Ocean Acidification: Batch 1 Sampling

 Near incubator, control group; far incubator, experimental group.

 All the principal investigators and super techs gather
for the big day--the results will be exciting, either way.

 Sampling: acid wash, rinse with ultrapure water three times,
rinse with sample three times (note: don't forget the threads!),
then fill your container to the neck, no more, no less.

Dr. Cochlan, lead PI, knows best; Chris Ikeda assists.

The two carboys (large bottles) on the ground are limiting the trace metals
 that are being analyzed in depth in the "Clean Room".
The process for collecting that water without contamination is incredible in itself.

Today’s the big day! Months of planning lead up to this experiment. We analyze samples from our most focused experiment of our fieldwork: the incubators. From the tireless work of Chris with his pH meter mash-up, Julian’s inorganic nutrient auto-analyzer, and so many on board along with the landward labs leading up to this research cruise, the incubators outside on the ship’s fantail have been monitored and the phytoplankton have been growing as expected. “It’s just like grass, it grows to a certain point until it runs out of nutrients,” Dr. Mark Wells, University of Maine, co-PI, explains. These incubators have been running for days with seawater and all of the organisms within from the first site. Methodically, each container within the incubator has been stressed in different ways as we may see naturally. The independent variable in this experiment has been the amount of available nutrients: nitrates, phosphates, silicates and iron. 

Limiting iron availability of a sample while modifying the pH
with infused carbon dioxide (CO2), just as we would see naturally.

One of seven pH meters used to monitor the acidity of the sample.
When the meter reads above 7.6,
CO2 is pumped through the lines to lower the pH back to 7.6.

Each line is fed from the carboys in the incubator to the computer
for recording and monitoring by Chris Ikeda (RTC-SFSU).

There are two incubators. One is the control; and the other is experimental. The control is seawater sampled while at sea. The experimental has same seawater with the pH controlled through a simulation of the natural process: by infusing CO₂ to lower the pH. Both are introduced to the same stressors at the same rate, limiting all undesired variables—a sign of a solid experiment.

Pressure gauges for each carbon dioxide tank.

With the introduction of more CO2 in the atmosphere, the acidity level of the ocean changes. "The chemistry of the ocean is dependent on the chemistry of the atmosphere" (Cochlan). Therefore, more carbon dioxide emissions in the atmosphere, more dissolved carbon dioxide in the oceans. Carbon dioxide in the ocean, a necessary component for plant life, turns to carbonic acid, slowly lowering the pH (raising the acid levels of the seas). The 100-year projection is a pH of 7.8 by 2100, causing problems with shell-bearing organisms and much more that is still unknown. This is ocean acidification.

We have intentionally targeted areas of upwelling along the Pacific Northwest because these are "sentinel sites that indicate the future" (lead PI, Cochlan, RTC-SFSU). There are two currents: surface water and deep water. Surface water currents (the first 100m of water) travel the earth’s surface in roughly five years, driven by the winds. Deep water currents (100m-4000⁺m), on the other hand, move slowly, taking 1000 to 1400 years to circulate. Oceanic deep water conveyors in the intermittent layer does resurface every 50-100 years in upwelling zones; therefore, by sampling from these zones, we are able to observe the future chemistry of the ocean. Unlike the surface water that reaches equilibrium with the atmosphere through interactive processes, the deep water continues to become more acidic at faster rate because the CO₂ is trapped under the blanket of surface water. The water sampled this week at our first site was nutrient rich, low in iron, and had a pH of 7.6. This water hasn't seen light since pre-industrial revolution—an indication of the ocean’s future normal in 20 to 50 years, not 100 as previously projected, according to co-PI, Charlie Trick, Western University. There is still a long way to go before making any substantial claims, but it does perk great interest. Upwelled zones naturally have a lower pH, but this may be an indication of the acidity level in the future. 

And, this is why we are experimenting: we simply want to sample cleanly, analyze honestly, and use methods in experiments that model the future accurately. The end result will be a presentation of the results. One of the mantras of the PI's onboard is that of Joe Friday from Dragnet, "Just the facts, ma'am." These men of integrity are prepared to title their peer-reviewed scientific paper as their results support their hypothesis or their results do not support their hypothesis. Either way it is one step closer to understanding the current path of our future and the steps that we can take to change that path. This is science. And, I would never know this without this experience first-hand.