Coupling of thraustochytrids and POM, and of bacterio- and phytoplankton in a semi-enclosed coastal area: implication for different substrate preference by the planktonic decomposers

Kimura, Hiroyuki; Sato, Makoto; Sugiyama, Chino; Naganuma, Takeshi

doi:10.3354/ame025293

Cited by 54 publications

(38 citation statements)

References 44 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Values for BACT, VLP, and VB were strongly correlated with the PCA 1 axis (POM/chl a; Table 2). Bacterial abundance often correlates with chl a (Cole et al 1988, Poremba et al 1999) and POM (Kimura et al 2001). In contrast to other studies, we observed no significant correlation between bacterial abundance and VLP with inorganic nutrients or DOM (Carlson & Ducklow 1996).…”

Section: Bacterial and Viral Abundancecontrasting

confidence: 56%

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Hodges¹,

Bano²,

Hollibaugh³

et al. 2005

Aquat. Microb. Ecol.

View full text Add to dashboard Cite

The pelagic bacterial community composition of the summertime Chukchi Sea (coastal Alaskan Arctic) was investigated under varying particle concentrations. Free-living and wholecommunity assemblages were compared using PCR-amplified 16S rDNA with denaturing gradient gel electrophoresis (PCR/DGGE) alongside traditional geochemical and microbial inventories. Algal blooms were characterized by increased microbial abundance, decreased species richness, and decreased similarity between free-living and whole-community bacterial assemblages. Bacterial and viral abundance correlated positively with a bloom index identified by principle components analysis that included particulate organic carbon and nitrogen, total organic carbon, and chlorophyll a, but not dissolved organic carbon or inorganic nutrients. The species richness of the free-living community correlated negatively with microbial abundance; differences between free-living and wholecommunity assemblages correlated positively with viral abundance. Algal blooms may therefore increase microbial abundance while stimulating a succession of the bacterial assemblage to fewer free-living species and more specialized particle-associated bacteria. Such community-level shifts are very likely to impact the fate of carbon in high production and export regions like the coastal Arctic. We speculate about the importance of viral lysis to such a succession.

show abstract

Section: Bacterial and Viral Abundancecontrasting

confidence: 56%

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Hodges¹,

Bano²,

Hollibaugh³

et al. 2005

Aquat. Microb. Ecol.

View full text Add to dashboard Cite

show abstract

“…Sulfide was below the detection limit (o0.01 mg l À1 ). Dissolved organic carbon ranged from 36.5 to 37.7 mg l À1 , indicating 15-30 times higher concentrations than those found in coastal seawater (Kimura et al, 2001) (Supplementary Table S2). …”

Section: Resultsmentioning

confidence: 99%

Microbial methane production in deep aquifer associated with the accretionary prism in Southwest Japan

et al. 2009

View full text Add to dashboard Cite

To identify the methanogenic pathways present in a deep aquifer associated with an accretionary prism in Southwest Japan, a series of geochemical and microbiological studies of natural gas and groundwater derived from a deep aquifer were performed. Stable carbon isotopic analysis of methane in the natural gas and dissolved inorganic carbon (mainly bicarbonate) in groundwater suggested that the methane was derived from both thermogenic and biogenic processes. Archaeal 16S rRNA gene analysis revealed the dominance of H 2 -using methanogens in the groundwater. Furthermore, the high potential of methane production by H 2 -using methanogens was shown in enrichments using groundwater amended with H 2 and CO 2 . Bacterial 16S rRNA gene analysis showed that fermentative bacteria inhabited the deep aquifer. Anaerobic incubations using groundwater amended with organic substrates and bromoethanesulfonate (a methanogen inhibitor) suggested a high potential of H 2 and CO 2 generation by fermentative bacteria. To confirm whether or not methane is produced by a syntrophic consortium of H 2 -producing fermentative bacteria and H 2 -using methanogens, anaerobic incubations using the groundwater amended with organic substrates were performed. Consequently, H 2 accumulation and rapid methane production were observed in these enrichments incubated at 55 and 65 1C. Thus, our results suggested that past and ongoing syntrophic biodegradation of organic compounds by H 2 -producing fermentative bacteria and H 2 -using methanogens, as well as a thermogenic reaction, contributes to the significant methane reserves in the deep aquifer associated with the accretionary prism in Southwest Japan.

