335 research outputs found
Preliminary testing of an apparatus to study bubble behaviour in the water column off Panarea Island (Italy): Cruise Report ECO2-5 (2012)
Physical, chemical and biological survey at submarine CO2vents off Panarea Island (Italy): cruise report ECO2-4 (2012)
The Ground CO2 Mapper. An innovative tool for the rapid and precise mapping of CO2 leakage distribution
The recently developed Ground CO2 Mapper (“Mapper” for short) is an inexpensive, light, robust, and
low power consuming tool for determining the distribution of CO2 at the soil-atmosphere contact as
an indicator of CO2 leakage. The basic premise behind the Mapper is that the contact between the
ground surface and the atmosphere represents an interval where CO2 leaking from the subsurface
can accumulate in anomalous concentrations due to two mechanisms, the higher density of CO2 with
respect to air and the tendency of wind speed (and thus mixing) to approach zero near the ground
surface due to frictional drag. Because of its measurement target and the tool’s very rapid response
time, Mapper surveys can be conducted very quickly at a high sampling density, yielding accurate
maps of CO2 spot anomalies. The unit can be used by anyone and deployed within only 5-10 minutes
after sensor and GPS signal warm-up. Here we describe the Mapper and present results from a site
of natural diffuse CO2 degassing in central Italy
Physical, chemical and biological survey at submarine CO2 vents off Panarea Island (Italy): cruise report ECO2-9
The Geological Storage of CO2: and what do you think? – Findings from the ECO2 project about the public perception of CO2 geological storage. Lay report
Spatial-temporal water column monitoring using multiple, low-cost GasPro-pCO2 sensors: implications for monitoring, modelling, and potential impact
Monitoring of the water column in the vicinity of offshore Carbon Capture and Storage (CCS) sites is needed to ensure site integrity and to protect the surrounding marine ecosystem. In this regard, the use of continuous, autonomous systems is considered greatly advantageous due to the costs and limitations of periodic, ship-based sampling campaigns. While various geochemical monitoring tools have been developed their elevated costs and complexities mean that typically only one unit can be deployed at a time, yielding single point temporal data but no spatial data. To address this the authors have developed low-cost pCO2 sensors (GasPro-pCO2) that are small, robust, stable, and which have a low power consumption, characteristics which allow for the deployment of numerous units to monitor the spatial-temporal distribution of pCO2, temperature, and water pressure in surface water environments. The present article details the results of three field deployments at the natural, CO2-leaking site near Panarea, Island. While the first consisted of 6 probes placed on the sea floor for a 2.5 month period, the other two involved the deployment of 20 GasPro units along a transect through the water column in the vicinity of active CO2 seeps over 2 – 4 days. Results show both transport and mixing processes and highlight the dynamic nature of the leakage-induced marine geochemical anomalies. Implications for monitoring programs as well as potential impacts are discussed
Gases and seabed fluid fluxes at the Panarea shallow hydrothermal vents (Aeolian Islands)
CO2 leaking into the shallow sediments and overlying seawater is partitioned in different forms, each
migrating at its own rate and having potentially different impacts. To begin with the CO2 gas will
migrate through the shallow subsurface either alone as a free gas or together with associated deep
fluids (e.g. brines), with the free-phase CO2 equilibrating with the surrounding pore waters/associated
brines. Migrating upward these fluids will enter the base of the water column, with the release of gas
bubbles (and possibly associated waters) from the sediments into the overlying seawater. The bubbles
will rise in the water column creating what is known as a bubble “flare” with the CO2 in the bubbles
dissolving in the surrounding surface water as they rise. Depending on the depth and the
chemical/physical characteristics of the water column, these bubbles may or may not reach the water
surface. Any co-migrating water/brine will also be released into the water column, creating a plume
having a chemical composition that is distinct from the surrounding seawater, consisting of dissolved
gases (mainly CO2), elements in the original brine, and elements liberated via CO2-induced water-rock
interaction. The height that this dissolved plume will reach in the water column will depend on the
original flow rate across the sediment-water interface and the density contrast between the plume
