A large part of the nutrient flux in deciduous forests is through fine root turnover, yet this process is seldom measured.

The high minimum light requirement of eelgrass Zostera marina L. suggests that this species has difficulty in maintaining a positive carbon balance except under high light conditions. The carbon balance of Z. marina can be studied by following seasonal changes in non-structural carbohydrate (NSC) reserves, however, little is known about the seasonal variation in NSC reserves in seagrasses or the influence of shading on NSC reserve content and distribution. Seasonal changes in eelgrass NSC reserves were measured In a shallow coastal lagoon, Chincoteague Bay, MarylandNirginia, USA, near the southern edge of this species' distributional range. Concentrations of sugar varied seasonally in leaves, rhizomes and roots, with maximum concentrations occurring in the rhizomes. In contrast, starch concentrations did not vary with the season, but were highest in the roots Seasonal peaks in rhizome NSC reserves parallel the spring and fall bimodal growth patterns observed for Z marina in the region. Total NSC reserves change from an estimated 52 to 7 3 g rn.? in June to 4 to 18 g m~' in January. or a decrease of 75 to 92%. Experimental shading for 3 wk in the spring reduced (p < 0.001) sugar but not starch concentrations in leaves (48%), rhizomes (40%) and roots (51 X). In addition, shading reduced (p 0.05) leaf biomass (34%), root and rhizome biomass (23 %) and density (27 %). Potential NSC reserve storage during shading was reduced by an estimated 66%. Spring appears to be an important time for both growth and storage of NSC reserves in Z. marina, and the NSC reserves are generally depleted throughout the remainder of the year. Turbidity during this springtime 'window of opportunity' may jeopardize subsequent survival as a result of inadequate NSC reserves to maintain a positive carbon balance dunng the rest of the year.

The nutritional versatility of dinoflagellates is a complicating factor in identifying potential links between nutrient enrichment and the proliferation of harmful algal blooms. For example, although dinoflagellates associated with harmful algal blooms (e.g. red tides) are generally considered to be phototrophic and use inorganic nutrients such as nitrate or phosphate, many of these species also have pronounced heterotrophic capabilities either as osmotrophs or phagotrophs. Recently, the widespread occurrence of the heterotrophic toxic dinoflagellate, Pfiesteria piscicida Steidinger et Burkholder, has been documented in turbid estuarine waters. Pfiesteria piscicida has a relatively proficient grazing ability, but also has an ability to function as a phototroph by acquiring chloroplasts from algal prey, a process termed kleptoplastidy. We tested the ability of kleptoplastidic P. piscicida to take up 15N‐labeled NH, NO, urea, or glutamate. The photosynthetic activity of these cultures was verified, in part, by use of the fluorochrome, primulin, which indicated a positive relationship between photosynthetic starch production and growth irradiance. All four N substrates were taken up by P. piscicida, and the highest uptake rates were in the range cited for phytoplankton and were similar to N uptake estimates for phagotrophic P. piscicida. The demonstration of direct nutrient acquisition by kleptoplastidic P. piscicida suggests that the response of the dinoflagellate to nutrient enrichment is complex, and that the specific pathway of nutrient stimulation (e.g. indirect stimulation through enhancement of phytoplankton prey abundance vs. direct stimulation by saprotrophic nutrient uptake) may depend on P. piscicida’s nutritional state (phagotrophy vs. phototrophy).

Despite growing interest in urbanization and its social and ecological impacts on formerly rural areas, empirical research remains limited. Extant studies largely focus either on issues of social exclusion and enclosure or ecological change. This article uses the case of sweetgrass basketmaking in Mt. Pleasant, South Carolina, to explore the implications of urbanization, including gentrification, for the distribution and accessibility of sweetgrass, an economically important nontimber forest product (NTFP) for historically African American communities, in this rapidly growing area. We explore the usefulness of grounded visualization for research efforts that are examining the existence of "fringe ecologies" associated with NTFP. Our findings highlight the importance of integrated qualitative and quantitative analyses for revealing the complex social and ecological changes that accompany both urbanization and rural gentrification.