Characterization and comparison of potential denitrifiers in microbial mats from King George Island, Maritime Antarctica

Effects of Sea Animal Activities on Tundra Soil Denitrification and nirS‐ and nirK-Encoding Denitrifier Community in Maritime Antarctica

“…The cluster III contained 16 OTUs and 66,761 sequences with 24.0% from PS, 49.8% from SS, and 26.2% from AL, whereas the cluster IV contained 13 OTUs and 42,125 sequences with 8.7% from PS, 39.2% from SS, and 52.1% from AL. These two clusters included 24.7 and 15.6% of total sequences, respectively, and were closely related to those from some lake or estuarine sediments, such as Yangtze lakes (MF776282; KU159621) ( Jiang et al, 2017 ), San Francisco Bay estuary (KR060158; KR060517) ( Lee and Francis, 2017 ), Yellow River Estuary (KF144040; KX952261) ( Li et al, 2014 ), Lake Baikal (MK460630), Chesapeake Bay estuary (EU725900) ( Fortunato et al, 2009 ), and microbial mats on King George Island (KC951296; KC951293; KC951286) ( Alcántara-Hernández et al, 2014 ). The cluster V contained one OTU and 53,453 sequences with 75.2% from AL, 24.7% from SS, and 0.1% from PS, and cluster VI also contained one OTU and 1,578 sequences with 88.7% from SS, 10.9% from AL, and 0.4% from PS.…”

“…The cluster II contained eight OTUs, and 51,450 sequences with 45.8% of the sequences from AL, 35.6% from PS, and 18.6% from SS, and they closely matched to those in estuarine sediments from San Francisco Bay (GQ453804) ( Mosier and Francis, 2010 ). The cluster III contained four OTUs and 25,099 sequences with 77.7% from SS, 11.6% from PS, and only 10.7% from AL, and their sequences were closely related to those found in the microbial mats of King George Island (KC951310) ( Alcántara-Hernández et al, 2014 ). The cluster IV contained 13 OTUs and 69,288 sequences, and 50.5% of sequences were from SS, 34.2% from PS, and only 15.3% from AL.…”

“…The abundance, distribution, and diversity of denitrifying genes in environments are affected by multiple environmental variables, such as temperature, pH, salinity, dissolved oxygen, organic matter, and dissolved inorganic nitrogen (NO 3 − , NO 2 − , and NH 4 + ) ( Cornwell et al, 2014 ; Zheng et al, 2015 ; Gao et al, 2016 ; Li et al, 2017 ). At present, the abundance, diversity, and distribution of denitrifying genes have been investigated in the Antarctic environment, mainly concentrating on soils of King Sejong Station and the Cape Burk area ( Jung et al, 2011 ; Han, 2013 ), Antarctic Peninsula ( Yergeau et al, 2007 ; Vero et al, 2019 ), and the McMurdo Dry Valley ( Ward and Priscu, 1997 ), and microbial mats of King George Island ( Alcántara-Hernández et al, 2014 ; Valdespino-Castillo et al, 2018 ). However, the information on the distribution of nirS‐ and nirK-encoding denitrifiers, and their major environmental drivers is still limited in tundra soils of maritime Antarctica.…”

“…It is well known that Antarctica has extreme climate conditions with strong winds, limited liquid water availability, and low nutrient contents ( Alcántara-Hernández et al, 2014 ). In coastal Antarctica, the ice-free tundra areas are often colonized by sea animals, such as penguins and seals, and tundra vegetation such as mosses, lichens, and algae.…”

Spatial patterns of microbial nitrogen genes along precipitation gradient in different temperate grasslands of Inner Mongolia, China

“…Moreover, the copy numbers of nirK and AOA did not change before their breaking points of 1.70 and 3.79℃ for MAT, respectively, indicating microorganism containing these genes may be less responsive to the lower arid under lower temperature in our sampling sites. Higher resistance of nirK and AOA was also observed in the polar regions and dryland ecosystems [51,60]. Furthermore, increased copy numbers of nirS and narG after a breaking point of 5.44℃ indicated stimulating effect of temperature itself may become dominant under such condition.…”