BROWN TIDES
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In response to these findings, the Maryland Department of Natural Resources began monitoring the distribution of Aureococcus in Maryland’s coastal bays in 1999 at 15 stations during the spring and early summer. Since that time Brown Tide has been found in all of the Maryland Coastal Bays. Maryland DNR continues to monitor Brown Tide blooms in the coastal bays each year.
In 1999, cell counts identified the algae at modest levels
(100,000-200,000 cells/ml) in all major coastal bays and tributaries, except
Sinepuxent. Significant levels (greater than 200,000 cells/ml) were observed
at Ocean Pines, Tingles Island, Trappe Creek and Taylors Landing
stations.
Survey results from 2000 sampling reveals cell densities greater than 200,000 cells/ml at Green Run Bay and Tingles Island and densities greater than 500,000 cells/ml at Newport Bay (645,070 cells/ml) and Public Landing (867,003 cells/ml). All the high cell counts were recorded in mid-May through mid-June. By late June, cell densities at all stations had decreased considerably to less than 35,000 cells/ml.
In 2001, Category 2 Brown Tide
blooms (35,000 - 200,000 cells/ml) were seen in late May in Trappe Creek
(112,723 cells/ml), Newport Bay (121,949 cells/ml) and Public Landing
(96,286 cells/ml) and in mid-June at Green Point (76,669 cells/ml) and
mid-Chincoteague Bay near Public Landing (94,872 cells/ml). Category
3 Brown Tide blooms (>200,000 cells/ml) were observed during
mid-June in the Newport Bay (494,158 cells/ml), Public Landing (680,793
cells/ml) and Tingles Island (268,923 cells/ml) areas.
See the weekly bloom
progression at Public landing.
2002 results showed Category 2 blooms throughout the entire coastal bays except southern Chincoteague Bay and Greys Creek. Category 3 blooms were documented at the Fenwick Ditch, Newport Bay, Public Landing, Tingles Island and aquaculture sites. 
Results for 2003 through June 6 indicate that the northern bays, Isle of Wight and Assawoman Bays, are experiencing Category 1 blooms while the lower St. Martin River and Newport Bay have seen Category 2 blooms. Chincoteague Bay has been experiencing a Category 3 bloom.
In 2004, Brown Tide bloomed in the southern bays. Category three blooms developed at Green Point, Public Landing and Tingles Island. The bloom at Public Landing lasted for over a month. Green point has now had a Category three bloom two years in a row and appears to have increased in bloom intensity over time. Category two blooms were documented at Newport Bay site and were also likely at the Trappe Creek and Nixon sites although bi-monthly sampling did not capture it).
* Adjusted BT counts refers to an adjustment factor that was applied to monoclonal results (new analysis technique starting in 2004) to make them comparable to previous years polyclonal results as well as thresholds established using polyclonal methods. View unadjusted monoclonal count data.
Cool spring temperatures during 2005 kept Aureococcus from blooming in May. However, rapidly increasing water temperatures in early June led to a brief bloom in the southern bays, where water temperatures quickly exceeded the optimum growth range for Brown Tide and the bloom crashed around June 8 (see DNR's continuous monitoring data at Public Landing). Low level category two blooms were recorded at nearly all the stations south of the Ocean City Inlet. Category three blooms were likely at Public Landing and Taylor’s landing although count data are not available.
* Adjusted BT counts refers to an adjustment factor that was applied to monoclonal results (new analysis technique starting in 2004) to make them comparable to previous years polyclonal results as well as thresholds established using polyclonal methods. View unadjusted monoclonal count data.
For more information contact Cathy
Wazniak (410-260-8638) |
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