Dataset for Factors Regulating Lake Periphyton Biomass and Nutrient Limitation Status Across Large Trophic Gradient

This data set contains results of a study on the response of Great Lakes periphyton to additions of nutrients. Nutrient Diffusing Substrata (NDS) with control, +nitrogen, +phosphorus, and +nitrogen and phosphorus treatments were deployed at 28 sites along the coast of Lake Superior, northern Lake Michigan, and Green Bay. Control NDS cups contained just 2% agar by weight while +nitrogen, +phosphorus, and +nitrogen and phosphorus treatments contained the agar and 0.5 M NH4Cl, KH2PO4, or both, respectively. Experiments were deployed between July 11-31, 2017 and retrieved 28-29 days later between August 8-28, 2017. Periphyton biomass as chlorophyll-a and ash free dry weight (AFDW) from NDS treatments is contained in the file “NDS_Chl_AFDW.csv”. Site locations and environmental parameters (water column nutrient concentrations, Kd, and chlorophyll) are contained in the file “SITES_PARAMETERS”.

Description
NDS_Chl_AFDW.csv: Periphyton chlorophyll-a (μg/cm2) and AFDW (mg/cm2) from NDS experiments. Each of the 5 replicates from each nutrient treatment (Con, N, P, N+P) are shown. Columns: site: Site of NDS experiment. treat: Treatment, con: control, N: nitrogen, P: phosphorus, NP: nitrogen and phosphorus. chl.a_microg/cm2: Periphyton biomass on NDS measured as chlorophyll-a (μg/cm2). AFWD_mg_cm2: Periphyton biomass on NDS measured as AFDW (mg/cm2). replicate: replicate number of sample (n=5). SITES_PARAMETERS.csv: Site locations as latitude and longitude with site Soluble Reactive Phosphorus (SRP), NO3-, Total Phosphorus (TP) and, Total Nitrogen (TN) concentrations expressed as μg/L. Water clarity as Kd, water column chlorophyll-a concentrations (μg/L), and water temperature (C) are also presented. Columns: site: Site of NDS experiment. lat: Latitude of site. long: Longitude of site. lake: Area where site is located. GB=Green Bay, MICH= North Shore of Lake Michigan, SUP: Lake Superior. deployment date: Date of NDS deployment. retrieval date: Date of NDS retrieval. temp.d_C: Water column temperature from deployment trip. temp.r_C: Water column temperature from retrieval trip. k(0.5d): Extinction Coefficient (Kd) calculated from 0.5m on deployment trip. k(1d): Extinction Coefficient (Kd) calculated from 1m on deployment trip. k(0.5r): Extinction Coefficient (Kd) calculated from 0.5m on retrieval trip k(1r): Extinction Coefficient (Kd) calculated from 1m on retrieval trip SRP.d_mircog/L: Water column SRP (μg/L) from deployment trip. SRP.r1_mircog/L: First rep of water column SRP (μg/L) from retrieval trip. SRP.r2_mircog/L: Second rep of water column SRP (μg/L) from retrieval trip. NO3.d_microg/L: Water column NO3- (μg/L) from deployment trip. NO3.r1_microg/L: First rep of water column NO3- (μg/L) from retrieval trip. NO3.r2_microg/L: Second rep of water column NO3- (μg/L) from retrieval trip. TP.r1_microg/L: First rep of water column TP (μg/L) from retrieval trip. TP.r2_microg/L: Second rep of water column TP (μg/L) from retrieval trip. TP.d1_microg/L: First rep of water column TP (μg/L) from deployment trip. TP.d2_microg/L: Second rep of water column TP (μg/L) from deployment trip. TN.r1_microg/L: First rep of water column TN (μg/L) from retrieval trip. TN.r2_microg/L: Second rep of water column TN (μg/L) from retrieval trip. TN.d_microg/L: Water column TN (μg/L) from deployment trip. chl.r_microg/L: Water column chlorophyll-a (μg/L) from retrieval trip. chl.d_microg/L: Water column chlorophyll-a (μg/L) from deployment trip.