Georgia Coastal Ecosystems LTER Data Set Details

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GCE-LTER Data Set Summary

Accession:

CHM-OTH-1702

Research Theme:

Chemistry (Research Study)

Contributors:

Hannah Whitby, Tim Hollibaugh, Stan van den Berg

Title:

Chemical speciation of copper in a salt marsh estuary near Sapelo Island, Georgia

Abstract:

The concentrations of dissolved copper (Cud), copper-binding ligands, thiourea-type thiols and humic substances (HSCu) were measured in estuarine waters adjacent to Sapelo Island, Georgia, USA, on a monthly basis from April to December 2014. Here we present the seasonal cycle of copper speciation within the estuary and compare it to the development of an annually occurring bloom of ammonia oxidising archaea (AOA) Thaumarchaeota, which require copper for many enzymes. Two types of complexing ligands (L1 and L2) were found to dominate with mean complex stabilities (log K'CuL) of 14.5 and 12.8. Strong complexation resulted in lowering of the free cupric ion (Cu2+) concentration to femtomolar (fM) levels throughout the study and to sub-fM levels during the summer months. A Thaumarchaeota bloom during this period suggests that this organism manages to grow at very low Cu2+ concentrations. Correlation of the concentration of the L1 ligand class with a thiourea-type thiol and the L2 ligand class with HSCu provide convincing evidence for the identity of the ligands. Due to the stronger complex stability, 82 - 99 % of the copper was bound to L1. Thiourea-type thiols form strong Cu(I) species, suggesting that ~90% copper is present as Cu(I) in this region, upsetting the paradigm of its predominance as Cu(II). In view of the very low concentration of free copper (pCu >15 at the onset and during the bloom) and a reputedly high requirement for copper, it is likely that the Thaumarchaeota are able to access the thiol-bound copper directly.

DOI:

10.6073/pasta/20fa453aa3ea20ec706f4c16ba0af1cc

Key Words:

ammonia, ammonia oxidising archaea, Archaea, blooms, cathodic stripping voltammetry, chemistry, copper, copper speciation, humic soils, microbial, organic ligands, Thaumarchaeota, thiols, thiourea

LTER Core Area:

Other Site Research

Research Themes:

GCE3 Area2 - Patterns within the Domain, Chemistry, Microbiology

Study Period:

08-Apr-2014 to 01-Dec-2014

Study Sites:

GCE-DP -- Duplin River, Georgia, USA

» Download Geographic Coverage: Google Earth

Project References:

Ammonia oxidation in the GCE domain

Research Protocols:

Trace metal sampling protocol (Georgia Coastal Ecosystems LTER)

Publications:

Whitby, H. 2016. Identifying the factors affecting copper speciation in estuarine, coastal and open ocean waters. Ph.D. Dissertation. University of Liverpool, School of Environmental Sciences, Department of Earth, Ocean and Ecological Sciences, Liverpool, England. 181 pages.

Whitby, H., Hollibaugh, J.T. and van den Berg, C.M. 2017. Chemical speciation of copper in a salt marsh estuary and bioavailability to Thaumarchaeota. Special Issue: Organic ligands - A key control on trace metal biogeochemistry in the ocean. Frontiers in Marine Sciences. 4. (DOI: 10.3389/fmars.2017.00178)

Downloads:

Data Table: CHM-OTH-1702 (Main data table for data set CHM-OTH-1702, 48 records)

Access: Public (released 07-Feb-2019)

Metadata: Text (ESA FLED), XML (Ecological Metadata Language)

Data Formats: Spreadsheet (CSV) [5.45kb], Text File [4.97kb], MATLAB (GCE Toolbox) [158.86kb], MATLAB (Variables) [123.66kb], Text Report [32.51kb]

Column List:(hide)

Column	Name	Units	Type	Description
1	Station	none	string	Station identifier
2	Date	YYYY-MM-DD hh:mm EDT	string	Sampling date and time (local time)
3	Latitude	degrees	floating-point	Station latitude
4	Longitude	degrees	floating-point	Station longitude
5	Depth	m	floating-point	Nominal depth at which the sample was taken (arm''s length, avoiding surface microlayer)
6	Salinity	PSU	floating-point	Salinity measured using LTER Hydrolab sonde
7	Temperature	°C	floating-point	Temperature measured using LTER Hydrolab sonde
8	Copper_Conc	nM	floating-point	Total dissolved copper using CSV with standard additions
9	Thiol_Conc	nM	floating-point	Concentration of thiourea-type thiols using CSV with standard additions
10	SRHA_Conc	mg/L	floating-point	Concentration of copper-binding Suwanee River Humic Acid (SRHA, International Humic Substances Society (IHSS) Standard II 2S101H) as mg SRHA L-1 using CSV with standard additions
11	Ligand1_Conc	nM	floating-point	Concentration of Cu-binding ligand class 1 using CLE-CSV
12	Ligand1_logK	none	floating-point	Log10 of the dissociation constant of ligand class 1
13	Ligand2_Conc	nM	floating-point	Concentration Cu-binding ligand class 2 using CLE-CSV
14	Ligand2_logK	none	floating-point	Log10 of the dissociation constant of ligand class 2
15	Copper2_Conc	M	exponential	Free Cu2+
16	CuL1_Bound	%	floating-point	Copper bound by ligand class 1, percent of total Copper
17	CuL2_Bound	%	floating-point	Copper bound by ligand class 2, percent of total Copper

Statistics:

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Citation:

Whitby, Hannah. 2017. Chemical speciation of copper in a salt marsh estuary near Sapelo Island, Georgia. Georgia Coastal Ecosystems LTER Project, University of Georgia, Long Term Ecological Research Network. http://dx.doi.org/10.6073/pasta/20fa453aa3ea20ec706f4c16ba0af1cc

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