Friday, August 30, 2013

Transitions

August 29, 2013

As we say goodbye to Rachel and the other participants of the first leg, we welcome the new arrivals for the second leg. I am Pete Morton, a postdoctoral researcher (like Rachel) with Bill Landing at Florida State University. I arrived in Madeira on the same day as the RV Brown, and joined our friends in port to celebrate the successful completion of the first leg.

While hotels are abundant in Madeira and other "holiday destinations," it is often more convenient and affordable to rent an apartment for the few days you are in town. We were very fortunate to find a four-bedroom apartment about 100 yards from the ship, for about 1/4 of the cost of a hotel room! Not only is it more economical to share an apartment, but it has allowed us plenty of relaxed opportunities to exchange information about the sampling and analytical operations.


View of the RV Brown from just outside our apartment in Funchal, Madeira

When preparing for a research cruise, you do your very best to prepare for any imaginable emergency. However, on occasion something will need to be fixed that requires resources beyond those immediately available at sea. During the first leg, we discovered that one of our laboratory van air conditioner units needed to be replaced. Having the short layover in Madeira made it possible to have a replacement unit shipped from the US to the RV Brown and installed while in port. Unfortunately, the ship's A/C system has required some repairs as well, and we are delayed leaving until Saturday, August 31. While it is certainly nice to enjoy some extra time in Madeira, these delays place a little extra stress on our upcoming schedule. It remains to be seen how this delay will affect our sampling schedule, but we hope that the extra stations sampled during the first leg will minimize the effect of the delayed departure.

Until then, we'll do our best to enjoy the sunny skies, cool sea breeze, and unhurried schedules :-)

The FSU trace metal team replacements: Randy (left) and Pete Morton

Friday, August 23, 2013

The Ocean, pH, and CO2


August 22, 2013

This is my final blog post, written as we transit from Station 70 into port in Maderia. The original plan for Leg 1 was to complete 66 stations. Due to everyone's hard work, crew and scientists, we were able to complete four more stations than planned. I have just collected the last set of aerosol samples from this leg of the cruise. Our last CTD cast was yesterday at 4 pm, at Station 69.  The last cast of Leg 1 happened at 1 am this morning, so there are some very tired people on board at the moment.

Yesterday, while our CTD was in the water, I took some pictures of the salts/CO2 lab. In this lab people are making high-precision measurements of salinity, total alkalinity, pH (not just as simple as putting a pH probe in a bucket of seawater!), total CO2 , (or dissolved inorganic carbon - actually these guys are out on the afterdeck in a lab van just like the trace metal group) and partial pressure of CO2  . SCUBA divers or anyone who's taken high school physics should know all about partial pressure and Boyle's Law - the amount of gas that is dissolved in a liquid is inversely proportional to depth and temperature. Since we know that atmospheric CO2 concentrations are increasing (we've just passed 400 parts per million - higher than any time in the last 800,000 years), and we know that the ocean is a net sink for CO2  (this means that the ocean absorbs more CO2 than it releases), we are interested in determining how the increase in atmospheric CO2 is, or will, affect the chemistry of the ocean.

The ocean is a giant buffer system which, on geological timescales (i.e. 1,000s of years) is in equilibrium. Our blood is also a buffering system. Our bodies can only function within a very narrow pH range. If our blood pH becomes too high (towards basic) or too low (too acidic), all sorts of bad things happen, such as proteins denaturing, red blood cells bursting or collapsing, enzymes are unable to work. So, in order to prevent organ failure and, untimely death, our blood pH is maintained within the optimal pH range. This process is called homeostasis.

