Water quality of pocosins and associated wetlands of the Carolina Coastal Plain

Abstract

We reviewed literature data on pocosins and associated wetlands of the Carolina coastal plain to 1) characterize the surface and subsurface water quality of undisturbed pocosins, 2) identify the processes controlling solution C, N, and P concentrations, and 3) examine the effects of disturbance on water quality and nutrient export. We hypothesized that the key to predicting nutrient losses from disturbed pocosins lies in understanding how disturbance affects both hydrologic export and the processes controlling solution C, N, and P concentrations. Since the development of pocosins for commercial forestry and agriculture involves a complex series of disturbances (drainage, vegetation removal, fire, and fertilization), we analyzed the specific effects of these component disturbances as well as the composite effects of agricultural and silvicultural development.Surface and subsurface waters of undisturbed pocosins are dominated by H + cations (100 -1000 geq/L) and SO+ z-anions (475 tzeq/L), with Ca2+ concentrations below 50 p.eq/L, and are chemically similar to more northern ombrotmphic bogs. However, pocosin waters are more acid and contain higher concentratiom of Na +, SO42-, and CI-, probably due to their coastal environment. Solution export of N from undisturbed pocosins is primarily as organic N (74 -88%), but even though organic P comprises 73 -93 % of total dissolved P in subsurface pore waters, 57 -87% of P exported is inorganic PC)+ 3". C:P ratios increase during the growing season in subsurface waters from 2355:1 in June to 9563:1 in August, as soluble organic P and PO43supply to in situ anion-exchange resins decline.Biological processes control C, N, and P transformations in pocosin soils and are strongly influenced by hydrology and P availability. Seasonal changes in water table depth suggest seasonal fluctuations in soft redox potential that could affect a variety of processes controlling water quality and nutrient export and may cause changes in the source o f pocosin drainage waters (surface, subsurface, or mineral soil), thus affecting water qua]i T. Phosphorus availability limits plant growth and may play an important roIe in controlling nutrient export due to its potential influence on rates of C, N, and P cycling.Drainage of otherwise undisturbed pocosins does not affect total runoff volume but may affect nutrient export due to changes in the source of drainage waters. Drainage coupled 418 WETLANDS, Volume 11, Special Issue, 1991 with vegetation removal increases total runoff, increasing freshwater inputs downstream. Fire increases soil nu~ient availability and may increase nutrient export when coupled with v egetation removal. Fertilization effects on nutrient export will be determined by fertilization frequency and by the degree of saturation of the immobilization capacity of soil mi~oorgan-isms, the uptake capacity of plant roots, and the sorption capacity of soil minerals. Agricultural development increases C, N, and P concentrations in drainage waters and N and P export. Silviculture may ha...

Human Impacts on Macrophyte Diversity, W Ater Quality and Some Soil Properties in the Madikane and Dufuya Wetlands of Lower Gweru, Zimbabwe

“…The high concentrations of total nitrogen recorded in water from both dambos ( Table 4) are not an unusual feature as it is a characteristic of water from peat soils. The levels of nitrogen recorded in this study are close to those reported in Carolina and coastal wetlands (Bruland et al, 2003;Walbridge and Richardson, 1991). Most of the nitrogen recorded in water could have been derived from peat soils through nitrification of ammonia produced from organic matter decomposition (Avinmelech et al, 1978) as evidenced by the high levels of nitrogen in the soil.…”

Restored Wetlands in Mid-Atlantic Agricultural Landscapes Enhance Species Richness of Amphibian Assemblages

“…The low pH of water on peat lands may have contributed to the lack of amphibian larvae at these sites. A pH below 6.3 limits anuran sperm mobility (Freda and Taylor 1992), and pH at natural and restored sites in this area are well below this value (Walbridge and Richardson 1991;Ducey et al 2011). Restoration site selection for this study was conducted by state NRCS staff and intended to be representative of restorations within the Coastal Plain physiographic province of their state.…”

Wetlands: History, Current Status, and Future

“…On mineral soils, the major problem appears to arise from increased sediment in ditches soon after construction and from surface material added to logging roads [30,31]. However, Richardson [32] and Walbridge and Richardson [33] estimated that *Native American word meaning "swamp on a hill." +Criteria used to determine which wetlands fall under the Clean Water Act jurisdictions.…”