海洋酸化对海胆浮游幼体钙化生长的影响及其机制

Ocean acidification due to increasing emissions of anthropogenic carbon dioxide has been seriously threatening marine organisms, marine food webs, marine ecosystems and commercial fishery. The objectives of this study are to investigate the impact of ocean acidification on larval calcification in the Sea Urchin Strongylocentrotus intermedius, understand the basic mechanism underlying, and access the potential threat of ocean acidification to commercial industry of the sea urchin Strongylocentrotus intermedius. To achieve our objectives, a laboratory experiment will be used to study ocean acidification levels of dissolved carbon dioxide predicted to occur in the ocean this century. Larval spicule calcification growth rate was assessed by calculating the increase of spicule length and diameter per unit time under different pH conditions, respectively. Three key phases of larval spicule calcification process will be focused on to reveal the basic mechanism by which ocean acidification alter larval spicule calcification: (1) To investigate whether there is any change in expressions of spicule matrix proteins after normal and acidified seawater treatments, spicule matrix proteins will be separated by SDS-PAGE and specific expressed spicule matrix proteins will be identified by mass spectrum; (2) The structure of amorphous calcium carbonate will be studied to see whether there are some changes after acidified seawater treatments; (3) The changes of time-series growth of calcite crystal will be tested under different pH conditions，respectively. In order to investigate whether or to what extent ocean acidification threats Strongylocentrotus intermedius commercial industry, larval floating rate,abnormality rate,survival rate of each developmental stage, body length change rate and whloe survival rate will be calculated and compared between normal seawater and acidified seawater treatments during artificial reproduction of Strongylocentrotus intermedius, respectively. This study will enrich our knowledge of the potential threats of ocean acidification on early development of marine organisms in the future, add more evidences to the pool of marine species' vulnerability to progressive ocean acidification, and as well might provide us more clues to find strategies for sustainable development of marine commercial industry in near-future climate change.

由于二氧化碳过量排放引起的海洋酸化，正逐渐对海洋生物、食物网、生态多样性及商业渔业构成严重威胁。本研究通过实验室模拟海洋酸化条件，研究海洋酸化对海洋浅海代表动物-海胆浮游幼体钙化生长的影响及机制。通过测量计算单位时间内虾夷马粪海胆浮游幼体骨针长度和直径的增长，明确不同程度海洋酸化与虾夷马粪海胆浮游幼体钙化生长速度之间的联系，并进一步研究海洋酸化对表征虾夷马粪海胆浮游幼体钙化生长过程的基质蛋白生成、无定形碳酸钙形态结构及碳酸钙晶体时序性生长的影响，阐明海洋酸化影响海胆浮游幼体钙化生长的机制。同时，在人工育苗中明确海洋酸化对虾夷马粪海胆幼体发育的影响程度，初步分析海洋酸化对海胆渔业及生态的潜在影响。本研究将为我们充分认识海洋酸化对海洋生物，尤其是海洋生命早期阶段的潜在影响提供更多数据，为深入研究海洋生物对未来海洋环境改变的响应机制以及未来海洋酸化条件下商业渔业的可持续发展提供参考。

海洋酸化是继“温室效应”之后又一由CO2 过量排放而引起的全球性环境问题，越来越多的研究证实，由CO2过量排放引起的海洋酸化，正严重威胁着海洋生态系统、海洋生物多样性和海洋生物食物链的动态平衡。海胆是海洋浅海生物的代表，也是重要的渔业资源。依据基金申请书、项目计划书和专家评审意见，本项目以虾夷马粪海胆（Strongylocentrotus intermedius）、马粪海胆（Hemicentrotus Pulcherrimus）和海刺猬（Glyptocidaris crenularis）为研究对象，通过显微观察、测量等手段，比较分析了不同酸化条件下，3种海胆受精率、胚胎形态、胚胎上浮率、浮游幼体形态以及钙化生长速度的差异，结果表明，海洋酸化可显著影响海胆幼体的生长、发育、成活和骨针的钙化生长速度，进而影响海胆的种群结构和海胆产业的健康发展。此外，本项目分别提取自然海水和不同酸化处理条件下各组海胆浮游幼体的RNA，构建了海胆响应海洋酸化的转录组信息库，并在此基础上，利用生物信息学手段和比较转录学方法，初步分析了海洋酸化影响海胆浮游幼体发育及钙化生长的分子网络，为进一步深刻了解海洋酸化对海胆这类海洋浅海代表生物的种群数量、结构以及生态的影响提供一定的线索，为研究海洋酸化对海洋生态系统、海洋生物多样性以及海洋生物链的影响提供理论基础。