The oceans work in much the same way. In seawater at pH 8.2 (the average pH of the global ocean) carbon dioxide exists predominantly in three forms (species): CO2, HCO3- and CO2-3. The dissolved carbonate species in seawater provide an efficient chemical buffer to various processes that change the properties of seawater. For instance, the addition of a strong acid such as hydrochloric acid (naturally added to the ocean by volcanism), is strongly buffered by the seawater carbonate system. Thus, the pH of seawater stays relatively constant. Of major concern is that scientists have noticed a decrease in oceanic pH in the last 100 years of about 0.1 pH unit (a 30% increase in hydrogen ions/protons). Although the ocean remains a basic medium (> pH 7), this phenomenon has been called 'Ocean Acidification' - or 'The other CO2 problem'. As life in the ocean has evolved to live at an optimum pH, deviation from this range has serious implications for life - especially for organisms that build calcium carbonate shells/skeletons, such as corals... which begin to dissolve as pH decreases.

I took some pictures of Kevin Sullivan (University of Miami - CIMAS) at work determining the partial pressure of CO2 in seawater, or more specifically, the fugacity of the gas (accurate calculations of chemical equilibrium for gases require the use of fugacity rather than the pressure). Don't tell anyone I told you to, but take a look at the Wikipedia page for a more complete explanation of fugacity of a gas: http://en.wikipedia.org/wiki/Fugacity.  Kevin says that he is not expecting to observe a change in the fugacity of CO2 over the last 10 years, despite an increase in atmospheric CO2 . This is reassuring and is testament to the efficiency of the ocean buffer system. The problem is that no one knows how much CO2  the ocean can absorb before the ocean can no longer buffer its pH efficiently. So even though on geological timescales we can expect the ocean pH to be effectively buffered, on the timescale of marine life cycles, a much less rosy picture is beginning to emerge.

(The following pics were all taken by me, Rachel Shelley)

Kevin Sullivan (University of Miami - CIMAS) at work determining
the fugacity of CO2 in water column samples - a novel use of a cooler!

A closer look at Kevin Sullivan's cooler. Despite the home-made look of Kevin's equipment,
it is a very sensitive piece of equipment, used for determining a fundamental property
of seawater and the global carbon cycle.

 
Pam (top) and me (bottom) don our survival suits - a perfect fit!!
 
Sunset off the port side...


... and moonrise off the starboard side.

Goodbye from me - the next post will be from Pete Morton (also a post-doc in the Landing lab at FSU).
 
(EOAS wants to thank Rachel for blogging about her experiences aboard the RV Ron Brown and for explaining and documenting the science being conducted.)

Monday, August 19, 2013


Life Aboard Ship



August 18, 2013

Day 15, and only 4.5 more days until we get into port in Madeira, Portugal. As always, the days have sped past. The first 3-4 days tend to be the hardest as you adjust to your new schedule and getting your sea-legs. After that, one day, more or less, blends into the next - especially when you have a 05:00 start scheduled for the next day, as we do tomorrow. Some groups aboard are running their analytical systems 24-7, and so are doing shifts. For the trace metal four, life is a little different. With the exception of Joe Resing, who is analyzing dissolved Fe and Al, we are collecting samples for analysis in our home labs. We are collecting samples from approximately every 1o of latitude, or every other station. This means that we don't have a regular schedule. Although we try to avoid doing our CTD casts in the middle of the night, sometimes, due to our arrival time on station, it is unavoidable. Our early start tomorrow will likely be followed by breakfast (07:00 - 08:00), and an nap!

Having said all days blend into each other, that is not entirely true. For example, Tuesday night is games night, and Saturday night is card night. I have yet to make either, due to schedule clashes, but card night in particular is the talk of the day on Sunday (i.e. today). It seems that the CO (Commanding Officer) cleaned up at poker last night!

Safety


Safety is taken very seriously on oceanic research cruises. On the Ron Brown, there is a safety drill at least once a week. Participation is mandatory. Last week there was a simulation of a fire in the laundry room; the result of 'someone putting their tennis shoes in a dryer.'  Smoke canisters were set off and the crew, some using Self-Contained Breathing Apparatus (SCBA; like SCUBA, but without the 'Underwater' part) had to respond by isolating and extinguishing the 'fire.'  We also did an abandon ship drill.

