Harmful Algal Blooms

Recurring algal blooms have been documented in the Barnegat Bay. Sometimes the growth is so explosive it creates an algal “bloom” with millions of organisms discoloring the water. This excessive growth causes an unhealthy increase in the amount of organic matter, a process called eutrophication. These blooms are typically characterized by the explosive growth of a single phytoplankton species, which can lead to negative impacts.

Excessive growth of some phytoplankton species generates harmful algal blooms (HABs), such as brown tides, yellow tides, red tides, and other types. The toxic forms are particularly dangerous to numerous organisms, including shellfishes, finfishes, and even humans. Secondary impacts include shading effects, altered grazing patterns, and changes in trophic dynamics that are detrimental to estuarine function. A number of HAB-forming species have been recorded in the Barnegat Bay-Little Egg Harbor Estuary, including Dinophysis spp., Gymnodinium (Karlodonium) spp., Heterosigma sp., and Prorocentrum spp.) (Olsen and Mahoney, 2001).

 

Barnegat Bay underwater
Photo credit: Mark Yokoyama
An underwater photo in Barnegat Bay shows heavy algae growth. © Mark Yokoyama
Algal bloom

Brown-tide blooms, caused by the minute alga, Aureococcus anophagefferens, were first reported in New Jersey coastal bays in 1988, with initial blooms documented in 1995, 1997, 1999, 2000, 2001, and 2002. No significant bloom was documented in 2003. These algal blooms can discolor the water brown and may cause negative impacts on shellfish, notably the ecologically and commercially important hard clam and scallop, as well as on seagrasses. Adverse shellfish impacts include a reduction in the growth of juvenile and adult shellfish (e.g., hard clams and mussels), reduced feeding rates in adult hard clams and other shellfish, recruitment failures, and even mortality of shellfish (Gastrich and Wazniak 2002). The dense shading of these blooms may also contribute to the loss of seagrass beds, which serve as important habitat for fish and shellfish. Monitoring for brown tide was discontinued in 2004.

More recently, emphasis has been placed on macroalgal blooms in shallow eutrophic estuaries. Green-tide forming taxa (e.g., Enteromorpha and Ulva) may be particularly problematic. When exposed to elevated nutrient levels, these plants can grow very rapidly to form sheet-like masses that drift along the bay bottom. Such high biomasses of macroalgae often degrade benthic habitats and communities.

Useful Harmful Algal Bloom Websites

Brown Tide in New Jersey (Rutgers/CRSSA)

NJDEP Brown Tide Newsletters (2000)
Brown Tide Bloom Index Report (Gastrich, M. D. and C. E. Wazniak. 2002)

Ecology and Oceanography of Harmful Algal Blooms

References

Gastrich, M. D. and C. E. Wazniak. 2002. A brown-tide bloom index based on the potential harmful effects of the brown-tide alga, Aureococcus anophagefferens. Aquatic Ecosystems Health & Management 33: 175–190.

Olsen, P. S. and J. B. Mahoney. 2001. Phytoplankton in the Barnegat Bay-Little Egg Harbor estuarine system: species composition and picoplankton bloom development. In: Kennish, M. J. (Ed.), Barnegat Bay-Little Egg Harbor, New Jersey: Estuary and Watershed Assessment. Journal of Coastal Research, Special Issue 32, pp. 115-143.

Reef

UNKNOWN

There is limited data available to quantify Wetland and Riparian Buffer Preservation, or updated data to quantify Wetland Acreage. The BBP has obtained funding and will begin assessment efforts for both targets, in the next few years.

 

 Hard Clam abundance has not been updated since 2012. Recovery of the stock will be guided by the Fishery Management Plan for Hard Clams, which is under development with the NJDEP, BBP, and other organizations. Reclam the Bay and other partners have continued to plant clams for restoration purposes. Continued plantings in strategic locations which maximize survival and reproduction is one strategy to pursue in the coming years. This work can use a model developed by Rutgers with BBP funding which identified areas where planted clams could have the greatest dispersal of their larvae and thus potentially maximally contribute to the recovery of the stock.

 Water Withdrawals were over the target in the 2021 report; USGS has not yet completed its latest update, so a definitive determination of status is not available. However, additional NJDEP data show that it is likely that we continue to not meet the target. Per capita water use has gone down, demonstrating the effectiveness of water-saving appliances and practices, but that decrease has been offset by population gains. 


IN PROGRESS

New maps quantifying Submerged Aquatic Vegetation extent were developed, but poor image clarity resulted in a high degree of uncertainty in the total acreage. NJDEP and Rutgers are working to resolve the uncertainty of these maps, and improve the total acreage estimate. Funding has also been obtained for further research and restoration activities. Several groups are developing potential restoration actions.

The USGS has completed the first phase of its study to identify minimum ecological flows in select Barnegat Bay tributaries. USGS scientists compared streamflow statistics between historical and current time periods to better understand trends in watershed flow conditions. This work provides a foundation for developing ecological flow targets in the Barnegat Bay watershed.  Similar to SAV extent, funding (approximately $450K) has been obtained by the BBP to complete the remaining phases necessary for threshold determination.

 

TARGETS ACHIEVED

No targets can be considered “Achieved” at this time.

 

NOT ACHIEVING

Several Public Swimming Beaches exceeded their safe swimming standards more frequently than during their baseline time period (2016-2018).

While most beaches are routinely safe for swimming, several problematic areas such as Beachwood, Hancock, Windward, and several lake beaches need track-down studies and restoration to pinpoint and address sources of bacteria.

Acres of Approved Shellfish Waters decreased from the last report. While this decrease was small, it represents a loss of previously approved waters. Similar to public beaches, track-down studies and restoration work are needed to pinpoint and address sources of bacteria.