Deoxygenation of Riverine Ecosystem

September 16, 2023

GS Paper III Environment and Ecology

Context:

An international research team led by Pennsylvania State University used artificial intelligence to reconstruct historically sparse water quality data from nearly 800 rivers across the United States and Central Europe to understand Riverine Ecosystem

Ocean Deoxygenation:

It is the overall decline in the oxygen content of oceanic waters.
Human activities are the primary cause of ocean deoxygenation in both coastal environments and in the open ocean.
The ocean absorbs more than 93% of the earth’s warming from climate change.
Warm water holds less oxygen than cold water, because the higher the temperature, the less soluble oxygen becomes.

Impact of Deoxygenation on marine life:

Deoxygenation is causing a wide range of effects on marine life, including reducing the quality and quantity of suitable habitat, also known as habitat compression, reducing growth rate, changing visual function, interfering with reproduction, and increasing disease susceptibility.

Key findings of Study about Riverine Ecosystem:

Warming of Rivers: Rivers are warming and losing oxygen faster than oceans, and deoxygenation could “induce acute death” for certain aquatic species aftecting Riverine Ecosystem.
- Magnitude of Warming in Riverine Ecosystem: The findings of the study showed that of nearly 800 rivers, warming occurred in 87 percent and oxygen loss in 70 per cent.
- Urban rivers vis-i-vis rural rivers: While urban rivers showed the most rapid warming, rural rivers witnessed the slowest warming but fastest deoxygenation.
- Impact of Deoxygenation on Riverine Ecosystem: Deoxygenation drives greenhouse gas emissions and leads to the release of toxic metals.
- Forecasting Future deoxygenation: Across all the rivers researchers studied, future deoxygenation rates were between 1.6 and 2.5 times higher than historical rates.
Challenges in Measuring Riverine Water Quality: Though riverine water temperature and dissolved oxygen levels are essential measures of water quality and ecosystem health, they are poorly understood as they are hard to quantify.
Flawed Assessment: Lack of consistent data across different rivers and the myriad of variables involved that can change oxygen levels in each watershed as the reasons for flawed assessments.