Microbial enzyme activities: peptidase activities in bulk seawater 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/742780
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 activities measured in bulk (not filter-fractionated) seawater. 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 activities measured in bulk (not filter-fractionated) seawater. 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.


Methods & Sampling

Water was collected via Niskin bottles mounted on a rosette, equipped with a CTD.

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]. Incubations with the seven low molecular weight substrates were set up in 4 ml cuvettes. For each substrate, triplicate cuvettes were filled with a total volume of 4 ml seawater for experimental incubations; single cuvettes were filled with 4 ml autoclaved seawater for killed control incubations. Substrate was added 100 micromolar concentrations. Fluorescence was measured over at 0 hrs, 24 h, 48h, and 72 h, using a mini fluorimeter. 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.


Data 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


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Data Files

File
ARK27-3_bulk_MCA_joined.csv
(Comma Separated Values (.csv), 45.26 KB)
MD5:64bd12c89e0460cd373d78e0f3ae5df8
Primary data file for dataset ID 742780

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Related Publications

Arnosti, C. (1996). A new method for measuring polysaccharide hydrolysis rates in marine environments. Organic Geochemistry, 25(1-2), 105–115. doi:10.1016/s0146-6380(96)00112-x https://doi.org/10.1016/S0146-6380(96)00112-X
Methods
Arnosti, C. (2003). Fluorescent derivatization of polysaccharides and carbohydrate-containing biopolymers for measurement of enzyme activities in complex media. Journal of Chromatography B, 793(1), 181–191. doi:10.1016/s1570-0232(03)00375-1 https://doi.org/10.1016/S1570-0232(03)00375-1
Methods
Balmonte, J. P., Teske, A., & Arnosti, C. (2018). Structure and function of high Arctic pelagic, particle‐associated and benthic bacterial communities. Environmental Microbiology, 20(8), 2941–2954. Portico. https://doi.org/10.1111/1462-2920.14304
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

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Parameters

ParameterDescriptionUnits
station_no

refers to station number for cruise

unitless
depth_no

sequence of depths sampled (1 is surface; higher numbers at greater depths)

unitless
depth_m

actual depth at which water collected

meters
cast_no

cast number (refers to cast of CTD/Niskin bottles on cruise)

unitless
ISO_DateTime_UTC

date and time in ISO format (yyyy-mm-ddTHH:MM:SS

unitless
Latitude

latitude; north is positive

decimal degreed
Longitude

longitude; east is postivie

decimal degreed
substrate

substrates for measurement of enzymatic activities. ara:arabinogalactan; chn:chondroitin sulfate; fuc:fucoidan; lam:laminarin ; pul:pullulan; xyl:xylan

unitless
timepoint

sampling point post-incubation

unitless
time_elapsed_hr

incubation time

hours
rep1_rate

replicate 1 hydrolysis rate

nanomoles/liter/hour (nmol L-1 h-1)
rep2_rate

replicate 2 hydrolysis rate

nanomoles/liter/hour (nmol L-1 h-1)
rep3_rate

replicate 3 hydrolysis rate

nanomoles/liter/hour (nmol L-1 h-1)
average

average of hydrolysis rates

nanomoles/liter/hour (nmol L-1 h-1)
std_dev

std deviation of hydrolysis rates

nanomoles/liter/hour (nmol L-1 h-1)
comments

url of CTD data in Pangaea database

unitless


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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. It permits scientists to observe the physical properties in real-time via a conducting cable, which is typically connected to a CTD to a deck unit and computer on a 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 term applies to profiling CTDs. For fixed CTDs, see https://www.bco-dmo.org/instrument/869934.

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
Niskin bottle
Generic Instrument Description
A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.


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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.


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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.



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Funding

Funding SourceAward
NSF Division of Ocean Sciences (NSF OCE)

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