Effects of ocean acidification on shell condition and survival of Puget Sound pteropods from laboratory experiment studies from 2012-05-10 to 2012-07-12 (NODC Accession 0125008)

This archival package 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.

本档案包收录了用于探究海洋酸化（ocean acidification）对普吉特湾翼足类（pteropods）壳体状态与存活率影响的实验室实验数据。
本研究以采集自美国西北大陆架城市化河口——普吉特湾的被壳翼足目（thecosome pteropod）物种螺旋海若螺（Limacina helicina）为研究对象，检验其暴露于普吉特湾及东北太平洋海域的高CO₂、低文石饱和状态（Ωa）环境时，是否会发生壳体溶解及死亡率改变。
我们共开展5项为期一周的实验，将采集自普吉特湾的翼足类置于4种碳化学条件下培养：当前夏季表层海水条件（CO₂浓度约460~500 μatm，Ωa≈1.59）、上升流（upwelling）时期的现行深水或表层海水条件（CO₂浓度约760及1600~1700 μatm，Ωa≈1.17与0.56），以及上升流时期的未来深水或表层海水条件（CO₂浓度约2800~3400 μatm，Ωa≈0.28）。
我们采用覆盖壳体溶解多维度特征的5项壳体特征评分体系，对壳体状态进行量化测定。在统计分析中以文石饱和状态作为碳化学条件的表征指标，并分别将Ωa作为连续数据集与离散处理组开展分析。
研究结果显示，壳体溶解程度随文石饱和状态降低呈线性升高；离散处理组对比表明，文石不饱和处理组的壳体溶解程度显著高于过饱和处理组。存活率随文石饱和状态升高呈线性提升，但离散处理组对比显示，除文石饱和状态最低的处理组外，其余各组存活率无显著差异。
上述结果表明，在饥饿条件下，东北太平洋海域当前及近未来预期的文石饱和状态对翼足类存活率的影响有限，但会显著影响壳体溶解程度。鉴于普吉特湾主海域的次表层水体冬季处于文石不饱和状态，夏季也可能出现文石不饱和情况，该物种在该河口的生存状态与存续潜力亟待进一步研究。