and surrounding seawater. Both the gas-induced and water plumes will then migrate laterally and
vertically as a result of the local currents, water column stratification, and density effects, meaning
that there is the potential for impact both in the near and far field for pelagic organisms, both in terms
of a lower pH and the possibility of elevated concentrations of toxic elements. This study was carried
out in the framework of two EC funded projects, RISCS and ECO2 related to research on sub-seabed
CO2 storage as climate change mitigation strategy, and potential impact on marine ecosystems. Here,
we investigated how CO2-leakage, a risk associated with subseafloor CO2-storage, can affect physical
and chemical characteristics of the surrounding ecosystem. We studied the Panarea natural
laboratory site (Aeolian Islands), where natural CO2 is leaking from the seafloor into the overlying
water column, as an analogue for a leakage scenario
Preliminary Experiments and Modelling of the Fate of CO2 Bubbles in the Water Column Near Panarea Island (Italy)
Although CO2 capture and storage in deep, offshore reservoirs is a proven technology, as illustrated by over 15 years of operation of the Sleipner site in the Norwegian North Sea, potential leakage from such sites into the overlying water column remains a concern for some stakeholders. Therefore, we are obliged to carefully assess our ability to predict and monitor the migration, fate, and potential ecosystem impact of any leaked CO2. The release of bubbles from the sea floor, their upward movement, and their dissolution into the surrounding water controls the initial boundary conditions, and thus an understanding of the behavior of CO2 bubbles is critical to address such issues related to monitoring and risk assessment. The present study describes results from an in situ experiment conducted in 12 m deep marine water near the extinct volcanic island of Panarea (Italy). Bubbles of a controlled size were created using natural CO2 released from the sea floor, and their evolution during ascent in the water column was monitored via both video and chemical measurements. The obtained results were modelled and a good fit was obtained, showing the potential of the model as a predictive tool. These preliminary results and an assessment of the difficulties encountered are examined and will be used to improve experimental design for the subsequent phase of this research
Water column monitoring at CO2 leaking sites near Panarea Island
The fate and transport of geologically produced CO2 that leaks from the sea floor into the overlying
water column has numerous important implications related to large scale carbon cycling and potential
impact on marine organisms, and is of interest for the development of improved monitoring
techniques and strategies for offshore Carbon Capture and Storage (CCS) sites. The CO2 leakage
areas off the east coast of Panarea Island, Italy provides an excellent environment to study these
processes given the wide range of different flux rates in relatively shallow water. The water column
at this site was monitored using two completely different but complementary approaches, continuous
monitoring along short 2D transects using GasPro pCO2 sensors and discrete seasonal sampling along
a 700 m transect crossing multiple leakage areas. Results are discussed in terms of the movement of
CO2, and associated tracers, in the water column
Developments since 2005 in understanding potential environmental impacts of CO2 leakage from geological storage
This paper reviews research into the potential environmental impacts of leakage from geological storage of CO2 since the publication of the IPCC Special Report on Carbon Dioxide Capture and Storage in 2005. Possible impacts are considered on onshore (including drinking water aquifers) and offshore ecosystems. The review does not consider direct impacts on man or other land animals from elevated atmospheric CO2 levels. Improvements in our understanding of the potential impacts have come directly from CO2 storage research but have also benefitted from studies of ocean acidification and other impacts on aquifers and onshore near surface ecosystems. Research has included observations at natural CO2 sites, laboratory and field experiments and modelling. Studies to date suggest that the impacts from many lower level fault- or well-related leakage scenarios are likely to be limited spatially and temporarily and recovery may be rapid. The effects are often ameliorated by mixing and dispersion of the leakage and by buffering and other reactions; potentially harmful elements have rarely breached drinking water guidelines. Larger releases, with potentially higher impact, would be possible from open wells or major pipeline leaks but these are of lower probability and should be easier and quicker to detect and remediate
- …