We characterized the pH environment currently experienced by Euphausia pacifica eggs and larvae at 2 stations in the northern end of Hood Canal in Puget Sound, Washington, USA (47.61, -122.94 and 47.66, -122.86; Puget Sound Regional Synthesis Model [PRISM] stations P14 and P15). The southwest station, P14, is deeper (180 m) than the northeastern station, P15 (130 m). Samples were collected during the day and night on 9−10 April and 15−16 June 2012. This design was chosen to sample during the spawning season of E. pacifica (approximately February to July) in an area where low pH waters occur. We collected physical and chemical data using a CTD profiler equipped with a pH sensor and Niskin bottles, which were used to collect water at 6 depths for spectrophotometric pH, total dissolved inorganic carbon (DIC), and total alkalinity (TA) analyses. The CTD pH sensor was not accurate, so it was only used to determine the shape of the pH profile relative to discrete measurements. Spectrophotometric pH was measured shipboard immediately after water sampling. Total alkalinity was measured by open-cell potentiometric titration, and DIC was measured by acidification and quantification either using a Licor-700 CO2 detector, or a CO2 coulometer.

This dataset contains the discrete bottle (CTD profile) data of the pH environment experienced by Euphausia pacifica eggs and larvae at two station the northern end of Hood Canal in Puget Sound, Washington. The southwest station, P14, is deeper (180 m) than the northeastern station, P15 (130 m). Samples were collected during the day and night on 9−10 April and 15−16 June 2012. Physical and chemical data were collected using a CTD profiler equipped with a pH sensor (SBE 18, Sea-Bird Electronics) and Niskin bottles. This design was chosen to sample during the spawning season of E. pacifica (approximately February to July) in an area where low pH waters occur.

This dataset contains laboratory experiment data that were collected to examine the effects of ocean acidification on shell condition and survival of Puget Sound pteropods. We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Ωa) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (~460-500 μatm CO2, Ωa ≈ 1.59), current deep water or surface conditions during upwelling (~760 and ~1600-1700 μatm CO2, Ωa ≈ 1.17 and 0.56), and future deep water or surface conditions during upwelling (~2800-3400 μatm CO2, Ωa ≈ 0.28). We measured shell condition using a scoring regime of five shell characteristics that capture different aspects of shell dissolution. We characterized carbon chemistry conditions in statistical analyses with Ωa, and conducted analyses considering Ωa both as a continuous dataset and as discrete treatments. Shell dissolution increased linearly as aragonite saturation state decreased. Discrete treatment comparisons indicate that shell dissolution was greater in undersaturated treatments compared to oversaturated treatments. Survival increased linearly with aragonite saturation state, though discrete treatment comparisons indicated that survival was similar in all but the lowest saturation state treatment. These results indicate that, under starvation conditions, pteropod survival may not be greatly affected by current and expected near-future aragonite saturation state in the NE Pacific, but shell dissolution may. Given that subsurface waters in Puget Sound’s main basin are undersaturated with respect to aragonite in the winter and can be undersaturated in the summer, the condition and persistence of the species in this estuary warrants further study.