Rising Ocean Temperatures And Carbon Dioxide Levels Threaten Global Mangrove Nurseries By Reducing Oxygen Availability

University of Gothenburg study warns that rising sea temperatures and CO2 levels are making it harder for fish to breathe in vital mangrove forest habitats.

By: AXL Media

Published: Mar 11, 2026, 5:03 AM EDT

Source: The information in this article was sourced from University of Gothenburg

Measuring the Chemical Pulse of Global Mangroves

Mangrove forests serve as critical tidal nurseries for a vast array of marine life, providing shelter for commercially significant fish species during periods of high tide. However, new research from the University of Gothenburg indicates that the balance of carbon dioxide and oxygen within these ecosystems is becoming increasingly precarious. By examining 23 separate mangrove areas worldwide, marine chemists have documented the extreme fluctuations that define these habitats, where low tide naturally brings a buildup of carbon dioxide and a depletion of oxygen that only specialized species can survive.

The Impact of Tidal Cycles on Marine Respiration

The habitability of mangrove waters is governed by the rhythmic movement of the sea, which acts as a respiratory system for the forest. When the tide rises, fresh seawater infuses the environment with oxygen while simultaneously flushing out accumulated carbon dioxide, creating a temporary window for sensitive fish to enter and feed. According to lead author Gloria Reithmaier, many mangrove systems are already experiencing conditions so extreme that these windows of safety are rapidly closing. The study marks the first time oxygen and carbon dioxide have been measured in tandem across a global selection of mangroves.

Escalating Stress in Tropical Environments

The research highlights a particularly dire situation in warm tropical regions, such as the Amazon and India, where carbon dioxide levels are already exceptionally high. In these areas, the environmental stress is reaching levels where even brief periods of low oxygen can prevent fish from utilizing the mangroves as a refuge. According to Reithmaier, these tropical systems are currently operating close to their biological limits, suggesting that highly diverse habitats near the equator may be the first to suffer the loss of sensitive marine populations as the climate warms.