Implicaciones del deterioro ambiental para los ecosistemas costeros. Estudio de caso: “Bahía de Guantánamo, Cuba”

Abstract

Bays ecosystems are being increasingly impacted by agro-industry, tourism, maritime port and fishing human activities associated with urban development, favoring the deteriorating environmental conditions. In Guantanamo Bay, the phytoplankton blooms have increased in the last five years. In October 2013, the environmental conditions that favor the occurrence of these events were evaluated, for which microbiological indicators (heterotrophic bacteria), phytoplankton (diversity and abundance) and chemical (dissolved oxygen (DO), chemical oxygen demand were employed (COD), nitrate plus nitrite (NOX), ammonium (NH4), total nitrogen (TN), total inorganic phosphorus (PO4) and total phosphorus (PT). In the bay an environmental imbalance associated with eutrophication and organic and inorganic contamination, with OD values below 5 mg.L-1 in the bottom layer and high values of COD (Xmean = 4.05 mg.L-1), NH4 (Xmean = 0.047 mg.L-1) and PO4 (Xmean = 0.013 mg.L-1); as well as an imbalance in the availability of nitrogen and phosphorus with a NT / PT ratio of 31.9. This situation is compounded by the residence time of the water (49 days on average and a maximum of 158 days), and altered rainfall patterns associated with climate variability. These environmental conditions stimulate the development of heterotrophic bacteria (27 x 104 UFC.mL-1), classified as eutrophic waters and favor changes in the composition and abundance of phytoplankton (Xmean = 1733 ± 705 cel.mL-1) as well as the development of harmful and / or toxic species, with a predominance of cyanobacteria indicator of environmental deterioration (Xmean = 1562 ± 707 cel.mL-1).