Water quality assessment in the coastal zone of Campeche, southeastern Gulf of Mexico

Abstract

The purpose of this study was to assess the water quality at several sites with anthropogenic impact in the southeastern Gulf of Mexico. Eight sites at 3 coastal localities with different kinds of anthropogenic activity were monitored in September and November 2016. Water temperature, salinity, pH, dissolved oxygen, inorganic nutrients, heavy metals in sediments, fecal coliforms and phytoplankton abundance were determined. The pH values and the dissolved oxygen suggested a predominance of photosynthetic activity. Elevated nutrient contents were associated with sites of rainwater discharge with anthropogenic activities, as well as with biogeochemical processes. Inorganic nutrients, especially ammonium, nitrites and nitrates, heavy metals, and phytoplankton abundance showed influences of anthropogenic factors and can be considered indicators of water quality, although fecal coliforms (up to 900 Most Probable Number 100 mL-1) were not a good indicator of fecal contamination. The Nanoflagellates were the most abundant, followed by diatoms. The non-toxic diatom Cylindrotheca closterium, known to be a bloom-forming species, and the harmful cyanobacterium Trichodesmium sp. showed proliferations on the order of 105 cells L-1. These phytoplankton responses are indicative of the eutrophication due to fluctuations in environmental conditions because of the intensity and type of human activities that take place in the study area.