Microbial enzyme activities: peptidase activities of sediment samples from the RV\Polarstern cruise ARKXXVII/3 in the Central Arctic Ocean and Laptev Sea, Aug-Sept. 2012

Website: https://www.bco-dmo.org/dataset/743018
Data Type: Cruise Results, experimental
Version: 1
Version Date: 2018-07-24

Project
» Latitudinal and depth-related contrasts in enzymatic capabilities of pelagic microbial communities: Predictable patterns in the ocean? (Patterns of activities)
ContributorsAffiliationRole
Arnosti, CarolUniversity of North Carolina at Chapel Hill (UNC-Chapel Hill)Principal Investigator
Copley, NancyWoods Hole Oceanographic Institution (WHOI BCO-DMO)BCO-DMO Data Manager

Abstract
This dataset includes peptidase hydrolysis rates from sediments to measure microbial enzyme activities. Links to archived CTD data are also provided. Five substrates linked to a 7-amido-4-methyl coumarin (MCA) fluorophore, one amino acid – leucine – and four oligopeptides – the chymotrypsin substrates alanine-alanine-phenylalanine (AAF) and alanine-alanine-proline-phenylalanine (AAPF), and the trypsin substrates glutamine-alanine-arginine (QAR) and glutamic acid-gylcine-arginine (EGR) – were used to measure exo- and endo-acting peptidase activities, respectively.


Coverage

Spatial Extent: N:88.809 E:130.5795 S:79.6502 W:31.21
Temporal Extent: 2012-08-09 - 2012-09-22

Dataset Description

This dataset includes peptidase hydrolysis rates from sediments to measure microbial enzyme activities. Links to archived CTD data are also provided. Five substrates linked to a 7-amido-4-methyl coumarin (MCA) fluorophore, one amino acid – leucine – and four oligopeptides – the chymotrypsin substrates alanine-alanine-phenylalanine (AAF) and alanine-alanine-proline-phenylalanine (AAPF), and the trypsin substrates glutamine-alanine-arginine (QAR) and glutamic acid-gylcine-arginine (EGR) – were used to measure exo- and endo-acting peptidase activities, respectively.


Acquisition Description

Surficial sediments were collected using a multi-corer.

Five substrates linked to a 7-amido-4-methyl coumarin (MCA) fluorophore, one amino acid – leucine – and four oligopeptides – the chymotrypsin substrates alanine-alanine-phenylalanine (AAF) and alanine-alanine-proline-phenylalanine (AAPF), and the trypsin substrates glutamine-alanine-arginine (QAR) and glutamic acid-gylcine-arginine (EGR) – were used to measure exo- and endo-acting peptidase activities, respectively. Hydrolysis rates of the substrates were measured as an increase in fluorescence as the fluorophore was hydrolyzed from the substrate over time [as in Hoppe, 1993; Obayashi and Suzuki, 2005]. For sediment measurements, peptidase activities were measured in a 1:2 (vol: vol) sediment: autoclaved seawater slurry. 100 micromolar concentrations of substrate were added to triplicate live and single autoclaved killed control incubations. 2 ml of slurry was centrifuged at each timepoint (0, 1h ,2h, and 4 h), filtered, and diluted with 1 ml borate buffer; fluorescence was measured in a 4 ml cuvette.  Hydrolysis rates were calculated from the rate of increase of fluorescence in the incubation over time relative to a set of standards of known concentration of fluorophore.

All incubations were conducted at 0 C in the dark.


Processing Description

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- reduced decimal precision of rate columns from 9 to 6 places


[ table of contents | back to top ]

Related Publications

Balmonte, JP, A. Teske, and C. Arnosti. (2018) Structure and function of high Arctic pelagic, particle-associated, and benthic bacterial communities. Environmental Microbiology IN PRESS
Results
Hoppe, HG. (1993). Use of fluorogenic model substrates for extracellular enzyme activity (EEA) measurement of bacteria, p. 423-431. In P. F. Kemp, B. F. Sherr, E. B. Sherr, and J. J. Cole (ed.), Handbook of methods in aquatic microbial ecology. Lewis Publishers, Boca Raton, FL 978-0873715645
Methods
Obayashi, Y., & Suzuki, S. (2005). Proteolytic enzymes in coastal surface seawater: Significant activity of endopeptidases and exopeptidases. Limnology and Oceanography, 50(2), 722–726. doi:10.4319/lo.2005.50.2.0722
Methods

[ table of contents | back to top ]

