National Marine Science Centre, Southern Cross University, PO Box 4321, Coffs Harbour, New South Wales 2450, Australia
School of Medical Sciences and School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales 2006, Australia.
Proc Biol Sci. 2018 Apr 11;285(1876). doi: 10.1098/rspb.2017.2684.
Understanding how growth trajectories of calcifying invertebrates are affected by changing climate requires acclimation experiments that follow development across life-history transitions. In a long-term acclimation study, the effects of increased acidification and temperature on survival and growth of the tropical sea urchin from the early juvenile (5 mm test diameter-TD) through the developmental transition to the mature adult (60 mm TD) were investigated. Juveniles were reared in a combination of three temperature and three pH/CO treatments, including treatments commensurate with global change projections. Elevated temperature and CO/pH both affected growth, but there was no interaction between these factors. The urchins grew more slowly at pH 7.6, but not at pH 7.8. Slow growth may be influenced by the inability to compensate coelomic fluid acid-base balance at pH 7.6. Growth was faster at +3 and +6°C compared to that in ambient temperature. Acidification and warming had strong and interactive effects on reproductive potential. Warming increased the gonad index, but acidification decreased it. At pH 7.6 there were virtually no gonads in any urchins regardless of temperature. The were larger at maturity under combined near-future warming and acidification scenarios (+3°C/pH 7.8). Although the juveniles grew and survived in near-future warming and acidification conditions, chronic exposure to these stressors from an early stage altered allocation to somatic and gonad growth. In the absence of phenotypic adjustment, the interactive effects of warming and acidification on the benthic life phases of sea urchins may compromise reproductive fitness and population maintenance as global climatic change unfolds.
了解钙化无脊椎动物的生长轨迹如何受到气候变化的影响，需要进行适应实验，这些实验需要跟踪生命史转变过程中的发育情况。在一项长期适应研究中，研究了酸化和温度升高对热带海胆从早期幼体（5 毫米测试直径-TD）到发育过渡到成熟成体（60 毫米 TD）的生存和生长的影响。幼体在三种温度和三种 pH/CO 处理的组合中进行培养，其中包括与全球变化预测相符的处理。升高的温度和 CO/pH 都影响了生长，但这两个因素之间没有相互作用。在 pH 7.6 时，海胆生长较慢，但在 pH 7.8 时则不然。生长缓慢可能是由于无法在 pH 7.6 时补偿体腔液酸碱平衡的能力所致。与环境温度相比，在+3 和+6°C 时生长更快。酸化和变暖对生殖潜力有强烈的相互作用。变暖增加了性腺指数，但酸化降低了它。在 pH 7.6 时，无论温度如何，几乎没有任何海胆有性腺。在未来变暖和酸化的综合情景下（+3°C/pH 7.8），海胆在成熟时更大。尽管幼体在未来变暖和酸化条件下生长和存活，但从早期开始，慢性暴露于这些胁迫因素会改变身体和性腺生长的分配。在没有表型调整的情况下，变暖和酸化对海胆底栖生命阶段的相互作用可能会损害生殖适应性和种群维持，因为全球气候变化正在展开。