This week, we did a full set of drills: 1) Fire; 2) Abandon ship; 3) Man overboard. Man overboard was the most exciting, with a full rescue simulated. Boatswain Bruce Cowden threw Oscar overboard (see pics). Oscar was equipped with not one, but three GoPro cameras to capture his dramatic rescue. The rescue boat was launched, and I can happily report that Oscar was successfully rescued and is recovering well from his ordeal.


Oscar
(photo: Rachel Shelley)


Oscar goes overboard!!
(photo: Bruce Cowden)
Onlookers include Boatswain Bruce, Engineer Megan, Captain Pickett, me (Rachel), and Christine.


Oscar's view of the Ron Brown - HELP!!!
(photo: Bruce Cowden)

Man overboard!!!
(photo: Rachel Shelley)

The rescue boat speeding to save Oscar!
(photo: Rachel Shelley)

Look at the color of that sea!! We are truly in blue water now. Primary production is low in this region of the North Atlantic. Major nutrients (nitrate and phosphate), as well as trace metal concentrations, are too low to support high biomass. As a result, visibility is excellent. At 28 m (84 ft) we can still clearly see our CTD rosette.




Oscar's rescue from his perspective
(photo: Bruce Cowden)

Junior Officer Jim Rosenberg, swims to Oscar's aid. Crew Mike, Megan and Nick watch from the rescue boat.

Oscar makes it safely back onto the Ron Brown
(photo: Rachel Shelley)

Clear water - the trace metal rosette at about 10 m.
(photo: Rachel Shelley)


Note that the bottles are all open. This indicates that the rosette is on the way down. We fire our bottles closed on the up-cast so that they are rinsed with seawater on the way down.


It's good to be the PI...


This is what post-docs in the Landing group are expected to do! This is a picture of me 'holding the umbrella' to keep Dr. Bill Landing shaded from the hot sun!
(photo: Bruce Cowden)
 


Thursday, August 15, 2013

Whales!!!

August 14, 2013

A quick hello to Pam's mum
from all on CLIVAR A16N, "Hello, Mrs. Barrett!"
 
 
 
Two days ago, on August 12th, we were treated to something(s) that most people will never have the opportunity to experience. Two fin whales, the second largest animal on the planet (growing up to 27.3 m (89.5 ft), weighing nearly 74 tons), were spotted. They came very close to the ship, and we were able to positively identify them as fin whales. In contrast to the slightly larger blue whale (30 m (98 ft) in length and 170 tons), fin whales do not raise their shoulders out of the water when they dive, their dorsal fin is more prominent and their water spouts don't shoot as high. The fin whale population was decimated during the commercial whaling era, and today the global population is estimated at between 100,000 - 119,000; classifying them as 'endangered' on the IUCN Red List of threatened species.


A fin whale  ☺   Note the small dorsal fin just sticking out of the water, to the left in the above picture.
(photo: Bruce Cowden)

We're being followed...


But that's not all! Ever since we first spotted them on Aug 5th, we have been followed by a pod of pilot whales. We know they are the same pod as one has a distinctive notch out of its (his?) dorsal fin. The whales catch up with us when we stop at the next station. They have been increasing in confidence, coming a little closer each day. So close that we noticed they had a baby with them a few days ago - and this baby is super-cute and playful. Finally, two days ago, the whales decided to watch us, like we were watching them. What seemed lie half the ship was out on the stern watching the pilot whales, along with a breath-taking sunset, when the whales started 'spy-hopping' to look at us. They would come up vertically from the water to look at us. Even the baby did this a couple of times! The exuberant baby would splash out of the water when it surfaced for air, which was met with much oo-ing and ah-ing from the assembled scientists and crew.



... and baby makes three! Close encounters of the whale kind! Pilot whales
(photo: Josh Levy)
 
 
And there's more ... one of the fin whales (or perhaps another one) wanted a slice of the action, so he came and did a casual swim-by off the port bow' providing yet another great photo opportunity.
 