Parameters

ParameterDescriptionUnits
station_norefers to station number for cruise unitless
depth_nosequence of depths sampled (1 is surface; higher numbers at greater depths) unitless
depth_mactual depth at which water collected meters
cast_nocast number (refers to cast of CTD/Niskin bottles on cruise) unitless
ISO_DateTime_UTCdate and time in ISO format (yyyy-mm-ddTHH:MM:SS unitless
Latitudelatitude; north is positive decimal degreed
Longitudelongitude; east is postivie decimal degreed
substratesubstrates for measurement of enzymatic activities. ara:arabinogalactan; chn:chondroitin sulfate; fuc:fucoidan; lam:laminarin ; pul:pullulan; xyl:xylan unitless
timepointsampling point post-incubation unitless
time_elapsed_hrincubation time hours
rep1_ratereplicate 1 hydrolysis rate nanomoles/liter/hour (nmol L-1 h-1)
rep2_ratereplicate 2 hydrolysis rate nanomoles/liter/hour (nmol L-1 h-1)
rep3_ratereplicate 3 hydrolysis rate nanomoles/liter/hour (nmol L-1 h-1)
averageaverage of hydrolysis rates nanomoles/liter/hour (nmol L-1 h-1)
std_devstd deviation of hydrolysis rates nanomoles/liter/hour (nmol L-1 h-1)
commentsurl of CTD data in Pangaea database unitless


[ table of contents | back to top ]

Instruments

Dataset-specific Instrument Name
Generic Instrument Name
CTD profiler
Generic Instrument Description
The Conductivity, Temperature, Depth (CTD) unit is an integrated instrument package designed to measure the conductivity, temperature, and pressure (depth) of the water column. The instrument is lowered via cable through the water column and permits scientists observe the physical properties in real time via a conducting cable connecting the CTD to a deck unit and computer on the ship. The CTD is often configured with additional optional sensors including fluorometers, transmissometers and/or radiometers. It is often combined with a Rosette of water sampling bottles (e.g. Niskin, GO-FLO) for collecting discrete water samples during the cast. This instrument designation is used when specific make and model are not known.

Dataset-specific Instrument Name
mini fluorometer
Generic Instrument Name
Fluorometer
Generic Instrument Description
A fluorometer or fluorimeter is a device used to measure parameters of fluorescence: its intensity and wavelength distribution of emission spectrum after excitation by a certain spectrum of light. The instrument is designed to measure the amount of stimulated electromagnetic radiation produced by pulses of electromagnetic radiation emitted into a water sample or in situ.

Dataset-specific Instrument Name
Generic Instrument Name
Multi Corer
Generic Instrument Description
The Multi Corer is a benthic coring device used to collect multiple, simultaneous, undisturbed sediment/water samples from the seafloor. Multiple coring tubes with varying sampling capacity depending on tube dimensions are mounted in a frame designed to sample the deep ocean seafloor. For more information, see Barnett et al. (1984) in Oceanologica Acta, 7, pp. 399-408.

Dataset-specific Instrument Name
Generic Instrument Name
Centrifuge
Generic Instrument Description
A machine with a rapidly rotating container that applies centrifugal force to its contents, typically to separate fluids of different densities (e.g., cream from milk) or liquids from solids.


[ table of contents | back to top ]

Deployments

ARK-XXVII-3

Website
Platform
R/V Polarstern
Start Date
2012-08-02
End Date
2012-10-08
Description
Project: Latitudinal and depth-related contrasts in enzymatic capabilities of pelagic microbial communities: Predictable patterns in the ocean? For other files related to this cruise, see https://www.pangaea.de/?q=ARK+XXVII%2F3.


[ table of contents | back to top ]

Project Information

Latitudinal and depth-related contrasts in enzymatic capabilities of pelagic microbial communities: Predictable patterns in the ocean? (Patterns of activities)

Coverage: Atlantic Ocean, Arctic Ocean, Pacific Ocean, Greenland


NSF Award Abstract:
Heterotrophic microbial communities are key players in the marine carbon cycle, transforming and respiring organic carbon, regenerating nutrients, and acting as the final filter in sediments through which organic matter passes before long-term burial. Microbially-driven carbon cycling in the ocean profoundly affects the global carbon cycle, but key factors determining rates and locations of organic matter remineralization are unclear. In this study, researchers from the University of North Carolina at Chapel Hill will investigate the ability of pelagic microbial communities to initiate the remineralization of polysaccharides and proteins, which together constitute a major pool of organic matter in the ocean. Results from this study will be predictive on a large scale regarding the nature of the microbial response to organic matter input, and will provide a mechanistic framework for interpreting organic matter reactivity in the ocean.

Broader Impacts: This study will provide scientific training for undergraduate and graduate students from underrepresented groups. The project will also involve German colleagues, thus strengthening international scientific collaboration.



[ table of contents | back to top ]

Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

[ table of contents | back to top ]