US GO-SHIP is part of the international GO-SHIP network of sustained hydrographic sections, supporting physical oceanography, the carbon cycle, and marine biogeochemistry and ecosystems. The US program is sponsored by US CLIVAR and OCB. Funded by the National Science Foundation and NOAA.

News

P18 Cruise report #6 Jan 5, 2017

Prepared by Rolf Sonnerup

We are now one week into Leg 2 of GO-SHIP P18 2016/17. About half of the scientific staff have changed hands. Sarah Purkey and I thank Brendan Carter and Annie Bourbonnais for remaining aboard to ease our transition, and in particular for leaving us with a crew of scientists in excellent spirits. Weather must’ve been great. One person who is sorely missed is Andy Stefanick, Jedi Master of the CTD and salt analysis, who returned home from Easter Island with a sprained ankle.

Read More

P18 Cruise report #5 Dec 30, 2016

Prepared by Brendan Carter

A map of our section with the yellow arrow highlighting what we’ve done this week. The thin black line at ~54°S shows the section of the Chilean EEZ where we are approved to conduct research.

Leg 1 came to an abrupt end one day early after an unexpected Chilean clearance problem. As noted in the previous weekly update, the Chilean clearance was expected to be granted at the last minute and allow us to proceed with our work in the EEZ surrounding Easter Island and the Island of Sala y Gomez. The problem came when the clearance documents that we received made no mention of the work we intended to do in that EEZ. Instead, the documents only approved work to be done at a later date on the approach to Punta Arenas (in a rectangle that looks like a thin black line on the map above). Fortunately, our planned stations are on the edge of the Easter Island EEZ, so we have the option of shifting the stations to international waters to the east (for a shift of up to 1 1/3° east). Rather than implementing this plan immediately, we decided it would be better to preserve sea time for leg 2 and transit to port 1 day early

We’d hoped we’d be able to resolve the confusion before leg 2 began. Unfortunately, it looks unlikely that our clearance will be able to be reviewed in time despite valiant efforts from Captain Kamphaus and our teams from the laboratories on land. It is therefore likely that these stations will need to be shifted east when they are occupied on leg 2. This is not an ideal outcome, but it is significantly better than skipping the stations

Read More

P18 Cruise report #4 Onward! Dec 18, 2016

Prepared by Brendan Carter

A map of our section, with the yellow arrow highlighting what we’ve done this week.

We’re on fire! (Figuratively, of course.)

Read More

P18 Cruise report #3 Across the Equator. Dec 12, 2016

Prepared by Brendan Carter

A map of our section, with the yellow arrow highlighting what we’ve done this week.

We have had another productive week. We crossed the Equator and started our journey across the Southern Hemisphere, completing 33 stations and the rest of our high-resolution Equatorial work in the process. We’ve had very few delays this week, and no significant ones. We are making good time, and are on track to make it far enough South to have a short and efficient transit to our end-of-leg-1 port call on Easter Island.

Read More

P18 Cruise report #2 Down the line. Dec 5, 2016

Prepared by Brendan Carter

A map of our section, with the yellow arrow highlighting what we’ve done this week. We have now emerged from the French and Mexican EEZs (red circles) with a complete set of measurements from each region. French? In the middle of that circle we passed through is a small island claimed by France named Clipperton. It is still the closest land to us.

It has been a pretty good week. We’ve hit our stride, and have begun completing our station work quickly and efficiently. We did 29 stations across 13.5° between Nov 28th and Dec 5th. The Brown has been averaging more than 10.5 kts between stations, our team is sending the CTD-sensor rosette package down to 10 meters off the ocean floor and bringing it back filled with water as quickly as we’d hoped, and we’ve had calm weather and no additional major delays. Our quick pace perhaps feels faster still due to the ~3700 m average depth of the stations, which is a bit shallower than many of our veteran repeat hydrographers are used to. We are testing the throughput of our teams various analytical systems despite using a 24 position rosette (vs. the 36 position rosettes that bring back 150% as much seawater).

Read More

P18 Cruise report #1 Clearance extended! Nov 27, 2016

Prepared by Brendan Carter

We are pleased to report that we are making our way south out of the Mexican EEZ and doing station work as we go. We were briefly faced with the difficult decision between waiting on station and abandoning the work in the Mexican EEZ. Some offshore islands make the Mexican EEZ more than twice as thick as the default 200 nautical mile (nm) limit along our track. This meant that going south to accomplish work outside of the EEZ while we waited was not a good solution, and also that an unusually large amount of station work (~15% of leg 1) would have been lost if we had given up on the EEZ. Ultimately, we spent nearly a day and a half waiting on station. We are now slightly behind our ambitious schedule, but relieved to be able to fill in these important measurements of the oxygen deficient zone (ODZ) off Mexico.