... and still more... Aug 11 and 12 was the peak of the Perseid meteor shower. Out in the open ocean, far from urban light pollution, we were perfectly positioned to witness the night-time show. As it turns out, Aug 11th was unfortunately cloudy, although I'm told the clouds parted at around midnight, and those lucky enough to be start-gazing were treated to a spectacular display. So, not wanting to miss out on the action, I grabbed my jacket and headed up to the bow at about 10 pm on Aug 12... and was not disappointed. My fellow star-gazers and I saw some truly fantastic shooting stars that night, and I went to bed very happy indeed.

Yesterday, Dr. Bill Landing (FSU chemical oceanography prof) gave a talk to the crew. He spoke about climate change, and how the CLIVAR program and this cruise is contributing to our knowledge of the global carbon cycle, and how it all fits into the larger picture of global climate change research. The talk was very well attended, prompting a number of pertinent questions from the ship's crew. Speaking to crew members afterwards, they said that they had enjoyed the talk and found it very informative, and that they appreciated having the chance to have the science explained in an informal setting. In return, Dr. Landing told them that the science party appreciates their involvement and all that they do to facilitate the smooth running of our research. Dr. Landing was also very grateful to Chief Scientist Molly Baringer, (AOML-NOAA), and Lt. Paul Chamberlain (Operations Officer) for the opportunity to discuss his research and its wider implications.  


Monday, August 12, 2013

Ambassadors, Scientists, and Science



In our complement of thirty scientists on this cruise, there are nine graduate and undergraduate students. One of our participants is a Miami-Dade County Public School high school teacher, Monica Mejia. Monica is working for Dennis Hansell, Rosenstiel School of Marine & Atmospheric Science (RSMAS), and Ann McNichol, Woods Hole Oceanographic Institute (WHOI), collecting samples for Dissolved Organic Carbon (DOC) for Hansell and Radiocarbon (14C) for McNichol.

Our cruise was covered by the Icelandic media. On July 31st we hosted ambassadors to Iceland from the United States (Luis E. Arreaga), United Kingdom (Stuart Gill), and Norway (Dag Holter). Staff of the embassies from Germany and Russia were also present. They were given a tour of the ship, ship life and an introduction to the CLIVAR / Go-SHIP Repeat Hydrography / Carbon Dioxide Program. News of this tour appeared in local press and the Ambassador of the United State's web page at the links below.
Some photos from the start of the cruise to date (all pictures taken by Rachel Shelley).


Aug. 3, 2013, 8:00am - Leaving port
 Harpa, the most expensive building in Icelandic history, is in the background


Aug. 3 - The pilot ship leaves us as we head out to the open sea.

Aug. 3 - The first CTD cast of CLIVAR A16N 2013!

Along with Conductivity, Temperature and Depth (CTD) measurements, this rosette samples water for chlorofluorocarbons (CFC), oxygen, nutrients, discrete pCO2, dissolved inorganic carbon, pH, total alkalinity, helium, tritium, 14C, δ15N, colored dissolved organic matter, and salinity. On average, 2000 - 240 samples per station are taken.


Aug. 3 - Dr. Bill Landing prepares for the first trace metal cast, with Pam Barrett looking on.


Eric Stassinos (UCSB) at work in the main lab.
Eric is processing water for colored dissolved organic matter (CDOM).



Styrofoam cups in the main lab

Meteorological and details of the ship's position are displayed in the main lab. In the foreground you can see a net of Styrofoam cups and manikin heads. Styrofoam contains a lot of air. One of the cool things to do on a ship which samples from great depth (several 1,000 m) is to send decorated Styrofoam objects down with the CTD rosette. The immense pressure at these depths compresses the air and shrinks the Styrofoam objects to a fraction of their original size. Watch this space for more pictures related to this! ☺  


Chris Langdon (UM), one-half of Team Oxygen, at his work station in the main lab.

