Macrophyte-induced variability in coastal ocean pH and consequences for invertebrate larvae

大气中二氧化碳浓度的增加正在以前所未有的速度使海洋环境酸化。然而，相对于公海，沿海海洋酸化的预测是混淆了碳酸盐化学的更大的固有的可变性，其中包括大型植物光合作用和呼吸引起的强烈的可变性。该提案解决了生态驱动的pH值变化和固有的可变沿海海洋的碳酸盐化学之间的相互作用，并将直接测试潜在的敏感的生命形式，无脊椎动物larvae.The的影响，本研究的目的是衡量自然pH值方差的主要沿海栖息地的影响，并评估这些pH值制度对发展无脊椎动物幼虫的影响。研究人员将把自然变异纳入一系列实验室和原位移植实验中，以测试pH值、变异机制和生理相关阈值如何影响海洋无脊椎动物幼虫的健康。他们将检验以下假设：（1）在与初级生产和群落呼吸循环相对应的可预测的空间和时间背景下，大型植物诱导碳酸盐化学变化。(2)浮游无脊椎动物幼虫的健康是敏感的pH值下降，但负面影响时，纳入可变pH值得到改善。（3）无脊椎动物幼虫的敏感性降低pH值是一个功能的发展模式：钙化的幼虫比非钙化的幼虫更敏感，和营养型（喂养）幼虫比营养型（非喂养）幼虫更敏感。为了验证这些假设，研究人员将在加州圣地亚哥的海带森林和海草床中描述碳酸盐化学的时空变化。利用离散水样测定总碱度和溶解无机碳，以及测量pH值、盐度和温度的连续自动仪器，碳酸盐化学变化的统计特征，他们将确定昼夜、季节和空间趋势以及最大变化频率、变化率、最低潜在pH值（极端统计）和生物学显著阈值。随后，将在实验室实验中模拟突出的大型植物诱导的pH值制度，并将其与海洋酸化预测相结合，以测试（a）pH值降低（8.1至7.3），（B）pH值变化的平均值，（c）平均pH值变化的方差，以及（c）脉冲暴露于极低pH值对多个物种的幼虫存活、生长和钙化反应的影响。幼虫反应的比较评估将为科学家，管理人员和决策者提供预测的幼虫类型（从而人口）最敏感或容忍预测的pH值制度。补充现场实验将暴露实验室产卵的幼虫已知的空间和时间的pH梯度下的温度，光线和食物的环境周期。Laravirus将被种植在伊斯基亚、意大利和加州南部的海带和海草床的二氧化碳排放口。这项研究是第一次调查的影响，自然波动制度下，在该领域的pH值下降对幼虫发育。这些实验室和实地研究将共同提供对碳酸盐化学性质自然变化在海洋酸化背景下的影响的机械理解，该项目将为下一代建立解决与海洋酸化有关的生态问题的能力。它将包括跨学科的研究生培训，涉及新的教师，并通过实地和实验室经验，促进本科生参与代表性不足的少数民族。调查结果将被纳入BO，底栖生态学，海洋化学和研讨会课程的研究生课程。战略伙伴关系已经建立了教育方案，目标是在圣地亚哥的中学女生，国家的科学感兴趣的公众，和学前学生参与科学博览会。该项目将把有关沿海生境和酸化的基本科学概念与持久的教育资源相结合，以提高学生和公众的科学理解。

Increased concentrations of atmospheric carbon dioxide are acidifying the marine environment at unprecedented rates. However, relative to the open ocean, predictions of ocean acidification for the coastal ocean are confounded by the greater inherent variability of carbonate chemistry which includes strong variability induced by macrophyte photosynthesis and respiration. This proposal addresses the interplay between anthropogenically driven pH changes and the inherently variable coastal ocean's carbonate chemistry, and will directly test the implications for a potentially sensitive life form, invertebrate larvae.The objectives of this study are to measure the impact of key coastal habitats on natural pH variance, and to evaluate the implications these pH regimes have for developing invertebrate larvae. The investigators will incorporate natural variability into a series of laboratory and in-situ transplant experiments to test how pH levels, variability regimes, and physiologically-relevant thresholds affect the health of marine invertebrate larvae. They will test the hypotheses that (1) Macrophytes induce variability in carbonate chemistry in a predictable spatial and temporal context corresponding to cycles of primary production and community respiration. (2) Planktonic invertebrate larval health is sensitive to decreased pH, but negative effects are ameliorated when incorporating variable pH. (3) Sensitivity of invertebrate larvae to decreases in pH is a function of developmental mode: calcifying larvae are more sensitive than non-calcifying larvae, and planktotrophic (feeding) larvae are more sensitive than lecithotrophic (non-feeding) larvae. To test these hypotheses the investigators will characterize temporal and spatial carbonate chemistry variability at kelp forests and seagrass beds in San Diego, California. With discrete water samples for the determination of total alkalinity and dissolved inorganic carbon, and continuous autonomous instruments which measure pH, salinity, and temperature, a statistical characterization of carbonate chemistry variability they will identify diurnal, seasonal and spatial trends as well as frequencies of maximum variation, rates of change, lowest potential pH (extreme statistics), and biologically-significant thresholds. Subsequently, prominent macrophyte-induced pH regimes will be mimicked in laboratory experiments and incorporated with ocean acidification predictions to test effects of (a) decreased pH (8.1 to 7.3), (b) varying pH about the mean, (c) changing variance about mean pH, and (c) pulsed exposure to extreme low pH, on larval survivorship, growth, and calcification responses of multiple species. A comparative assessment of the larval responses will provide scientists, managers, and policy-makers with predictions of larval types (and thus populations) most sensitive or tolerant to forecasted pH regimes. Complementary field experiments will expose laboratory-spawned larvae to known spatial and temporal pH gradients under ambient cycles of temperature, light, and food. Larvae will be outplanted at CO2 vents in Ischia, Italy, and in southern California kelp and seagrass beds. This study is the first to investigate the implications of pH declines on larval development under natural fluctuating regimes, and in the field. Together, these laboratory and field studies will offer a mechanistic understanding of the effects of natural variance of carbonate chemistry in the context of ocean acidification.The Project will build capacity for the next generation to address ecological problems associated with ocean acidification. It will incorporate interdisciplinary graduate student training, involve new faculty, and promote undergraduate student engagement via field and laboratory experiences for underrepresented minorities. Findings will be integrated into graduate courses in BO, benthic ecology, marine chemistry, and seminar courses. Strategic partnerships have been established with educational programs that target middle school girls in San Diego, the nation's science-interested public, and precollege students involved in science fairs. The PIs will blend basic science concepts concerning coastal habitats and acidification with enduring educational resources to enhance scientific understanding by students and the public.