Mercury Biomagnification Through a Coral Reef Ecosystem

Abstract

Total mercury (Hg) and stable isotopes of nitrogen and carbon were determined in the muscle tissue of 50 species of fishes and invertebrates collected at two sites along the Florida reef tract from April 2012 -December 2013. The objective was to test the hypothesis that high biodiversity in coral reefs leading to complex food webs with increased lateral links reduces biomagnification. However, Hg levels ranged as high 6.84 mg/kg. Interestingly, it was not highest in great barracuda (Sphyraena barracuda), considered the top predatory fish, but instead in small porkfish (±95% confidence interval) to 0.201 ±0.07. These TMS were also within the ranges of slopes reported for food webs in other ecosystems; thus, biomagnification of Hg in muscle tissue was not reduced in the system.

Hydrothermal sulphur bacteria enhance mercury availability for coastal marine organisms

“…could accumulate harmful levels of Hg. Besides, the MSWC of these predators’ muscles are low in the Florida Keys, notably contaminated with inorganic Hg (Frederick et al, 2005), especially for Sphyraena barracuda (minimum MSWC = 80 g.week -1 ; Rumbold et al, 2018). Generally, both diffusive and dietary Hg integration pathways probably occurring near the mouth of the discharge channel could have contaminated all low trophic levels organisms living nearby, and this Hg could then be biomagnified in the Bouillante Bay (e.g.…”

“…Six active volcanic areas around the world, including freshwater sources and waterways around the Soufrière volcano in Guadeloupe, with the highest Hg concentrations in the study(Bagnato et al, 2009) B: Florida, contaminated with runoff waters charged in HgCl2 and MeHg(Frederick et al, 2005). Data from Florida Bay for water and sediments(Rumbold et al, 2011), and from Keys Archipelago for animals(Rumbold et al, 2018).…”