4.2 Aquatic Communities
contamination, DO defciencies, and high concentrations of toxic metals in the water column and bottom (McAllister et al. 1996 ; Deaton et al. 2010).
Of all the sources of sediment loading, sedimentation from agriculture has been cited as one of the largest contributors to water pollution in the southeastern states (SAFMC 1998 ; Deaton et al. 2010) . Other upland sources of runof and contaminants also contribute to water quality degradation in estuarine aquatic communities. For instance, development and associated runof and sewage inputs in the upper end of a watershed and confned animal operations (primarily swine, poultry) and associated nutrient and microbial contamina- tion in the lower end of a watershed contribute signifcantly to poor water quality (Deaton et al. 2010) . Algal blooms tend to occur when nutrient loads are not fushed because water fow is slow, water depths are low, and where mixing of the water column is reduced due to salinity and/or temperature gradients. Blue-green algae are usually associated with blooms in freshwater areas and they have lower nutritional value to aquatic life than other types of algae. Dinofagellates and other fagellated algae are usually responsible for algal blooms in estuarine and marine waters (Smayda 1989; NC Sea Grant 1997; Mallin et al. 2000b; Deaton et al. 2010) . Some dinofagellate species release toxic chemicals into the water column that harm fsh and shellfsh by afecting their nervous systems and paralyzing their respiratory systems (Tyler 1989; Deaton et al. 2010) . Invasive Species . Foreign organisms in the discharge of ships’ ballast water at or near ports have resulted in the introduction and spread of nonnative invertebrate animals, algae, bacteria, and dinofagellates (Deaton et al. 2010) . Removal of dams and other passage barriers (locks) create a pathway for nonnative species to move between freshwaters and brackish water environments, including movement upstream from brackish estuarine waters into river drainages as a saltwater wedge expands into freshwaters. Te water mold Aphanomyces invadans is an invasive fungal pathogen that infects school- ing fsh species in low-salinity or fresh water and is suspected to have been introduced to the United States through another infected invasive species, the Northern Snakehead Fish (Blazer et al. 2002; Deaton et al. 2010 ). Te Australian Spotted Jellyfsh can consume large quantities of plankton, eggs, and larvae in the water column and has been found in Bogue Sound and at Sunset Beach. Te invasion of the Indo-Pacifc lionfsh in marine waters of North Carolina will likely impact estuarine aquatic communities through direct predation, competition, and overcrowding (Deaton et al. 2010).
Tere are also a number of noxious weeds that can be found in fresh and moderately brack- ish waters of slow moving streams or waters protected from strong tidal currents and wave
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2015 NC Wildlife Action Plan
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