Browsing by Author "Haag, Scott"

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    Brown Tide Assessment Project in NJ Coastal Waters: A comparison of three bloom years (2000-2002) with two non-bloom years (2003-04): Research Project Summary
    (Trenton, N.J. : New Jersey Department of Environmental Protection, Division of Science, Research and Technology, 2006-08) Pecchioli, Joel A.; Lathrop, Richard; Haag, Scott
    Brown tides are caused by the rapid population growth (“bloom”) of a minute alga, Aureococcus anophagefferens. To determine whether these blooms are a threat to coastal waters in New Jersey, the Division of Science Research and Technology implemented the Brown Tide Assessment Project from 2000-2004. The primary objectives of this study are to (1) characterize the spatial and temporal occurrence of brown tides in Barnegat Bay-Little Egg Harbor, (2) identify those environmental factors that may promote the development and maintenance of brown tides, and (3) analyze the risk of brown tides to submerged aquatic vegetation communities. Category 2 (> 35,000 cells ml-1) and Category 3 (> 200,000 cells ml-1) A. anophagefferens blooms occurred throughout the study area in 2000-2002 (mean abundances exceeded 190,000 cells ml-1), while none of the monthly means in 2003/04 were classified as a Category 2 or 3 bloom. Category 3 blooms generally occurred during months with mean water temperatures above 14 C, and a minimum temperature above 13.5 C; and with mean salinity between 26 and 31 ppt, and a minimum salinity of at least 17 ppt. However, these environmental conditions do not always result in the occurrence of a Category 3 bloom. Concentrations of total nitrogen, dissolved organic nitrogen, and nitrite + nitrate were higher during the bloom year of 2002 compared to the non-bloom years of 2003/04. In contrast, ammonia showed lower concentrations during 2002. Category 3 brown tides did not occur in any month where the Toms River flow exceeded 200 ft3 sec-1. A Cartographic and Regression Tree Analysis identified ammonia and dissolved organic nitrogen concentrations, and the Toms River flow, as factors that distinguished Category 1 (< 35,000 cells ml-1) and Category 3 A. anophagefferens blooms. However, it appears that the observed differences in nitrogen species concentrations may be a result of A. anophagefferens blooms impacting nutrient cycles, rather than nutrient levels initiating the brown tides. Analysis of the risk of brown tides to submerged aquatic vegetation habitat indicated that 50% of the mapped habitat in Barnegat Bay-Little Egg Harbor is potentially at risk of negative impacts. Graphic displays of the spatial patterns of A. anophagefferens abundance and selected environmental factors can be viewed at: http://crssa.rutgers.edu/projects/btide/index.html.
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    Brown Tide Bloom Assessment Project in NJ Coastal Waters: 2000-2002: Research Project Summary
    (Trenton, N.J. : New Jersey Department of Environmental Protection, Division of Science, Research and Technology, 2003-10) Downes Gastrich, Mary; Lathrop, Richard; Haag, Scott; Weinstein, Michael P.; Danko, Michael; Caron, David A.; Shaffner, Rebecca
    Brown tide blooms, caused by the rapid growth of a minute alga, Aureococcus anophagefferens, caused the demise of the scallop industry in coastal bays of Long Island, NY, in the mid-1980s. These blooms were also suspected in Barnegat Bay, NJ, at the same time but were not confirmed until 1995. Because of limited data, and to determine whether these blooms were a threat to coastal waters in NJ, the Division of Science Research and Technology (DSRT) established the Brown Tide Assessment Project to assess brown tide blooms in Barnegat Bay-Little Egg Harbor (BB/LEH) from 2000-2002 through 1) mapping the abundances of the brown tide using the Brown Tide Bloom Index; 2) assessing the relationship between the brown tide abundances and environmental factors (e.g., salinity, temperature, nitrogen species); and 3) analyzing of the risk of brown tide blooms to submerged aquatic vegetation communities. Brown tide abundances were detected at all stations; the most severe brown tide blooms (Category 3), as well as less severe (Category 2) blooms, recurred during each of the three years of sampling and covered significant geographic areas of the BB/LEH. While the highest abundances of brown tide are positively associated with warmer water temperatures and higher salinity, these factors are not sufficient to promote blooms. Extended drought conditions with corresponding low freshwater inputs and elevated bay water salinities occurred during this time, possibly contributing to these blooms. Abundances of brown tide in New Jersey coastal bays are high enough to cause potentially harmful effects on juvenile hard clams. Results of the analysis of the risk of brown tide blooms to submerged aquatic vegetation (SAV) habitat indicated that 35% of the state’s SAV habitat in BB/LEH is at significant risk of negative impacts due to brown tide blooms. Over 70% of the state’s SAV habitat is located in BB/LEH. Graphic displays of the spatial patterns of the brown tide blooms and environmental factors can be viewed at: http://crssa.rutgers.edu/projects/btide/index.html.