmed by the dominance of eutrophic and hypereutrophic diatom species. Organic matter δ13C values decreased after 1965 A.D., seemingly contradicting other indicators of recent eutrophication in the southern basin of Lake Petén Itzá. Relatively depleted δ13C values in recent sediments, however, may reflect a contribution from 13C-depleted sewage effluent. Increased δ15N of organic matter after 1965 A.D. indicates changes in the dissolved inorganic nitrogen delivered to the lake. The relatively small increase in δ15N (∼0.6‰ ) is less than might be expected with nitrate loading from sewage and soils, and might be offset by the presence of nitrogen-fixing cyanobacteria with low δ15N values.