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Ask a Responder: Q&A with the Chief Scientist, Subsurface Monitoring Unit

Photo of Sam Walker

NOAA's Dr. Sam Walker coordinates the subsurface monitoring program from the Unified Area Command (UAC) in New Orleans.  Dr. Walker is on detail to NOAA's Integrated Ocean Observing System (IOOS) program as a Senior Technical Data Manager. He was called upon for his expertise as a scientist and strategic planner to support the response effort.

What are your responsibilities as chief scientist for the subsurface monitoring program?

The primary responsibilities are to coordinate overall subsurface monitoring efforts and liaison with the Unified Area Command (UAC).  This means making recommendations to the UAC about the use of technologies, synthesizing and presenting findings, and coordinating the transfer of information across a range of user communities.  We have maintained a consistent focus on science-based decision making, and that requires close coordination with the operational teams, federal, state, and academic scientists who are assisting with the monitoring and sampling efforts.  Under the guidance of NOAA's Science Support Coordinators I helped frame the subsurface program elements, including the incorporation of IOOS community ocean gliders, and worked to provide guidance for ongoing sampling missions. I also helped form the data management team that transferred subsurface monitoring data from the platforms, such as the ships, gliders and aircraft, to the UAC. As the response went on and the subsurface monitoring unit continued to grow other scientists, including Dr. Janet Baran of NOAA, rotated in to co-lead the position.

The primary goal of the subsurface monitoring program is to provide information to support the UAC's decision-making process. We interact with the UAC to make sure their information needs are met.  Those needs changed frequently because this was a constant spill, not a finite event. To get the information we need, we use integrated ocean observing to apply a number of technologies and multiple platforms in order to understand the dynamic situation. We focus on where the oil is, where it dispersed, and its potential pathways to the surface and across the continental shelf.  In addition to informing the UAC, we help prepare and disseminate results with the help of our Emergency Response Management Application (ERMA) colleagues and the National Oceanographic Data Center (NODC), along with a range of academic partners.

What are the biggest challenges in preparing for a subsurface monitoring mission?

The most obvious challenge is the time frame. Putting together an ocean observation cruise with expert scientists usually takes many months to a year to plan.  Working as a team, we were often able to do this in a week or less. This is one of the subsurface monitoring unit's true success stories. We showed that with an expert technical team and a clear objective you can execute something this scientifically and logistically challenging if the demand and the desire are there.

We also found that communications once the vessels were underway was a challenge.  We hold daily vessel coordination calls and keep a record of what the vessels are doing, while providing them a forum to exchange observations and provide insight based on the needs of the UAC We also have had to contend with weather and other potential hazards, such as shipping traffic and restricted zones around the wellhead.  It is always a problem to work around those things, but we do it by maintaining communications relays and, to the greatest extent possible, preparing our teams in advance.

Data analysis is still underway, but what are some findings of the subsurface monitoring program?

Currently, the primary goal of subsurface monitoring is to identify whether there is any actionable oil and if so, to determine where it is. We found potentially actionable oil where we expected to find it, that is, in nearshore locations with sandy sediments, such as off beaches where it could become entrained in the surf. So far, deepwater sediment sampling has not shown masses of oil on the seafloor. Water sampling in deep water showed a highly-dispersed hydrocarbon signature from the beginning. The oil is in very small particles.  Once it's dispersed, the oil isn't going to put itself back together.

The subsurface monitoring program is not just a NOAA effort. What is the involvement of the academic community?

In addition to the federal and state scientists, we've had many academic scientists embedded on the team since day one. They have all helped tremendously.  We invited academic experts to head sampling missions as chief scientists. They typically brought along additional researchers and equipment.  Most of the gliders we used came from universities.  Academic researchers helped us understand the normal conditions of the sediments and the water column and to identify hypoxic conditions and harmful algal blooms.  The subsurface monitoring program interacted with a lot of academics - not just the embedded scientists, but through frequent communications with researchers who were on vessels in the Gulf independent of the subsurface monitoring program.

Is there anything about your experience supporting the response that really stays with you?

I think all the time about the commitment made by a tremendous number of people.  Thousands of people sacrificed a lot, including great amounts of time with their families. In the SMU alone, there have been people from 25 or more States.  They come from the academic, private, nonprofit, state, and Federal sectors and the responsible party. They're working incredible hours to help the people of the Gulf get back to normal, productive lives as quickly as possible. We remind ourselves every day that our greatest responsibility is meeting the needs of the Gulf citizens and ensuring the health of this important ecosystem

Is there anything else you'd like to say?

I'd like to highlight the role of the NOAA Corps in the response. NOAA Corps officers are highly-skilled, great communicators, and the perfect people to serve as the backbone of the subsurface monitoring program. They led operations teams throughout the response, effectively made the transition to overseeing the data management aspects, and commanded NOAA ships on sampling missions, including crucial involvement during the sensitive wellhead integrity test (WIT).  The NOAA Corps officers have been incredibly accommodating and professional at all times and are an incredible resource for the agency and the Nation.  In addition, I'd like to recognize my colleagues in the IOOS community who immediately responded in very practical ways to the emergency response, from providing surface current information to supporting the use of ocean gliders that provided important ocean state data.  I have had incredible support from my home program office. Everyone in the Subsurface Monitoring Unit has served the response in a valuable and professional manner.