Trophic amplification of climate warming

Area of Science:

• Marine ecology
• Ecosystem dynamics
• Climate change impacts

Background:

• Ecosystems can abruptly shift between stable states, influenced by internal factors or external drivers.
• Marine ecosystems, particularly heavily exploited ones, have experienced abrupt shifts attributed to fishing, climate change, or both.
• Understanding the mechanisms driving these shifts is crucial for effective ecosystem-based fisheries management.

Purpose of the Study:

• To investigate the role of temperature as a driver of trophodynamics in the North Sea ecosystem.
• To elucidate the internal mechanisms through which temperature changes establish new ecosystem dynamic regimes.
• To explore trophic amplification as a driver of ecosystem state shifts.

Main Methods:

• Employed an end-to-end ecosystem modeling approach.
• Included all trophic levels: primary producers, consumers (primary, secondary, tertiary), and detritivores.
• Analyzed long-term data (nearly 50 years) on North Sea ecosystem dynamics and temperature.

Main Results:

• Temperature has been a significant driver of North Sea trophodynamics for approximately 50 years.
• A recent pronounced temperature change initiated a new ecosystem dynamic regime via internal mechanisms.
• Temperature-induced nonlinearities, ecological thresholds, and trophic amplification altered species relationships.
• Trophic amplification favored jellyfish in the plankton and decapods/detritivores in the benthos.

Conclusions:

• Temperature can induce ecosystem shifts similar to those often attributed to overfishing.
• Trophic amplification offers an alternative mechanism to positive feedback in driving ecosystem regime shifts.
• Findings are critical for advancing ecosystem-based fisheries management (EBFM) in exploited marine environments.