TY - JOUR
T1 - Different carboxyl-rich alicyclic molecules proxy compounds select distinct bacterioplankton for oxidation of dissolved organic matter in the mesopelagic Sargasso Sea
AU - Liu, Shuting
AU - Parsons, Rachel
AU - Opalk, Keri
AU - Baetge, Nicholas
AU - Giovannoni, Stephen
AU - Bolaños, Luis M.
AU - Kujawinski, Elizabeth B.
AU - Longnecker, Krista
AU - Lu, Yue Han
AU - Halewood, Elisa
AU - Carlson, Craig A.
N1 - Publisher Copyright:
© 2020 The Authors. Limnology and Oceanography published by Wiley Periodicals, Inc. on behalf of Association for the Sciences of Limnology and Oceanography.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - Marine dissolved organic matter (DOM) varies in its recalcitrance to rapid microbial degradation. DOM of varying recalcitrance can be exported from the ocean surface to depth by subduction or convective mixing and oxidized over months to decades in deeper seawater. Carboxyl-rich alicyclic molecules (CRAM) are characterized as a major component of recalcitrant DOM throughout the oceanic water column. The oxidation of CRAM-like compounds may depend on specific bacterioplankton lineages with oxidative enzymes capable of catabolizing complex molecular structures like long-chain aliphatics, cyclic alkanes, and carboxylic acids. To investigate the interaction between bacteria and CRAM-like compounds, we conducted microbial remineralization experiments using several compounds rich in carboxyl groups and/or alicyclic rings, including deoxycholate, humic acid, lignin, and benzoic acid, as proxies for CRAM. Mesopelagic seawater (200 m) from the northwest Sargasso Sea was used as media and inoculum and incubated over 28 d. All amendments demonstrated significant DOC removal (2–11 μmol C L−1) compared to controls. Bacterioplankton abundance increased significantly in the deoxycholate and benzoic acid treatments relative to controls, with fast-growing Spongiibacteracea, Euryarcheaota, and slow-growing SAR11 enriched in the deoxycholate treatment and fast-growing Alteromonas, Euryarcheaota, and Thaumarcheaota enriched in the benzoic acid treatment. In contrast, bacterioplankton grew slower in the lignin and humic acid treatments, with oligotrophic SAR202 becoming significantly enriched in the lignin treatment. Our results indicate that the character of the CRAM proxy compounds resulted in distinct bacterioplankton removal rates of DOM and affected specific lineages of bacterioplankton capable of responding.
AB - Marine dissolved organic matter (DOM) varies in its recalcitrance to rapid microbial degradation. DOM of varying recalcitrance can be exported from the ocean surface to depth by subduction or convective mixing and oxidized over months to decades in deeper seawater. Carboxyl-rich alicyclic molecules (CRAM) are characterized as a major component of recalcitrant DOM throughout the oceanic water column. The oxidation of CRAM-like compounds may depend on specific bacterioplankton lineages with oxidative enzymes capable of catabolizing complex molecular structures like long-chain aliphatics, cyclic alkanes, and carboxylic acids. To investigate the interaction between bacteria and CRAM-like compounds, we conducted microbial remineralization experiments using several compounds rich in carboxyl groups and/or alicyclic rings, including deoxycholate, humic acid, lignin, and benzoic acid, as proxies for CRAM. Mesopelagic seawater (200 m) from the northwest Sargasso Sea was used as media and inoculum and incubated over 28 d. All amendments demonstrated significant DOC removal (2–11 μmol C L−1) compared to controls. Bacterioplankton abundance increased significantly in the deoxycholate and benzoic acid treatments relative to controls, with fast-growing Spongiibacteracea, Euryarcheaota, and slow-growing SAR11 enriched in the deoxycholate treatment and fast-growing Alteromonas, Euryarcheaota, and Thaumarcheaota enriched in the benzoic acid treatment. In contrast, bacterioplankton grew slower in the lignin and humic acid treatments, with oligotrophic SAR202 becoming significantly enriched in the lignin treatment. Our results indicate that the character of the CRAM proxy compounds resulted in distinct bacterioplankton removal rates of DOM and affected specific lineages of bacterioplankton capable of responding.
UR - http://www.scopus.com/inward/record.url?scp=85078654284&partnerID=8YFLogxK
U2 - 10.1002/lno.11405
DO - 10.1002/lno.11405
M3 - Article
AN - SCOPUS:85078654284
SN - 1939-5590
VL - 65
SP - 1532
EP - 1553
JO - Limnology and Oceanography
JF - Limnology and Oceanography
IS - 7
ER -