Dataset: Global reconstruction of particle size distribution and carbon export

Name: Global reconstructions of particle biovolume, size distribution, and carbon export flux from the seasonal euphotic zone and maximum winter time mixed layer from particle profiles conducted during cruises from 2008 to 2020
Published: 2023-02-02
Keywords: Carbon Export, Biological pump, Particulate Matter, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.856942.2

Spatial Extent: N:90 E:180 S:-90 W:-180

Temporal Extent: 2008 - 2020

Project:

Collaborative Research: Understanding the distribution and biogeochemical role of anaerobic microenvironments in the ocean (Ocean Particles and Microenvironments)

Principal Investigator:

Daniele Bianchi (University of California-Los Angeles, UCLA)

Co-Principal Investigator:

Daniel Clements (University of California-Los Angeles, UCLA)

BCO-DMO Data Manager:

Amber D. York (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-02-02

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Global reconstructions of particle biovolume, size distribution, and carbon export flux from the seasonal euphotic zone and maximum winter time mixed layer from particle profiles conducted during cruises from 2008 to 2020

Abstract:

Global reconstructions of particle biovolume, size distribution, and carbon export flux from the seasonal euphotic zone and maximum winter time mixed layer.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2023-02-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.856942.2	2023-02-17
2021-08-02	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.856942.1	2021-11-17

Methods & Sampling

Methodology:

This work is based on the compilation of over 6800 profiles of particulate matter observations from Underwater Vision Profilers (UVP5) (Rainer, 2021). The biovolume of the particle size distribution is calculated as the equivalent spherical volume of the particle size distribution (PSD), by summing the product of particle counts time particle volume in each size class. The slope of the PSD is calculated assuming a power law distribution for the particle abundance, by linear least square fit of the log of particle counts vs. the log of particle size. These quantities are estimated from two different depth horizons, the mixed layer depth (MLD_Export.nc) and the euphotic zone depth (Euphotic_Export.nc). To convert sparse observations to a global climatology, we trained 100 ensembles of regressions trees (Random Forests, RF) to predict biovolume and slope based on their relationship to well-sampled physical and biogeochemical predictors.

We calculate the particle sinking speed and carbon content by combining PSD reconstruction (biovolume and slope) with an empirical relationship between particle size, carbon content and sinking speed, the parameters of which are optimized to match in situ particle flux observations (Bisson et al. 2018). The flux values are calculated as the sum of the PSD time the sinking carbon parameters, for each grid cell. The error for reconstructed quantities is given by the standard deviation of 100 independent realizations of the RF reconstructions.

Sampling and analytical procedures:

This dataset contains a compilation of data from multiple sources. A list of all datasets and the associated information, including cruise name, is included.

Observations of Particle size and biovolume are made via the UVP5 camera, which is lowered in the water column on a CTD rosette. Images are captured at up to 30 images per second while the instrument is lowered at 1m/s. Images are analyzed and the pixel size of each particle is translated into a particle size, and the abundance calculated, following the method described by Picheral et al. (2010).  

The data is compiled from multiple sources published and unpublished, and was accessed from EcoPart, the particle module of EcoTaxa https://ecotaxa.obs-vlfr.fr/part/ (Picheral et al., 2017).

Instruments:

Observations of particle abundance and biovolume were made with the Underwater Vision Profiler, version 5 (UVP5).

Data Processing Description

BCO-DMO Data Manager Processing Notes:
* Version 2 added to replace Version 1 on 2023-02-02. The .nc files were changed after modifying the calculation of particle Flux from PSD, thus updated the flux fields to reflect the more robust estimates. Specifically, a Monte Carlo approach was used with injected randomness to robustly optimize the results.

Data Files

File

Euphotic Zone Depth
filename: Euphotic_Export.nc

(NetCDF, 17.07 MB)
MD5:9da072d807b07c80f1df61ee038b9462

This file shows the reconstructed particles size distribution and particle flux from the base of the euphotic zone. All data are generated using a random forest machine learning model. Here we show the monthly climatological reconstructions of the PSD and resulting calculated flux. 

