Ocean Observatories as a Tool to Advance Gas Hydrate Research

M Scherwath,M Riedel,D Chatzievangelou,M Heesemann,L Thomsen,A Duda,M Römer,J Schwendner

doi:10.1029/2019ea000762

Abstract

AbstractSince 2009, unprecedented comprehensive long‐term gas hydrate observations have become available from Ocean Networks Canada's NEPTUNE cabled ocean observatory at the northern Cascadia margin. Several experiments demonstrate the scientific importance of permanent power and Internet connectivity to the ocean floor as they have advanced the field of gas hydrate related research. One example is the cabled crawler Wally at Barkley Canyon, enabling live in situ exploration of the hydrate mounds and its associated benthic communities through the crawler's mobility and permanent accessibility throughout the year. Another example is a bubble‐imaging sonar at Clayoquot Slope, revealing the strong relationship between ebullition of natural gas and tidal pressure, without apparent correlation to earthquakes, storms, or temperature fluctuations, in year‐long continuous recordings. Finally, regular observatory maintenance cruises allow additional science sampling including echo‐sounder surveys to extend the observatory footprint. Long‐term trends in the data are not yet apparent but can also become evident from continuous measurements, as ocean observatories such as NEPTUNE are built for a 25‐year lifetime, and expansion of the observatory networks makes these findings comparable and testable.

Highlights

Gas hydrate systems are dynamic environments with potential long‐term variations that require continuous long‐term observations to fully understand the complete spectrum of these systems (e.g., Berndt et al, 2014; Heeschen et al, 2003; Suess et al, 2001)
Since 2009, unprecedented comprehensive long‐term gas hydrate observations have become available from Ocean Networks Canada's NEPTUNE cabled ocean observatory at the northern Cascadia margin
Canada is operating cabled observatories since 2006, is providing direct access to, and serves continuous data from two highly active gas hydrate systems on the northern Cascadia margin since 2009, enabling the science community to begin to understand these dynamic changes in ways not seen before (Barnes et al, 2011; Heesemann et al, 2014)

Summary

Introduction

Gas hydrate systems are dynamic environments with potential long‐term variations that require continuous long‐term observations to fully understand the complete spectrum of these systems (e.g., Berndt et al, 2014; Heeschen et al, 2003; Suess et al, 2001). Canada is operating cabled observatories since 2006, is providing direct access to, and serves continuous data from two highly active gas hydrate systems on the northern Cascadia margin since 2009, enabling the science community to begin to understand these dynamic changes in ways not seen before (Barnes et al, 2011; Heesemann et al, 2014)

Cascadia Margin and its Gas Hydrate Research Seafloor Infrastructure

Seafloor Crawler Wally at Barkley Canyon

Vent Imaging at Clayoquot Slope

Monitoring Processes Below the Seafloor

Findings

Conclusions