Dataset: Coastal phytoplankton and mercury dynamics in watersheds along the U.S. East Coast from New Jersey to Maine assessed using particulate and dissolved samples collected in 2015 and 2016

The data in each year are grouped by Location, Filter size, and measured parameters for each size fraction, as well as the measured dissolved parameters:

Location: state, site name and sub-location (in many instances these are sites with high (HOC) and low (LOC) organic carbon sediments), sampling month and sampling time in terms of tide (HT = high tide, LT = low tide, FL = falling and RS = rising tide; if more than one sample at a tide was collected, this is indicated, e.g. HT1, HT2), latitude and longitude

Filter size: Filtering protocols were not exactly identical between years. In 2015, samples were sequentially filtered so particulate samples are >20 µm (large fraction) and 0.2-20 µm (small fraction). In 2016, water was sampled through filters independently so samples are >2 µm (bulk) and <20 µm (small fraction). For each filter, the following parameters were measured and are recorded: total suspended solids (TSS, mg/L), chlorophyll a (Chl a, µg/L) and phaeopigment (Pha, µg/L), particulate total Hg (part. HgT, pmol/g) and particulate methylmercury (part. MeHg, pmol/g).

Dissolved parameters: For each location, a filtered sample was analyzed for: dissolved total mercury (diss. HgT, pM), dissolved methylmercury (diss. MeHg, pM), and dissolved organic carbon (DOC, µM). Salinity and temperature (degrees C) were also recorded for each sample.