Detrital diversity influences estuarine ecosystem performance

Area of Science:

• Estuarine ecology
• Marine biology
• Ecosystem science

Background:

• Estuarine detrital resources are changing due to seagrass and mangrove loss, algal blooms, and invasive species.
• These changes may affect benthic ecosystem processes, including primary production and nutrient cycling.

Purpose of the Study:

• To test how detrital source richness, mix identity, and biomass influence benthic primary production, metabolism, and nutrient fluxes in estuaries.
• To understand the implications of altered detrital inputs on estuarine ecosystem functioning.

Main Methods:

• Manipulated eight detrital sources (mangrove, seagrass, native/invasive algae) in an estuarine sandflat.
• Applied 12 treatments with varying detrital mixes (2 or 4 sources) and biomass (40g or 60g) to 72 plots.
• Measured nutrient fluxes (NH4+, DIN, DON) and benthic metabolism (oxygen flux, productivity) over two months.

Main Results:

• Detrital mix identity significantly influenced nutrient uptake and efflux, but not source richness or biomass.
• Gross and net primary productivity, oxygen flux, and nutrient fluxes (NOX, DIP) were higher with low detrital source richness.
• Detrital source identity and richness are key drivers of estuarine ecosystem performance.

Conclusions:

• Changes in the types and diversity of detrital inputs significantly alter estuarine ecosystem processes.
• Continued impacts on estuarine macrophytes will likely modify detritus-fueled productivity.
• Further research is needed to predict the consequences of future changes in detrital resources.