Mercury isotopic evidence for the importance of particles as a source of mercury to marine organisms.

The origin of methylmercury in pelagic fish remains unclear, with many unanswered questions regarding the production and degradation of this neurotoxin in the water column. We used mercury (Hg) stable isotope ratios of marine particles and biota to elucidate the cycling of methylmercury prior to incorporation into the marine food web. The Hg isotopic composition of particles, zooplankton, and fish reveals preferential methylation of Hg within small (< 53 µm) marine particles in the upper 400 m of the North Pacific Ocean.

A Time Series of Water Column Distributions and Sinking Particle Flux of and Domoic Acid in the Santa Barbara Basin, California.

Water column bulk abundance and the dissolved and particulate domoic acid (DA) concentrations were measured in the Santa Barbara Basin (SBB), California from 2009⁻2013 and compared to bulk cell abundance and DA concentrations and fluxes in sediment traps moored at 147 m and 509 m. abundance throughout the study period was spatially and temporally heterogeneous (<200 cells L to 3.8 × 10⁶ cells L, avg.