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

<p>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:</p>

<p><strong><u>Location</u></strong>: 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</p>

<p><strong><u>Filter size</u></strong>: Filtering protocols were not exactly identical between years. In 2015, samples were sequentially filtered so particulate samples are &gt;20 µm (large fraction) and 0.2-20 µm (small fraction). In 2016, water was sampled through filters independently so samples are &gt;2 µm (bulk) and &lt;20 µm (small&nbsp;fraction).&nbsp;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).</p>

<p><strong><u>Dissolved parameters</u></strong>: 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.</p>