Eutrophication decreases salt marsh resilience through proliferation of algal mats
Eutrophication decreases salt marsh resilience through proliferation of algal mats
复制标题
DOI：
10.1016/j.biocon.2017.05.019
复制
发表时间：
2017-08
影响因子：
5.9
通讯作者：
K. Wasson;R. Jeppesen;C. Endris;Danielle C. Perry;A. Woolfolk;Kathryn M. Beheshti;M. Rodríguez;R. Eby;E. Watson;F. Rahman;J. Haskins;Brent B. Hughes
中科院分区：
文献类型：
--
作者：
K. Wasson;R. Jeppesen;C. Endris;Danielle C. Perry;A. Woolfolk;Kathryn M. Beheshti;M. Rodríguez;R. Eby;E. Watson;F. Rahman;J. Haskins;Brent B. Hughes
在全球范围内，许多河口都受到周围流域人类土地使用的营养负荷的影响。营养水平增加的一个后果是机会性大型藻类的增殖。我们试图了解空间和时间动态的短暂的大型藻类垫，并研究其对盐沼的影响，在中央加州的富营养化河口。一个时间序列分析，跨越80年显示，藻藻的频率呈指数增长的盐沼，并在河口，这增加了沿着与化肥使用的营养盐浓度高度相关。沉积物δ 15 N分析表明，在过去的50年中，由于农业肥料的养分负荷急剧增加。我们监测了15个盐沼地块沿着银行边缘，并检测到藻类残骸覆盖和盐沼覆盖，开花，树冠高度之间的负相关关系。此外，藻类的破坏还导致河岸边缘植被的退缩，加剧了河岸侵蚀。我们还实验性地将藻类残骸添加到盐沼边缘地块。藻类增加减少盐沼覆盖，开花，和冠层高度，并增加撤退率。通过整合时间序列分析，同位素数据，藻类和沼泽监测和操纵实验，我们已经确定了强大的联系增加人为营养负荷，增加藻类残骸覆盖，减少沼泽恢复力和沼泽栖息地转化为泥滩通过银行侵蚀。因此，减少富营养化河口的营养输入对于保护和恢复盐沼并增强其在海平面上升面前的恢复力至关重要。
Globally, many estuaries are affected by nutrient loading from human land uses in the surrounding watersheds. One consequence of increased nutrient levels is proliferation of opportunistic macroalgae. We sought to understand spatial and temporal dynamics of ephemeral macroalgal mats and to examine their effects on salt marsh in a eutrophic estuary in central California. A time series analysis spanning 80 years revealed that algal wrack has increased exponentially in frequency on the salt marsh, and was highly correlated with nutrient concentrations in the estuary, which have increased along with fertilizer use. Analysis of sediment δ15N showed a dramatic increase in nutrient loads attributable to agricultural fertilizer over the past 50 years. We monitored 15 salt marsh plots along the bank edge and detected a negative relationship between algal wrack cover and salt marsh cover, flowering, and canopy height. Moreover, algal wrack led to retreat of vegetation from the bank edge, and increased bank erosion. We also experimentally added algal wrack to salt marsh edge plots. Algal addition decreased salt marsh cover, flowering, and canopy height, and increased retreat rate. By integrating time series analyses, isotope data, algal and marsh monitoring and manipulative experiments, we have identified robust linkages between increased anthropogenic nutrient loading, increased algal wrack cover, reduction in marsh resilience and conversion of marsh habitat to mudflat through bank erosion. Decreasing nutrient inputs to eutrophic estuaries is thus essential for conservation and restoration of salt marshes and enhancing their resilience in the face of sea level rise.