Figure 1.
Changes in pHT (total scale) and dissolved oxygen obtained via bubbling estuarine seawater (salinity = 30) with N2 gas (black circles) and found naturally (white circles) in the Forge River, NY, USA, during summer 2012.
Figure 2.
Levels of dissolved oxygen and pHT during experiments.
A. Experiments delivering N2 gas, CO2 gas, and air to seawater with A. irradians larvae (black squares), two month old M. mercenaria (red diamonds), or four month old M. mercenaria (blue circles) as presented in Figures 2, 4 and 5. Points are means ±1 S.D. B. Experiment with water from the Forge River, NY, USA, and A. irradians larvae left unamended (red), amended with sodium carbonate (yellow), or aerated (green). Points are means of measurements during individual days of the experiment. Crosses present the mean ±S.D. for the entire experiment.
Figure 3.
Performance of A. irradians larvae exposed to two levels of dissolved oxygen and pHT.
(A) Percent survival and (B) percent metamorphosis of surviving A. irradians larvae during exposure to two levels of pH and dissolved oxygen. (C) Percent survival and (D) percent metamorphosis of surviving A. irradians larvae in water naturally low in dissolved oxygen and pH (umamended), low oxygen with normal low pH (via the addition of sodium carbonate), or with normal oxygen and pH (via aeration with and without sodium carbonate). There was no metamorphosis in the unamended and sodium carbonate treatments. Points are means ±1 S.D. Dissolved oxygen and pH levels are presented in Figures 2. Complete carbonate chemistry is given in Tables S1 and S2, while statistical analyses appear in Tables S5, S6, S8, and S9.
Figure 4.
Size of early life stage A. irradians larvae, grown under two levels of pH and dissolved oxygen.
A. Experiment with mixing gases, and B. Experiment manipulating naturally low oxygen and low pH water with aeration and sodium carbonate Bars are means ±S.D. Complete carbonate chemistry from experiments appear in Tables S1 and S2 while statistical analyses appear in Tables S7 and S10. Shared lower case letters indicate treatments that are not significantly different (p>0.05). Statistical comparisons were among metamorphosed individuals only in panel A, but was between individuals of the same cohort that were metamorphosed individuals in the aerated treatment and larvae in other treatments in panel B as no individuals had metamorphosed in those treatments.
Figure 5.
Performance of M. mercenaria exposure to two levels of pH and dissolved oxygen.
A. Percent survival of two month old individuals, B. Growth of two month old individuals, C. Growth of four month old individuals. Bars are means ±S.D. Dissolved oxygen and pH levels are presented in Figure 2. Complete carbonate chemistry appears in Tables S3 and S4, while statistical analyses appear in Tables S11, S12, and 13. Shared lower case letters indicate treatments that are not significantly different (p>0.05).