Samples were originally kept cold until filtered within several days of collection, and since 2002 have been filtered immediately in the field. Filtered samples were frozen until analysis. Particulate samples are filtered in the lab using vacuum filtration., and TSS is calculated from the mass of particulates per volume of sample. Particulate C and N mass was calculated by analyzing the filters using a CHN analyzer, and converted to concentration by dividing by the filtered volume. Analysis was conducted at UNH either by the lab of Ted Loder (samples with grid-code = UNH_Grab) at MBL (grid-code = Sigma Grab and Lab_ID = NA) or at UNH by the lab of Bill McDowell (grid-code = Sigma Grab and Lab_ID = McDowell Lab, starting in 2014, unique sample IDs used by the McDowell Lab are entered). Samples analyzed at the McDowell Lab below the detection limit were entered as 0. The detection limit is 5 µg/L for NH4 (0.36 µM) , PO4 (0.16 µM) and NO3 (0.36 µM).
Samples were analysed using Lachat methods.
RESEARCH LOCATION: x and y coordinates given below are in MA State Plane NAD83 (meters). Sites were georeferenced to a gridded river network with 120m grid sizes. X and Y coordinates reflect slight shifts to ensure proper placement on the digital river network. Contributing area is listed in km2.
RESEARCH LOCATION: x and y coordinates given below are in MA State Plane NAD83 (meters). Sites were georeferenced to a gridded river network with 120m grid sizes. X and Y coordinates reflect slight shifts to ensure proper placement on the digital river network. Contributing area is listed in km2.
Permanent_ID Site X Site Y Description Site ID in SigmaNutrients
YSI-SB 225840 919310 Suburban Headwater Stream SB
YSI-CC 247680 946790 Forested Headwater Stream CC
YSI-CS Wetland Headwater Stream CS
YSI-IR 232080 923630 Upper Ipswich R.
YSI-FB 240600 934310 Fish Br.
IP24 254280 936350 Mouth of the Ipswich (Sylvania Dam) ID
10 246600 944510 Mouth of the Parker (Central St.) PD