Canopy effects of octocoral communities on sedimentation: modern baffles on the shallow-water reefs of St. John, USVI
Canopy effects of octocoral communities on sedimentation: modern baffles on the shallow-water reefs of St. John, USVI
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DOI：
10.1007/s00338-021-02053-6
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发表时间：
2021-01-29
期刊：
影响因子：
3.5
通讯作者：
Lasker, H. R.
中科院分区：
文献类型：
--
作者：
Cerpovicz, A. F.;Lasker, H. R.
最近在浅加勒比海珊瑚礁的存在和丰富的物种的变化已经离开珊瑚礁作为一些珊瑚礁的主导功能组，创造了一个'动物森林'与相关的树冠。这种过渡改变了珊瑚礁的轮廓，可能影响水流和沉积作用。我们研究了沉积环境上的浅水边缘礁系统的南海岸的圣约翰，USVI的珊瑚林的影响。沉积环境的特点是冠层或非冠层的基础上的珊瑚密度。在15个成对的位置使用土块卡和沉积物捕集器的珊瑚冠层的流动和沉积的影响进行了评估。珊瑚礁的树冠改变了水流，导致树冠内的湍流程度更高。在密集的珊瑚冠层地区的沉积物陷阱积累了大量的沉积物，颗粒较粗，较圆。沉积物中的有机物含量收集的陷阱是更大的树冠内比外面it.The增加的湍流树冠内可能是由于波驱动的振荡流相互作用的珊瑚群落。沉积物陷阱在树冠可能有更大的沉积物积累，由于再悬浮的沉积物从树冠内和沉积的进口沉积物流量减少树冠内。珊瑚冠层的存在和沉积物在其中的改造可能会影响成功的解决幼虫和珊瑚礁结构的演变。
Recent shifts in the presence and abundance of species on shallow Caribbean coral reefs have left octocorals as the dominant functional group on some reefs, creating an 'animal forest' with an associated canopy. This transition changes the reef profile potentially affecting flow and sedimentation. We examined the effects of an octocoral forest on the depositional environment on a shallow-water fringing reef system on the south shore of St. John, USVI. The depositional environment was characterized as canopy or non-canopy based on octocoral density. The effect of the octocoral canopy on flow and sedimentation was assessed using clod cards and sediment traps at 15 paired locations. The octocoral canopy altered flow resulting in greater levels of turbulence within the canopy. Sediment traps in areas of dense octocoral canopy accumulated greater amounts of sediment, with coarser, more rounded grains. Organic content of sediments collected in the traps was greater within the canopy than outside of it. The increase in turbulence within the canopy was likely due to wave-driven oscillatory flow interacting with the octocoral colonies. Sediment traps in the canopy likely had greater sediment accumulation due to both resuspension of sediments from within the canopy and deposition of imported sediments as flow decreased within the canopy. The presence of octocoral canopies and the reworking of sediment within them may affect the success of settling larvae and the evolution of reef structure.