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

大型植物引起的沿海海洋 pH 值变化及其对无脊椎动物幼虫的影响

• 批准号: 0927445
• 负责人: Lisa Levin
• 金额: $ 37万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927445&HistoricalAwards=false
• 关键词: Macrophyte; induced; variability; coastal; ocean

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.

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因碳酸盐化学的更大固有变异性而受到干扰，其中包括由大型植物光合作用和呼吸引起的强烈变异性。该提案解决了人为驱动的 pH 变化与固有变化的沿海海洋碳酸盐化学之间的相互作用，并将直接测试对潜在敏感生命形式无脊椎动物幼虫的影响。本研究的目的是衡量关键沿海栖息地对自然 pH 值变化，并评估这些 pH 值对无脊椎动物幼虫发育的影响。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 水平、变异状况和生理相关阈值如何影响海洋无脊椎动物幼虫的健康。他们将测试以下假设：（1）大型植物在与初级生产和群落呼吸周期相对应的可预测的空间和时间背景下诱导碳酸盐化学的变化。 (2) 浮游无脊椎动物幼体的健康对 pH 值降低很敏感，但当 pH 值变化时，负面影响会得到改善。 (3) 无脊椎动物幼虫对 pH 值降低的敏感性是发育模式的函数：钙化幼虫比非钙化幼虫更敏感，浮游营养（取食）幼虫比卵磷脂（非取食）幼虫更敏感。为了检验这些假设，研究人员将描述加利福尼亚州圣地亚哥海带森林和海草床的碳酸盐化学变化的时间和空间特征。通过离散水样测定总碱度和溶解的无机碳，以及连续自动仪器测量 pH、盐度和温度、碳酸盐化学变异性的统计特征，他们将识别每日、季节和空间趋势以及最大频率变化、变化率、最低潜在 pH（极端统计）和具有生物学意义的阈值。随后，将在实验室实验中模拟大型植物引起的 pH 值，并与海洋酸化预测相结合，以测试 (a) pH 值下降（8.1 至 7.3）、(b) 改变 pH 值平均值、(c) 改变方差值的影响。平均 pH 值，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。对幼虫反应的比较评估将为科学家、管理者和政策制定者提供对预测 pH 值最敏感或最耐受的幼虫类型（以及种群）的预测。补充现场实验将在环境温度、光照和食物循环下将实验室产卵的幼虫暴露在已知的空间和时间 pH 梯度中。幼虫将被种植在意大利伊斯基亚岛的二氧化碳排放口以及加利福尼亚州南部的海藻和海草床中。这项研究首次在自然波动条件下和实地调查了 pH 值下降对幼虫发育的影响。这些实验室和现场研究将共同​​提供对海洋酸化背景下碳酸盐化学自然变化影响的机制理解。该项目将为下一代培养解决与海洋酸化相关的生态问题的能力。它将纳入跨学科研究生培训，吸引新教师，并通过针对代表性不足的少数族裔的现场和实验室经验来促进本科生的参与。研究结果将被纳入 BO、底栖生态学、海洋化学和研讨会课程的研究生课程中。我们与针对圣地亚哥中学生、全国对科学感兴趣的公众以及参与科学博览会的大学前学生的教育项目建立了战略合作伙伴关系。 PI 将把有关沿海栖息地和酸化的基本科学概念与持久的教育资源相结合，以增强学生和公众的科学理解。