Godbold Jasmin A, Hale Rachel, Wood Christina L, Solan Martin
1Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, European Way, Southampton, SO14 3ZH UK.
2Biological Sciences, University of Southampton, Highfield Campus, Southampton, SO17 1BJ UK.
Biogeochemistry. 2017;135(1):89-102. doi: 10.1007/s10533-017-0340-y. Epub 2017 Jun 9.
Fundamental changes in seawater carbonate chemistry and sea surface temperatures associated with the ocean uptake of anthropogenic CO are accelerating, but investigations of the susceptibility of biogeochemical processes to the simultaneous occurrence of multiple components of climate change are uncommon. Here, we quantify how concurrent changes in enhanced temperature and atmospheric pCO, coupled with an associated shift in macrofaunal community structure and behavior (sediment particle reworking and bioirrigation), modify net carbon and nutrient concentrations (NH-N, NO-N, PO-P) in representative shelf sea sediment habitats (mud, sandy-mud, muddy-sand and sand) of the Celtic Sea. We show that net concentrations of organic carbon, nitrogen and phosphate are, irrespective of sediment type, largely unaffected by a simultaneous increase in temperature and atmospheric pCO. However, our analyses also reveal that a reduction in macrofaunal species richness and total abundance occurs under future environmental conditions, varies across a gradient of cohesive to non-cohesive sediments, and negatively moderates biogeochemical processes, in particular nitrification. Our findings indicate that future environmental conditions are unlikely to have strong direct effects on biogeochemical processes but, particularly in muddy sands, the abundance, activity, composition and functional role of invertebrate communities are likely to be altered in ways that will be sufficient to regulate the function of the microbial community and the availability of nutrients in shelf sea waters.
与海洋吸收人为排放的二氧化碳相关的海水碳酸盐化学和海表温度的根本变化正在加速，但关于生物地球化学过程对多种气候变化因素同时出现的敏感性的研究却并不常见。在此，我们量化了温度升高和大气pCO₂的同时变化，以及大型动物群落结构和行为（沉积物颗粒再加工和生物灌溉）的相关转变，如何改变凯尔特海代表性陆架海沉积物栖息地（泥质、砂泥质、泥砂质和砂质）中的净碳和营养物浓度（NH₄-N、NO₃-N、PO₄-P）。我们发现，无论沉积物类型如何，有机碳、氮和磷的净浓度在很大程度上不受温度和大气pCO₂同时升高的影响。然而，我们的分析还表明，在未来环境条件下，大型动物物种丰富度和总丰度会降低，这种降低在从粘性沉积物到非粘性沉积物的梯度上有所不同，并且对生物地球化学过程产生负面影响，尤其是硝化作用。我们的研究结果表明，未来环境条件不太可能对生物地球化学过程产生强烈的直接影响，但特别是在泥砂质沉积物中，无脊椎动物群落的丰度、活性、组成和功能作用可能会发生改变，这些改变足以调节微生物群落的功能以及陆架海水中营养物的可用性。
