Abstract. A retrospective analysis revealed that water quality in the coastal bays of Maryland (USA) has been declining over the past decade, as evidenced by increases in total nitrogenous nutrients and in outbreaks of brown tides caused by the pelagophyte Aureococcus anophagefferns. However, the increases in total nitrogen are not a function of increases in inorganic nitrogen, but rather a function of increases in dissolved organic nitrogen (DON). A near-decadal record (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004) demonstrates that an approximate doubling of DON over this time period correlates with a similar increase in total chlorophyll and an even larger increase in the proportion of chlorophyll that is composed of brown tide. Additionally, on an annual basis overall chlorophyll levels and strength of the brown-tide blooms were related to the DON availability that developed during the prior months. Aureococcus anophagefferens is a harmful algal bloom species that preferentially uses DON for its nutrition over inorganic nitrogen forms and thus is a symptom of organic rather than inorganic nitrogen-based eutrophication. These results demonstrate that long-term changes in nutrient quantity and composition have occurred in the coastal bays of Maryland during the past decade and that total phytoplankton biomass, as well as the proliferation of brown tide, are related to these changes. Whether these changes are evidence of a long-term trajectory or represent a shortterm anomaly will be revealed in future monitoring.

Abstract. The mid-Atlantic coastal bays are shallow coastal lagoons, separated from the Atlantic Ocean by barrier sand islands with oceanic exchanges restricted to narrow inlets. The relatively poor flushing of these lagoon systems makes them susceptible to eutrophication resulting from anthropogenic nutrient loadings. An intensive water quality and seagrass monitoring program was initiated to track ecological changes in the Maryland and Virginia coastal bays. The purpose of this study was to analyze existing monitoring data to determine status and trends in eutrophication and to determine any associations between water quality and living resources. Analysis of monitoring program data revealed several trends: (1) decadal decreases in nutrient and chlorophyll concentrations, followed by recently increasing trends; (2) decadal increases in seagrass coverage, followed by a recent period of no change; (3) blooms of macroalgae and brown tide microalgae; and (4) exceedance of water quality thresholds: chlorophyll a (15 lg/L), total nitrogen (0.65 mg/L or 46 lmol/L), total phosphorus (0.037 mg/L or 1.2 lmol/L), and dissolved oxygen (5 mg/L) in many areas within the Maryland coastal bays. The water quality thresholds were based on habitat requirements for living resources (seagrass and fish) and used to calculate a water quality index, which was used to compare the bay segments. Strong gradients in water quality were correlated to changes in seagrass coverage between segments. These factors indicate that these coastal bays are in a state of transition, with a suite of metrics indicating degrading conditions. Continued monitoring and intensified management will be required to avert exacerbation of the observed eutrophication trends. Coastal lagoons worldwide are experiencing similar degrading trends due to increasing human pressures, and assessing status and trends relative to biologically relevant thresholds can assist in determining monitoring and management priorities and goals.

Environmental mycobacteria are of increasing concern in terms of the diseases they cause in both humans and animals. Although they are considered to be ubiquitous in aquatic environments, few studies have examined their ecology, and no ecological studies of coastal marine systems have been conducted. This study uses indirect gradient analysis to illustrate the strong relationships that exists between coastal water quality and the abundance of Mycobacterium spp. within a U.S. mid-Atlantic embayment. Mycobacterium species abundance and water quality conditions (based on 16 physical and chemical variables) were examined simultaneously in monthly samples obtained at 18 Maryland and Virginia coastal bay stations from August 2005 to November 2006 (n ‫؍‬ 212). A quantitative molecular assay for Mycobacterium spp. was evaluated and applied, allowing for rapid, direct enumeration. By using indirect gradient analysis (environmental principalcomponents analysis), a strong linkage between eutrophic conditions, characterized by low dissolved-oxygen levels and elevated nutrient concentrations, and mycobacteria was determined. More specifically, a strong nutrient response was noted, with all nitrogen components and turbidity measurements correlating positively with abundance (r values of >0.30; P values of <0.001), while dissolved oxygen showed a strong negative relationship (r ‫؍‬ ؊0.38; P ‫؍‬ 0.01). Logistic regression models developed using salinity, dissolved oxygen, and total nitrogen showed a high degree of concordance (83%). These results suggest that coastal restoration and management strategies designed to reduce eutrophication may also reduce total mycobacteria in coastal waters.

Water quality in the Maryland/Virginia Coastal Bays has been declining for many years from anthropogenic inputs, but conditions appear to have worsened abruptly following a shift from long-term dry to long-term wet conditions in the early 2000s. Annually and regionally averaged total nitrogen concentrations are approximately twofold higher, but ammonium (NH 4 +) concentrations are up to an order of magnitude higher than in the early 1990s. Averaged nitrate concentrations, however, changed to a lesser degree throughout the time course; water column concentrations remain very low. Total phosphorus has only increased in some bay segments, but increases in phosphate (PO 4 3−) have been more pervasive. There were differences in the year in which large increases in each nutrient were first noted: PO 4 3− in~2001-2002, followed by NH 4 +~a year later. The effects of a combination of steadily increasing anthropogenic nutrient increases from development, superimposed on nutrient loads from farming and animal operations, and groundwater inputs were accelerated by changes in freshwater flow and associated, negatively reinforcing, biogeochemical responses. Regionally, chlorophyll a concentrations have increased, and submersed aquatic vegetation has decreased. The system is now characterized by sustained summer picoplanktonic algal blooms, both brown tide and cyanobacteria. The retentive nature of this coastal lagoon combined with the reducing nature of the system will make these changes difficult to reverse if the current dual nutrient management practices are not accelerated.