Wynne Timothy T, Stumpf Richard P
National Centers for Coastal Ocean Science, National Oceanic and Atmospheric Administration, 1305 East-West Highway, Silver Spring, MD 20910, USA.
Toxins (Basel). 2015 May 12;7(5):1649-63. doi: 10.3390/toxins7051649.
Lake Erie, the world's tenth largest freshwater lake by area, has had recurring blooms of toxic cyanobacteria for the past two decades. These blooms pose potential health risks for recreation, and impact the treatment of drinking water. Understanding the timing and distribution of the blooms may aid in planning by local communities and resources managers. Satellite data provides a means of examining spatial patterns of the blooms. Data sets from MERIS (2002-2012) and MODIS (2012-2014) were analyzed to evaluate bloom patterns and frequencies. The blooms were identified using previously published algorithms to detect cyanobacteria (~25,000 cells mL-1), as well as a variation of these algorithms to account for the saturation of the MODIS ocean color bands. Images were binned into 10-day composites to reduce cloud and mixing artifacts. The 13 years of composites were used to determine frequency of presence of both detectable cyanobacteria and high risk (>100,000 cells mL-1) blooms. The bloom season according to the satellite observations falls within June 1 and October 31. Maps show the pattern of development and areas most commonly impacted during all years (with minor and severe blooms). Frequencies during years with just severe blooms (minor bloom years were not included in the analysis) were examined in the same fashion. With the annual forecasts of bloom severity, these frequency maps can provide public water suppliers and health departments with guidance on the timing of potential risk.
伊利湖是世界上面积第十大的淡水湖，在过去二十年里，有毒蓝藻反复爆发。这些蓝藻爆发对娱乐活动构成潜在健康风险，并影响饮用水处理。了解蓝藻爆发的时间和分布情况，可能有助于当地社区和资源管理者进行规划。卫星数据提供了一种研究蓝藻爆发空间模式的方法。分析了来自MERIS（2002 - 2012年）和MODIS（2012 - 2014年）的数据集，以评估蓝藻爆发的模式和频率。使用先前发表的算法来检测蓝藻（约25,000个细胞/毫升），并对这些算法进行了改进，以考虑MODIS海洋颜色波段的饱和度，从而识别蓝藻爆发情况。图像被整理成10天的合成图像，以减少云层和混合伪影。利用这13年的合成图像来确定可检测到的蓝藻和高风险（>100,000个细胞/毫升）蓝藻爆发的出现频率。根据卫星观测，蓝藻爆发季节在6月1日至10月31日之间。地图显示了所有年份（包括轻度和重度蓝藻爆发）蓝藻爆发的发展模式和最常受影响的区域。以同样的方式研究了仅出现重度蓝藻爆发年份（分析中不包括轻度蓝藻爆发年份）的频率。通过年度蓝藻爆发严重程度预测，这些频率地图可以为公共供水商和卫生部门提供潜在风险时间方面的指导。
