Denitrifying bacteria in the limnetic zone of Lake Tota, Colombia

Abstract

The objective of study was to isolate and determine the identity of denitrifying bacteria from limnetic areas of Lake Tota (Colombian Andes) with and without rainbow trout production activities. We examined the relationships between the lake’s physicochemical factors (oxygen, nitrogen, and phosphorus content) and two bacterial communities (denitrifying bacteria and coliforms). Water samples were taken 20m below the surface from July to September at five limnetic zones; two of which were close to rainbow trout farming areas. In each zone, the concentrations of oxygen, nitrogen, and phosphorus were measured. To identify and quantify the abundance of bacteria, the most probable number (MPN) technique was used, employing minimal medium for denitrifying bacteria and medium for nitrate reducing bacteria (NRB). A greater number of denitrifying bacteria were found in the fish farming zones, identifying bacteria of the genera Bacillus, Pseudomonas, Nocardia, and Streptomyces. The number of nitrate-reducing bacteria revealed statistically significant differences throughout the sampling period, increasing from July to September and was related to a decrease in precipitation. The density of NRB and total phosphorus were directly correlated. High bacterial densities of denitrifyingbacteria and coliforms are indicative of changes from oligotrophic to eutrophic states in the studied limnetic areas.

Whole genome sequence of denitrifying bacterium Stutzerimonas stutzeri strain NGHE31, collected from an eutrophic wetland in Sunamganj, Bangladesh, following the 2017 flash floods

“…Stutzerimonas stutzeri is a Gram-negative, facultative anaerobic bacterium belonging to the Gammaproteobacteria that has been frequently reported to coexist with cyanobacterial species in eutrophic ecosystems ( 1 – 3 ). S. stutzeri is an important natural denitrifier, and studies have also shown its promising applicability in bioremediation, pollutant degradation, and wastewater treatment, owing to its rich repertoire of genes involved in the metabolism of organic and toxic compounds ( 4 – 6 ).…”

Sub-Liquid and Atmospheric Measurement Instrument To Autonomously Monitor the Biochemistry of Natural Aquatic Ecosystems

“…Studies suggest that naturally occurring microorganisms in fresh and saltwater play diverse roles in ecosystems and are essential to Earth’s biogeochemical cycles . Depending on the aquatic environment, microorganisms in lentic systems can thrive in the littoral zone, a region of a liquid body near the shoreline, well-lighted, shallow, and warmer than other regions of the water; limnetic zone, further away from the shore, colder and having sunlight only in the upper 100 feet or so; benthic zone, at depths without any oxygen and sunlight; subterranean systems, with varied salt concentrations and pH levels (acidophiles and alkaliphiles); salty water bodies, with higher salt concentration, (halophiles), higher pH, and lower nutrients; and hydrothermal vents and within biofilms, a grouping of cells surrounded by a polymer matrix providing a protective barrier to the external environment. The activity in these ecosystems may also vary seasonally, and by monitoring them continuously over a long time, a detailed account of the nutrient and gas cycling can be established .…”