Mitigating Harmful Algae Blooms with Clay and Crab Shells

August 18, 2010
Harmful algal blooms, like this Microcystis bloom in the Sassafras River in 2000, can have a direct and immediate impact on the Chesapeake Bay's aquatic life. Photo courtesy Md. Department of Natural Resources.

Excess nutrients are polluting the waters of the Chesapeake Bay, providing just one local example of global problems impacting our region. Worldwide, coastal residents annually observe the byproducts of low oxygen waters including blooms of harmful algae and cyanobacteria. In fact, Chesapeake scientists have observed summer blooms of toxic and non-toxic strains of Microcystis aeruginosa for at least the last 50 years.

An August 2010 grant from the National Oceanic and Atmospheric Administration is allowing a team of researchers, led by UMCES@IMET scientist Dr. Allen Place, to test the efficiency of using suspended clays to remove toxic blooms of Microcystis aeruginosa from the water. The researchers will also assess whether this technique will have an impact on submerged aquatic vegetation, clams and fish.

The research will determine concentrations of local sediments and commercial clays that combined with the flocculating compound chitosan will be used to flocculate and sediment local M. aeruginosa populations.

The team will use cultures of toxic and non-toxic algae populations to determine the sediment and chitosan concentrations needed to stop their growth. They will rely on quantitative real-time PCR methodology to ascertain removal of M. aeruginosa from the water column in both laboratory experiments and in field tests. They will also test and monitor the blooms impacts on submerged aquatic vegetation and local fish populations.

The grant is one of three Atlantic Coast projects supported by NOAA’s Prevention, Control and Mitigation of Harmful Algal Blooms (PCMHAB) program which aims to develop methods to prevent harmful blooms from forming and to control or reduce existing blooms or bloom impacts. NOAA will transition the best of these methods into new coastal resource management strategies.

Dr. Place will work with UMCES@IMET scientist Dr. Holly Bowers, Dr. Kevin Sellner from the Chesapeake Research Consortium, Dr. Michael Paolisso from University of Maryland College Park and researchers Bruce Michael and Cathy Wazniak from the Maryland Department of Natural Resources.

Many types of algae are present in Atlantic waters. While most are non-threatening, some are harmful to the marine environment, coastal economies and even cause serious human illnesses. Advances in monitoring and forecasting are giving an early warning of impending blooms but impacted communities and businesses want new methods to combat harmful algal species and their costly impacts.