What is Phosphorus?
Phosphorus is a naturally occurring nutrient that is essential for plant growth. It is found in soils, human and animal waste, lawn fertilizers, and living organisms, among other sources. It is important to monitor for phosphorus levels, as it can be a key indicator of the health of our waterbodies.
Talking Phosphorus (P)
Phosphorus is a key element monitored by our science team in Adirondack lakes and ponds. Through the Adirondack Lake Assessment Program (ALAP), dedicated volunteers and professionals collect water samples to deepen our understanding of phosphorus levels and their impact on aquatic ecosystems. Plants and algae require phosphorus, nitrogen, and additional micronutrients to survive. Phosphorus plays a key role in photosynthesis, helping plants convert sunlight into energy, produce sugars, and grow properly. However, excessive phosphorus can disrupt aquatic ecosystems and negatively affect water quality, posing challenges for humans and aquatic life alike.
Phosphorus and Cyanobacteria
Understanding how phosphorus influences water quality helps address complex challenges like Harmful Algal Blooms (HABs). Despite their name, HABs are not caused by algae but by cyanobacteria - tiny photosynthetic microorganisms that produce oxygen in waterbodies.
The difference between algae and cyanobacteria is their cellular structure: algae have a nucleus and have membrane bound organelles, while cyanobacteria lack these features. Phosphorus serves as a critical energy source for cyanobacteria, particularly when it is attached to particles suspended in the water. Runoff from fertilizers, discharges from wastewater treatment facilities, and leaching from septic systems are common sources of elevated phosphorus levels. This problem becomes even more pronounced in shallow water, where less dilution allows phosphorus to become more concentrated and readily available to cyanobacteria, fueling HABs.
Impacts from high Phosphorus levels
When measuring phosphorus in the Adirondacks, it’s important to recognize that baseline concentrations vary across different types of lakes and ponds. Oligotrophic waterbodies—characterized by high transparency, low nutrient levels, with high oxygen concentrations—typically have phosphorus levels below 10 µg/L (micrograms per liter). In contrast, highly nutrient-rich eutrophic lakes often exhibit phosphorus concentrations exceeding 20 µg/L, reflecting their greater productivity and potential for algal blooms. As phosphorus is released from rocks, soils, and human inputs, the likelihood of HABs rises. These blooms can release cyanotoxins harmful to animals and humans and are difficult to manage once they occur.
Phosphorus in the Winter
Phosphorus loading occurs when elevated levels of phosphorus enter a waterbody, typically as a result of significant runoff events, such as heavy rainfall or winter snowmelt. During these events, phosphorus stored in the soil, discharged from wastewater treatment facilities, or naturally accumulated in the environment can be released into nearby water systems. As rain or snowmelt flows through rivers and streams, it transports this phosphorus to larger lakes or ponds, causing a sudden spike in concentrations. This influx of phosphorus can have significant impacts on water quality and ecosystem health. Along with monitoring that is done as part of ALAP, our science team collects water quality data as part of the Adirondack Long Term Monitoring Program (ALTM). These efforts, combined with those supported by the Lake Champlain Basin Program, can help researchers better understand the impacts of phosphorus in the winter months, especially as the region is experiencing shorter, more variable winters due to climate change.
To learn more about phosphorus in Adirondack lakes, view our publications page to view reports and research conducted on waterbodies across the region.