Dissolved Oxygen

Background

Dissolved oxygen refers to the amount of oxygen dissolved in a body of water. It is key to understanding the health of an ecosystem and its suitability for supporting aquatic life. Fish, plants and other aquatic organisms depend on dissolved oxygen for survival. Low levels of oxygen can stress wildlife and cause fish die-offs. Water is oxygenated in various ways, including current or flow or as a byproduct of photosynthesis. Rivers and streams, with fast moving and turbulent waters will have a higher DO level than a stagnant pond or lake. Oxygen levels also depend on the temperature of the water with colder water holding more oxygen than warmer water. Generally, the optimal DO level for an aquatic ecosystem is 6-9 mg/L. 

Dissolved oxygen reading sites 

Methodology 

Dissolved Oxygen was measured using a YSI ProQuatro water quality meter at six sites across Brooklyn, Manhattan and Queens. 

YSI ProQuatro meter in use 

Results and Discussion

The dissolved oxygen levels found at all the sites indicate that the East River has healthy levels of oxygen capable of supporting a large range of life. The oxygen levels at each site was dependent on how much the water was moving. The river was slower moving at locations such as Bridge Park Dr or Tiffany St Pier resulting in lower levels of oxygen. At Pier 5 or Corlears Hook, there was more flow resulting in slightly higher levels of oxygen. It is also possible that certain regions or segments of the river have different oxygen levels. Generally, sites that were further north along the river had decreasing levels of oxygen. Oxygen levels were also generally similar to other nearby rivers such as the Harlem and Hudson rivers. This further shows that the East river is capable of supporting life, as both the Harlem and Hudson rivers support complex ecosystems. It is important to note that oxygen levels tend to fluctuate and can be impacted by factors like water temperature and tidal movement.