Short-term growth and biomechanical responses of the temperate seagrass Cymodocea nodosa to CO2 enrichment
Short-term growth and biomechanical responses of the temperate seagrass Cymodocea nodosa to CO2 enrichment
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DOI：
10.3354/meps12153
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发表时间：
2017-05-31
影响因子：
2.5
通讯作者：
Solan, Martin
中科院分区：
文献类型：
--
作者：
de los Santos, Carmen B.;Godbold, Jasmin A.;Solan, Martin
海草通常被认为是气候变化的“赢家”，因为当它们暴露在日益加剧的海洋酸化环境中时，它们表现出更高的光合作用、碳固定和生长速率。然而，问题仍然存在，这种生长增强是否损害了植物的生物力学特性，改变了它们对结构损伤和叶片脱落的脆弱性。本文研究了CO2富集降低pH对温带海草Cymodocea nodosa生长、形态和破叶力的短期（6周）影响。研究发现，短期气候变化预估值（pH 8.04）下的植物生物量平衡为正，导致茎叶丰度增加。然而，我们还发现，在当前酸化水平（pH值8.29）和长期酸化水平（pH值7.82）下，植物生物量平衡为负。叶片形态（平均叶片长度、厚度和宽度）在我们施加的酸化梯度中是不变的，尽管叶片在代表短期气候变化的[CO2]下略强。综上所述，这些发现表明，随着海洋化学的中短期变化，结藻的生长和机械抗性可能会出现微妙的增加，但这些积极影响不太可能在长期内保持。我们的研究强调，在考虑气候变化的可能后果时，需要考虑环境条件与海草群落结构和功能的多个方面的变化之间的相互依赖性。
Seagrasses are often regarded as climate change 'winners' because they exhibit higher rates of photosynthesis, carbon fixation and growth when exposed to increasing levels of ocean acidification. However, questions remain whether such growth enhancement compromises the biomechanical properties of the plants, altering their vulnerability to structural damage and leaf loss. Here, we investigated the short-term (6 wk) effects of decreasing pH by CO2 enrichment on the growth, morphology and leaf-breaking force of the temperate seagrass Cymodocea nodosa. We found that the plant biomass balance under levels of acidification representative of short-term climate change projections (pH 8.04) was positive and led to an increase in leaf abundance in the shoots. However, we also found that plant biomass balance was negative under levels of acidification experienced presently (pH 8.29) and those projected over the long-term (pH 7.82). Leaf morphology (mean leaf length, thickness and width) was invariant across our imposed acidification gradient, although leaves were slightly stronger under [CO2] representative of short-term climate change. Taken together, these findings indicate that a subtle increase in growth and mechanical resistance of C. nodosa is likely to occur following short-to medium-term changes in ocean chemistry, but that these positive effects are unlikely to be maintained over the longer term. Our study emphasises the need to account for the interdependencies between environmental conditions and variations in multiple aspects of the structure and functioning of seagrass communities when considering the likely consequences of climate change.