Gulf of Fonseca - Physical Geography

Physical Geography

The Gulf of Fonseca covers an area of approximately 3,200 square kilometres (1,200 sq mi), with a coastline that extends for 261 kilometres (162 mi), of which 185 kilometres (115 mi) are in Honduras, 40 kilometres (25 mi) in Nicaragua, and 29 kilometres (18 mi) in El Salvador.

The climate in the Gulf is typical of tropical and subtropical regions, with two distinct seasons, the rainy and the dry. The Gulf receives nearly 80% of its total yearly rainfall of 1,400–1,600 millimetres (55–63 in)) during the rainy season from May to November. The dry season occurs between December and May and contributes to an annual evaporation rate of 2,800 millimetres (110 in). As a result of less water flowing into the Gulf, the currents tend to flow inward from the Pacific Ocean, and levels of salinity in the estuaries increase, and seasonal drought occurs.

Temperatures in the Gulf average between 25 and 30 °C; March and April are the warmest months and November and December the coolest. Relative humidity varies between 65 and 86% depending on location. In contrast, the interior of the country is semi-tropical and cooler with an average temperature of 26 °C.

The vegetation of the wetland ecosystem is dominated by species of mangroves. Of the six species of mangrove identified in the Gulf, Red Mangrove (Rhizophora mangle) is the most common, mostly occupying the areas permanently inundated by the tides. Black Mangrove (Bruguiera gymnorrhiza) is the second most pervasive species and is generally found around the rivers where sediments are deposited along the shoreline. White Mangrove (Laguncularia racemosa) is the third most dominant, followed by Botoncillo (Conocarpus erectus); both are generally found further inland and are inundated by the tide less frequently. The dominance of different species over others correlates with the frequency of inundations, water quality, and levels of salinity.

The cycle of tides is 2.3 metres (7 ft 7 in) on average per day in the Gulf. During low tides the soils are inhabited by crabs, conch, and other species. During the high tide the mangrove forests serve as a feeding ground and habitat for fish, shrimp, and other species, as the root structure of mangroves provide a refuge from larger predators.