Belowground stressors and long-term seagrass declines in a historically degraded seagrass ecosystem after improved water quality
Belowground stressors and long-term seagrass declines in a historically degraded seagrass ecosystem after improved water quality
复制标题
DOI：
10.1038/s41598-017-14044-1
复制
发表时间：
2017-10-31
影响因子：
4.6
通讯作者：
Kendrick, Gary A.
中科院分区：
文献类型：
--
作者：
Fraser, Matthew W.;Kendrick, Gary A.
在水质改善的生态系统中，海草数量持续减少可能是沉积物压力造成的。最常被引用的海草生态系统衰退的例子之一是西澳大利亚州的科伯恩湾，在20世纪60年代至80年代，由于水质差，75%的海草（2169公顷）消失了。科伯恩湾的水质随后有所改善，但一些地区的芽密度继续下降。在这里，我们调查了沉积物的压力（硫化物入侵和重金属）下降Posidonia sinuosa拍摄密度在科伯恩声音。海草d34S耗尽的网站与海草下降的历史，表明在这些网站的海草硫化物胁迫。沉积物和海草中的重金属（铁，锌，锰，铬，铜和镉）没有显示出明确的模式与拍摄密度或生物量，并大大减少了类似的测量在20世纪70年代末。而海草镉浓度与海草生物量和地上部密度呈负相关。高浓度的镉会干扰陆生植物的硫代谢，但对海草的影响仍有待探讨。鉴于硫化物入侵可以阻止海草重新定居并导致海草数量减少，退化海草生态系统的管理计划应包括对沉积物压力源和水质的管理，以提供全面的管理。
Continued seagrass declines in ecosystems with improved water quality may be driven by sediment stressors. One of the most cited examples of a seagrass ecosystem with declines is Cockburn Sound, Western Australia, where 75% of seagrasses (2169 ha) were lost in the 1960s-1980s due to poor water quality. Water quality has subsequently improved in Cockburn Sound, yet shoot density declines continue in some areas. Here, we investigated if sediment stressors (sulfide intrusion and heavy metals) contributed to declining Posidonia sinuosa shoot densities in Cockburn Sound. Seagrass d34S were depleted at sites with a history of seagrass declines, indicating seagrasses at these sites were under sulfide stress. Heavy metals (Fe, Zn, Mn, Cr, Cu and Cd) in sediments and seagrasses did not show clear patterns with shoot density or biomass, and largely decreased from similar measurements in the late 1970s. However, seagrass cadmium concentrations were negatively correlated to seagrass biomass and shoot density. High cadmium concentrations interfere with sulfur metabolism in terrestrial plants, but impacts on seagrasses remain to be explored. Given that sulfide intrusion can prevent recolonization and drive seagrass declines, management plans in degraded seagrass ecosystems should include management of sediment stressors and water quality to provide comprehensive management.