Sediment Fluxes and Carbon Burial Inshore and Offshore
Sediment Fluxes and Carbon Burial Inshore and Offshore Vancouver Island Using Seafloor Observatories Martin Scherwath (ONC) Pere Puig (ICM-CSIC) Gwyn Lintern (NRCan) 26 Feb 2019 - Ocean Observatory Council Meeting
Sediment Workshop Participation • 15 External • incl. 3 online • 7 ONC • Participants from • Spain • U. K. • Netherlands • Germany • U. S. • Canada • Half of group newly engaged • Great, highly collaborative group
Delta Dynamics Lab (inshore) – Highlights Marine Geology 2012 EOS 2010 Aquadopp intensity in bottom metre, June 5, 2015 Platform shifted into 1. 5 m deeper water at this time Aquascat gives concentrations 0 cm 100 cm 01: 00 02: 00 am PST Journal Highlight Sedimentology 2016
Delta Dynamics Lab (inshore) – Future Papers • Committed 1. Long term changes on Fraser Delta and Roberts Bank (lead: Gwyn Lintern) 2. River conditions versus sedimentation rates (lead: Gwyn Lintern) 3. Track plume to sponge reefs (lead: Gwyn Lintern) 4. Comparison of platform designs (lead: Michael Clare) • Potential short term (1 -2 years) – not underway 1. Turbidity event detection (and recurrence frequency) from ADCP data converted to scalar time-series 2. Full data analysis of strong recent turbidity event from fully instrumented DDL platform • Potential Medium Term (3 -5 years) – underway 1. Settling plume, turbidity maximum and flocculation conditions. Look at settling velocities, bottom fluid mud layers and long-term bed elevations (lead: Gwyn Lintern) 2. Turbidity currents – investigating structure, power, and changes to bed throughout flows. 3. Statistics (Louis), runout (Pope), structure (Daniela)? 4. Flow structure from Aquascat suspended sediment profiler (lead: Gwyn Lintern) 5. What role do hydrophones play in monitoring? (lead: Gwyn Lintern) 6. What are concentrations? (lead: Gwyn Lintern) 7. Effect of earthquakes and seasonal groundwater flow in relation to Roberts Bank pore pressures • Potential medium and long term (3 -10 years) • 3 papers (long term) already underway • 9 papers not yet underway (3 medium term, 6 long term)
Delta Dynamics Lab (inshore) – Open Questions • Plume dynamics, deposits, contaminants • Climate change • Animal behaviour • Tidal energy • Whole carbon story from source to sink
Delta Dynamics Lab (inshore) – Future Proposals • Lintern (NRCan) developing Niskin bottle sampling device to capture turbidity flow sediment and concentrations, to be deployed at the Delta Dynamics Laboratory platform (coming for March 2019 inshore cruise) • Rebuild DDL platform for improved deployment on smaller vessels (Lintern, NRCan) • