Macroalgae

Seaweeds (a.k.a. – macroalgae) are a diverse group of algae represented by a wide range of growth forms. In general, seaweeds are divided into 3 groups based on their color, green, brown or red, though colors range greatly.

While seaweeds share some characteristics of “higher” plants, they lack the complex reproductive structures (flowers) and specialized functional tissues (roots, stems, and leaves) of seagrasses and land plants. Seaweeds reproduce asexually (vegetative growth) and sexually (release of spores).

Algal Blooms

Excessive nutrient inputs - like nitrogen - can cause algae blooms. Green macroalgae grows fastest in response to an overabundance of nutrients. The macroalga species Ulva lactuca, or Sea lettuce, is one of the most common macroalgae species to cause blooms. When it “blooms” in nutrient-rich waters, it reproduces quickly, fragments and continues to grow until it outcompetes itself, creating a “mat” on the bottom which begins to decompose. The decomposing macrolagae reduces oxygen and releases nitrogen back into the waterbody, continuing the cycle. These conditions (known as eutrophic) threaten the health of marine ecosystems.

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Contributions at all levels will be directed toward our Macroalgae + Water Quality restoration, research, and education initiatives. Back to the Bays is an Initiative of Cornell Cooperative Extension of Suffolk County, a registered 501(c)(3). Our EIN is 11-6081424 and contributions are tax-deductible to the fullest extent of the law.

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Current Projects

Hog Creek Macroalgae Removal

Made possible by East Hampton Town’s Community Preservation Fund (CPF). The CPF grant supports our remediation effort in Hog Creek, reducing groundwater nitrogen inputs. Located in Springs, Hog Creek provides essential habitat for wildlife and a welcome space for recreational activities.

CCE Marine Program identified sites surrounding Hog Creek where the highest levels of groundwater nutrients enter the waterbody. At these sites, our groundwater experts installed and manage permeable reactive barriers (PRBs) that significantly lessen the amount of nitrogen in groundwater before it enters Hog Creek. Our coastal plant experts are leading bioextraction efforts to harvest macroalgae (specifically Ulva) that will be collected and weighed to quantify biomass, and approximate how much nitrogen is being removed through the harvest. Field trips and involvement in the harvest will be made available to local schools.

CCE + Macroalgae

Past Projects

  • CCE completed a macroalgae bioextraction pilot project in Accabonac Harbor in 2018. Results varied, with the most growth and largest harvests over groundwater seepage points.

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