ERDDAP > info > bcodmo_dataset_925726_v1

Grid DAP Data	Sub- set	Table DAP Data	Make A Graph	W M S	Source Data Files	Acces- sible	Title	Sum- mary	FGDC, ISO, Metadata	Back- ground Info	RSS	E mail	Institution	Dataset ID
		data	graph		files	public	[Total dissolved Cr concentration and isotopic composition in the ETNP from RR1804-05 and KM1919-20] - Total dissolved chromium (Cr) concentration and isotopic composition in the Eastern Tropical North Pacific from samples collected on R/V Roger Revelle and R/V Kilo Moana in April-May 2018 and Sept-Oct 2019 (Cr Isotope Oceanography of the Eastern Tropical North Pacific Ocean)		M	background			BCO-DMO	bcodmo_dataset_925726_v1

The Dataset's Variables and Attributes

Row Type	Variable Name	Attribute Name	Data Type	Value
attribute	NC_GLOBAL	cdm_data_type	String	Other
attribute	NC_GLOBAL	Conventions	String	COARDS, CF-1.6, ACDD-1.3
attribute	NC_GLOBAL	creator_email	String	info at bco-dmo.org
attribute	NC_GLOBAL	creator_name	String	BCO-DMO
attribute	NC_GLOBAL	creator_url	String	https://www.bco-dmo.org/
attribute	NC_GLOBAL	doi	String	10.26008/1912/bco-dmo.925726.1
attribute	NC_GLOBAL	Easternmost_Easting	double	-105.7
attribute	NC_GLOBAL	geospatial_lon_max	double	-105.7
attribute	NC_GLOBAL	geospatial_lon_min	double	-115.2
attribute	NC_GLOBAL	geospatial_lon_units	String	degrees_east
attribute	NC_GLOBAL	geospatial_vertical_max	double	3500.0
attribute	NC_GLOBAL	geospatial_vertical_min	double	6.0
attribute	NC_GLOBAL	geospatial_vertical_positive	String	down
attribute	NC_GLOBAL	geospatial_vertical_units	String	m
attribute	NC_GLOBAL	infoUrl	String	https://www.bco-dmo.org/dataset/925726
attribute	NC_GLOBAL	institution	String	BCO-DMO
attribute	NC_GLOBAL	license	String	The data may be used and redistributed for free but is not intended for legal use, since it may contain inaccuracies. Neither the data Contributor, ERD, NOAA, nor the United States Government, nor any of their employees or contractors, makes any warranty, express or implied, including warranties of merchantability and fitness for a particular purpose, or assumes any legal liability for the accuracy, completeness, or usefulness, of this information.
attribute	NC_GLOBAL	sourceUrl	String	(local files)
attribute	NC_GLOBAL	summary	String	Understanding the cycling of chromium (Cr) and how chromium stable isotopes (δ53Cr) are altered in response to different processes in the modern ocean is important in our interpretation of marine sedimentary δ53Cr records, a promising redox proxy. Therefore, it is crucial to investigate the geochemical processes of Cr in reducing environments such as oxygen deficient zones (ODZs). In this study, we investigated the cycling of Cr in the Eastern Tropical North Pacific (ETNP) ODZ by analyzing the [Cr] and δ53Cr of total dissolved Cr and Cr(III). Our Cr(III) data at two inshore stations shows profile features and Cr reduction isotopic fractionation factor (-1.5‰) similar to an offshore station in a previous study. We also observed significant Cr scavenging signals in the upper 1000 meters (m) throughout the ODZ with an inshore-offshore variability in its magnitude. Specifically, anoxic bottom waters on the continental slope see the greatest Cr scavenging with heaviest δ53Cr (+1.85‰). Our estimates of the scavenged Cr isotopic composition are within error of the anoxic and euxinic marine sedimentary δ53Cr. This implies that the vertical transport of Cr to the seafloor and subsequent diagenesis may not generate significant isotopic fractionation for Cr. This is the first thorough investigation into the Cr cycling in the ETNP ODZ and demonstrated promising usage of marine sedimentary δ53Cr as a redox proxy for ancient oceans. In the ODZ, oxygen is consumed by degrading sinking particles and reaches extremely low levels (too low to support aerobic life) from 100m to 800m depth. However, microbes that can use other oxidants such as nitrate to metabolize organic carbon live there, and we showed that they also convert soluble anionic chromate Cr(VI) to cationic Cr(III), about half of which is scavenged onto sinking particles and removed to the seafloor. This reduction is accompanied by preferential reduction of light Cr isotopes, so the Cr(III) is 1.3‰ lighter than the source Cr(VI). The removal of part of this light Cr(III) by scavenging leaves the residual total Cr heavier than the source Cr. The analyzed samples listed here were chosen to be from the center and margins of the ETNP ODZ and over extremely reducing continental margin sediments.
attribute	NC_GLOBAL	title	String	[Total dissolved Cr concentration and isotopic composition in the ETNP from RR1804-05 and KM1919-20] - Total dissolved chromium (Cr) concentration and isotopic composition in the Eastern Tropical North Pacific from samples collected on R/V Roger Revelle and R/V Kilo Moana in April-May 2018 and Sept-Oct 2019 (Cr Isotope Oceanography of the Eastern Tropical North Pacific Ocean)
attribute	NC_GLOBAL	Westernmost_Easting	double	-115.2
variable	Cruise		String
attribute	Cruise	long_name	String	Cruise
attribute	Cruise	units	String	unitless
variable	Station		String
attribute	Station	long_name	String	Station
attribute	Station	units	String	unitless
variable	Latitude		float
attribute	Latitude	actual_range	float	15.1, 27.1
attribute	Latitude	long_name	String	Latitude
attribute	Latitude	units	String	degrees_north
variable	longitude		float
attribute	longitude	_CoordinateAxisType	String	Lon
attribute	longitude	actual_range	float	-115.2, -105.7
attribute	longitude	axis	String	X
attribute	longitude	ioos_category	String	Location
attribute	longitude	long_name	String	Longitude
attribute	longitude	standard_name	String	longitude
attribute	longitude	units	String	degrees_east
variable	depth		int
attribute	depth	_CoordinateAxisType	String	Height
attribute	depth	_CoordinateZisPositive	String	down
attribute	depth	actual_range	int	6, 3500
attribute	depth	axis	String	Z
attribute	depth	ioos_category	String	Location
attribute	depth	long_name	String	Depth
attribute	depth	positive	String	down
attribute	depth	standard_name	String	depth
attribute	depth	units	String	m
variable	CTD_Oxygen		float
attribute	CTD_Oxygen	actual_range	float	0.63, 231.18
attribute	CTD_Oxygen	long_name	String	Ctd_oxygen
attribute	CTD_Oxygen	units	String	micromoles per kilogram (umol/kg)
variable	total_dissolved_Cr		float
attribute	total_dissolved_Cr	actual_range	float	2.26, 5.02
attribute	total_dissolved_Cr	long_name	String	Total_dissolved_cr
attribute	total_dissolved_Cr	units	String	nanomoles per kilogram (nmol/kg)
variable	total_dissolved_d53Cr		float
attribute	total_dissolved_d53Cr	actual_range	float	0.6, 1.85
attribute	total_dissolved_d53Cr	long_name	String	Total_dissolved_d53cr
attribute	total_dissolved_d53Cr	units	String	permil (‰)

The information in the table above is also available in other file formats (.csv, .htmlTable, .itx, .json, .jsonlCSV1, .jsonlCSV, .jsonlKVP, .mat, .nc, .nccsv, .tsv, .xhtml) via a RESTful web service.