Iron, cadmium, and chromium in seagrass (Thalassia testudinum) from a coastal nature reserve in karstic Yucatán

Abstract

The management of protected areas in karstic regions is a challenge because flooded cave systems form there and provide underground hydrological conducts that may link different zones. As a consequence, affectations to the protected areas can possibly occur as a consequence of human activities in remote areas and may therefore pass undetected. Thus, the monitoring of possible contaminants in these regions is becoming imperative. In this work, we analyze the concentration of essential (iron) and non-essential metals (cadmium and chromium) in the seagrass Thalassia testudinum that grows in Yalahau Lagoon, located in a near-to-pristine protected area of the Yucatán Peninsula, close to the rapidly developing touristic belt of the Mexican Caribbean. Salinity and silicate patterns show that Yalahau is an evaporation lagoon, where groundwater discharge is important. High iron (> 400 μg/g), cadmium (>4 μg/g), and chromium (≈ 1 μg/g) concentrations were found in the area of highest groundwater input of the lagoon. High levels (5.1 μg/g) were also found near the town dump. In the rest of the sampling sites, metal concentrations remained near to background levels as estimated from other works. Temporal changes of concentrations in the seagrass tissues show also a local input and an input from the groundwater that could provoke an environmental problem in the Yalahau Lagoon in the near future.

Phytoplankton blooms associated with upwelling at Cabo Catoche

“…Téllez et al, 1993;Null et al, 2014), hence they are unlikely to be the main source of nutrients in the present study, furthermore, the nutrients recorded were temporally associated with the YUW during the upwelling scenario in April and July. Silicate could be used as an indicator to identify nutrient runoff from the coast (Avelar et al, 2013), however, in April and July, the highest concentration of silicate was temporally associated with cold water at offshore sites ( Fig. 10, d).…”

Elevated trace elements in sediments and seagrasses at CO2 seeps

“…Trace elements, as the term suggests, normally occur in very low concentrations. At low levels they are not toxic, and some are essential for cellular process that support life (Avelar et al, 2013). At higher concentration, trace elements such as arsenic (As), copper (Cu), mercury (Hg) and lead (Pb) can be harmful to coastal biota (Stumm Morgan, 1995).…”

Cadmium and morphological alterations in the rotifer Philodina cf. roseola (Bdelloidea: Philodinidae) and the worm Aeolosoma hemprichi (Annelida: Aeolosomatidae)

“…Currently, there are 58 reports of cadmium in water and 16 reports in tissues of aquatic organisms in the Yucatan Peninsula (Pacheco-Ávila et al, 2011;Rojas-Minguer & Morales-Vela, 2010;Avelar et al, 2013;Solís et al, 2008;& Tah-Euan, 2009). However, there is still a lack of information regarding the sensitivity of aquatic species to cadmium.…”