Mapping cold-water coral biomass: an approach to derive ecosystem functions
Mapping cold-water coral biomass: an approach to derive ecosystem functions
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DOI：
10.1007/s00338-020-02030-5
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发表时间：
2020-12-04
期刊：
影响因子：
3.5
通讯作者：
Roberts, J. M.
中科院分区：
文献类型：
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作者：
De Clippele, L. H.;Rovelli, L.;Roberts, J. M.
这项研究提出了一种新的方法，产生了第一个冷水珊瑚礁生物量图，用于评估相关的生态系统功能，如碳(C)储量和周转量。我们关注了明古莱珊瑚礁群的两个主要生态系统工程师，珊瑚Lophelia pertusa（碎石，活的和死的框架）和海绵Spongosorites coralliophaga。首先，结合生物（高清视频、采集标本）、环境（多波束测深提取）和生态系统功能（耗氧量值）数据，计算生物量、碳储量和周转量，为碳收支评估提供依据。其次，利用这些值，我们采用随机森林模型来预测整个珊瑚礁的活珊瑚和海绵生物量。据估计，食藻S. coralliophaga的全礁平均生物量为304 T（范围为168-440 T），其中含有10 T（范围为5-18 T）的储量。珊瑚群落（活骨架和死骨架）的平均骨骼质量估计为3874 T（骨骼质量范围为507-9352 T），平均生物量为209 T（生物量范围为26-515 T），平均储量为465 T（生物量范围为60-1122 T）。这些估计值被用来计算碳周转率，使用文献中可用的呼吸数据。这些计算表明，与珊瑚碎石相关的外生和微生物动物群是该地区碳周转量的最大贡献者，平均为163亿吨年（-1）（范围149-176亿吨年（-1））。据估计，活的和死的白杨骨架平均每年翻转32℃（-1）（范围4-93℃（-1））和44℃（-1）（范围6-139℃（-1））。我们的计算表明，明古莱礁的倾覆量是相同深度的软沉积物区域的3到7倍（平均为4倍）。作为概念的证明，从地表水初级生产力向珊瑚礁提供所需的C。由于65-124 T C年（-1）是由自然沉积提供的，我们的研究表明，珊瑚礁翻转了平均241 T C年（-1）（160-400 T C年（-1）），因此珊瑚礁的平均117-176 T C年（-1）（范围36-335 T C年（-1））将由潮汐下流和/或深水平流提供。我们的研究结果表明，监测和/或管理表面初级生产力将是保护冷水珊瑚礁生态系统的关键考虑因素。
This study presents a novel approach resulting in the first cold-water coral reef biomass maps, used to assess associated ecosystem functions, such as carbon (C) stock and turnover. We focussed on two dominant ecosystem engineers at the Mingulay Reef Complex, the coral Lophelia pertusa (rubble, live and dead framework) and the sponge Spongosorites coralliophaga. Firstly, from combining biological (high-definition video, collected specimens), environmental (extracted from multibeam bathymetry) and ecosystem function (oxygen consumption rate values) data, we calculated biomass, C stock and turnover which can feed into assessments of C budgets. Secondly, using those values, we employed random forest modelling to predictively map whole-reef live coral and sponge biomass. The whole-reef mean biomass of S. coralliophaga was estimated to be 304 T (range 168-440 T biomass), containing 10 T C (range 5-18 T C) stock. The mean skeletal mass of the coral colonies (live and dead framework) was estimated to be 3874 T (range 507-9352 T skeletal mass), containing a mean of 209 T of biomass (range 26-515 T biomass) and a mean of 465 T C (range 60-1122 T C) stock. These estimates were used to calculate the C turnover rates, using respiration data available in the literature. These calculations revealed that the epi- and microbial fauna associated with coral rubble were the largest contributor towards C turnover in the area with a mean of 163 T C year(-1) (range 149-176 T C year(-1)). The live and dead framework of L. pertusa were estimated to overturn a mean of 32 T C year(-1) (range 4-93 T C year(-1)) and 44 T C year(-1) (range 6-139 T C year(-1)), respectively. Our calculations showed that the Mingulay Reef overturned three to seven (with a mean of four) times more C than a soft-sediment area at a similar depth. As proof of concept, the supply of C needed from surface water primary productivity to the reef was inferred. Since 65-124 T C year(-1) is supplied by natural deposition and our study suggested that a mean of 241 T C year(-1) (range 160-400 T C year(-1)), was turned over by the reef, a mean of 117-176 T C year(-1) (range 36-335 T C year(-1)) of the reef would therefore be supplied by tidal downwelling and/or deep-water advection. Our results indicate that monitoring and/or managing surface primary productivity would be a key consideration for any efforts towards the conservation of cold-water coral reef ecosystems.