Are Tidal Salt Marshes Exposed to Nutrient Pollution more Vulnerable to Sea Level Rise?

Over the past four decades, Long Island, NY, USA, has lost coastal
wetlands at a rate of 4% per decade due to submergence. In this study, we
examined relationships between the rate of tidal salt marsh loss and
environmental factors, including marsh elevation, tidal range, and
wastewater exposure through analysis of stable isotope ratios of marsh
soils and biota. Our goal was to identify factors that increase
vulnerability of marshes to sea level rise, with a specific emphasis on
the potential role of poor water quality in hastening marsh loss. Our
results suggest that wastewater exposure may accelerate loss of intertidal
marsh, but does not negatively impact high tidal marsh resilience to sea
level rise. And while marsh elevation and tidal range were statistically
significant predictors of marsh loss, they similarly displayed opposite
relationships among marsh zones. This study suggests that different
functional zones of coastal salt marshes may not respond similarly to
global change factors, and that elevation may be an important factor
mediating eutrophication effects to coastal salt marshes.

过去四十年来，美国纽约州长岛因海平面淹没，以每十年4%的速率丧失滨海湿地。本研究通过分析盐沼土壤与生物群落的稳定同位素比值（stable isotope ratios），探究了潮间带盐沼（tidal salt marsh）丧失速率与环境因子（包括盐沼高程、潮差及废水暴露）之间的关联。本研究旨在识别提升盐沼对海平面上升脆弱性的因子，重点关注水质恶化在加速盐沼丧失过程中的潜在作用。研究结果表明，废水暴露可能加速潮间带盐沼的丧失，但不会对高潮位盐沼应对海平面上升的抗逆能力产生负面影响。尽管盐沼高程与潮差是盐沼丧失的统计学显著预测因子，但二者在不同盐沼带中呈现出相反的关联关系。本研究提示，滨海盐沼的不同功能带对全球变化因子的响应可能存在差异，且高程可能是介导富营养化（eutrophication）对滨海盐沼影响的关键因子。