Krill excretion boosts microbial activity in the Southern Ocean
Javier Arístegui1, Carlos M Duarte2, Isabel Reche3
1Instituto de Oceanografía y Cambio Global (IOCAG), Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
Plos One
|March 4, 2014
Summary
Antarctic krill excretion significantly boosts heterotrophic bacteria growth in the Southern Ocean. This krill-bacterial recycling enhances nutrient cycling, potentially increasing primary productivity.
Area of Science:
- Marine biology
- Microbial ecology
- Oceanography
Background:
- Antarctic krill are significant nutrient sources in the Southern Ocean.
- Krill excretion releases both inorganic and organic compounds into the water column.
Purpose of the Study:
- To investigate the role of krill excretory products in stimulating heterotrophic bacterial growth.
- To determine if krill excretion products, not just ammonium, are key drivers of bacterial activity.
Main Methods:
- Three experiments were conducted using bacterial assemblages without grazers.
- Dissolved ammonium and organic excretory products from krill were added to these assemblages.
- Bacterial growth and production were measured in response to these additions.
Main Results:
- Krill excretion products, excluding ammonium alone, caused a tenfold increase in bacterial growth and production.
- Bacterial growth rates in the Southern Ocean appear limited by resources, not potential.
Conclusions:
- Krill excretion is a major stimulant for heterotrophic bacteria in the Southern Ocean.
- This krill-bacterial interaction facilitates efficient nutrient recycling.
- Enhanced bacterial activity contributes to increased primary productivity in krill swarm areas.
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