Chris Langdon (University of Miami), is one-half of team oxygen. The other member of his team is Laura Stolenberg (visiting researcher, University of Miami). The dissolved oxygen (dO2) concentration of the ocean is a sensitive measure of climate change. Dissolved O2 gets into the deep interior of the ocean via the subduction of cold, dense water at high latitudes. As polar ice melts, due to global warming, water becomes fresher and warmer, and, therefore, less dense. This slows down the resupply of dO2 to the deep ocean. Over the years, Chris and his co-workers have noticed a steady decline in dO2 concentration. This is bad news for things that live in the ocean. For example, fish such as tuna avoid low dO2 waters, and change their migratory behavior accordingly. You may also have heard about oceanic 'dead zones'; there is a very large one in the Gulf of Mexico. Dead zones are increasing due to increasing agriculture run-off, for example. As dead zones increase, so does the area of the ocean that is avoided by fish. This has major implications for the future of fisheries.

Segmented-flow analyzer

The segmented-flow analyzer determines concentrations of the major nutrients in seawater (nitrate + nitrate, phosphate, silicate). This instrument is operated round the clock by two people, Eric Wisegarver (PMEL-NOAA) and Charlie Fischer (AOML-NOAA).


Anthony Dachille (LDEO) hard at work
Anthony is measuring δ18O, helium and tritium, and was on A16N in 2003


Some of the computers in the survey lab


Chief scientist, Molly Baringer, AOML-NOAA - Still smiling!

An awe-inspiring sunset. One of the best things about going to sea is the amazing sunsets and sunrises.


Joe Resing & Pam Barrett in the trace metal van

Joe is running water column samples for dissolved Fe and Al. Pam is controlling the deck box, which determines the depth at which the GO-Flo bottles close and sample water.

Kristy McTaggart at work in the electronics lab


The crew of the RV Ronald H. Brown on CLIVAR A16N leg 1


The scientists on the RV Ronald H. Brown on CLIVAR A16N leg 1


The main lab
Yes, that is a ping pong table! Ultimate ping pong!!

Friday, August 9, 2013

Whales!

August 7, 2013

Firstly, we saw whales! A large pod of pilot whales decided to come and investigate what we were doing, and treated us to a show on Aug. 5th. The day before, while the trace metal rosette and CTD were in the water, we saw water spouts from humpback whales off in the distance. Exciting times!



Pilot whale pod August 5th
(photo courtesy of Monica Mejia)


The Science...

Approximately 50% of photosynthesis occurs in the ocean. The vast majority of photosynthetic organisms in the ocean are phytoplankton, too small to be seen individually without the aid of a microscope. Yet, Phytoplankton ('phyton' from the Greek for plant) form the base of all marine food webs. Primary producers (photosynthetic organisms) use  sunlight to convert carbon (in the form of carbon dioxide) to energy, producing oxygen as a bi-product of this reaction. Thus, they are a fundamental component of the global carbon cycle.

Like terrestrial plants, marine plants require nutrients (the major nutrients are nitrate and phosphate) for growth. For many years scientists were puzzled about why there were large expanses of open ocean with a plentiful supply of the major nutrients but low productivity. About 25 years ago, John Martin, a scientists at Moss Landing Marine Labs, California, proposed that productivity in these areas was limited by the availability of dissolved iron (Fe). This theory was tested in the equatorial Pacific (one of the High Nutrient Low Chlorophyll, HNLC, regions; chlorophyll is an analog for primary productivity in the ocean), and the results indicated that iron limitation could, indeed, limit productivity and biomass in the ocean (Martin, et al., 1994, Nature, 371). Since that time it has become apparent that many other elements (e.g. Co, Cu, Zn, and others) have the potential to limit (or co-limit) primary production. This is because these elements are essential components of many of the enzymes involved in photosynthesis and/or major nutrient uptake and assimilation. In much the same way as we require a balance of nutrients and trace elements for a healthy diet, phytoplankton do too.