File Parameters (Name,Description,Units,Missing data identifier):

latitude,cell-center latitude,degrees north,NaN

longitude,cell-center longitude,degrees east,NaN

time,month of reconstruction,month,NaN

area,cell area,m^2,NaN

Depth,Monthly export horizon,m,NaN

obs_bv,average observed particle biovolume,ppm,NaN

obs_slope,average observed particle size distribution slope,unitless,NaN

pred_bv,reconstructed particle biovolume,ppm,NaN

stdev_bbv,reconstructed particle biovolume standard deviation,ppm,NaN

pred_slope,reconstructed particle size distribution slope,unitless,NaN

stdev_slope,reconstructed particle size distribution slope standard deviation,unitless,NaN

flux,reconstructed particle carbon flux from the euphotic zone,mgC/m^2/dCocoaLigature1,NaN

stdev_flux,reconstructed particle carbon flux,mgC/m^2/d,NaN

Mixed-layer Depth
filename: MLD_Export.nc

(NetCDF, 16.01 MB)
MD5:cec7853036be1ac5efd322811b201f2e

This file shows the reconstructed particles size distribution and particle flux from the base of the maximum mixed layer. All data are generated using a random forest machine learning model. Here we show the monthly climatological reconstructions of the PSD and resulting calculated flux. 

File Parameters:

Name,Description,Units,Missing data identifier

latitude,cell-center Latitude,degrees north,NaN

longitude,cell-center Longitude,degrees east,NaN

time,climatological month,month,NaN

area,cell surface area,m^2,NaN

depth,Monthly export horizon,M,NaN

obs_bv,average observed particle biovolume,ppm,NaN

obs_slope,average observed particle size distribution slope,unitless,NaN

pred_bv,reconstructed particle biovolume,ppm,NaN

stdev_bbv,reconstructed particle biovolume standard deviation,ppm,NaN

pred_slope,reconstructed particle size distribution slope,unitless,NaN

stdev_slope,reconstructed particle size distribution slope,unitless,NaN

flux,reconstructed particle carbon flux from the mixed layer,mgC/m^2/dCocoaLigature1,NaN

stdev_flux,reconstructed flux standard deviation,mgC/m^2/dCocoaLigature1,NaN

Supplemental Files

File

Cruise List
filename: cruise_list.csv

(Comma Separated Values (.csv), 2.72 KB)
MD5:d7697c97f905330988429eaf9dd1a136

A list of cruises during which the particle profiles were conducted.  More information about these cruises can be found at EcoTaxa (http://ecotaxa.obs-vlfr.fr).

Parameters (data column name, and description):

"Cruise", Cruise identifier in EcoPart (EcoTaxa)

"Year_of_cruise_start",Year of cruise start in format yyyy

"Number_of_profiles", Number of profiles from the cruise

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1635632

Deployments

None available yet

Instruments

Underwater Vision Profiler

Supplied Name: nderwater Vision Profiler, version 5 (UVP5)

Supplied Description:

Observations of particle abundance and biovolume were made with the Underwater Vision Profiler, version 5 (UVP5).

Instrument Type

Generic Name: Underwater Vision Profiler

Acronym: UVP

Generic Description:

A description of the UVP instrument can be found in the following publication: Picheral, M., L. Guidi, L. Stemmann, D. M. Karl, G. Iddaoud, and G. Gorsky. 2010. The Underwater Vision Profiler 5: An advanced instrument for high spatial resolution studies of particle size spectra and zooplankton. Limnol. Oceanogr. Meth. 8: 462-473. (access the PDF at URL: http://cmore.soest.hawaii.edu/cmoredata/LMO/Guidi/Picheral_2010.pdf)

Parameters

None available yet

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Database

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Dataset: Global reconstruction of particle size distribution and carbon export