2018-07-26

Attendance: Denise Kulhanek, Gary Acton, Jason Sylva (external member), Lisa Brandt, Vinny Percuoco, Erik Moortgat, Algie Morgan, David Houpt, Lorri Peters, Brian LeVay, Don Sims, Katerina Petronotis [Zoom: Jeffrey Ryan (external member), Ann Dunlea (external member), Kara Bogus]

1) Microbiology workshop paper (Jason/Kara)

The team intends for a final draft to be finished by the end of July 2018. As an update to Tech Note 28 the document contains: shipboard methods, recommendations based on the number of microbiologists shipboard, and expectations for shore-based microbiologists. In early August 2018 it will be sent to a subset of the microbiology community for review before submission.

ACTION: Jason and co-authors finish draft, circulate, and submit Tech Note

2) New external members

Jeffrey Ryan (University of South Florida), Exp 352, 366

Ann Dunlea (WHOI), Exp 346, 378

3) Cahn balance software re-write (Erik/Algie)

The re-write went into production on X376 and scientists have commented that they really like the new interface (GUI). In addition to weighing samples, it has a feature to set the range based on instrument. ‘History’ is the final component left to be completed. [PowerPoint with screenshots available on LWG Google Site]

ACTION: Vinny will update the user guide; Vinny/Algie finish ‘History’ component

4) Reduction of porewater volume for alkalinity (Erik)

Following a recommendation from X369 evaluations spectrophotometer methods using less porewater were investigated. The method has to be run real-time and is not realistic in our shipboard setting. Also would still need to measure pH separately. [PowerPoint with screenshots available on LWG Google Site]

ACTION: close

5) Microtiter plate techniques for ammonia, silica (David)

Similar to alkalinity there have been comments about the sample volume for other methods and microtiter plate techniques were suggested. There are many microplate vendors and the method would use similar or lower sample volumes. However, the method would still require hand-pipetting, would only reduce sample size by ~50uL, and based on the ranges specified by manufacturers may produce less precise data. [PowerPoint with screenshots available on LWG Google Site]

ACTION: Discontinue looking into microtiter plate techniques. Lisa Brandt will investigate a module for the IC that would include spectrophotometer.

6) Sulfate blank in the IC (Lisa B./Aaron)

This has been an ongoing issue where 1-2mmol is measured (should be zero). This was discussed in a X375 cruise evaluation – our sulfate range is composed of two curves (both linear).

ACTION: Lisa will update the lab manuals to reflect the need for a low- and high-range standard curve.

7) GC calibration for void gas measurements (Lisa B./Aaron)

Modifications to the GC (Luer Lock, valve) will improve this in the future. Agilent will also visit and make modification to the unit onshore, which will be swapped with the shipboard unit. If results are positive, we could retire GC3 and add another NGA.

8) LN2 generator replacement (David)

Repaired and will be returned to the ship during tie-up period.

9) HF methods and alternatives

TAS would like for the Geology and Geochem/Microbio LWGs to consider a policy that would limit the amount of HF (6 – 10L) available on each expedition. The goal of the policy is to make the work environment safer without completely restricting the use of HF given that many palynologists still think its use is required. The policy would also note that safer non-HF methods should be used preferably whenever such methods make it possible to achieve the objective. [Further details in “palynology_non-HF_overview” on LWG Google Site]

ACTION: Laurel circulated a survey to community members. With the Geology LWG a set of recommendations was submitted to management and a new set of HF/non-HF guidelines was adopted.

10) ICP Nomenclature

We have consistently used ICP-AES for Inductively-Coupled Plasma – Atomic Emission Spectrometry in the past. Our new Agilent, uses ICP-OES for their instrument name. Adopting ICP-OES formally would mean changes in many locations (database components, LORE reports, analysis codes, data publishing, user guides, reports). The name has evolved with instrument capabilities, however we are still using it for AES currently.

ACTION: The name will not be changed in the databases, analysis code, user guides, etc. The use of the phrasing ‘ICP-AES’ vs. ‘ICP-OES’ will be addressed in the methods section of individual expedition reports and proceedings.

11) Expedition Reviews/Evaluations: 374 and 375 (All)

see below

12) Other

SEM-EDS testing status (Tobias): tabled til next meeting

Igpet Rockware Plotting Software (Tobias): tabled til next meeting

Expedition 374

Cruise Evaluations

1) The only minor point to bring up is that we had intermittent problems with one of the conductivity detectors on the IC. The technicians however worked non-stop to figure out the problem – a very frustrating process when intermittent problems occur, as every analytical chemist knows. Their committed and careful work however ensured that the issue did not compromise our data collection.

