Phenological shifts in lake stratification under climate change

Area of Science:

• Environmental Science
• Climate Science
• Ecology

Background:

• Lake stratification, a key physical process, significantly influences aquatic ecosystems by controlling resource availability.
• Variations in stratification phenology (timing of onset and break-up) have profound ecological consequences.
• Global changes in lake stratification phenology remain largely unknown.

Purpose of the Study:

• To investigate historical and projected changes in lake stratification phenology across the Northern Hemisphere.
• To understand the impact of climate change on lake stratification timing from 1901 to 2099.

Main Methods:

• Utilized a lake-climate model ensemble for projections.
• Incorporated long-term observational data for historical analysis.
• Focused on the Northern Hemisphere to assess regional changes.

Main Results:

• Under a high-greenhouse-gas-emission scenario, stratification is projected to begin 22 days earlier and end 11 days later by 2100.
• This results in a significant prolongation of stratification duration (33 days).
• Accelerated lake deoxygenation and increased phosphorus release from sediments are likely consequences.

Conclusions:

• Projected changes in lake stratification phenology will significantly impact lake ecosystems.
• Prolonged stratification is expected to exacerbate deoxygenation, affecting nutrient cycling.
• Potential for irreversible changes in lake ecosystems due to altered lifecycle events and environmental conditions.