And this is where the trace metal group come into the picture. The trace metal component of the CLIVAR/CO2 Repeat Hydrography Program (A16N-2003, as well as a number of other CLIVAR cruises in other ocean basins) provided an important opportunity to measure water column profiles of dissolved (dFe and dAl) and particulate Fe and Al (pFe and pAl) and other trace elements across entire ocean basins as well as the distributions of total and soluble aerosol Fe and Al. Such high-resolution profiling (60 nautical miles) revealed fine-scale features in the distributions of Fe and Al, and other trace elements, which were previously unrecognized. Coupling aerosol and water column sampling reinforces the concept that dust input significantly influences the trace element chemistry of the upper water column.

Pam (left) and Rachel tending the tag lines on the trace metal CTD (Conductivity, Temperature and Density sensors. The sensors used to monitor these fundamental parameters are mounted below the 10L (GO-Flo) water collection bottles) and rosette as it's lifted over the stern railing into the ocean. Reggie (far left) gives commands to the A-frame operator, Nick.
(photo courtesy of Monica Mejia)

The CLIVAR/CO2 Repeat Hydrography Program is an international, interdisciplinary research program with the goal of collecting and modeling hydrographic and tracer data from the world's oceans on a roughly 10-year cycle (http://ushydro.ucsd.edu/index.html). This program monitors the invasion of anthropogenic CO2 and macronutrient/micronutrient cycling, primary and secondary productivity, and carbon flux to the deep ocean. The data collected from previous CLIVAR cruises reveal many previously unknown features in the distributions of dissolved and particulate trace metals, as well as the aerosol chemistry of Fe that are not currently expressed in existing models.

Dr. Bill Landing mans the winch that lowers and lifts the CTD rosette, while Joe is in the clean lab van manning the deck box which controls the depth at which the GO-Flos are remotely closed, thus collecting water from that depth.
(photo courtesy of Monica Mejia)

One unanticipated result from A16N in 2003 was the identification of a large region at low latitudes greatly depleted the biogenic particulate calcium (Ca), likely the result of subsurface waters with a relatively low carbonate saturation-state. Decreases in particulate Ca may strongly impact the export of carbon in this region, allowing more recycled CO2 to be readily mixed into the near-surface layer. Such findings provide the impetus to examine this same section a decade later to answer key questions. For example, are individual surface and subsurface trace-element features in a steady state? How might they respond to both short-term variability and decadal trends in dust inputs? The Barbados dust record (Joe Prospero, Pers. Comm.) indicates a decrease in dust flux by as much as 20-30% to the Atlantic over the last 10-15 years. Based on the 2003 trace metal data, initial estimates of residence times for both surface and subsurface trace-metal features are from <1 to <2 years. How have these features responded to variations in dust deposition (the major source of trace elements to many open ocean regions) over the intervening years? As for the carbonate system, will increasing ocean acidification cause the biogenic particulate Ca deficit to shoal or increase in range?

Dr. Bill Landing putting water-tight tape over the electrical connections in the aerosol sampler before leaving port in Reykjavik. A vacuum pump draws air over filters that are housed under the triangular lid. The aerosols are analyzed for total (bulk) trace metal loading and soluble trace metals. We are interested in the soluble fraction as it is this fraction that is the most readily available to phytoplankton.
(photo courtesy of Monica Mejia)


On CLIVAR A16N 2013, the trace metal team consists of:

Leg 1:
  • Rachel Shelley (postdoctoral associate and leg 1 blogger, FSU)
  • William (Bill) Landing (Principal Investigator and professor, FSU)
  • Joseph Resing (Principal Investigator and professor, Univ. Washington and PMEL/NOAA)
  • Pamela Barrett (Graduate Student, Univ. Washington)
Leg 2:

  • Pamela Barrett
  • Peter Morton (postdoctoral associate and leg 2 blogger, FSU)
  • Randy Morton (volunteer, FSU)
  • Nathan Buck (technician, PMEL)