ACTION: None. New conductivity detector installed. Old sent to shore.

2) The ICP-OES is rather new on the ship and data are hence not uploaded directly to LIMS. Personally I appreciated to be able to go through the data quality control myself (after an introduction from Vinny) and decide what data to have uploaded. This may however not be the case for future scientists.

ACTION: Discuss with scientists as appropriate. Vinny has built an Excel program to handle ICP-OES data which allows raw data to be converted to tabular form and appropriate lines picked by scientists.

3) All fine – particularly the HF safety induction was very good and is something I recommended to my lab manager back in my laboratory (we use the Honeywell brochures and safety induction presentations each year; I however had not seen the video before).

ACTION: None. Additional efforts to reduce volume of HF stored/used shipboard are underway.

4) I was surprised to see great facilities in geochemistry lab and core deck lab.

5) it would be good to also have the instrumental facilities for biogenic opal measurements

ACTION: None. This measurement is not common, ephemeral, or necessary for operational decisions.

Tech Report

6) Poor precision we traditionally have encountered with the ammonium analysis was investigated towards the end of cruise….Further testing should be done on subsequent expeditions. Specifically, try using the same reagent mixture for the rinse as is used for the sample (Phenol/Ethanol + Oxidizing Solution + Water + Sodium Nitroprusside). The density and miscibility should be identical. Therefore, the cuvette should flush more efficiently, thus, providing better precision. The default rinse time we use is the maximum rinse time the Cary Autosampler can do, so we cannot simply rinse longer.

ACTION: This was implemented on X376 and will be used moving forward. Vinny will update the user guide.

7) ICP: We performed an extensive test of combusted and non-combusted sediments at the beginning of the cruise and found there to be no apparent value in using combusted powders over non-combusted sediments. In addition, the certifications for the reference materials are not valid if the standard has been combusted. Therefore, it was decided to perform our ICP analysis using sediments/standards that were freeze-dried, crushed, and homogenized, then fluxed. We believe this a more efficient ICP workflow because it removes the LOI step. But this is probably something that should be discussed in the next chemistry lab working group meeting.

ACTION: update the user guide to reflect that combustion is not necessary (current hard rock ICP method).

8) The GC Sampler 80 (S/N CH00264637) was installed on the GC2-PFT for configuration. Many attempts were made to get this sampler configured, including tickets with Agilent, but no headway was made….After these changes, running sequence tables started to work....The Gerstel autosmpler is being sent home (surplus?).

ACTION: Send to surplus or preferred alternative (other campus labs, etc.).

Expedition 375

Cruise Evaluations

1) The chemistry lab has been much improved since the last time I sailed (X344), and both

technicians (Lisa Brandt and Aaron Mechler) did a fantastic job and were both helpful

and knowledgable.

2) Sulfate concentrations are not linear on the IC over the range of in situ concentrations expected in continental margin environments. Unlike the pelagic setting (which I believe had been the focus of many of the 2017-2018 cruises) sulfate values range from seawater to depletion in continental margins. Accurate sulfate determination at low concentrations are critical in these environments for defining the sulfate-methane transitions (important for understanding aspects of biogeochemical cycling) and as a contamination tracer. Below the SMTZ, in situ sulfate concentrations are theoretically zero, thus we use the presence of sulfate in the pore water sample to correct for drilling related contamination. My understanding is that during previous expeditions, sulfate concentrations measured by the IC were never less than 1 mM. The reason for this is that sulfate measurements over the entire range of expected concentrations is not linear using this method. Thus, you need two calibration curves, one for the low range of values and one for the higher range. We implemented new standards and two curves during X375 and were able to evaluate concentrations less than 1 mM and were able to even get good data at concentrations as low as 0.2 mM. I recommend having a low calib curve that ranges from 0.1 mM to 2 mM, and a high calibraion curve that ranges from 2- 28.9 mM.

ACTION: Already implemented. Lisa B. will update user guides.

3) Similar to sulfate by IC, ammonium by the spectrophotometer is not linear over the calibration range typically used in the chem lab (0-3 mM). At first, the ammonium data that we were acquiring using the shipboard method were terrible with precisions >10%. I quickly realized it was the result of a non-linear calibration curve. I suggest calibrating over the range of 0-1000 uM making sure to have standards at the low end (~50 uM). If samples have NH4 greater than 1 mM, dilute first before adding reagents.

ACTION: Add to the user guide that user should exercise caution and be aware of sample range.

