Occupy ALOHA 2012: A tribute to Bob Dylan

Guest blog post by Shimi Rii.

This is not really about the public outrage of tropical island privatization or an accolade to the man still kicking and rocking "Like a Rolling Stone". This is about a ~90-day occupation of Station ALOHA, an ocean station located roughly 100 km north of the island of ‘Oahu. The official name of the research expedition is Hawaii Ocean Experiment - Dynamics between Light and Nutrients (HOE-DYLAN)[1] - headed by the distinguished University of Hawai‘i Professor of Oceanography (and acronym specialist) Dr. David Karl. Hoe in Hawaiian means to paddle, to work together, and well, Dave is an avid Dylan fan.

"The need to run a HOE-DYLAN expedition is based on the observations we've been making for the last 20 years," Dave told me in his office with large windows lined with thriving green plants, each in their perfectly chosen vases, "some of which you made in your Master's thesis." My graduate student heart beamed at the shout-out by the director of National Science Foundation-sponsored Center for Microbial Oceanography: Research and Education (C-MORE).

"It all has to do with the variability in time and space of biogeochemical processes, including things like solar energy capture, carbon cycle and nitrogen dynamics, that occur in an area that shouldn't have much time and space variability."

Uh-huh. I nodded vigorously in understanding, thankful for the voice memo app on my iPhone, my mind already activating Google Translate for a public audience. What Dave means is that a seemingly homogeneous ocean that has been extensively characterized experiences changes on time and space scales that scientists still don't understand. Thus, even if global climate change came knocking on the door of the Pacific Ocean, we would not be in a position to make reliable predictions.

Located at 22° 45'N and 158° 00'W, Station ALOHA is frequented near monthly by the scientists of the Hawaii Ocean Time-series (HOT) program[2], and has been for the past 23+ years. Scientists make measurements to examine how certain characteristics of the North Pacific Subtropical Gyre (NPSG) change over time. These are the exact measurements that have shown us that the surface ocean pH is decreasing significantly at a rate of -0.0019 ± 0.0002 per year[3], in correlation with increasing atmospheric carbon dioxide levels measured at the Mauna Loa Observatory on the Big Island of Hawai‘i.

Though tropical Hawaiian waters often seem clear, blue, and basically the same everywhere, data acquired by the HOT program have revealed evidence of seasonal patterns in the cast of microbial players and their activities[4]. In the NPSG, reportedly the largest circulation feature on Earth, a deep, permanent pycnocline (a layer where there is a sharp change in density) creates a glass ceiling in the water column. As a result, dense, nutrient-rich waters from the deeper depths rarely mix into the upper, light-filled, nutrient-poor waters. These boundaries have persisted since the Pliocene period (10⁷ years ago) or earlier. Thus, with ample light but scarce food, the phytoplankton community in the NPSG has evolved to live efficiently and sustainably through rapid recycling of nutrients and maximum utilization of resources.

Based on experimental results and observations, scientists have assembled a comprehensive picture of the sustainable lifestyle of the Pacific Ocean: a resident population of Little Green Microbe Gina-ococcus hangs out all throughout the year, while opportunistic Big Brown Microbe Bob-olenia makes several unexpected appearances in the spring and summer months. Alliances have formed between some microbes to help each other out during summer periods of extremely high light and low nutrients: Symbiotic Microbe Syd-chelia makes a deal with Bob that he'll produce the nitrogen Bob needs, if Bob supplies Syd with a home...and some carbon.

Some of these seasonal patterns occur year after year. However, HOT scientists have discovered that monthly measurements are not quite enough to bear witness to all spontaneous activities in the clear blue sea.

"There are event-scale phenomenon and we still to this day don't understand how to really reconcile that with the physics of the ocean, " exclaimed Dave, puzzled and excited. Oceanic features, driven by dynamics of waves and tides, wind and other geophysical motions, "impart a fabric in the ocean that makes it behave differently from day to day and place to place." These features, though large (2-2000 km), are subtle, short-lived, non-steady-state events that produce unexpected blooms of various microbes in the ocean, disrupting seasonal patterns in everything from total rate of photosynthesis to the total amount of fish in the region.

