Sea Education Association, P.O. Box 6, Woods Hole, Massachusetts 02543, United States.
Environ Sci Technol. 2014 May 6;48(9):4732-8. doi: 10.1021/es4053076. Epub 2014 Apr 24.
We present an extensive survey of floating plastic debris in the eastern North and South Pacific Oceans from more than 2500 plankton net tows conducted between 2001 and 2012. From these data we defined an accumulation zone (25 to 41 °N, 130 to 180 °W) in the North Pacific subtropical gyre that closely corresponds to centers of accumulation resulting from the convergence of ocean surface currents predicted by several oceanographic numerical models. Maximum plastic concentrations from individual surface net tows exceeded 10(6) pieces km(-2), with concentrations decreasing with increasing distance from the predicted center of accumulation. Outside the North Pacific subtropical gyre the median plastic concentration was 0 pieces km(-2). We were unable to detect a robust temporal trend in the data set, perhaps because of confounded spatial and temporal variability. Large spatiotemporal variability in plastic concentration causes order of magnitude differences in summary statistics calculated over short time periods or in limited geographic areas. Utilizing all available plankton net data collected in the eastern Pacific Ocean (17.4 °S to 61.0 °N; 85.0 to 180.0 °W) since 1999, we estimated a minimum of 21,290 t of floating microplastic.
我们对 2001 年至 2012 年间在北太平洋东部和南太平洋进行的 2500 多次浮游生物拖网调查中的漂浮塑料碎片进行了广泛调查。根据这些数据，我们在北太平洋副热带环流中定义了一个积累区（25 至 41°N，130 至 180°W），该区域与几个海洋数值模型预测的海洋表面流汇聚导致的积累中心非常吻合。单个表层拖网的最大塑料浓度超过 10^6 个/km^2，浓度随与预测积累中心距离的增加而降低。在北太平洋副热带环流之外，塑料浓度的中位数为 0 个/km^2。我们无法检测到数据集中存在可靠的时间趋势，这可能是由于空间和时间变化的相互影响。塑料浓度的大时空变化导致在短时间内或在有限的地理区域内计算的汇总统计数据的数量级差异。利用自 1999 年以来在东太平洋（17.4°S 至 61.0°N；85.0°W 至 180.0°W）收集的所有可用浮游生物网数据，我们估计漂浮的微塑料至少有 21290 吨。