The rain sampler is installed and ready to go. When it rains, an infrared sensor signals the lid to come off the bucket. The bucket contains a plastic funnel attached to a LDPE bottle which collects the rain. After the rain stops, the rain is collected and stored for trace metal determination by ICP-MS at the National High Magnetic Field Laboratory, FSU.
(photo courtesy of Monica Mejia)
 
The FSU group are collecting samples of marine aerosols, rainwater and dissolved trace metals in the water column (down to 1000 m depth). All our analysis will occur in the lab at FSU. The Univ. Washington group are collecting samples for particulate trace metals in the water column and analyzing water column samples for dissolved Fe and Al on board the ship. We are also collecting samples for other researchers, e.g. mercury in seawater, and pteropods (a taxa that are very sensitive to a decrease in the decrease in the carbonate saturation state of the ocean).









Monday, August 5, 2013

CLIVAR A16 N 2013 (GO-SHIP/CO2 Repeat Hydrography Cruise)


June 4 to August 11, 2003: The A16N cruise took place aboard the NOAA ship Ronald H. Brown under the auspices of the National Oceanic and Atmospheric Administration (NOAA). The first hydrographic leg (June 19 - July 10) was from Reykjavik to Funchal, Madeira along the 20°W meridian and the second leg (July 15 - August 11) continued operations from Funchal to Natal, Brazil on a track southward and ending at 6°S, 25°W. The research was the first in a decadal series of repeat hydrography sections jointly funded by NOAA-OGP and NSF-OCE as part of the CLIVAR/CO2/hydrography/tracer program (http://www.pmel.noaa.gov/co2/story/A16N)

Ten years later... : August 3, 2013: The NOAA research vessel, Ronald H. Brown, leaves Reykjavik, Iceland to embark on a voyage that will reoccupy the same cruise track as it did 10 years ago. On board are scientists from fourteen universities/institutions, including two from EOAS/FSU (Bill landing and Rachel Shelley). In fact, many of the same scientists (and many new ones) are on board, excited to see differences and/or similarities in their comparison with their earlier data from line A16N. To see the range of parameters that we will be measuring during A16N, take a look at this link: http://www.aoml.noaa.gov/ocd/gcc/A16N/.

What's the point?

The aim of this cruise is to investigate how much anthropogenic (generated by human activity) carbon dioxide has been taken up by the ocean. Atmospheric CO2 concentrations have increased rapidly since the start of the industrial revolution (circa 1850). Although there are a number of well-studied natural processes that release CO2to the atmosphere (e.g. volcanic eruptions), models can only capture the current rapid increase in atmospheric CO2 concentrations if they factor in human activities (i.e. fossil fuel burning). In order to do this, scientists are measuring tracers that inform us of carbon cycling. For example, one such tracer is CFCs (chlorofluorocarbons - a group of very stable, and persistent, organic compounds that were used as refrigerants and aerosol propellants). In the late 1980s CFC use was regulated and their use has been phased out, after it was found that their use contributed significantly to ozone depletion in the upper atmosphere ('the ozone hole'). As the ocean is in contact with the atmosphere, gas exchange across the ocean-atmosphere interface results in the ocean absorbing an atmospheric 'signature' that can be accurately dated. This information then identifies the water mass which can be traced on its flow path around the global ocean, which in turn provides data on how other gases (such as CO2 ) are cycled by the ocean.
The ocean is the major global sink for CO2. What that means is that more CO2is absorbed by the ocean than by any other sink (the next most important sink is terrestrial plants). If the ocean did not absorb as much anthropogenic CO2 as it does, the global average temperature would be much higher than it is currently. One of the many things that people are trying to establish is just how much excess CO2 the ocean can absorb, and what the implications for less (or more storage) would be. For that, they need data!
Over the next few weeks, I will introduce you to the scientists behind the instruments, but for now, here's some photos...


Global map of the hydrographic sections with carbon system measurements
 



The RV Ronald H. Brown in port in Reykjavik, Iceland




The cabins on the Ron Brown. Two people share a cabin (or stateroom). I have the top bunk (not much headroom!).
The bathroom (or head) is shared between four people.