Brown tides are part of growing world-wide incidences of harmful algal
blooms (HAB) which are caused by a proliferation of single-celled marine
plants called phytoplankton. One species of phytoplankton, the
microscopic alga Aureococcus anophagefferens may bloom in such
densities that the water turns dark brown, a condition known as "brown
tide." In 1985, severe brown tides were first reported in the Peconic
Bays of eastern Long Island, New York, in Narragansett Bay, Rhode Island
and possibly in Barnegat Bay, New Jersey. Since then, brown tide has
intermittently occurred with variable intensity in Barnegat Bay and in
the bays of Long Island.
Brown tide has had particularly detrimental effects on the Peconic
Bay ecosystem and the economy of eastern Long Island. During intense
bloom conditions, densities of the brown tide organism can approach two
million cells per milliliter. These numbers far surpass typical mixed
phytoplankton densities of 100 to 100,000 in that same volume. Eelgrass
beds which serve as spawning and nursery grounds for shellfish and
finfish may have been adversely impacted by decreased light penetration,
at least in part, due to brown tide blooms.
The Peconic Estuary
bay scallop industry, at one point worth almost $2 million annually, was
virtually eradicated to a dockside value of merely a few thousand
dollars. Oysters, hard clams and possibly blue mussels have also been
impacted, to varying degrees, by brown tide although long-term impacts
on these shellfish are unknown. Although not known to be a health threat
to humans, the presence of brown tide may reduce people's desire for
recreational fishing, boating, and swimming in affected waters.
Advances have been made regarding the identification and characterization of Aureococcus anophagefferens.
However, the factors that cause bloom conditions and those that allow
blooms to persist need further investigation. For this reason the Brown
Tide Research Initiative was developed in the late 1990s as a partnership between the National Oceanic and Atmospheric
Administration's (NOAA) Coastal Ocean Program (COP) and New York Sea Grant. The research, supported
by the BTRI effort, was documented in the Initiative's report series.
The first three-year $1.5 million BTRI program (1996-1999) was
developed to increase knowledge concerning brown tide by identifying the
factors and understanding the processes that stimulate and sustain
brown tide blooms. Continued funding for BTRI in 1999-2001, as a $1.5
million three-year effort, came once again from NOAA’s COP.
Prior to the first phase of this initiative, a peer review-based
competitive Call for Proposals highlighted the most critical information
gaps identified at the 1995 Brown Tide Summit. This process resulted in
the selection of eight outstanding and complementary research projects
supported by the BTRI. According to BTRI-funded researcher Patricia
Glibert, "The strength of this initiative was the multi-faceted
approach," combining a focused research effort of biological, chemical
and physical oceanographical expertise together with a unique networking
opportunity for information and idea exchange among the investigators.