Long-term changes in microbial and biochemical parameters in the Central Indian Basin

Raghukumar, Chandralata; Nath, B. Nagender; Sharma, Rahul; Bharathi, P. A. Loka; Dalal, S.G.

doi:10.1016/j.dsr.2006.08.003

Cited by 13 publications

(8 citation statements)

References 51 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Baltic Sea (Nordrü gensche Bodden; brackish water) Liu et al 2009 0.09-1.37 mmol g 21 h 21 (dry wt) Chinese shallow lakes (freshwater) Sediments were air-dried and sieved before incubations Raghukumar et al 2006 Up to 0.12 mmol g 21 h 21 (dry wt, in undisturbed sediments)…”

Section: Discussionmentioning

confidence: 99%

Phosphatases relieve carbon limitation of microbial activity in Baltic Sea sediments along a redox‐gradient

Steenbergh

Bodelier

Hoogveld

et al. 2011

Limnology & Oceanography

View full text Add to dashboard Cite

The relationship between phosphatase activity and the element limiting microbial activity (carbon [C], nitrogen [N], or phosphorus [P]) was studied experimentally in sediment from four stations in the Baltic Sea located along a depth transect from oxic to anoxic bottom waters. The role of extracellular phosphatases was assessed by determining the percentages of intact cells that could be labeled with an artificial substrate for phosphatases (i.e., enzyme-labeled fluorescence 97 phosphatase substrate [ELF]) using a flow cytometer. Phosphatase activity was detected in sediment slurries from all sites either with or without prior incubation under oxic or anoxic conditions. In addition, ELF-labeled cells were detected in all incubated sediments, indicating that intact cells bearing phosphatases contribute to the phosphatase activity. Phosphatase activities and percentages of ELF-labeled cells were lower for the anoxic than for the oxic slurry incubations. Phosphatases are likely used to relieve the limitation of microbial activity by utilizable C in these recently deposited, organic C-rich sediments in the Baltic Sea. In marine sediments overlain by anoxic bottom waters, the biological and chemical mechanisms of P retention are often less efficient than in oxic settings and the P released to relieve C limitation escapes to the overlying water. This explains the ongoing higher P fluxes from sediments overlain by anoxic bottom waters.

show abstract

Section: Discussionmentioning

confidence: 99%

Phosphatases relieve carbon limitation of microbial activity in Baltic Sea sediments along a redox‐gradient

Steenbergh

Bodelier

Hoogveld

et al. 2011

Limnology & Oceanography

View full text Add to dashboard Cite

show abstract

“…Furthermore, Alagarsamy (2003) has reported that the contribution of hydrolysable carbohydrates and amino acids to the total organic carbon in Oman margin sediments is only 10% and the remaining being recalcitrant in nature. Proteolytic and starch hydrolyzing microflora are well documented in non-OMZ sediments of India (Nair et al 2000;Raghukumar et al 2006). In the OMZ sediments amylase and gelatinase were expressed by 37 and 33% of the isolates, respectively reflecting the presence of these biopolymers.…”

Section: Extracellular Enzymatic Activity and Its Ecological Implicatmentioning

confidence: 99%

16SrRNA and enzymatic diversity of culturable bacteria from the sediments of oxygen minimum zone in the Arabian Sea

Divya

Soumya

Nair

2010

Antonie van Leeuwenhoek

View full text Add to dashboard Cite

Sediment underlying the oxygen minimum zone of the eastern Arabian Sea is rich in organic matter. Bacteria in this sediment-water interface are of great ecological importance as they are responsible for decomposing, mineralizing and subsequent recycling of organic matter. This study has for the first time addressed the phylogenetic and functional description of culturable bacteria of this region. Genotypic characterization of the isolates using amplified rDNA restriction analysis (ARDRA) followed by 16SrRNA sequencing grouped them into various phylogenetic groups such as Firmicutes, Gammaproteobacteria, Low G+C Gram positive bacteria, Actinobacteria and unaffiliated bacteria. Among the enzyme activities, phosphatase was predominant (52%) and was associated with all the phylotypes followed by amylase (37%) and gelatinase (33%). These hydrolytic enzymes were expressed at a wide range of temperature and pH. Firmicutes expressed most of the hydrolytic activities, consistent with a role in degradation of organic matter. Multiple enzyme expression (>/=3) was exhibited by Actinobacteria (100%), followed by unaffiliated group (62.5%) and Firmicutes (61.5%). Besides hydrolytic enzymes, the phylotypes also elaborated functional enzymes such as nitrate reductase and catalase (58 and 81% of the isolates, respectively). In the oxygen minimum zone, the diversity was high with 28 phylotypes. Culturable bacterial assemblages encountered were Bacillus sp., Halobacillus sp., Virgibacillus sp., Paenibacillus sp., Marinilactibacillus sp., Kytococcus sp., Micrococcus sp., Halomonas sp. and Alteromonas sp. The high diversity and high percentage of extracellular hydrolytic enzyme activities of the culturable bacteria reflect their important ecological role in biogeochemical cycling of organic matter in the oxygen minimum zone.

show abstract

“…The quantification of ATP provides a potentially convenient means of determining in situ microbial biomass in environmental samples. This method has been widely used for the determination of total microbial populations in soils (Marin et al, 2005;Oliveira and Pampulha, 2006), seawater and marine sediments (Avilov and Avilova, 2009;Raghukumar et al, 2006;Stoeck et al, 2000) and for assessment of microbial contamination of foodstuffs (Aycicek et al, 2006b;Davidson et al, 1999;Zwartkruis et al, 1999) and surfaces (Aycicek et al, 2006a). Our method of choice ("Aqua-Trace®" swab kits) allows obtaining results within minutes after core opening.…”

Section: Discussionmentioning

confidence: 99%

Microbial community composition and biogeochemical processes in cold-water coral carbonate mounds in the Gulf of Cadiz, on the Moroccan margin

et al. 2011

View full text Add to dashboard Cite

Long-term changes in microbial and biochemical parameters in the Central Indian Basin

Cited by 13 publications

References 51 publications

Phosphatases relieve carbon limitation of microbial activity in Baltic Sea sediments along a redox‐gradient

Phosphatases relieve carbon limitation of microbial activity in Baltic Sea sediments along a redox‐gradient

16SrRNA and enzymatic diversity of culturable bacteria from the sediments of oxygen minimum zone in the Arabian Sea

Microbial community composition and biogeochemical processes in cold-water coral carbonate mounds in the Gulf of Cadiz, on the Moroccan margin

Contact Info

Product

Resources

About