Contributors | Affiliation | Role |
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Lamborg, Carl | University of California-Santa Cruz (UCSC) | Principal Investigator |
Hammerschmidt, Chad | Wright State University | Co-Principal Investigator |
Rauch, Shannon | Woods Hole Oceanographic Institution (WHOI BCO-DMO) | BCO-DMO Data Manager |
Concentrations of dissolved and particulate mercury species collected on GN01 (HLY1502, US GEOTRACES Arctic cruise), including elemental, total, monomethyl- and dimethylmercury.
Dissolved Mercury Species:
Samples were collected according to Cutter and Bruland 2012, utilizing a trace metal clean rosette (GT-C rosette). Samples above 20 m were pumped from a hole drilled in the ice far away from the ship, using clean sampling techniques.
Sample bottles were cleaned according to Hammerschmidt et al. 2012.
Dissolved mercury analyses were performed at sea, with the exception of monomethylmercury. The full methodology may be found in the Hg Cook Book, and more detailed method descriptions can be found in Lamborg et al. 2012, Hammerschmidt and Bowman 2012, Bowman et al. 2015, Bowman et al. 2016.
Dissolved species of mercury were measured with a Tekran Model 2500 CVAFS Mercury Detector. Analysis of total mercury (HgT; Fitzgerald and Gill 1979, Bloom and Fitzgerald 1988, Bloom 1989) has a method detection limit of 0.10 pM, and procedural duplicates varied by 11 ± 5% (n = 17).
Elemental mercury (Hg0) was analyzed according to Fitzgerald and Gill (1979), Bloom and Fitzgerald (1988) and Bloom (1989). The method detection limit was 0.04 pM and procedural duplicates varied by 11 ± 14% (n = 8).
Monomethylmercury (MMHg) was analyzed according to Bowman and Hammerschmdit (2011), Tseng et al. (2004) and Munson et al. (2014). The method detection limit was 0.020 pM, and procedural duplicates averaged 11 ± 8% (n =5).
Dimethylmercury (DMHg) was analyzed according to Bowman and Hammerschmidt (2011), Tseng et al. (2004) and Baya et al. (2013). The method detection limit was 0.012 pM.
Particulate Mercury Species:
Sample collection with in-situ pumps is outlined in Bishop et al. 2012.
Particulate samples were frozen and transported to Wright State University (Dayton, OH) where they were analyzed within 6 months of collection. Filter punches were digested in acid-cleaned polypropylene containers with 8 mL of 2N HNO3 (Baker Instra-Analyzed). After analysis of MMHg, an aliquot of digestate was oxidized with BrCl solution for total Hg determination, according to Hammerschmidt & Fitzgerald (2006). All analyzes were performed on Tekran Model 2500 CVAFS Mercury Detector.
Particulate HgT analysis was done according to Fitzgerald & Gill (1979), Bloom & Fitzgerald (1988), and Bloom (1989). The method detection limit was 0.75 pmol/kg, and procedural duplicates averaged 7 ± 6 RPD (n = 16).
Particulate MMHg was analyzed according to Tseng et al. (2004). The detection limit for the method was 0.075 pmol/kg.
While at sea, variable gas pressure in the gas chromatograph caused irregular MMHg peak retention times, making it indecipherable from the inorganic Hg peak. Accordingly, seawater samples ranging from 0.25 to 2 L, were acidified to 1% with sulfuric acid and shipped frozen to Wright State University for analysis.
The following WOCE Quality Flags were used:
2 – Ok,
3 – Questionable,
4 – Bad Analysis,
5 – Sample lost,
6 – Mean of replicates,
9 – Sample was not collected for Hg analysis.
"nd" indicates no data.
"bdl" indicates below detection limit.
BCO-DMO Processing:
- replaced "-999", "-999.000", and "NaN" with "nd" as missing data identifier;
- replaced Hg_0_D_CONC_BOTTLE_jo6zdp value for sample 11947 with "nd" as requested by PI;
- renamed fields to conform with BCO-DMO naming conventions;
- replaced dates 08/12/2015 with 12/08/2015 to match DD/MM/YYYY format used throughout dataset;
- added ISO8601 format date-time fields;
- 2021-02-03: replaced dataset with version 2, which removes the duplicate, incorrect row for Sample_ID 10840.
