Microbial enzyme activities: polysaccharide hydrolase activities of gravity filtered seawater samples from the RV\Sonne cruise SO248 in the South and North Pacific, along 180 W, May, 2016

Website: https://www.bco-dmo.org/dataset/743274
Data Type: Cruise Results, experimental
Version: 1
Version Date: 2018-07-31

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 polysaccharide hydrolysis rates measured on particles collected from gravity-filtered seawater. Gravity filtered samples were collected on RV/Sonne cruise SO248 in May 2016. Links to archived CTD data are also provided.


Coverage

Spatial Extent: N:58.9 E:-176 S:-30.0008 W:176
Temporal Extent: 2016-05-02 - 2016-05-29

Dataset Description

This dataset includes polysaccharide hydrolysis rates measured on particles collected from gravity-filtered seawater. Gravity filtered samples were collected on RV/Sonne cruise SO248 in May 2016. Links to archived CTD data are also provided.


Acquisition Description

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

Experiments on (operationally defined) particles were carried out by gravity-filtering water through 3 um pore size filters.  1/12th sections of the 3 um pore-size filters were submerged in 15 mL artificial seawater; enzyme activities were measured as described below.

The potential of the seawater microbial community associated with large particles (> 3 micrometer pore size filter) to hydrolyze six high-molecular-weight polysaccharides (arabinogalactan, chondroitin sulfate, fucoidan, laminarin, pullulan, and xylan) was investigated in surface and bottom water. For each substrate, three  15 mL falcon tubes were filled with autoclaved artificial seawater and one 15 mL falcon tube was filled with autoclaved seawater and a blank filter piece to serve as a killed control. Substrate was added at 3.5 uM monomer-equivalent concentrations, except for fucoidan, which was added at 5 uM concentrations (a higher concentration was necessary for sufficient fluorescence signal). Two 15 mL falcon tubes – one with seawater and one with autoclaved seawater – with no added substrate served as blank controls. Incubations were stored in the dark at as close to in situ temperature as possible. Subsamples of the incubations were collected at time zero, and at six subsequent timepoints. At each timepoint, 2 mL of seawater was collected from the 50 mL falcon tube using a sterile syringe, filtered through a 0.2 um pore size syringe filter, and stored frozen until processing.

The hydrolysis of high molecular weight substrate to lower molecular weight hydrolysis products was measured using gel permeation chromatography with fluorescence detection, after the method of Arnosti [1996, 2003]. In short, the subsample was injected onto a series of columns consisting of a 21 cm column of G50 and a 19 cm column of G75 Sephadex gel. The fluorescence of the column effluent was measured at excitation and emission wavelengths of 490 and 530 nm, respectively. Hydrolysis rates were calculated from the change in molecular weight distribution of the substrate over time, as described in detail in Arnosti [2003].

ara = arabinogalactan
chn = chondroitin sulfate
fuc = fucoidan
lam = laminarin 
pul = pullulan
xyl = xylan


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; time_elapsed from 7 to 0 places


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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

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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)
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)
filter_umfilter pore size used for gravity filtration micrometers


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Instruments

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.

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
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
Gel Permeation Chromatograph
Generic Instrument Description
Instruments that separate components in aqueous or organic solution based on molecular size generally for molecular weight determination. Gel permeation chromatography (GPC) is a type of size exclusion chromatography (SEC), that separates analytes on the basis of size.


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Deployments

SO248

Website
Platform
R/V Sonne
Start Date
2016-05-01
End Date
2016-06-03
Description
Project: Latitudinal and depth-related contrasts in enzymatic capabilities of pelagic microbial communities: Predictable patterns in the ocean? For related research from this cruise, see https://www.pangaea.de/?q=SO248


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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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