In:
Biogeosciences, Copernicus GmbH, Vol. 20, No. 11 ( 2023-06-12), p. 2065-2098
Abstract:
Abstract. Bacteriohopanepolyols (BHPs) are a diverse class of lipids
produced by bacteria across a wide range of environments. In this study, we
aim to further identify BHPs related to ecological niches and/or specific
bacteria by characterizing the distribution of BHPs in suspended particulate
matter (SPM) of the water column and in sediments in a range of lakes and
coastal lagoons from the Azores Archipelago, as well as in a co-culture
enriched for methanotrophs. Sediment samples from Azorean lakes with low-oxygen conditions during the summer months (i.e., Azul, Verde, Funda, and
Negra) contain relatively high abundances of BHPs that are typically
associated with methane-oxidizing (methanotrophic) bacteria (i.e.,
aminotetrol, aminopentol, and methylcarbamate-aminopentol), as well as the
ethenolamine-BHPs (i.e., ethenolamine-BHpentol and ethenolamine-BHhexol) and
the N-formylated aminoBHPs. Both ethenolamine-BHPs and N-formylated
aminoBHPs were also detected in a methanotroph–methylotroph co-culture that
was enriched from a lake. In the SPM of all water columns,
bacteriohopanetetrol (BHT), BHT cyclitol ether, and aminotriol are the
dominant BHPs. In SPM from Lake Funda, nucleoside BHPs (i.e.,
Me-adenosylhopaneHG-diMe (where HG refers to head group), N1-methylinosylhopane, 2Me-N1-inosylhopane,
and Me-N1-inosylhopane) are present in low abundance or absent under oxic
conditions but increase in concentration near the chemocline, suggesting
potential in situ production of these nucleoside BHPs rather than an allochthonous
origin. In contrast, sediments from shallow, well-mixed lakes (i.e.,
Empadadas, São Jorge, and Lomba) contain higher abundances of
adenosylhopane and N1-methylinosylhopane, which likely originate from
bacteria living in nearby soils. Based on our current results we revised the
existing Rsoil index, which was previously used to infer terrestrial
inputs to aquatic environments, to exclude any potential nucleosides
produced in the lake water column (Rsoil-lake). In the coastal lagoons,
Cubres East and Cubres West, methoxylated BHTs were detected, and higher abundances
of ethenolamine-BHT were observed. This study highlights the diversity of
BHPs in lakes and coastal lagoons and their potential as taxonomic markers
for bacteria associated with certain ecological niches, which can be
preserved in sedimentary records.
Type of Medium:
Online Resource
ISSN:
1726-4189
DOI:
10.5194/bg-20-2065-2023
DOI:
10.5194/bg-20-2065-2023-supplement
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2023
detail.hit.zdb_id:
2158181-2
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