Prokaryotic extracellular enzymatic activity in relation to biomass production and respiration in the meso‐ and bathypelagic waters of the (sub)tropical Atlantic

Baltar, Federico; Arı́stegui, Javier; Sintes, Eva; Aken, Hendrik M. van; Gasol, Josep M.; Herndl, Gerhard J.

doi:10.1111/j.1462-2920.2009.01922.x

Cited by 112 publications

(141 citation statements)

References 89 publications

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“…6A-D) are in the same range as those obtained in a previous Atlantic study (Baltar et al 2009a), which is the only other study where kinetic parameters have been determined throughout the whole oceanic water column. As in the present study, Baltar et al (2009a) reported a decrease in the V max of LAPase (~12 to 3 nmol l -1 h -1 ) and APase (~0.3 to 0.1 nmol l -1 h -1 ) and an increase in the K m of LAPase (~400 to 1200 µM) and APase (~2 to 23 µM) with depth down to 4500 m. Tamburini et al (2002) obtained lower K m values (ranging between 0.4 and 1.1 µM) for LAPase in the Mediterranean deep-waters (down to 2000 m depth) than in the present study. However, the APase K m values (0.05 to 1.2 µM) reported by Tamburini et al (2002) are in the same range as the APase K m we obtained.…”

Section: Discussionsupporting

confidence: 72%

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High dissolved extracellular enzymatic activity in the deep central Atlantic Ocean

Baltar¹,

Arı́stegui²,

Gasol³

et al. 2010

Aquat. Microb. Ecol.

115

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The distribution of prokaryotic abundance (PA), prokaryotic heterotrophic production (PHP), and suspended particulate organic material (POM), as well as total and dissolved (operationally defined as passing through 0.2 µm pore size filters) potential extracellular enzymatic activities (EEA; α-and β-glucosidase [AGase and BGase], leucine aminopeptidase [LAPase], and alkaline phosphatase [APase]) were determined in the meso-and bathypelagic waters of the (sub)tropical Atlantic along an eastern zonal transatlantic transect and a western N-S transect. Significant differences between both transects were found for POM concentration but not for PA, PHP (except in the subsurface and oxygen minimum layer), and dissolved and total EEA. PHP decreased by 3 orders of magnitude from the lower euphotic zone to bathypelagic waters, while PA and cell-specific PHP decreased only by 1 and 2 orders of magnitude, respectively. The proportion of the dissolved to the total EEA was high in the dark ocean for all the enzymes, ranging from 54 to 100, 56 to 100, 65 to 100 and 57 to 97% for AGase, BGase, LAPase and APase, respectively. The kinetic parameters (V max and K m ) of both the dissolved and total fractions of LAPase and APase were very similar throughout the water column, suggesting a similar origin for both dissolved and particulate EEA. Significant correlations of both dissolved and total EEA were found with prokaryotic metabolism and the POM pool. Based on the previous notion that the fraction of dissolved EEA is higher in particle-attached than in free-living microbes, our results suggest that microbial activity in the dark ocean occurs mainly on colloidal and particulate material. This is in agreement with recent genomic evidence. However, these colloidal and particulate materials are prone to disruption during the sampling process. Hence, more selective sampling techniques are needed to specifically collect these deep-water aggregates that probably represent hotspots of microbial activity in the deep ocean.

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Section: Discussionsupporting

confidence: 72%

“…However, most of these applications have been restricted to the euphotic zone and coastal seas (Sala et al 2001, Zaccone et al 2003, Williams & Jochem 2006. Only a few EEA profiles are available for the whole water column of the open ocean (Koike & Nagata 1997, Hoppe & Ullrich 1999, Baltar et al 2009a.…”

Section: Introductionmentioning

confidence: 99%

High dissolved extracellular enzymatic activity in the deep central Atlantic Ocean

Baltar¹,

Arı́stegui²,

Gasol³

et al. 2010

Aquat. Microb. Ecol.

115

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“…Much of the glucose taken up by microbial communities in the northern Gulf of Mexico may be respired to CO 2 rather than incorporated into biomass (Arnosti and Steen, 2013); a similar situation may explain high peptidase activities and lower rates of bacterial protein production. High rates of enzyme activities thus do not necessarily correlate directly with increases in microbial biomass, an observation that has been also made in the deep North Atlantic (Baltar et al, 2009). …”

Section: Microbial Biomass and Activitiesmentioning

confidence: 90%

Linking Heterotrophic Microbial Activities with Particle Characteristics in Waters of the Mississippi River Delta in the Aftermath of Hurricane Isaac

et al. 2016

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Riverine runoff often triggers microbial responses in coastal marine environments, including phytoplankton blooms and enhanced bacterial biomass production that drive the transformation of dissolved and particulate organic matter (POM) on its way from land to the deep ocean. We measured concentrations and characteristics of POM, concentrations of dissolved organic carbon (DOC), and bacterial community abundance and activities in the water column at three sites near the Mississippi River Delta about 2 weeks after Hurricane Isaac made landfall in late August 2012. River plumes had salinities of >30 PSU and high levels of DOC (210-380 µM), resulting from the storm surge that pushed large quantities of marine waters upstream. Relatively high concentrations of phytoplankton POM and low levels of microbial exopolymeric particles (TEP and CSP) suggested that storm-induced riverine discharge triggered the development of phytoplankton blooms that were in their initial stages at the time of sampling. Surface water POM had C/N ratios of 5-7 and strong protein-like fluorescence signals in the base-extracted POM (BEPOM) fraction at the two sites closer to the river mouth (Stns. TE and MSP). Freshly produced POM triggered a two-fold increase in heterotrophic bacterial biomass production ( 3 H-leucine incorporation) and a four-fold increase in bacterial peptide hydrolysis (activities of leucine-aminopeptidase). In contrast, elevated DOC concentrations coincided with only moderate bacterial community activity, suggesting that heterotrophic bacterial metabolism near the Mississippi River Delta in the aftermath of Hurricane Isaac was more closely linked with autochthonous primary production.

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“…We followed the same procedure previously described in Baltar et al (2009). Briefly, EEA was determined after substrate addition and incubation using a spectrofluorometer (Fluorolog-3) with a microwell plate reader (MicroMax 384, Horiba) at excitation and emission wavelengths of 365 and 445 nm, respectively.…”

Section: Microbial Extracellular Enzymatic Activity (Eea)mentioning

confidence: 99%

Fronts at the Surface Ocean Can Shape Distinct Regions of Microbial Activity and Community Assemblages Down to the Bathypelagic Zone: The Azores Front as a Case Study

Baltar

Arı́stegui

2017

Front. Mar. Sci.

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Prokaryotic extracellular enzymatic activity in relation to biomass production and respiration in the meso‐ and bathypelagic waters of the (sub)tropical Atlantic

Cited by 112 publications

References 89 publications

High dissolved extracellular enzymatic activity in the deep central Atlantic Ocean

High dissolved extracellular enzymatic activity in the deep central Atlantic Ocean

Linking Heterotrophic Microbial Activities with Particle Characteristics in Waters of the Mississippi River Delta in the Aftermath of Hurricane Isaac

Fronts at the Surface Ocean Can Shape Distinct Regions of Microbial Activity and Community Assemblages Down to the Bathypelagic Zone: The Azores Front as a Case Study

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