Abstract

Characterization of physical variables at La Escollera, a human-made coastal lagoon in Santa Marta, Colombian Caribbean. Bol. Invest. Mar. Cost. [online]. 2020, vol.49, n.2, pp.25-48.  Epub Dec 20, 2020. ISSN 0122-9761.  https://doi.org/10.25268/bimc.invemar.2020.49.2.925.

Coastal lagoons are a focus of primary production and a refuge for biodiversity due to their relative confinement and low depth. La Escollera is a human-made coastal lagoon in El Rodadero, Santa Marta (Colombian Caribbean), excavated in the early 1980s to hold a marina and its fringes planted with mangroves. To generate a baseline of physical variables that contribute to the nderstanding of water circulation and its influence on ecosystem attributes, salinity, temperature, sea level and light penetration data are outinely obtained through electronic recorders and handheld sensors. Salinity and temperature data from January 2017 to February 2018 ollowed the seasonal pattern of the open sea in the Santa Marta area, alternating between lower temperature (minimum of 24.6 °C) and dgher salinity (maximum of 38.9) in the dry season and coastal upwelling (December to April), an between higher temperature (maximum !4.7 °C) and lower salinity (< 35) in the rainy season (May to November), with the lowest salinity values after persistent rains (minimum 5.1). The water column is generally well mixed and stratified after heavy showers in the rainy season (mixing rapidly in hours or days). This seems to be mainly due to tidal exchange with the sea, the tide oscillating from +0.37 to -0.31 m (maximum range 0.68 m [one-year ata]), and following the regular astronomical pattern of mixed tides in the Caribbean. Lagoon waters are regularly green and of varied ransparency except during heavy rains, after which they become brownish. Vertical light extinction is generally high and not very variable 2-6.5 % cm-1), but the light frequently reaches the bottom, which allows the presence of benthic macroalgae in some portions of the lagoon.

Keywords : coastal lagoons; marinas; tides; salinity; temperatur.

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