LTREB: Long Term Studies of Salt Marsh Primary Production

这项研究的长期目标是了解盐沼初级生产和土壤化学如何随着人为和自然环境的变化而变化。这项正在进行的研究结果表明，不同年份的盐沼产量存在很大差异，这似乎是由沼泽土壤的盐浓度引起的，海平面、洪水频率、土壤化学和化学循环之间的复杂相互作用不仅影响盐沼，还影响与盐沼相关的整个河口。已建立的沼泽生产力增加、高土壤盐度和海平面上升之间的关系表明，在两种情况下，生产力将下降：1)盐沼的相对海拔上升并变得不利于生长，或2)目前的快速海平面上升速度下降。建议在今后五年进行研究，以检验下列假设：第一，当海平面上升速度减慢或逆转时，长期观察到的沼泽初级生产力的增加将会逆转；其次，沼泽土壤中养分浓度的长期变化将与沼泽产量的变化平行。这项研究将为预测沿海湿地对海平面变化的反应提供科学依据——海平面变化在路易斯安那州等沿海地区尤为重要。它还提供了有助于环境管理者了解水质趋势的结果。这项研究还为几个更广泛的倡议做出了贡献，这些倡议的重点是了解盐沼生态，并由几个联邦机构资助。

The long-term goal of this research is to understand how salt marsh primary production and soil chemistry will change in response to increasing anthropogenic and natural environmental modifications. Results from this ongoing study show that there are large differences between years in salt marsh production that appear to be caused by salt concentration of marsh soils, and that complex interactions among sea level, flooding frequency, soil chemistry and chemical cycles affect not only salt marshes, but their entire associated estuaries. The established relationship between increasing marsh productivity, high soil salinity and increasing sea level rise suggests that productivity will decline under two conditions: 1) the relative elevation of the salt marsh rises and becomes unfavorable for growth or 2) the current rapid rate of sea level rise decreases. Research is proposed over the next five years that will test the following hypotheses: first, the long-term observed increase in marsh primary production will reverse when the rate of sea level rise slows or reverses; and second, long-term changes in nutrient concentrations in marsh soils will parallel changes in marsh production. This study will provide a scientific basis for predicting how coastal wetlands will respond to changing sea level - a problem of particular importance in coastal areas like Louisiana. It also provides results that will help environmental managers to understand trends in water quality. The study also contributes to several broader initiatives focused on understanding salt marsh ecology, and funded by several federal agencies.