Nitrification and Denitrification: Probing the Nitrogen Cycle in Aquatic Environments

Area of Science:

• Marine microbiology
• Biogeochemistry
• Molecular ecology

Background:

• Nitrogen cycling is crucial for marine ecosystems.
• Detecting microorganisms involved in nitrogen cycling is essential for ecological studies.
• Existing methods for studying nitrogen cycle microorganisms are sophisticated but can be enhanced.

Purpose of the Study:

• To review and highlight advancements in molecular methods for detecting marine nitrogen-cycling microorganisms.
• To discuss the application of phylogenetic and functional gene probes in marine biogeochemical investigations.
• To emphasize the complementary nature of molecular techniques and in situ rate measurements.

Main Methods:

• Development of probes based on phylogenetic sequences (e.g., rRNA).
• Development of probes based on functional genes or proteins (e.g., nitrite reductase).
• Polymerase Chain Reaction (PCR) primer design for specific microbial groups like ammonia oxidizers.

Main Results:

• Significant progress has been made in developing probes for ammonia oxidizers, with optimized PCR primers.
• Functional probes targeting nitrite reductase show promise for detecting denitrifying bacteria.
• Molecular approaches complement traditional methods for quantifying in situ transformation rates.

Conclusions:

• Molecular methods, including phylogenetic and functional gene probes, are powerful tools for studying marine nitrogen cycling.
• These techniques enhance our ability to identify and understand specific microbial groups involved in nitrogen transformations.
• Combining molecular detection with rate measurements provides a comprehensive approach to understanding the regulation and environmental control of marine biogeochemical processes.