A Relationship Between Ice and Phosphorus Movement in a Level Three Tributary to Lake Champlain

The largest lake in New England, Lake Champlain is under threat. This beautiful body faces challenges to its health. One of these threats is phosphorus pollution (LCC, 2019). Phosphorus when in excess provides for cyanobacterial growth. Cyanobacteria produce toxins that can negatively affect animals and humans (World Health Org., 2019). These blooms are often so dense that recreational use is not possible for weeks at a time in some parts of the lake. (Missisquoi Bay Basin Study, LCBP 2019)

Phosphorus moves into the lake via several methods and can be “loaded”, (stored in lake sediments,) and later released. Phosphorus can be transported from point and non-point sources by being dissolved in water and/or attached to particulate (Randall, 2002). Research has focused historically on liquid water transport of phosphorus. In northern climates such as where the Lake Champlain Basin is located water can be in solid form (frozen) for 2-3+ months of the year. This winter period is punctuated by thaw episodes in which ice in the rivers and stream pathways to the Lake can move. This ice grinds along the bottom and banks of the tributaries collecting particulate as it makes its way downstream to Lake Champlain.

Does ice contribute to phosphate movement through tributaries to Lake Champlain?

Ice and liquid water samples were collected over a two-year period from Black Creek. Black Creek is the largest tributary to the Missisquoi River. The Missisquoi River is the main source of water for Missisquoi Bay which located on the northeastern end of Lake Champlain. The samples were then analyzed for phosphorus content and total suspended solids (TSS).

A relationship was established between the presence of TSS and phosphorus. The amount of phosphorus and TSS found in the ice samples indicates ice may play a role in the transport of phosphorus in tributaries to Lake Champlain.