Distribution and characteristics of ultraviolet absorption and fluorescenceof dissolved organic matter in a large lake (Lake Biwa, Japan)

Hayakawa, Kazuhide; Kojima, Reiji; Wada, Chizuru; Suzuki, Takehito; Sugiyama, Yuko; Kumagai, Tetsu; Takei, Naoko; Bamba, Daiya

doi:10.1016/j.jglr.2016.02.006

Cited by 9 publications

(5 citation statements)

References 33 publications

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“…These facts evoke an additional hypothesis that CL500-11 utilize substrates secondary produced in situ by microbial processes ( Ogawa et al, 2001 ; Jiao and Zheng, 2011 ; Guillemette and del Giorgio, 2012 ). Indeed, studies have demonstrated that, similar to marine systems ( Timko et al, 2015b ; Shen and Benner, 2018 ), DOM is more photo-labile in the hypolimnion than in the epilimnion ( Hayakawa et al, 2016 ; Yamada et al, 2018 ), suggesting that a part of hypolimnetic DOM is produced in situ and distinct from DOM produced and accumulated in the epilimnion, which likely consist of already-photobleached substrates such as carboxylic acids ( Bertilsson and Tranvik, 2000 ). Correspondingly, a low number of transporters for carboxylic acids was found in CL500-11 MAGs compared to other freshwater microbes ( Denef et al, 2016 ), pointing to a non-preferred utilization of these photobleached compounds.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, CL500-11 MAGs harbor a high number of transporters for di- and oligopeptide, as well as transporters for spermidine/putrescein, and branched-chain amino acids ( Denef et al, 2016 ; Mehrshad et al, 2018 ). Such nitrogen-rich, protein-like DOM can be originated from remnants of bacterial cell walls ( McCarthy et al, 1998 ; Nagata et al, 2003 ) and membranes ( Tanoue et al, 1995 ), and consumption of such DOM by the microbial community in the oxygenated hypolimnion have been suggested by DOM profiling by stoichiometry ( Kim et al, 2006 ) and by excitation and emission matrices ( Thottathil et al, 2013 ; Hayakawa et al, 2016 ) in Lake Biwa. One CL500-11 MAG also included a transporter for N -acetylglucosamine, a breakdown product of bacterial cell walls ( Denef et al, 2016 ; Mehrshad et al, 2018 ).…”

Section: Resultsmentioning

confidence: 99%

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The Broad Habitat Spectrum of the CL500-11 Lineage (Phylum Chloroflexi), a Dominant Bacterioplankton in Oxygenated Hypolimnia of Deep Freshwater Lakes

et al. 2018

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CL500-11 (phylum Chloroflexi) is one of the most ubiquitous and abundant bacterioplankton lineages in deep freshwater lakes inhabiting the oxygenated hypolimnion. While metagenomics predicted possible eco-physiological characteristics of this uncultured lineage, no consensus on their ecology has so far been reached, partly because their niche is not clearly understood due to a limited number of quantitative field observations. This study investigated the abundance and distribution of CL500-11 in seven deep perialpine lakes using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). Samples were taken vertically (5–12 depths in each lake) and temporally (in two lakes) at the deepest point of the lakes located in Switzerland, Italy, and Austria with varying depth, trophic state, mixing regime, and water retention time. The results showed a dominance of CL500-11 in all the lakes; their proportion to total prokaryotes ranged from 4.3% (Mondsee) to 24.3% (Lake Garda) and their abundance ranged from 0.65 × 105 (Mondsee) to 1.77 × 105 (Lake Garda) cells mL-1. By summarizing available information on CL500-11 occurrence to date, we demonstrated their broad habitat spectrum, ranging from ultra-oligotrophic to meso-eutrophic lakes, while low abundances or complete absence was observed in lakes with shallow depth, low pH, and/or short water retention time (<1 year). Together with available metagenomic and geochemical evidences from literatures, here we reviewed potential substrates supporting growth of CL500-11. Overall, the present study further endorsed ubiquity and quantitative significance of CL500-11 in deep freshwater systems and narrowed the focus on their physiological characteristics and ecological importance.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

The Broad Habitat Spectrum of the CL500-11 Lineage (Phylum Chloroflexi), a Dominant Bacterioplankton in Oxygenated Hypolimnia of Deep Freshwater Lakes

et al. 2018

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“…In such a lake, accumulation and remineralization of organic matter in the hypolimnion are important biogeochemical processes (Wetzel, 2001). Recent studies have suggested that dissolved organic matter (DOM) in the oxygenated hypolimnion is enriched by the slowly consumed semi-labile fraction (Maki et al, 2010) and can be transformed into a more recalcitrant form by microbes (Thottathil et al, 2013;Hayakawa et al, 2016), as shown by the microbial carbon pump theory proposed for the ocean (Ogawa et al, 2001;Yamashita and Tanoue, 2008;Jiao and Zheng, 2011;Hansell, 2013). Other studies have demonstrated that nitrification (Small et al, 2013), dark carbon fixation (Callieri et al, 2014), and methane oxidation (Murase and Sugimoto, 2005;Bornemann et al, 2016) are also present in the oxygenated hypolimnion.…”

