DOI: 10.5061/dryad.d21t5/1
title: Colvard and Helmuth Ecol Appl Data

description: Table 1
These data are of the % Nitrogen recorded in the experiment F. vesiculosus tissue following the duration of the experiment (36 d), the relative growth rate of the algal tissue, and the projected surface area growth rate of the algal tissue. These data are for ambient and nutrient-enriched F. vesiculosus tissue.

Table 1 – N in Seawater
These data are of Nitrogen levels recorded in seawater collected from the experimental mesocosms in order to establish differences in nutrient-enriched treatment compared to ambient conditions.

Table 1 – Jr. PAM Data
These data correspond to the Photosynthetic Quantum Yield of PSII and the Non-photosynthetic Quenching (NPQ) of the apical tip and wing region of F. vesiculosus. These measurements were conducted using a Pulse Amplitude Modulation chlorophyll fluorometer (Jr. PAM, Walz, Effeltrich, Germany) at the conclusion of the nutrient enrichment experiment (day 36). Ten individuals were haphazardly selected for both ambient and nutrient-enriched treatments, one alga from each replicate mesocosm.

Figure 1
These data correspond to the Photosynthesis vs. Irradiance curves for ambient (control) and nutrient-enriched (treatment) individuals at 10°C, 14°C, and 18°C. O2 production was the mean quantifiable measure of photosynthesis of F. vesiculosus, and standard error was calculated from the n= 5 replicate algal tissue used in this experiment. The three temperatures are representative of average (10°C), warm (14°C), and hot (18°C) seawater temperature conditions during summer months in Nahant, MA. 

Figure 2 and 3
These data correspond to the Photosynthetic Thermal Performance measurements [Dark respiration (Rd) and Maximum gross photosynthesis (Pgross,max)] of ambient and nutrient-enriched F. vesiculosus tissue were conducted from 6°C to 30°C. 

Figure 4
We calculated the yearly average Pnet for F. vesiculosus located at Nahant, MA from hourly recorded environmental data recorded near Nahant, MA from May 2013 to December 2014, and compared those results to a simulated increase in seawater temperature +3°C above recorded temperatures, which is the anticipated average rise in seawater temperature by the end of the century for this region. Using ecologically relevant irradiance (I, 0 – 1500 𝜇mol photons m-2s-1) and seawater temperature (0 – 30°C) combinations, we used the equation to calculate Pnet (described in the manuscript) to predict net photosynthesis (Pnet) for ambient and nutrient-enriched conditions. These predictive models are based on the best curve fits for Pgross,max (a curvilinear, third degree polynomial fit) and Rd (a linear fit) for both treatments. Pgross,max, Rd, and α (initial slope of PE curves) were temperature dependent for ambient and nutrient-enriched conditions. Since the Pnet model is only valid when F. vesiculosus is submerged, during periods of aerial exposure at low tide Pnet was assumed to be 0.

Supplemental 

Figure S1
Seawater temperature data recorded from May 2013 to May 2015 at Pump House Beach, Nahant, MA, near the Northeastern Marine Science Center. All temperature counts are when the HOBO pendant logger was completely submerged, &gt;2 m tidal height. 

Table S1
Summary data for the photosynthesis vs. irradiance curve (PE curve) values Pgross,max, α, IK, and Rd. For each respective temperature conditions (10°C, 14°C, and 18°C) is the average ambient condition and the average nutrient-enriched treatment (n=5 temperature-1).