Sermilik Fjord 2021 mercury concentration data:

Data are sorted by time of sample collection. Cast numbers correspond to CTD data available via the NSF Arctic Data Center (doi:10.18739/A2HD7NT9K), except for surface samples collected by hand in Apuseeq Fjord, a lake and river near Tiilerilaaq, and a river near Tasiilaq.

Within Sermilik Fjord, samples were collected using a rosette carrying eight 8-L bottles (Standard Model 110A, 8 L) fired by a Seabird Autofiring Module at pre-determined depths due to deployment with a non-conductive cable. Pressure [dbar] is the pressure at which the AFM was programmed to fire, while depth [m] is the depth recorded by the CTD at the time the AFM fired.
Outside the fjord on the continental shelf, the rosette could not be used due to the sea state. Instead, water samples were collected with two line-mounted Niskin bottles (Model 1010 Niskin Water Sampler, 2.5 L) using a manual messenger. For these samples, "programmed pressure" indicates line out at the time the messenger was dropped.

Samples were collected in 0.25 L precleaned borosilicate glass bottles (I-Chem) for total mercury (THg) and methylmercury (MeHg) analysis. After sample collection, both THg and MeHg samples were acidified to 0.4% ultrapure hydrochloric acid (Optima, Fisher Chemical), stored at 4 degrees C, and analyzed within 6 months of sampling by the Schartup Lab at Scripps Institution of Oceanography. Concentrations are given in units of pM.

For additional information and detailed sample analysis methods, please see corresponding publication: Lindeman, Straneo, Adams, Nelson, and Schartup, 2023 (submitted).