We currently have three ongoing projects. One project focuses on the physical oceanography and meteorology of coastal Georgia as part of the GCE-LTER network, and the other project focuses on hydrothermal vents near the Juan de Fuca Ridge as part of Ocean Networks Canada and naturally occurring hydrocarbon seeps in the Gulf of Mexico.
1) Coastal Georgia: This project has been part of the Georgia Coastal Ecosystems Long Term Ecological Research Network (GCE-LTER) (see our link on GCE-LTER: https://gce-lter.marsci.uga.edu/public/app/personnel_bios.asp?id=ddiiorio) through the National Science Foundation since 2000. Much of the data collection began in 2001 and continues to present. This includes sea level, meteorological, and hydrographic data at various locations in the GCE domain. Most of this data is currently available for download (at: https://gce-lter.marsci.uga.edu/), while some data is still in the processing stages. Our team is also focused on modeling the physical parameters of the Duplin River (near Sapelo Island, GA) to understand the exchange between ocean and estuary; this model is forced by observed data collected under the GCE-LTER project.
One unique aspect to the project was the deployment of a horizontal ADCP (HADCP) to monitor the real time flow of the Duplin River. Our December 2016 deployment of the HADCP was successful, real-time Duplin River velocity data were monitored from Dec2016, intermittently not collecting, to mid 2020. See: http://gce-lter.marsci.uga.edu/portal/stations/gce_adcp/index.xml
It is not currently collecting data as a new dock is being built (as of this writing).
Here is a slideshow video of the HADCP's initial installation: https://www.dropbox.com/s/jhwbx39653g1opw/HADCPdeploymentvideo.mov?dl=0
2) Juan de Fuca Ridge: Our group is part of the Ocean Networks Canada, previously known as NEPTUNE Canada (see: http://www.oceannetworks.ca/). For this project, the technology of FASS has been vastly improved (through the help of ASL Environmental Sciences) with two major modifications. This instrument now uses reciprocal acoustic transmission at two separate vertical levels and will be permanently cabled to the seafloor near the Main Endeavor vent field offshore of the southern region of Vancouver Island, BC. The primary advantage of reciprocal transmission is the ability to resolve both vertical buoyant flows and horizontal advective flows, as well as improving turbulence measurements and speed of sound estimations. Being permanently cabled, battery life or data storage are no longer a concern. These acoustic measurements are essential for developing accurate and realistic 3-D models of hydrothermal vent plumes and their interaction with the ambient ocean.
Update: 24 Nov 2021: The production of the new FASS system has proved to be an engineering challenge; however, it is currently in the final stages of production and testing. We are hoping for a 2023 deployment.
3) Gulf of Mexico - Bush Hill Area (GC185 Block)
Status: Awaiting Final Vessel Schedule, deployment likely in 2023.
Our work in the GOM at the GC600 lease block in 2017 was successful. From that we have formulated new questions, methods and procedures that we will employ in the GC185 block near Bush Hill. Bush Hill is the northernmost mound on the 184-185 block boundary. The ridge system starting at Bush Hill is around 8km in length, and likely has many naturally occurring hydrocarbon seeps along its length.
Below is an example of our intended deployment scheme. We will have ADCPs that cover the entire water column (~700m), from surface to bottom. Cameras and other novel video imaging techniques will be employed to assess the visual changes in the seep site, and to get a measure of the turbulence related to the rising of a methane or oil bubbles. We will utilize Sentinel-1 SAR imagery to isolate oil slicks (using deep learning methods) within the region above our study area. We will estimate the vertical velocity of the buoyant hydrocarbon seep of interest with 2 methods, acoustically and optically.
A more formal description:
We will conduct an integrated sampling and modeling program over a three month period to improve our understanding of the fundamental physics and key parameters governing hydrocarbon transport from the source to the surface. The project will (1) collect unprecedented in-situ data at the source that will inform on bubble size distribution, volume and momentum fluxes, turbulence and entrainment, and vertical upwelling during the initial rise to reveal potential connections with the near-bed turbulence characteristic and hydrographic conditions; 2) determine the best numerical approach, using existing models initialized with measured source characteristics and full water column hydrographic conditions, that will simulate bubble plumes and individual bubbles, to predict the hydrocarbon trajectory and distribution in the water column and on the surface; and 3) refine satellite estimates of surface residence time for oil slicks using measured surface currents that can be used for comparison to model predictions of surfacing hydrocarbons.
The state of knowledge remains limited, in regards to entrainment and vertical upwelling in natural hydrocarbon bubble plumes and their role in hydrocarbon transport, due to the paucity of measurements in the deep ocean. Marine hydrocarbon seeps play a prominent role in biogeochemical processes and influence hydrocarbon-dependent microbial populations, ecosystem structure, and trophic networks, on the seafloor and in the water column. Improved knowledge of the role of entrainment and upwelling in hydrocarbon transport is required to formulate and advance our understanding of bubble dissolution rates that control methane flux, a key but poorly quantified variable in the global carbon cycle, primary production, atmospheric chemistry and climate models.
Recent Completed Projects:
1) Gulf of Mexico - MegaPlume Area (GC600 Block): Our group is part of the Gulf of Mexico Research Initiative (GoMRI). “The ultimate goal of the GoMRI will be to improve society’s ability to understand, respond to and mitigate the impacts of petroleum pollution and related stressors of the marine and coastal ecosystems, with an emphasis on conditions found in the Gulf of Mexico.” (see our groups link on GoMRI: http://research.gulfresearchinitiative.org/research-awards/projects/?pid=270)
See Daniela on youtube talking about our work in GOM: (https://www.youtube.com/watch?v=OJv9j78Esuo&feature=youtu.be)
The abundance of hydrocarbons in Gulf of Mexico (GOM) makes this study site an exciting place to acquire knowledge regarding the relationship between underground hydrocarbons and physical oceanography. In Summer 2017 our goal is to deploy FASS, 4 and 5 beam ADCP’s and CTD’s on the sea floor of GOM where naturally occurring oils and methane gases are emitted. We will characterize the vertical upwelling velocity of gas hydrates and its role in vertical transport of methane and oil to the surface, as well as improve our understanding of horizontal and vertical dispersal processes in the turbulent bottom boundary layer by making time series measuring of 3-D velocity and hydrographic properties near naturally occurring seeps. Our instruments will be deployed and recovered within a period of ~90 days. If all goes as planned our group will produce the an in-situ time-series of vertical transport in a bubble plume rising from a natural seep. We will use a model, forced by these observed data, to investigate acoustic scattering theory to quantify the bubble plumes at hydrocarbon seeps.
Update: 24 Jan 2020: Instruments were deployed in September 2017 and retrieved in January 2018. Rather than a methane seep as originally planned, we focused on an oily seep near the original Megaplume study site in the GC600 block. We deployed: 1) 2 deep water cameras to capture video of the oil seep, 2) 4 beam ADCP's with frequency of 300 and 600 kHz, 3) 2 - 40 m moorings with 5 CTD's placed at 9 meter intervals beginning at ~4 to 40 mab, and the 4) Acoustic Scintillation Flow Meter to measure the vertical velocity of the oily plume. Unfortunatetly, we were not able to deploy our new 5 beam ADCP. An AUV was used to identify/view the study site, it was equipped with side-scan, multi-beam, and a sub-bottom profiler. Data has been archived with GoMRI ( https://research.gulfresearchinitiative.org/research-awards/projects/?pid=270 ).