Boosted food web productivity through ocean acidification collapses under warming

Area of Science:

• Marine ecology
• Climate change biology
• Food web dynamics

Background:

• Predicting climate change impacts on food webs is limited by simplified laboratory studies.
• Understanding trophic interactions across multiple levels is crucial for ecological predictions.

Purpose of the Study:

• To investigate how ocean acidification and warming affect a three-level marine food web.
• To determine the combined effects of elevated CO2 and temperature on trophic linkages.

Main Methods:

• Utilized a large-scale mesocosm experiment simulating future ocean conditions.
• Examined changes in primary (algae), secondary (invertebrates), and tertiary (fish) producers.
• Assessed the propagation of effects through different trophic levels.

Main Results:

• Elevated CO2 and temperature increased primary production.
• Elevated CO2 enhanced bottom-up forcing across all trophic levels.
• Elevated temperature reduced secondary production, causing declines in invertebrate populations due to increased predator consumption.

Conclusions:

• Anthropogenic CO2 can enhance food web productivity, but warming acts as a stressor, negating these benefits.
• The balance between resource enrichment and consumption determines food web stability and fisheries production under climate change.