An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques
An Assessment of Environmental Changes in Three Lakes from King's County (Nova Scotia, Canada) Using Diatom-Based Paleolimnological Techniques
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DOI：
10.2166/wqrj.2008.012
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发表时间：
2008-05
影响因子：
2
通讯作者：
Joshua R. Thienpont;B. Ginn;B. Cumming;J. Smol
中科院分区：
文献类型：
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作者：
Joshua R. Thienpont;B. Ginn;B. Cumming;J. Smol
210Pb测年。分析表明，每个系统都发生了变化，但跟踪了不同的生态系统变化。塔珀湖和乔治湖记录了变化，这可能主要与气候变暖有关，硅藻组合从工业化前由Aulacoseira spp.的优势转变。到现在由星环藻主导的地位。除了最近与气候有关的变化外，大约1820年至1970年期间塔珀湖核心的进一步硅藻变化与流域干扰(农业、林业和水电基础设施建设)相吻合。自1950年左右以来，黑河湖记录到硅藻推断的总磷有所增加，这可能是由于黑河水系被蓄水发电以及随后陆地径流的变化所致。对国王郡其他六个湖泊的前后(即自上而下)的沉积物分析提供了进一步的证据，表明该地区正在受到气候变化的影响(Aulacoseira spp.减少，浮游硅藻类群增加)，以及其他环境压力因素(如酸化)。然而，在九个研究湖泊中的任何一个，我们都没有记录到硅藻推断的营养水平与海岸线小屋开发相一致的显著增加。诸如此类的古湖沼学研究使湖泊管理者能够将当前的湖泊状况置于长期背景下，从而为有效的湖泊管理提供重要的背景数据。
210 Pb dating. Analyses showed that each system has changed, but tracked different ecosystem changes. Tupper and George lakes recorded shifts, which are likely primarily related to climatic warming, with diatom assemblages changing from a preindustrial dominance by Aulacoseira spp. to present-day dominance by Cyclotella stelligera. In addition to the recent climatic-related changes, further diatom changes in the Tupper Lake core between approximately 1820 and 1970 were coincident with watershed disturbances (farming, forestry, and construction of hydroelectric power infrastructure). Black River Lake has recorded an increase in diatom-inferred total phosphorus since about 1950, likely due to impoundment of the Black River system for hydroelectric generation and subsequent changes in land runoff. Before-and-after (i.e., top-bottom) sediment analyses of six other lakes from King’s County provided further evidence that the region is being infl uenced by climatic change (decreases in Aulacoseira spp., increases in planktonic diatom taxa), as well as showing other environmental stressors (e.g., acidifi cation). However, we recorded no marked increase in diatom-inferred nutrient levels coincident with shoreline cottage development in any of the nine study lakes. Paleolimnological studies such as these allow lake managers to place the current limnological conditions into a long-term context, and thereby provide important background data for effective lake management.