From the headwaters to the sea:The role of riparian,alluvial,and tidal wetlands to filter nutrients and ameliorate eutrophication  

作　　者：Christopher B.Craft Shanze Li Tian Xie 

机构地区：[1]School of Public and Environmental Affairs,Indiana University,Indiana,Bloomington,USA [2]University of Georgia Marine Institute,Darien,Georgia,USA [3]State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research,Beijing,China [4]Department of Water Ecology and Environment,China Institute of Water Resources and Hydropower Research,Beijing,China [5]State Key Joint Laboratory of Environmental Simulation and Pollution Control,School of Environment,Beijing Normal University,Beijing,China

出　　处：《River》2022年第2期133-141,共9页江河(英文)

基　　金：supported by Grants OCE-062059,OCE-1237140,and OCE-1832178 from the National Science Foundation;This is the University of Georgia Marine Institute Publication Number 1106.

摘　　要：Wetlands are known for their ability to trap sediment and eliminate pollutants from the surrounding catchment.However,less is known regarding the differential role of headwater,mid-catchment,and coastal wetlands in filtering these materials.Soil accretion,organic carbon(C),total nitrogen(N),and total phosphorus(P)were measured in wetlands from the headwaters to the mouth of the Altamaha River,Georgia,USA to assess how sediment deposition,C sequestration,and N and P burial vary along the waterway.Soil cores(n=2 per site)were collected from riparian,upper and lower alluvial,tidal freshwater forest and marsh,brackish marsh,and salt marsh.Two-centimeter depth increments were analyzed for^(137)Cs,to determine soil accretion,bulk density,and C,N,and P concentration.Accretion exhibited a bimodel distribution with the highest rates in riparian wetlands of the headwaters(3.9 mm/year)and in tidal fresh and brackish marshes(4.7–5.4 mm/year)of the estuary.Accretion rates were considerably lower in alluvial and tidal fresh forests and salt marshes(0.9–2.5 mm/year).Carbon sequestration and N burial followed a similar trend with the greatest accumulation in soils of tidal fresh and brackish marshes(102–150 g C/m^(2)/year,7.1–9.5 g N/m^(2)/year)that had not only high accretion but also high organic matter content(11%–12%C).Riparian soils with their low C content,high bulk density,and high P content had much greater sediment deposition(3310 g/m^(2)/year)and P burial(2.75 g P/m^(2)/year)than other wetlands along the waterway(180–1730 g sediment/m^(2)/year,0.23–0.90 g P/m^(2)/year).Results suggest that,in the Altamaha River,sediment deposition and P removal are maximized in the headwaters thereby protecting downstream freshwaters from the effects of P eutrophication.Tidal fresh and brackish marshes with their high rates of N burial can aid in protecting estuaries from N enrichment,many of which suffer from the effects of N eutrophication.Results from this study are scalable to other rivers of the southeastern U.S.pied

关 键 词：EUTROPHICATION organic matter soil accretion topography WETLANDS 

分 类 号：P73[天文地球—海洋科学]