Analyzing Eutrophication Conditions in the Gulf of Mexico Using the SIMAR Integral Marine Water Quality Index (ICAM-SIMAR-Integral)

The ocean is a priority for governments and international organizations. Large-scale, in situ ocean water quality monitoring programs are not very feasible due to the high costs associated with their implementation and operation. In this work, we present a tool for assessing ocean conditions, the SIMAR Integrated Marine Water Quality Index (ICAM-SIMAR-Integral), composed of two satellite parameters and three numerical models. We evaluated its spatiotemporal variability at 10 sites in the Gulf of Mexico, which have dissimilar environmental conditions. We validated its use by comparing it with the TRIX trophic index at 41 sites. To construct the index, the five parameters were standardized using a logarithmic equation and then summed, weighted according to their relationship with eutrophication. An index with a scale of 1 to 100 was obtained, divided into five classification intervals: oligotrophic, mesotrophic, eutrophic, supertrophic, and hypertrophic. The median values of the index and its parameters exhibited significant spatial and temporal variability, consistent with the literature’s criteria regarding their values and eutrophication thresholds. Comparison with TRIX showed no significant differences, validating the implementation of ICAM-SIMAR-Integral as an easily interpreted early warning system for managers and decision-makers in conservation matters. This index will allow for continuous, large-scale monitoring of the ocean, thereby contributing synoptically to its sustainable use.