In recent years, the Foundation has been moving forward with projects that address two very serious threats to our freshwater pond ecosystems: harmful algae blooms (caused by excess nutrients) and invasive plant species (specifically common reed, or Phragmites australis).
Although algae are a normal component of all freshwater ponds, their populations can rapidly increase under conditions where excess nutrients are present. HABs are caused by a particular type of algae: Cyanobacteria (or blue-green algae), which sometimes produce toxins that can be harmful to people and pets by affecting the skin, liver, nervous system, and intestines. Because of these potential serious public health risks, the Foundation is working with the Nantucket Land Council to develop management strategies at several sites.
As the owner of most of the land immediately surrounding Capaum Pond, the Foundation engaged with SWCA Environmental Consultants to receive permitting from the Nantucket Conservation Commission to initiate management work at this site. This enabled us to proceed with an alum application (to control nutrients that feed algae growth) and algaecide treatment (to control the algae itself) during the spring and summer of 2021. Although the pond subsequently experienced a minor HAB that was quickly treated with algaecide, no additional HABs developed for the remainder of the season. This is in stark contrast to previous summers when the pond hosted continuously blooming HABs for most of August and September. Although we are cautiously optimistic that we are making progress, additional management work on this pond will be needed going forward, as there is still algae and elevated phosphorus levels present.
During the summer of 2021, SWCA also conducted a biological assessment of Gibbs Pond, which is surrounded Foundation property in the Middle Moors just west of the Milestone Cranberry Bog. Gibbs Pond has similarly experienced ongoing HABs, which have been particularly severe in recent years. Like Capaum Pond, this assessment work is allowing us to develop potential management options for this pond so that we can proceed with permitting followed by management in the summer of 2022.
Additional pond management projects include continued HAB monitoring and treatment at Pest House Pond in Shimmo, as well as non-native, invasive Phragmites management along NCF-owned shorelines of Hummock and Long Ponds. We also conduct collaborative weekly pond surveys with the Nantucket Land Council, Town of Nantucket, and several additional partners to provide notifications to the public about the current locations HABs and their potential serious health impacts to both humans and pets. The Foundation’s pond management efforts are generously supported by a grant from the Gund Family, in memory of former Trustee member Lulie Gund.