Section: Introductionmentioning

confidence: 99%

Ubiquity and quantitative significance of bacterioplankton lineages inhabiting the oxygenated hypolimnion of deep freshwater lakes

Okazaki

Fujinaga

Tanaka

et al. 2016

Preprint

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Freshwater bacterioplankton in the oxygenated hypolimnion are reportedly dominated by specific members that are distinct from those in the epilimnion. However, no consensus exists regarding the ubiquity and abundance of these bacterioplankton, which is necessary to evaluate their ecological importance. The present study investigated the bacterioplankton community in the oxygenated hypolimnia of 10 deep freshwater lakes. Despite the broad geochemical characteristics of the lakes, 16S rRNA gene sequencing demonstrated that many predominant lineages in the hypolimnion were shared by several lakes and consisted of members occurring in the entire water layer and members specific to the hypolimnion. Catalyzed reporter deposition fluorescence in situ hybridization (CARD-FISH) revealed that representative hypolimnion-specific lineages, CL500-11 (Chloroflexi), CL500-3, CL500-37, CL500-15 (Planctomycetes), and the MGI group (Thaumarchaeota), together accounted for 1.5-32.9% of all bacterioplankton in the hypolimnion of the lakes. Furthermore, an analysis of micro-diversification based on single-nucleotide variation in the partial 16S rRNA gene sequence (oligotyping) suggested the presence of hypolimnion-specific ecotypes among the lineages occurring in the entire water layer (e.g., acI and Limnohabitans). Collectively, these results demonstrate the uniqueness, ubiquity, and quantitative significance of bacterioplankton in the oxygenated hypolimnion, motivating future studies to focus on their eco-physiological characteristics.

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“…This is consistent with the CDOM pool being dominated by terrestrial runoff for most lakes. The protein‐like component is an indicator of autochthonous production from microbial sources (Hayakawa et al., 2016). This increased at lower elevations, consistent with increased biological production in lakes with higher nutrient levels.…”

Section: Discussionmentioning

confidence: 99%

Chromophoric Dissolved Organic Matter and Dissolved Organic Carbon in Lakes Across an Elevational Gradient From the Mountains to the Sea

Juetten

Strecker

Harrison

et al. 2022

Earth and Space Science

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Dissolved organic matter (DOM) in lakes across elevation gradients is a complex function of topography, climate, vegetation coverage, land use, and lake properties. To examine sources and processing of DOM from sea level to mountain lakes (3–1,574 m), we measured dissolved organic carbon (DOC) concentrations and chromophoric dissolved organic matter (CDOM) optical properties, lake characteristics, and water quality parameters in 62 freshwater lakes in the Pacific Northwest, USA. Higher elevation lakes had lower DOC concentrations and absorbance. These lakes had higher forest cover and minimal wetlands in their watershed, in addition to low nutrients, water temperatures, and chlorophyll a in the lake itself. Two humic‐like and one protein‐like fluorescent component were identified from excitation‐emission matrix spectroscopy. The index of recent autochthonous contribution (BIX), fluorescence index (FIX), and SR optical indices showed that most lakes were dominated by terrestrially derived material. The humification index (HIX) and specific ultra‐violet absorbance (SUVA254) were consistent with more aromatic humic CDOM at lower elevations. The lower fluorescence of humic‐like components at higher elevation was attributed to lower inputs from vegetation. The relative contribution of the protein‐like component increased at higher elevation. This may be due to reduced allochthonous terrestrial inputs relative to in situ production of autochthonous material or increased photochemical/biological degradation of allochthonous material. Differences in optical characteristics associated with the amount and source of CDOM were observed across the elevational gradient. These differences were driven by characteristics at both within‐lake and watershed scales.

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Distribution and characteristics of ultraviolet absorption and fluorescenceof dissolved organic matter in a large lake (Lake Biwa, Japan)

Cited by 9 publications

References 33 publications

The Broad Habitat Spectrum of the CL500-11 Lineage (Phylum Chloroflexi), a Dominant Bacterioplankton in Oxygenated Hypolimnia of Deep Freshwater Lakes

The Broad Habitat Spectrum of the CL500-11 Lineage (Phylum Chloroflexi), a Dominant Bacterioplankton in Oxygenated Hypolimnia of Deep Freshwater Lakes

Ubiquity and quantitative significance of bacterioplankton lineages inhabiting the oxygenated hypolimnion of deep freshwater lakes

Chromophoric Dissolved Organic Matter and Dissolved Organic Carbon in Lakes Across an Elevational Gradient From the Mountains to the Sea

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