File |
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Hg.csv (Comma Separated Values (.csv), 103.34 KB) MD5:a203dc3c0794518f48a1da3135aaf39d Primary data file for dataset ID 827530 |
Parameter | Description | Units |
Station_ID | Station number | unitless |
Start_Date_UTC | Date and time at the start of the sampling event, according to the event log. Format: DD/MM/YYYY | unitless |
Start_Time_UTC | Date and time at the start of the sampling event, according to the event log. Format: hh:mm | unitless |
Start_ISO_DateTime_UTC | Date and time (UTC) at start of the sampling event; formatted to ISO8601 standard: YYYY-MM-DDThh:mmZ | unitless |
End_Date_UTC | Date and time at the end of the sampling event, according to the event log. Format: DD/MM/YYYY | unitless |
End_Time_UTC | Date and time at the end of the sampling event, according to the event log. Format: hh:mm | unitless |
End_ISO_DateTime_UTC | Date and time (UTC) at end of the sampling event; formatted to ISO8601 standard: YYYY-MM-DDThh:mmZ | unitless |
Start_Latitude | Latitude of sample collection | degrees North |
Start_Longitude | Longitude of sample collection | degrees East |
End_Latitude | Latitude of sample collection | degrees North |
End_Longitude | Longitude of sample collection | degrees East |
Event_ID | GEOTRACES event number | unitless |
Sample_ID | GEOTRACES unique sample ID number | unitless |
Sample_Depth | Depth of sample collection | meters (m) |
Hg_0_D_CONC_BOTTLE_jo6zdp | Elemental mercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_0_D_CONC_BOTTLE_jo6zdp | One standard deviation of Hg_0_D_CONC_BOTTLE_jo6zdp | picomoles per kilogram (pmol/kg) |
Flag_Hg_0_D_CONC_BOTTLE_jo6zdp | Elemental mercury quality flag (WOCE) | unitless |
Hg_D_CONC_BOTTLE_ntd14w | Total dissolved mercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_D_CONC_BOTTLE_ntd14w | One standard deviation of Hg_D_CONC_BOTTLE_ntd14w | picomoles per kilogram (pmol/kg) |
Flag_Hg_D_CONC_BOTTLE_ntd14w | Total mercury quality flag (WOCE) | unitless |
Hg_DM_D_CONC_BOTTLE_9fiz3v | Dimethylmercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_DM_D_CONC_BOTTLE_9fiz3v | One standard deviation of Hg_DM_D_CONC_BOTTLE_9fiz3v | picomoles per kilogram (pmol/kg) |
Flag_Hg_DM_D_CONC_BOTTLE_9fiz3v | Dimethylmercury quality flag (WOCE) | unitless |
Hg_MM_D_CONC_BOTTLE_ny980n | Monomethylmercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_MM_D_CONC_BOTTLE_ny980n | One standard deviation of Hg_MM_D_CONC_BOTTLE_ny980n | picomoles per kilogram (pmol/kg) |
Flag_Hg_MM_D_CONC_BOTTLE_ny980n | Monomethylmercury quality flag (WOCE) | unitless |
Hg_SPT_CONC_PUMP_bf7clc | Total particulate mercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_SPT_CONC_PUMP_bf7clc | One standard deviation of Hg_SPT_CONC_PUMP_bf7clc | picomoles per kilogram (pmol/kg) |
Flag_Hg_SPT_CONC_PUMP_bf7clc | Total particulate monomethylmercury quality flag (WOCE) | unitless |
Hg_MM_SPT_CONC_PUMP_58nleq | Particulate monomethylmercury measurement | picomoles per kilogram (pmol/kg) |
SD1_Hg_MM_SPT_CONC_PUMP_58nleq | One standard deviation of Hg_MM_SPT_CONC_PUMP_58nleq | picomoles per kilogram (pmol/kg) |
Flag_Hg_MM_SPT_CONC_PUMP_58nleq | Particulate monomethylmercury quality flag (WOCE) | unitless |
Dataset-specific Instrument Name | Tekran Model 2500 or 2600 CVAFS Mercury Detector |
Generic Instrument Name | Cold Vapor Atomic Fluorescence Spectrophotometer |
Dataset-specific Description | Cold Vapor Atomic Fuorescent Spectrometer (CVAFS) quantitatively measures volatile heavy metals, such as mercury. Gaseous mercury atoms are carried to the detector via inert gas, excited by a UV light source, and radiate the absorbed energy. The fluorescence is detected by either a photomultiplier tube or UV photodiode. |
