Using carbon isotopes of bulk sedimentary organic matter to reconstruct the history of nutrient loading and eutrophication in Lake Erie
Using carbon isotopes of bulk sedimentary organic matter to reconstruct the history of nutrient loading and eutrophication in Lake Erie
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DOI：
10.4319/lo.1995.40.5.0918
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发表时间：
1995-07
影响因子：
4.5
通讯作者：
C. Schelske;D. Hodell
中科院分区：
文献类型：
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作者：
C. Schelske;D. Hodell
使用三个核心中的沉积有机C（S13C，）和非磷灰石无机P（NAIP）的V3C测量对伊利湖的湖泊生产率进行了重建。推断的湖泊生产力变化与磷负荷的历史变化有关。 p载荷在森林清理和早期定居后缓慢增加，然后从1940年代末呈指数级增长，从1940年代末到197os，并在1970年代中期后最终减少，以响应为了提高水质而实施的管理实践。同样，NAIP的沉积物积累速率在1940年代和195OS期间迅速增加，在1960年代末和197OS期间达到峰值，然后在1970年代中期后下降。 613C的信号（标准化）归一化，以说明大气中V3C中历史悠久的1.4O/OO耗竭，这反映了沉积物中NAIP积累的反映。我们的结果表明，在1970年代中期，大湖区的古生物生产力达到了峰值，但此后由于P减排计划而下降。 NAIP和613C ORGC的推断趋势是P限制的湖泊系统中预测的趋势，并证明有机C的碳同位素比可以用作大型深层湖中古生物的代理。
Lacustrine productivity in Lake Erie was reconstructed using measurements of V3C of sedimented organic C (S13C,,,) and non-apatite inorganic P (NAIP) in three cores. Inferred changes in lacustrine productivity were related to historic changes in phosphorus loading. P loading increased slowly after forest clearance and early settlement in the late 18OOs, then increased exponentially from the late 1940s to early 197Os, and finally decreased after the mid- 1970s in response to management practices implemented to improve water quality. Similarly, the sediment accumulation rate of NAIP increased rapidly during the 1940s and 195Os, peaked during the late 1960s and early 197Os, and then decreased after the mid-1970s. The signal of 613C,, normalized to account for the historic 1.4o/oo depletion in V3C of atmospheric CO, mirrors that for accumulation of NAIP in sediments. Our results show that paleoproductivity peaked in the lower Great Lakes during the mid- 1970s but has since declined as a result of P abatement programs. Inferred trends for NAIP and 613C Orgc are those predicted in P-limited lacustrine systems and demonstrate that the carbon isotopic ratio of organic C can be used as a proxy for paleoproductivity in large, deep lakes.