Recovery of the seabed following marine aggregate dredging on the Hastings Shingle Bank off the southeast coast of England
Recovery of the seabed following marine aggregate dredging on the Hastings Shingle Bank off the southeast coast of England
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DOI：
10.1016/j.ecss.2007.06.004
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发表时间：
2007-12-01
影响因子：
2.8
通讯作者：
Vanstaen, Koen
中科院分区：
文献类型：
--
作者：
Cooper, Keith;Boyd, Sian;Vanstaen, Koen
本研究的目的是调查疏浚强度对海底的物理和生物恢复时间的影响。在Hastings Shingle岸确定了两个海底区域，以前分别受到相对较高和较低程度的疏浚强度。还选择了两个参照区进行比较。在2001 - 2004年期间，每年都对所有四个地点进行监测，采用声、视频和抓取取样相结合的技术。由于该场地最后一次疏浚是在1996年，因此旨在提供疏浚停止后5 - 8年的数据序列。然而，在2002年和2003年期间，意外地恢复了在高强度场地内的疏浚工作，从而得以对海底重新疏浚的直接影响和后果进行额外评估。在2003年疏浚停止后，可以对恢复的早期阶段进行评估。从疏浚现场的结果提供了一个有用的洞察早期和后期阶段的物理和生物恢复。最近和历史上的疏浚轨道特征的比较提供了轨道侵蚀的证据。然而，在停止疏浚8年后，仍然可以看到痕迹。在高疏浚强度的工地内，自2003年停止疏浚后，石化化相对较快。而不是表明一个完全恢复，我们认为，这个最初的“殖民社区”可能会进入一个过渡阶段，最终达到平衡。这一假设得到了低烈度场址的结果的支持，据判断，该场址的生物恢复需要7年时间。需要进一步监测以检验这一点。另一种解释是，快速恢复可能是由于大量的Sabellaria spinulosa定居。由于在高密度场地内恢复疏浚限制了我们对长期恢复的评估，因此尚不可能假设7年的生物恢复期将适用于该地点或更远地点的其他更密集疏浚区域。皇冠版权所有（C）2007由爱思唯尔有限公司出版。保留所有权利。
The aim of this study was to investigate the effect of dredging intensity on the physical and biological recovery times of the seabed following marine aggregate dredging. Two areas of seabed, previously subject to, respectively, relatively high and lower levels of dredging intensity, were identified on the Hastings Shingle Bank. Two reference areas were also selected for comparative purposes. All four sites were monitored annually over the period 2001-2004, using a combination of acoustic, video and grab sampling techniques. Since the site was last dredged in 1996, this was intended to provide a sequence of data 5-8 years after cessation of dredging. However, an unexpected resumption of dredging within the high intensity site, during 2002 and 2003, allowed an additional assessment of the immediate effects and aftermath of renewed dredging at the seabed. The early stages of recovery could then be assessed after dredging ceased in 2003. Results from both dredged sites provide a useful insight into the early and latter stages of physical and biological recovery. A comparison of recent and historic dredge track features provided evidence of track erosion. However, tracks were still visible 8 years after the cessation of dredging. Within the high dredging intensity site, recolonisation was relatively rapid after the cessation of dredging in 2003. Rather than indicating a full recovery, we suggest that this initial 'colonization community' may enter a transition phase before eventually reaching equilibrium. This hypothesis is supported by results from the low intensity site, where biological recovery was judged to have taken 7 years. Further monitoring is needed in order to test this. An alternative explanation is that the rapid recovery may be explained by the settlement of large numbers of Sabellaria spinulosa. As the resumption of dredging within the high intensity site limited our assessment of longer-term recovery it is not yet possible to assume that a 7-year biological recovery period will be applicable to other, more intensively dredged areas at this or more distant locations. Crown Copyright (C) 2007 Published by Elsevier Ltd. All rights reserved.