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Subsurface Oil Monitoring Overview

Map of All Sampling Locations

The Unified Area Command coordinated comprehensive monitoring of the water, coastal areas, and sediments in the Gulf of Mexico to make sure all oil that could be cleaned up (actionable oil) is found and properly responded to. Government and academic oceanographers, chemists, and biologists onshore and on a fleet of vessels operating in the Gulf collected tens of thousands of samples. The data from the subsurface oil monitoring program support a step-by-step process leading to oil removal and restoration of the Gulf.

Data, Analysis, and Findings

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Click Here to Download PDF

Subsurface Monitoring Unit strategy document available

Click here to download the PDF.

Where is the Oil?


Where Can You Fish?


Where Can You Swim?

Where is the Oil?   Where is the Oil?   Where is the Oil?
is an online tool that provides near-real time information about the response effort.
      Visit DeepWater Horizon/
BP Oil Spill
: Federal Fisheries Closure and Other Information.
      A Beach Status Website maintains up-to-date information for beaches impacted by the spill.  


Map of All Sampling Locations

What are Scientists and Responders Looking For?

Oil on the water surface, on marshes, and on beaches can be seen by the naked eye, allowing removal efforts to be carried out. However, oil in the deep water or in sediments often requires the need for highly specialized instruments to detect very low concentrations of oil, due both to its location and to chemical and physical changes it has undergone. Finding subsurface oil requires a comprehensive strategy and advanced technology.


Subsurface Oil

Subsurface oil typically consists of diffuse clouds of microscopic oil droplets that disperse and rapidly change in size and extent due to natural processes. The oil continues to diffuse and degrade until it is no longer present in concentrations that can be cleaned or removed at sea.

Download the Deep Sea Subsurface Oil Assessment.

Submerged Oil

The oil that spilled from the Deepwater Horizon normally floats. However, it can get sticky and pick up particles, like sand, that eventually make it heavy and cause it to sink. This is less likely to happen in the open ocean, but can happen in nearshore areas, such as if the oil is near a shallow sand bar or washes onto the beach and is then washed back out to sea by waves.

Download the Near Shore Submerged Oil Assessment.


Snare Sentinel CTD Rosette

What is Subsurface Monitoring?

Ships continue to deploy on water and sediment sampling missions to offshore and deep water areas. Government and academic scientists work together on these vessels, using a number of oceanographic instruments to collect data that will be analyzed for indicators of the presence of oil. For instance, CTD rosettes gather basic data about salinity, temperature, and pressure, and carry bottles that collect water samples at numerous points in the water column. Fluorometers use a beam of light to measure indicators of oil in the water column. Corers collect sediment samples from the seafloor. In nearshore areas, scientists collect sediment samples and deploy snare sentinels to detect the presence or absence of oil in the water.


Where are we Looking?

All Sampling April 28th to October 28, 2010
All Sampling April 28th to October 28, 2010
Check here for updated visual data of sampling maps.









Video From The Gulf

NOAA Scientist explains subsurface monitoring techniques
NOAA Scientist explains subsurface monitoring techniques
Click to see videos from the Gulf:









Newsletter Archive

Subsurface Monitor Newsletter
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