Generic Instrument Description | A Cold Vapor Atomic Fluorescent Spectrophotometer (CVAFS) is an instrument used for quantitative determination of volatile heavy metals, such as mercury. CVAFS make use of the characteristic of mercury that allows vapor measurement at room temperature. Mercury atoms in an inert carrier gas are excited by a collimated UV light source at a particular wavelength. As the atoms return to their non-excited state they re-radiate their absorbed energy at the same wavelength. The fluorescence may be detected using a photomultiplier tube or UV photodiode. |
Dataset-specific Instrument Name | GT-C rosette |
Generic Instrument Name | GO-FLO Teflon Trace Metal Bottle |
Dataset-specific Description | Samples were collected according to Cutter and Bruland 2012, utilizing a trace metal clean rosette (GT-C rosette). |
Generic Instrument Description | GO-FLO Teflon-lined Trace Metal free sampling bottles are used for collecting water samples for trace metal, nutrient and pigment analysis. The GO-FLO sampling bottle is designed specifically to avoid sample contamination at the surface, internal spring contamination, loss of sample on deck (internal seals), and exchange of water from different depths. |
Dataset-specific Instrument Name | McLane in-situ pump |
Generic Instrument Name | McLane Pump |
Dataset-specific Description | McLane in-situ pumps were used to collect the 1–51 um size fractioned samples. |
Generic Instrument Description | McLane pumps sample large volumes of seawater at depth. They are attached to a wire and lowered to different depths in the ocean. As the water is pumped through the filter, particles suspended in the ocean are collected on the filters. The pumps are then retrieved and the contents of the filters are analyzed in a lab. |
Website | |
Platform | USCGC Healy |
Report | |
Start Date | 2015-08-09 |
End Date | 2015-10-12 |
Description | Arctic transect encompassing Bering and Chukchi Shelves and the Canadian, Makarov and Amundsen sub-basins of the Arctic Ocean. The transect started in the Bering Sea (60°N) and traveled northward across the Bering Shelf, through the Bering Strait and across the Chukchi shelf, then traversing along 170-180°W across the Alpha-Mendeleev and Lomonosov Ridges to the North Pole (Amundsen basin, 90°N), and then back southward along ~150°W to terminate on the Chukchi Shelf (72°N).
Additional cruise information is available in the GO-SHIP Cruise Report (PDF) and from the Rolling Deck to Repository (R2R): https://www.rvdata.us/search/cruise/HLY1502 |
Description from NSF award abstract:
In pursuit of its goal "to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions", in 2015 the International GEOTRACES Program will embark on several years of research in the Arctic Ocean. In a region where climate warming and general environmental change are occurring at amazing speed, research such as this is important for understanding the current state of Arctic Ocean geochemistry and for developing predictive capability as the regional ecosystem continues to warm and influence global oceanic and climatic conditions. The three investigators funded on this award, will manage a large team of U.S.scientists who will compete through the regular NSF proposal process to contribute their own unique expertise in marine trace metal, isotopic, and carbon cycle geochemistry to the U.S. effort. The three managers will be responsible for arranging and overseeing at-sea technical services such as hydrographic measurements, nutrient analyses, and around-the-clock management of on-deck sampling activites upon which all participants depend, and for organizing all pre- and post-cruise technical support and scientific meetings. The management team will also lead educational outreach activities for the general public in Nome and Barrow, Alaska, to explain the significance of the study to these communities and to learn from residents' insights on observed changes in the marine system. The project itself will provide for the support and training of a number of pre-doctoral students and post-doctoral researchers. Inasmuch as the Arctic Ocean is an epicenter of global climate change, findings of this study are expected to advance present capability to forecast changes in regional and globlal ecosystem and climate system functioning.
