Rates of N₂ production and diversity and abundance of functional genes associated with denitrification and anaerobic ammonium oxidation in the sediment of the Amundsen Sea Polynya, Antarctica

详细信息    查看全文

• 作者：Ayeon Choi^a ; Hyeyoun Cho^a ; Sung-Han Kim^a ; Bo Thamdrup^b ; SangHoon Lee^c ; Jung-Ho Hyun^a ; ^{hyunjh@hanyang.ac.kr" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Diversity ; Abundance ; Denitrification ; Anaerobic ammonium oxidation ; Amundsen Sea Polynya ; Antarctica
• 刊名：Deep Sea Research Part II: Topical Studies in Oceanography
• 出版年：2016
• 出版时间：January 2016
• 年：2016
• 卷：123
• 期：Complete
• 页码：113-125
• 全文大小：2080 K

文摘

A combination of molecular microbiological analyses and metabolic rate measurements was conducted to elucidate the diversity and abundance of denitrifying and anaerobic ammonium oxidation (anammox) bacteria and the nitrogen gas (N₂) production rates in sediment underlying the highly productive polynya (Stns. 10 and 17) and the sea-ice zone on the outer shelf (Stn. 83) of the Amundsen Sea, Antarctica. Despite the high water column productivity, the N₂ production rates by denitrification (0.04–0.31 nmol N cm⁻³ sed. h⁻¹) and anammox (0.13–0.26 nmol N cm⁻³ sed. h⁻¹) were lower than those measured in other polar regions. In contrast, gene copy number (10⁶–10⁷ copies cm⁻³ of nirS and nosZ genes targeting denitirifiers and 10⁵–10⁷ copies cm⁻³ of 16S rRNA genes related to anammox bacteria) of the two bacterial groups at Stn. 17 was similar compared to those of other organic-rich environments. The majority of the nirS sequences were affiliated with Gammaproteobacteria (54% and 61% of the total nirS gene at Stns. 17 and 83, respectively), which were closely related to Pseudomonas aeruginosa. Most nosZ sequences (92% and 72% of the total nosZ genes at Stns. 17 and 83, respectively) were related to the Alphaproteobacteria, which were closely related to Ruegeria pomeroyi and Roseobacter denitrificans. Most (98%) of the sequences related to anammox bacteria were affiliated with Candidatus Scalindua at Stn. 17. Consequently, despite the low metabolic activity, the abundance and composition of most denitrifying and anammox bacteria detected from the ASP were similar to those reported from a variety of marine environments. Our results further imply that increased labile organic matter production resulting from a shift of the phytoplankton community from Phaeocystis to diatoms in response to rapid melting of sea ice stimulates metabolic activities of the denitrifying and anammox bacteria, thereby enhancing the N removal process in the ASP.