Differences of Nitrogen Transformation Pathways and Their Functional Microorganisms in Water and Sediment of a Seasonally Frozen Lake, China

Abstract

Nitrogen is one of the most important elements involved in ecosystem biogeochemical cycling. However, little is known about the characteristics of nitrogen cycling during the ice-covered period in seasonally frozen lakes. In this study, shotgun metagenomic sequencing of subglacial water and sediment from Lake Ulansuhai was performed to identify and compare nitrogen metabolism pathways and microbes involved in these pathways. In total, ammonia assimilation was the most prominent nitrogen transformation pathway, and Bacteria and Proteobacteria (at the domain and phylum levels, respectively) were the most abundant portion of microorganisms involved in nitrogen metabolism. Gene sequences devoted to nitrogen fixation, nitrification, denitrification, dissimilatory nitrate reduction to ammonium, and ammonia assimilation were significantly higher in sediment than in surface and subsurface water. In addition, 15 biomarkers of nitrogen-converting microorganisms, such as Ciliophora and Synergistetes, showed significant variation between sampling levels. The findings of the present study improve our understanding of the nitrogen cycle in seasonally frozen lakes.

Water Environment Pollution and Control in the Dual-Carbon Background

“…The paper "Differences of Nitrogen Transformation Pathways and Their Functional Microorganisms in Water and Sediment of Seasonally Frozen Lake, China" [1] improves the understanding of the nitrogen cycle in seasonally frozen lakes. Shotgun metagenomic sequencing of subglacial water and sediment from Lake Ulansuhai was performed to identify and compare nitrogen metabolism pathways and microbes involved in these pathways.…”

“…In this wide "Water Environment Pollution and Control" framework, this Special Issue aimed to provide important knowledge and lay a sound scientific foundation for the control and management of water environment pollution by studying the environmental behaviors and bioavailabilities of various pollutants. The thirteen articles in this Special Issue focusing on water environmental pollution and control are mainly divided into four categories: (1) the composition characteristics and environmental behaviors of the pollutants in the surface water (i.e., the Chinese lakes Ulansuhai [1], Hulun Lake [2], Tai Lake [3], Shahu Lake [4], and Russian Ancient lakes [5]); (2) the assessment of groundwater and aquifer interaction [6] and the sources, risks, and management of groundwater pollution [7]; (3) the impact of polluted water on human health [8][9][10]; and (4) the removal of pollutants in water [11][12][13].…”

“…Since the call for papers was announced in 2022, and after a rigorous peer-review process, thirteen papers have been accepted for publication in the Special Issue [1][2][3][4][5][6][7][8][9][10][11][12][13], which include eleven research papers [1][2][3][4]6,[8][9][10][11][12][13] and two reviews [5,7]. We offer brief highlights of the published papers below.…”