show abstract

“…Therefore, all tested thraustochytrid species had the potential to degrade a wide variety of organic substrates, confirming that thraustochytrids play a role in the decomposition of organic detritus. In this regard, it is worth noting that the production of enzymes has occasionally been reported for thraustochytrids (Bahnweg 1979a,b, Raghukumar et al 1994, Bremer & Talbot 1995, Raghukumar & Raghukumar 1999 and their role in the decomposition of organic matter has been postulated in both benthic and pelagic environments (Kimura et al 2001, Bongiorni & Dini 2002, Bongiorni et al 2005.Ecto-and exo-enzymatic activities of β-D-glucosidase, L-aminopetidase, β-D-galactosidase, lipase and alkaline phosphatase, expressed under fixed culturing conditions, are reported in Table 3. Density of cultured thraustochytrids ranged between 1.6 and 36.6 × 10 5 cells ml -1…”

mentioning

confidence: 93%

Enzymatic activities of epiphytic and benthic thraustochytrids involved in organic matter degradation

Bongiorni

Pusceddu²,

Danovaro³

2005

Aquat. Microb. Ecol.

View full text Add to dashboard Cite

Thraustochytrids are marine osmo-heterotrophic protists which have been isolated from different habitats and substrates. These organisms are typically encountered in association with refractory substrates, but the extent of their role in organic matter decomposition is still unknown. We isolated 11 thraustochytrid strains from different substrates and tested all species for their potential constitutive ecto-(cell-surface associated) and exo-(free released) enzymatic activities. Our results indicate that the investigated strains exhibited a wide spectrum of enzymes involved in the hydrolysis of all classes of organic compounds, suggesting that thraustochytrids are capable of degrading a large variety of substrates. The enzymatic pools were similar among all strains, and exhibited a good production of lipase, a selection of protease and a poor pool of carbohydrate degradation enzymes. However, different isolates displayed different spectra and intensities of enzymatic activities. The comparison of enzymatic activities of 2 thraustochytrid strains and the total enzymatic activities measured in their natural substrates suggested that thraustochytrids, although representing a minor fraction of the total benthic microbial biomass, are contributors to the degradation of highly refractory organic compounds. KEY WORDS: Thraustochytrids · Enzymatic activities · Organic matter degradation · Marine sediments Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 41: [299][300][301][302][303][304][305] 2005 measured the exo-(free released) and ecto-(cellsurface associated) enzymatic activities of a subset of enzymes produced by all strains, to quantify the potential capability of thraustochytrids in degrading attached and free substrates. Additional measurements of total enzymatic activities in origin sediments of 2 of the 11 cultured strains were also carried out in order to provide a first estimate of the potential thraustochytrid contribution to organic matter degradation in marine sediments. MATERIALS AND METHODSStrain isolation and culture. Thraustochytrids were isolated from a variety of substrates (see Table 1 for details). After accurate washing with sterile artificial seawater, aliquots of the substrate and/or sediments were plated on Modified Vishniac's Medium (0.1% glucose, 0.01% yeast extract, 0.01% peptone, 0.1% gelatine hydrolysate, 1.2% agar in seawater, pH 7.0) or baited with sterile pine pollen (Raghukumar 2002). Strains were incubated at 20 ± 1°C until the appearance of colonies (within 3 to 7 d). Cells were then transferred to fresh agar plates or pine pollen suspensions, and supplemented with antibiotics (1 mg ml -1 of penicillin G and streptomycin sulphate) to suppress bacterial growth.Enzymatic profiles. We grew 11 axenic strains in the liquid medium (see 'Strain isolation and culture' above for description) under continuous gentle shaking (150 rpm), till the late exponential growth phase was reached (ca. 96 h). Bacterial contamination was checked by...

show abstract

Coupling of thraustochytrids and POM, and of bacterio- and phytoplankton in a semi-enclosed coastal area: implication for different substrate preference by the planktonic decomposers

Cited by 54 publications

References 44 publications

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Microbial methane production in deep aquifer associated with the accretionary prism in Southwest Japan

Enzymatic activities of epiphytic and benthic thraustochytrids involved in organic matter degradation

Contact Info

Product

Resources

About

Coupling of thraustochytrids and POM, and of bacterio- and phytoplankton in a semi-enclosed coastal area: implication for different substrate preference by the planktonic decomposers

Cited by 54 publications

References 44 publications

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Microbial methane production in deep aquifer associated with the accretionary prism in Southwest Japan

Enzymatic activities of epiphytic and benthic thraustochytrids involved in organic matter degradation

Contact Info

Product

Resources

About

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study

Illustrating the importance of particulate organic matter to pelagic microbial abundance and community structurean Arctic case study