GEOTRACES Community Practices
https://repository.oceanbestpractices.org/handle/11329/408
2024-03-29T01:49:45ZGO FLO Repair: Dr GO-FLO presents: Cleaning your new General Oceanic's GO-FLO. [Training video]
https://repository.oceanbestpractices.org/handle/11329/1232
GO FLO Repair: Dr GO-FLO presents: Cleaning your new General Oceanic's GO-FLO. [Training video]
Cutter, Gregory
The video shows how to disassemble and clean [ and reassemble] GO Flo bottles used in GEOTRACES to take uncontaminated marine water samples. 23.44 mins. A go-flo bottle is used to collect water samples for research of plankton, nutrient, pigment particles etc. A go-flo bottle is similar to a Niskin bottle except that a go-flo bottle is designed to avoid sample contamination. A water sample collected by a Niskin bottle can be contaminated by a microlayer present on the water surface enriched in organic material, trace elements and dust. The go-flo bottle is lowered into the water by a cable from the research vessel. It features a close-open-close operation. Contrary to the Niskin bottle, the go-flo bottle enters the water closed to avoid any possible contamination with the water surface. The top and bottom of the bottle are equipped with a stopper ball, which first have to rotate 90 degrees to open or close the bottle. As the bottles are lowered into the water, the increased hydrostatic pressure causes the pressure release valve to pop in and the balls to rotate 90 degrees and thereby opening the bottle. Generally, this happens at a depth of approximately 10 m. Just like the Niskin bottle, the go-flo bottle is provided by a messenger. This is a weight that is launched at specific depth of interest form a research vessel down to the go-flo bottle. The messenger will trigger a chain reaction to close the bottle.
The go-flo bottle can be deployed individually, serially or composed in a rosette.
2014-01-01T00:00:00ZRapid and noncontaminating sampling system for trace elements in global ocean surveys.
https://repository.oceanbestpractices.org/handle/11329/1228
Rapid and noncontaminating sampling system for trace elements in global ocean surveys.
Cutter, Gregory A.; Bruland, Kenneth W.
A system for the rapid and noncontaminating sampling of trace elements with volumes of up to 36 L per depth and including the dissolved and particulate phases has been developed for ocean sections that are a crucial part of programs such as International GEOTRACES. The system uses commercially available components, including an aluminum Seabird Carousel with all titanium pressure housings for electronics and sensors to eliminate zinc sacrificial anodes and holding twenty‐four 12 L GO‐FLO bottles, and a 7500 m, 14 mm Vectran conducting cable (passing over an A‐frame with nonmetallic sheave) spooled onto a traction winch. The GO‐FLO bottles are stored and processed in a clean lab built into a 20' ISO container. To minimize contamination, the GO‐FLO bottles are triggered when the carousel is moving upward into clean water at 3 m min−1. Analyses of salinity and nutrients in bottle samples from the stopped versus moving carousel show no detectable smearing, whereas the contamination‐prone trace elements show the samples are uncontaminated when compared with other clean sampling methods. Based on the use of this system on three major cruises, the launch‐sample‐recover time for the carousel (2 bottles triggered per depth) is 1 h per 1000 m, and dissolved and particulate sampling time averages 6 h per hydrocast. Thus, the system described here meets all the requirements for ocean basin sampling for trace elements: rapid, good hydrographic fidelity, and noncontaminating.
2012-01-01T00:00:00ZSetting up and assessing a trace element sampling system – lessons learned.
https://repository.oceanbestpractices.org/handle/11329/984
Setting up and assessing a trace element sampling system – lessons learned.
Cutter, Greg
Based on 11 years of experience, Greg Cutter, GEOTRACES Standards and Intercalibration past co-chair, has summarised the recommendations that nations developing a trace metal-clean sample system need to consider for successful sampling.
2019-01-01T00:00:00ZIntercalibration in Chemical Oceanography.[Webpage]
https://repository.oceanbestpractices.org/handle/11329/415
Intercalibration in Chemical Oceanography.[Webpage]
Cutter, Gregory A.; Croot, Peter L.; Andersson, Per S.
This Special Issue, the first of its kind for the journal, is devoted to the topic of intercalibration as applied to chemical measurements in the ocean. Rather than giving a formal metrological definition of intercalibration, it is simply the open sharing of data and expertise by analysts to obtain the same, and hopefully accurate, value for a given parameter such as the concentration, isotopic composition, or chemical speciation of a trace element. Laboratories are said to be intercalibrated when they all get the same values within the experimental errors. It is important to note that this does not mean that each individual laboratory needs to be using the same analytical techniques or even sampling methods, it only is the final results that count; this will be evident in the special issue papers that follow. Most of the papers in this issue are a result of the intercalibration phase of GEOTRACES, an international program to examine the biogeochemistry of trace elements and isotopes (TEIs) in the world s oceans. As so many countries are participating in GEOTRACES and sampling all oceans, it was essential that intercalibration included sampling and sample handling in addition to the analytical steps. Moreover, GEOTRACES studies TEIs in the dissolved and particulate phases, and their chemical forms or speciation, so these add even more to the complexity of performing an intercalibration. All of these aspects of intercalibration in the real ocean are touched upon in this special issue.
2012-01-01T00:00:00ZSampling and Sample-handling Protocols for GEOTRACES Cruises. Version 3, August 2017.
https://repository.oceanbestpractices.org/handle/11329/409
Sampling and Sample-handling Protocols for GEOTRACES Cruises. Version 3, August 2017.
Cutter, Gregory; Casciotti, Karen; Croot, Peter; Geibert, Walter; Heimbürger, Lars-Eric; Lohan, Maeve; Planquette, Hélène; van de Flierdt, Tina
The GEOTRACES Standards and Intercalibration (S&I) Committee is charged with
ensuring that the data generated during GEOTRACES are as precise and accurate as
possible, which includes all the steps from sampling to analysis. Thus, sampling methods
for dissolved and particulate constituents must take a representative (of the water
depth/water mass) and uncontaminated sample, the samples must be stored (or
immediately analyzed) in a fashion that preserves the concentrations (activities) and
chemical speciation, and the analyses of these samples must yield accurate data
(concentration, activity, isotopic composition, and chemical speciation). To this end,
experiences from the 2008-2010 GEOTRACES Intercalibration Program, actual
GEOTRACES cruises from 2010-2017, and other related intercalibration efforts, helped
to create the protocols in this document. However, methods continually evolve and the
GEOTRACES S&I Committee will monitor these advances as validated by
intercalibrations and modify the methods as warranted. The protocols here are divided
into trace element and isotope groups: Hydrography and Ancillary Parameters,
Radioactive Isotopes, Radiogenic Isotopes, Trace Elements, Nutrient Isotopes, Optics,
and BioGEOTRACES parameters. Those who contributed to preparing these protocols
are listed in Appendix 1 and are sincerely thanked for their efforts in helping
GEOTRACES and the worldwide TEI community.
2017-01-01T00:00:00Z