4) I suggest letting the shipboard geochemists perform QA/QC on all data in the chem lab before being uploaded to the database. When one looks at the database, every line on the ICP is present and there is no way currently to tell which lines yield better results. There is no calibration files along with the data etc. . . so one cannot evaluate the precision, accuracy, etc... During X375, I first evaluated all of the data from all instruments, then uploaded them. For the ICP in particular, I submitted the wavelength for each element with the highest quality data to the database. This will restrict researchers in the future from using bad data in their research activities and papers.

ACTION: Make explicit to scientists that this is possible. Do not average data.

5) The Li data on the ICP was not optimal. We were able to improve the data quality by adding a matrix match to all standards. The standard shipboard procedure was to matrix match some of the standards but not all. This did not impact the other analytes much, but had a large impact on Li. We ended up using a 35 ppt matrix match for all standards, and this greatly improved the quality of the Li analyses. There was also a rather large drift in the B data during each run. The amount of drift was not consistent. By proper use of drift standards, we were able to apply a drift correction to the data. Again, if the data is automatically uploaded to the database, it would be incorrect. I first applied the drift correction, then uploaded the data. Even better, a ascii or other file associated in the database with calibration and run data would be helpful, and would cut down of reporting erroneous data in studies using archive IODP data.

ACTION: Matrix match for majors and minors has been used previously. In the future, the Data Publishing project will address this. In the meantime, this is on Data1 but scientists should be made aware of this.

6) The Ca, and to a lesser extent Mg, data produced on the IC are problematic. This is not a huge issue as the Ca and Mg data on the ICP are good, but should be further investigated. Ca is consistently high relative to what the standard value should be, as is Mg. I suggest looking into this issue, and figuring out what is causing the increase in Ca intensity.

ACTION: None. This problem can sometimes occur with improper use of ICP data.

7) We also had issues with the IC anion data (Cl, sulfate, Br) towards the end of the expedition. The baseline was variable, and there were sudden drops in the anion intensities that appeared random but would occur over about 5 sample injections. The calculated concentrations releative to the calib curve for standards and samples would suddently decrease, and about 5 samples later would increase back to their known values. This issue should also be investigated. I decided not to report some of the IC Cl, Br, and SO4 data from the last as a result of this problem.

ACTION: None. There was a bubble in detector, fixed now. Sulfate suppressor was clogged; now cleaned.

8) It would be nice to be able to evaluate CO2 concentrations on the NGA. I remember that this was standard in the past, but is no longer routinely done. I am not sure if it is because you do not have the correct column or if there is no calibration gas, but VG and HS CO2 concentrations are scientifically valuable and would be a nice addition to the shipboard organic geochemistry dataset.

ACTION: Vinny will re-standardize this.

9) As mentioned previously, both Aaron and Lisa were great and provided assistance trouble-shooting these issues.

10) One last thing, it is okay to acid clean the syringes used with the squeezers and to re-use them. However, after about one reuse, they become sticky and difficult to push down the plunger. ONce this happens, they should be discarded and new ones should be used.

ACTION: None. This is to be determined by the sailing scientist.

Tech Report

11) The oil drain hose on the right press was blown off spraying oil all over the place. It was zip tied back in place until we had time to investigate and fix the issue. Found that the pump unit was sitting on top of the hose crimping it and preventing overflow oil from returning to the pump reservoir. Right press was rebuilt in the process. Middle press was often not lowering after pressing open. This press was also rebuilt to fix the problem. Both the middle and right press continue to have oil leaking around the base.

ACTION: Continue to monitor.

12) We were not able to get a good calibration on the TCD, the values were scattered and not linear. After some back and forth with folks on shore, we discovered that we had been injecting on the wrong inlet. Should be injecting on the back inlet, not the front, even though the front one looks more obvious. Tried a new calibration which looked a bit better. I then did some blank injections, and got large O2 and N2 peaks, was told this was just due to air in the sample loop. I then injected what should have been mostly helium gas, and still got O2 and N2 peaks of about the same size. I made sure that the method I was running was the same as the one on shore, still got big O2 and N2 peaks.

ACTION: Continue to monitor.

13) IC, only one instance where there were clogs in the line between the outlet of the UF cell and the black/black peristaltic pump tubing, and another clog in the outlet from the peristaltic tubing to the line going to the injection valve. The clogs developed even with running flush blanks after the sample run. We were told that the samples were very clay-y and might have had particles that made it through the .45 uM filter.

ACTION: Clean out more frequently.