Craig McNeil

Principal Oceanographer

AIRS Department


Affiliate Assistant Professor, Oceanography


Joseph Resing


Cooperative Institute for Climate, Ocean, and Ecosystem Studies

Daniel Stilwell

Virginia Tech

Bradley Department of Electrical + Computer Engineering

Jeffrey Beeson

Oregon State University

Cooperative Institute for Marine Resource Studies

Susan Merle

Oregon State University

Cooperative Institute for Marine Resource Studies

Tamara Baumberger

Oregon State University

Cooperative Institute for Marine Resource Studies



Characterizing PNW Seafloor Methane Seeps

Using a Fleet of Small AUVs

Pilot Studies on Lake Washington

Coastal Washington Survey Cruise

Methane is a potent greenhouse gas, and is released into the ocean from the seafloor as gas bubbles via methane seeps. Despite the prevalence of seeps along continental margins, data is limited, and their impacts on the ocean and atmosphere, both positive and negative, are poorly understood. To advance our knowledge about methane seeps, we are pursuing an approach to map and characterize methane seeps over wide areas. We are using easily deployable and relatively inexpensive autonomous underwater vehicles (AUVs) equipped with imaging sonars and custom sensors to find and map seeps and measure associated bubbles and dissolved methane right at the source and up through the water column.

Seeps are Ubiquitous on the Cascadia Margin

Goals + Objectives

Recent efforts to map seafloor methane seeps have shown them to be ubiquitous at widely varying depths along the coastal zone from Vancouver Island to northern California – a region known as the Cascadia Margin. More than 1300 emission sites have been discovered to date.

Autonomous undersea vehicles (AUVs) will be deployed on the coastal ocean off Oregon and Washington to characterize several methane emission sites at depths up to 500 m.

  • Where and a what rate does methane enter the water column from Cascadia Margin seeps?
  • How many sites release methane that reaches the air-sea boundary?
  • How important are tides in modulating methane release from seeps?
  • Do the rising bubbles have the potential to transport nutrients from the seafloor to the shallow ocean?
  • do geological features control the location of bubble streams?
  • How can AUV characterization of seep fluxes along the Cascadia Margin be used to improve the regional methane flux estimates made by shipboard surveys?

Clockwise from left: bubble streams detected in sonar data, bubble streams escaping from the seafloor, a REMUS 100 AUV, temperature measurements being taken by ROV at a seep site, and the VT-690 AUV. Images courtesy of Ocean Exploration Trust (ROV captures) and NOAA Pacific Marine Environmental Laboratory (sonar image).

NOAA Ocean Exploration

This research is funded by NOAA Ocean Exploration beginning in fiscal year 2022. The research team responded to a proposal solicitation to conduct or support ocean exploration resulting in outcomes that provide or enable initial assessments about unknown or poorly understood regions of U.S. waters.