University of South Florida, College of Marine Science, St. Petersburg, Florida, United States of America.
University of South Florida, College of Marine Science, St. Petersburg, Florida, United States of America.
Harmful Algae. 2022 Aug;117:102289. doi: 10.1016/j.hal.2022.102289. Epub 2022 Jul 19.
Harmful algal blooms of the toxic dinoflagellate Karenia brevis occur almost annually on the West Florida Shelf (WFS) of the eastern Gulf of Mexico. To date, however, comprehensive assessments of K. brevis bloom spatial extent and temporal occurrence are lacking due to limitations in the two primary bloom monitoring techniques: microscopy evaluation of field-collected water samples and satellite remote sensing of ocean color. This is despite community efforts in expanding sampling coverage statewide and developing remote sensing algorithms to interpret color changes of surface waters. In this work, an approach is developed to combine the strengths of both techniques to estimate mean bloom occurrence frequency and bloom intensity as well as bloom extent at weekly, bi-weekly, monthly, and annual intervals between 2003 and 2019. Here, due to technical constraints on ocean color remote sensing, a bloom is defined as waters with K. brevis concentrations greater than 1.5 × 10 cells L. While microscopy examination of surface water samples provides K. brevis cell concentrations to help delineate bloom locations from Moderate Resolution Imaging Spectrometer on Aqua (MODIS/A) images, the imagery provides far more synoptic and frequent observations to make the bloom characterization statistically meaningful. Such derived bloom statistics often show bloom patterns that are not always known previously or at the time of the event, and in some years, they also differ from those determined from microscopic taxonomy data alone. For example, in terms of bloom size, two major bloom periods are observed in 2005 - 2007 and 2014 - 2018, respectively, when annual cumulative bloom size exceeded ∼50,000 km. While preliminary in nature, the approach and results from this work may represent a first step to integrate water sample analysis and satellite remote sensing towards an improved characterization of K. brevis blooms on the WFS.
有毒甲藻凯伦藻的有害藻华几乎每年都会在墨西哥湾东部的西佛罗里达架（WFS）发生。然而，由于两种主要的藻华监测技术的限制，对凯伦藻藻华的空间范围和时间发生情况仍缺乏全面评估：现场采集水样的显微镜评估和海洋颜色的卫星遥感。尽管全州范围内扩大采样覆盖范围和开发遥感算法以解释地表水颜色变化的社区努力，但情况仍然如此。在这项工作中，开发了一种方法来结合这两种技术的优势，以估计 2003 年至 2019 年间每周、每两周、每月和每年的平均藻华发生频率、藻华强度和藻华范围。在这里，由于海洋颜色遥感的技术限制，藻华定义为凯伦藻浓度大于 1.5×10 个细胞 L 的水域。虽然对地表水样本进行显微镜检查可以提供凯伦藻细胞浓度，以帮助从 Aqua（MODIS/A）上的中分辨率成像光谱仪（MODIS/A）图像中区分藻华位置，但图像提供了更多的同步和频繁的观测，以使藻华特征具有统计学意义。这种衍生的藻华统计数据通常显示出以前或事件发生时并不总是已知的藻华模式，而且在某些年份，它们也与仅从微观分类学数据确定的模式不同。例如，就藻华规模而言，分别在 2005-2007 年和 2014-2018 年观察到两个主要的藻华期，当时年度累计藻华规模超过约 50,000 km。尽管初步性质，但这项工作的方法和结果可能代表了整合水样分析和卫星遥感以改善 WFS 上凯伦藻藻华特征的第一步。
