Most of the coastal wetlands of the South Atlantic region of the United States are expected to diminish in size in response to the opposing forces of increasing human population growth and accelerating rates of rising sea level. We evaluated several models that project the response of coastal wetlands to rising sea level and concluded that current models appear unsuited for wetlands of the Albermarle‐Pamlico peninsula of North Carolina. We came to this conclusion after we examined the distribution of wetlands, elevation contours, estimates of surface slope, soil types, and peat deposits on the peninsula. Most of the data were obtained from U.S. Geological Survey topographic quadrangle maps, U.S. Fish and Wildlife Service National Wetlands Inventory maps, U.S. Soil Conservation Service soil surveys, and inventories of peat deposits. Some unusual features of this peninsula are low elevation (56% of total area <1.5 m), extensive coverage by wetlands (53%) and hydric soils (90%), negligible slopes of the land surface, virtual absence of tides, and lack of abundant sources of sediment. In the process of reconstructing how past rises in sea level most likely led to present conditions, it became apparent that vertical accretion of peat in situ is largely responsible for landscape features in areas where elevations are lowest. Were it not for these deposits, the land surface area of the peninsula would be decreasing relative to sea level. This situation contrasts sharply with areas in the eastern United States fringed by tidal marshes, which are undergoing overland migration at a rate dictated by landward slope and the rate of rising sea level. If the rate of sea level rise accelerates, it is doubtful if vertical accretion rates of peat can prevent submergence of extensive areas of wetlands in the Albermarle‐Pamlico peninsula. Land use and drainage in the lowest elevations of the peninsula are currently being affected by sea level. Future land management of the peninsula will be constrained by potential landscape changes as a result of rising sea level.

The extent of O2 transport from aerial plant tissue into the root zone was evaluated for several floating and emergent aquatic macrophytes that have characteristics favorable for wastewater treatment. The highest O2 transport rates from aerial tissue into the root zone were associated with plants having a small root mass. As root mass increased, the rate of O2 transport decreased for aquatic macrophytes evaluated. Pennywort (Hydrocotyle umbellata L.) had the highest O2 transport rate of all aquatic macrophytes with an overall rate of 3.49 g O2 kg−1 dry root mass h−1. Pickerelweed (Pontederia cordata L.) had the highest O2 transport capacity of emergent plants with a rate of 1.54 g O2 kg−1 h−1. Waterhyacinth [Eichhornia crassipes (Mart.) Sollms], an important floating aquatic plant in wastewater treatment, had a transport rate of 1.24 g O2 kg−1 h−1. Nitrification in a waterhyacinth‐based water treatment system due to O2 transport was calculated to vary from 6 to 22 kg ha−1 d−1.

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Multiple stable isotopes were used to determine the effectiveness of distinguishing among several dominant riparian species and aquatic macrophytes both spatially (three sites) and temporally (three seasons) along an 8-km reach of a blackwater stream. The differences in isotopic composition were used to assess contributions of various organic matter sources to the detrital pool of the stream. Samples of riparian and aquatic macrophyte vegetation and detritus were collected at three times to represent early leaf-out (April), mid-summer (August), and just prior to abscission (October). Each sample was analyzed for stable isotopes of carbon δC, nitrogen δN, and sulfur δS Within a site and sampling date, δC-values were significantly different among certain riparian species and detritus samples. Species differences persisted between seasons. δS values were the most variable of the three elements examined although they remained fairly constant through time within each species and site. The results suggest that temporal changes in isotopic compositions of riparian species and aquatic macrophytes are site-specific. Discriminant analysis dissimilarity plots (based on all three isotopes) demonstrated that the contribution of species to the detrital pool depended on the site and season. At the upper site, detritus was isotopically most similar to Quercus laurifolia and Sparganium americanum in April, and the aquatic macrophytes (S. americanum and Potamogeton spp.) in August and October. At the middle site, detritus was most similar to Carpinus caroliniana and Q. nigra in April but no single source was similar to detritus in August or October. At the lower site, detritus was most similar to Taxodium distichum for all three seasons.