Tuesday, September 24, 2019

Fish Killing Algae Essay Example | Topics and Well Written Essays - 500 words

Fish Killing Algae - Essay Example The specific consideration within the article is ten fish mortality events that occurred, primarily involving Atlantic menhaden fish, between July through September 2000 in Delaware, USA. While thermal imaging revealed the occurrence of harmful algae during the 1987 North Carolina incident, such imaging was not successful in detecting elements of the 2000 occurrences. Still, a variety of boaters and residents from the area consistently reported the occurrence of the harmful toxins. There were approximately 2 million dead fish identified in one region, Bald Creek. These fish were examined and they revealed no major lesions. The reason given for the death of these fish was attributed to a lack of dissolved oxygen in the water. While a lack of dissolved oxygen was given as a major consideration in the fish deaths, further examination was conducted. Samples from two of these events were sent to a laboratory for analysis. These samples were taken on August 17th and August 18th. Both of these samples were examined within a twenty-hour period following their extraction. In addition to these samples, live samples were extracted at a later period. The collection of the samples were sent to the Center for Marine Science (CMS) and examined. Ultimately, the complete set of these samples were archived, including both preserved and unpreserved sampled. This constituted the first stage of the analysis. This analysis demonstrated that in addition to the low dissolved oxygen rates there was a phytoplankton bloom dominated by Chattonella cf. verruculosa. Still, the samples from the DNREC area that were collected did not demonstrate the presence of toxic species.The next stage of the research implemented microscopic examin ation of the samples from the fish kill site. These examinations demonstrated that the fish contained a single-cell Raphidophyte alga Chattonella cf. verruculosa. Additionally, naturally occurring brevetoxins were detected in the microscopic fish samples. The next stage of the investigation involved chromatographic, immunochemical, and spectroscopic analyses. These analyses confirmed the presence of brevetoxins. Notably, this was the first confirmed report of these toxins in the area. The analyses continued testing the water for the presence of these materials. By October the study revealed that there was no longer a presence of verruculosa in the area. These findings demonstrated that it is necessary to continually monitor the waters as a means of ensuring they are free from harmful brevetoxins.

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