Read More

P18 Cruise report #0 Nov 20, 2016

Prepared by Brendan Carter

After one more delay that pushed our sailing date back to 1500 on Saturday, Nov. 12th, we are excited and relieved to be underway.

This was the original start of this report written on Nov. 13th. Unfortunately, we since returned to San Diego for diagnosis and repairs to the port Z drive. It was an approximately 48 hour round trip followed by an additional 5 days in port with 2 sea trials. We are pleased to again be about a day from port and heading to the P18 line. The modified schedule has us getting to Easter Island around Christmas. The date of the Punta Arenas arrival at the end of leg 2 is less certain. This report contains an updated timeline of issues affecting the P18 schedule at the bottom (dates of new updates are in bold).

Read More

P18 Cruise report #-1: Port Repairs Nov 9, 2016

Prepared by Brendan Carter

The first leg of the P18 GO-SHIP project was scheduled to begin Monday Nov. 7th, so I owe an update. However, “Report 0” is being saved for the day we depart from San Diego, CA for the first station on the P18 line at 110°W. Hence “Report -1.” The delay of our start date owes to lingering mechanical issues on the NOAA Vessel Ronald H. Brown (henceforth the “Brown”) that were identified after a dry dock period in San Francisco, CA. A timeline of the repairs and discoveries can be found at the end of this update. Our working departure date estimate is now Thursday Nov. 10th.

Read More

P18 Cruise Blogs Nov 5, 2016

Follow scientists as they work on the R/V Ronald H. Brown.

GO-SHIP P18 2016 Cruise Blog

Read More

I09N 2016 Weekly Report 5 Apr 26, 2016

From Leticia Barbero and Carmen Rodreguez **(Co-Chief Scientists)

Mission accomplished! We are happy to report that we have now completed all of
our science objectives…and then some!

We finished our last station on Sunday afternoon at 19:50. We are now in transit to
Phuket, Thailand, where we expect to arrive on Thursday April 28th at 08:00 am
local time.

In this last week we completed the “bow tie” section of the cruise. We have been so
lucky weather- and instrument-wise that over the first 4 weeks we gained enough
time to be able to add 2 bonus stations. Since our last planned station was at the
border of the Indian EEZ, we couldn’t add any extra stations further north. Instead,
we extended the bow tie section westward to re-occupy two additional stations
from the I01E WOCE line. We went as far west as possible without entering Sri
Lankan EEZ waters, up to 84.75W, and then continued with the rest of our planned
stations. These two extra stations allowed us to sample an area with particularly
high carbon in the bottom waters and fresher surface waters. There should be some
interesting results from these samples.

Over the last 5 weeks we have done a total of 113 stations, plus trace metals casts,
optics casts and continuous underway sampling (while on station and in between
stations). Even leftover water from the niskins was used for unplanned
measurements to be run back in our labs. We have an excellent quality dataset to
work with when we get back to land. As we moved northwards we observed a
freshening of surface waters, a drop in subsurface oxygen levels, high carbon
concentrations in the western region, and I’m sure we have a lot of interesting
biogeochemical information that will come from all the samples to be ran back in
our home labs.

On this cruise we have had two groups in charge of carbon measurements (NOAA
for underway pCO2 and DIC, and UCSD for pH and alkalinity). GO-SHIP is one of the
few programs where the CO2 system is over-determined (i.e. where we measure
more than 2 of the 4 parameters that characterize the carbonate system). This
enables us to evaluate not only the carbon exchange with the atmosphere, or
changes in carbon storage over time, but also to evaluate the quality of the
measurements themselves (e.g. by comparing measured DIC against the value
calculated from pH and alkalinity). Below you can see preliminary results for this
comparison. The average difference between measured and calculated DIC values is
2.1 ± 1.8 μmol/kg. This speaks highly of the quality of the measurements. Great job!

I think everyone on board agrees that this has been a very successful cruise. It feels
good to go home with a sense of accomplishment, but it probably feels even better
just to know that we will be setting foot back on land in just a couple more days.

Don’t forget to check our blogs for new entries:

We want to thank everyone on board, science and ship’s crew alike, for a great
cruise. Thank you also to the people back on land who provided shore-side
assistance.

Leticia and Carmen, Chief-scientists I09N.

Read More