How elevated nitrogen load affects bacterial community structure and nitrogen cycling services in coastal water

Area of Science:

• Marine microbiology
• Aquaculture science
• Environmental science

Background:

• Aquaculture intensification accelerates coastal nutrient pollution, leading to eutrophication.
• Excess nutrients negatively impact coastal ecosystems and economies.
• Planktonic microbial communities play a crucial role in nutrient cycling.

Purpose of the Study:

• To investigate the impact of coastal aquaculture on planktonic microbial communities over one year.
• To understand how aquaculture influences coastal water quality and nitrogen cycling.
• To identify specific bacterial groups and functional pathways affected by aquaculture activities.

Main Methods:

• Monitoring coastal planktonic microbial communities over a 12-month period.
• Analyzing water quality parameters, including total inorganic nitrogen concentrations.
• Utilizing PICRUSt2 for predicting nitrogen cycle-related functional pathways from inferred genomes.

Main Results:

• Active fish farms showed increased total inorganic nitrogen, favoring Alpha- and Gammaproteobacteria.
• Bacterial alpha diversity positively correlated with nitrogen levels; active farming influenced community structure.
• Enhanced nitrogen load correlated with increased dissimilatory nitrate reduction and denitrification pathways.

Conclusions:

• Active and fallowed aquaculture practices rapidly impact coastal planktonic bacterial communities.
• Aquaculture significantly influences nitrogen cycling and associated microbial functions.
• Findings are crucial for sustainable aquaculture and water resource management.