In fact, cohorts Bob and Syd make up these unpredictable summer blooms in the NPSG, which can be responsible for a significant portion (up to ~20%) of "new", not sustainably recycled, production in the oceanic gyres[5].

But how to predict the unpredictable? On several occasions in the past 23 years, HOT scientists arrived at Station ALOHA only to discover that they had missed a rare algal bloom event, or that they were scheduled to return to shore just as something interesting was starting to happen. Thinking of this, I'm reminded of the time I drove my friends to the beach to show them the must-see Friday Night Fireworks. When we got there at 8 pm, fighting counter-flow traffic and staring at the wisps of smoke in the air, my friends glared at me as I wondered, "were Bob and Syd here?" We would never know.

HOE-DYLAN is an extended field experiment aimed at doing exactly that: squatting on the beach in time for the first blast all the way to the finale. Using several levels of tools such as satellites and automated seagliders, all the way to pure human power, C-MORE scientists are hoping that HOE-DYLAN will bring them several steps closer to determining the forcing functions of these elusive phenomena. This experiment will focus on light and nutrients as primary agents of change that may promote these rare (exploding) algal blooms. Through a series of cruises from June through September, a group of scientists from University of Hawai‘i, Oregon State University, Massachusetts Institute of Technology, University of California Santa Cruz, Woods Hole Oceanographic Institute and Monterey Bay Aquarium Research Institute are "occupying" Station ALOHA in order to obtain extensive coverage of hourly to weekly scale changes in ocean physics (e.g., light fields, currents, internal tides), chemistry (e.g., nutrients, gases, and trace metals) and biological processes (e.g., photosynthesis, respiration and nitrogen fixation).

Proposal: Take what we do once a month and let's do it every single day for 90 days. Translation: I have been acid washing a lot of bottles this summer.

As I stood up to thank Dave for the interview, I asked him, "What is your favorite Bob Dylan song?"

He quickly dug out the concert program from the Newport Folk Festival 1965 and started reminiscing about when Dylan Went Electric. "It's All Over Now, Baby Blue," he told me, was Dylan's farewell song as he was booed off the stage.

"How do you keep your office plants looking so healthy?" I prodded, obviously not wanting to get back to acid washing.

"It's probably a light thing," winked Dave.

Fore more information on the HOE-DYLAN program, click here.

Link to Station ALOHA

Link to C-MORE

[1] http://hahana.soest.hawaii.edu/hoedylan/hoedylan.html

[2] Karl, D. and R. Lukas, 1996. The Hawaii Ocean Time-series (HOT) program: Background, rationale, and field implementation. Deep-Sea Research II 43: 129-156. http://hahana.soest.hawaii.edu/hot/

[3] Dore, J.E., R. Lukas, D.W. Sadler, M.J. Church, and D.M. Karl, 2009. Physical and biogeochemical modulation of ocean acidification in the central North Pacific. Proceedings of the National Academy of Sciences 106: 12235-12240.

[4] Karl, D.M., R.R. Bidigare and R.M. Letelier, 2002. Sustained and aperiodic variability in organic matter production and phototrophic microbial community structure in the North Pacific Subtropical Gyre. In: le B. Williams, P.J., Thomas, D.N., Reynolds, C.S. [Eds.], Phytoplankton Productivity, Carbon Assimilation in Marine and Freshwater Ecosystems. Blackwell Science Ltd., Malden, pp. 222-264.

[5] Dore, J.E., R.M. Letelier, M.J. Church, R. Lukas and D.M. Karl, 2008. Summer phytoplankton blooms in the oligotrophic North Pacific Subtropical Gyre: Historical perspective and recent observations. Progress in Oceanography 76: 2-38.

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