Megafaunal Ecology of the Western Clarion Clipperton Zone
Megafaunal Ecology of the Western Clarion Clipperton Zone
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DOI：
10.3389/fmars.2021.671062
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发表时间：
2021-07-01
影响因子：
3.7
通讯作者：
Smith, Craig R.
中科院分区：
文献类型：
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作者：
Durden, Jennifer M.;Putts, Meagan;Smith, Craig R.
克拉里昂克利珀顿区(CCZ)是中太平洋的一个广阔区域，深海海床是未来多金属结核开采的重点。CCZ海床从东到西呈现出大范围的环境梯度，包括影响底栖动物群落结构和功能的有机质供应和结核丰度。整个CCZ的保护区网络被称为特殊环境关注区(APEIS)，已被指定涵盖这一变化。以前对底栖环境和大型动物群落的大多数研究都集中在CCZ东部，没有研究这些大规模梯度的影响，也没有对网络设计进行测试。海山是该区域非均质性的另一个来源。我们研究了CCZ西部三个顶端的大型底栖动物生态，跨越了一系列的环境条件。我们使用海底摄影和直接采样相结合的方法，评估了三个Apei的深海平原和其中两个Apei的海山上的环境和大型动物栖息地。我们发现，三个深海平原的环境条件在水深、结核丰度和覆盖度、沉积物粒度分布和估计的有机质通量方面有所不同。大型底栖动物密度低，多样性高，站位间常见的形态类型很少，许多形态类型只能观察到一次。异生生物在组合中占主导地位。有机质输入越少，结节丰度越高，无脊椎动物的密度和多样性越大。与平原相比，同一峰顶的海山没有结核，沉积物也更粗。海山上的无脊椎动物大型动物多样性低于平原，海山上记录的大多数形态类型只在海山上发现。低的地貌类型重叠也表明Apeis之间以及海山和邻近的深海平原之间几乎没有连通性。我们的结果首次对CCZ西部的海底生境和大型动物生态进行了评估，突出了影响底栖生物群落的环境梯度，并对评估保护区网络的设计具有重要意义。
The Clarion Clipperton Zone (CCZ) is a vast area of the central Pacific Ocean where the abyssal seabed is a focus for future polymetallic nodule mining. Broad-scale environmental gradients occur east-to-west across the CCZ seabed, including organic matter supply and nodule abundance, factors that influence benthic faunal community structure and function. A network of protected areas across the CCZ, called Areas of Particular Environmental Interest (APEIs), has been designated to cover this variation. Most previous studies of the benthic environment and megafaunal communities have focussed on the eastern CCZ, leaving the impact of these large-scale gradients unexamined and the network design untested. Seamounts are a further source of heterogeneity in the region. We examined the benthic megafaunal ecology of three APEIs in the western CCZ, spanning a range of environmental conditions. We used a combination of seabed photography and direct sampling to assess the environment and megafauna on the soft sediment habitats on the abyssal plain in three APEIs, and seamounts in two of those APEIs. We found that environmental conditions on abyssal plains differed between the three APEIs in terms of water depth, nodule abundance and coverage, sediment particle size distribution, and estimated organic matter flux. Megafauna were low density and high diversity, with few common morphotypes between sites and many morphotypes being observed only once. Xenophyophores dominated the assemblages. The density and diversity of invertebrates were greater at the sites with lower organic matter inputs and greater nodule abundance. Seamounts in the same APEIs were nodule-free and had coarser sediments than on the plain. Invertebrate megafaunal diversity was lower on the seamounts than on the plains, and most morphotypes recorded on the seamounts were only found on seamounts. Low morphotype overlap also suggests little connectivity between APEIs, and between seamounts and adjacent abyssal plains. Our results provide the first evaluation of the seabed habitats and megafaunal ecology in the western CCZ, highlighting environmental gradients that influence benthic communities, and are important for evaluating the design of the network of protected areas.