Novak J M, Watts D W
USDA-ARS-Coastal Plains Soil, Water and Plant Research Center, 2611 West Lucas St., Florence, SC 29501, USA.
J Environ Qual. 2006 Oct 27;35(6):1975-82. doi: 10.2134/jeq2006.0077. Print 2006 Nov-Dec.
A close relationship has been reported between sediment organic C (SedOC) content and its P sorption capacity (P(max)) and total P (TP) concentration. Phosphorus sorbed to organically complexed cations is a proposed explanation for this relationship. The objectives of this study were (i) to determine relationships between in-stream wetland SedOC content and both the sediment's P(max) and TP concentrations, and (ii) to ascertain the role of both organically complexed and oxalate-extractable cations on the sediment P(max) and TP values. The sediment's oxalate-extractable Fe (Fe(ox)) and Al (Al(ox)) contents were determined using acidified ammonium oxalate, while sodium pyrophosphate was used to extract organically complexed cations (Al(pryo), Ca(pyro), Fe(pyro), Mg(pyro), and Mn(pyro)). Both the sediment's P(max) and TP contents were strongly correlated with its SedOC concentration (r(2) > 0.90, P < 0.001). Only the Al(ox) contents were significantly correlated with TP and P(max), suggesting that amorphous Al forms have an important role in P sorption. All five pyrophosphate-extracted cations were significantly correlated with SedOC contents. Regression analyses showed that the Al(pyro) accounted for 88% of the variation in sediment P(max) values, whereas a combination of Al(pyro) and Ca(pyro) accounted for 98% of the variation in sediment TP concentrations. Additionally, Al and Ca chelated by SedOC compounds also have an important role in P binding and indicate that a linkage exists between the wetlands SedOC and P(max) content and its ability to accumulate TP. This study identified that two different mechanisms have significant roles in regulating P sorption by sediments in a southeastern Coastal Plain in-stream wetland.
据报道，沉积物有机碳（SedOC）含量与其磷吸附容量（P(max)）和总磷（TP）浓度之间存在密切关系。磷吸附到有机络合阳离子上被认为是这种关系的一种解释。本研究的目的是：（i）确定溪流湿地SedOC含量与沉积物的P(max)和TP浓度之间的关系，以及（ii）确定有机络合阳离子和草酸盐可提取阳离子对沉积物P(max)和TP值的作用。使用酸化草酸铵测定沉积物的草酸盐可提取铁（Fe(ox)）和铝（Al(ox)）含量，而使用焦磷酸钠提取有机络合阳离子（Al(pryo)、Ca(pyro)、Fe(pyro)、Mg(pyro)和Mn(pyro)）。沉积物的P(max)和TP含量均与其SedOC浓度密切相关（r(2)>0.90，P<0.001）。只有Al(ox)含量与TP和P(max)显著相关, 表明无定形铝形态在磷吸附中起重要作用。所有五种焦磷酸钠提取的阳离子均与SedOC含量显著相关。回归分析表明，Al(pryo)占沉积物P(max)值变化的88%，而Al(pryo)和Ca(pyro)的组合占沉积物TP浓度变化的98%。此外，被SedOC化合物螯合的铝和钙在磷结合中也起重要作用，表明湿地SedOC与P(max)含量及其积累TP的能力之间存在联系。本研究确定，两种不同机制在调节东南部沿海平原溪流湿地沉积物的磷吸附中起重要作用。