As the United States' contribution to the International GEOTRACES Arctic Ocean initiative, this project will be part of an ongoing multi-national effort to further scientific knowledge about trace elements and isotopes in the world ocean. This U.S. expedition will focus on the western Arctic Ocean in the boreal summer of 2015. The scientific team will consist of the management team funded through this award plus a team of scientists from U.S. academic institutions who will have successfully competed for and received NSF funds for specific science projects in time to participate in the final stages of cruise planning. The cruise track segments will include the Bering Strait, Chukchi shelf, and the deep Canada Basin. Several stations will be designated as so-called super stations for intense study of atmospheric aerosols, sea ice, and sediment chemistry as well as water-column processes. In total, the set of coordinated international expeditions will involve the deployment of ice-capable research ships from 6 nations (US, Canada, Germany, Sweden, UK, and Russia) across different parts of the Arctic Ocean, and application of state-of-the-art methods to unravel the complex dynamics of trace metals and isotopes that are important as oceanographic and biogeochemical tracers in the sea.
NSF Award Abstract:
In this project, investigators from Woods Hole Oceanographic Institution and Wright State University participating in the 2015 U.S. GEOTRACES Arctic expedition will measure total mercury and mercury species in seawater, particles, sediments, snow and ice samples to better understand its cycling in the Arctic Ocean. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. In its methylated form, mercury poses a serious human and ecosystem health threat, and this research will provide important information on the extent and rate of change of mercury in the sensitive Arctic ecosystem. Results from this study will be shared through outreach efforts to middle schools students in the Dayton, Ohio area, and the research will involve training for graduate and undergraduate students.
Mercury is a toxic trace metal that originates from natural and anthropogenic sources, and can enter the oceans through many processes, most importantly atmospheric deposition, riverine discharge, and coastal erosion in the Arctic Ocean. Mercury in the ocean can be transformed into varying species by a variety of abiotic and biotic processes. Its transformation to methylmercury is of primary concern as it can biomagnify in food webs. Wildlife in the Arctic has experienced unprecedented increases of methylmercury in their tissues during the past 200 years. While there has been a great deal of research related to mercury cycling in the Arctic in recent years, there remain large gaps in fundamental understanding, particularly with respect to mercury distributions and speciation. The researchers will 1) measure the concentration of four mercury species in the water column, particles, sediments, snow and sea ice samples, 2) determine the concentration of other related chemical species (thiols and snow/ice bromine), and 3) explore the mercury-related genomics of bacteria in various samples. Results from this work will yield new insights into the extent and rate of change of mercury loadings in the Arctic Ocean.
GEOTRACES is a SCOR sponsored program; and funding for program infrastructure development is provided by the U.S. National Science Foundation.
GEOTRACES gained momentum following a special symposium, S02: Biogeochemical cycling of trace elements and isotopes in the ocean and applications to constrain contemporary marine processes (GEOSECS II), at a 2003 Goldschmidt meeting convened in Japan. The GEOSECS II acronym referred to the Geochemical Ocean Section Studies To determine full water column distributions of selected trace elements and isotopes, including their concentration, chemical speciation, and physical form, along a sufficient number of sections in each ocean basin to establish the principal relationships between these distributions and with more traditional hydrographic parameters;
* To evaluate the sources, sinks, and internal cycling of these species and thereby characterize more completely the physical, chemical and biological processes regulating their distributions, and the sensitivity of these processes to global change; and
* To understand the processes that control the concentrations of geochemical species used for proxies of the past environment, both in the water column and in the substrates that reflect the water column.
GEOTRACES will be global in scope, consisting of ocean sections complemented by regional process studies. Sections and process studies will combine fieldwork, laboratory experiments and modelling. Beyond realizing the scientific objectives identified above, a natural outcome of this work will be to build a community of marine scientists who understand the processes regulating trace element cycles sufficiently well to exploit this knowledge reliably in future interdisciplinary studies.
Expand "Projects" below for information about and data resulting from individual US GEOTRACES research projects.
Funding Source | Award |
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NSF Division of Ocean Sciences (NSF OCE) | |
NSF Division of Ocean Sciences (NSF OCE) |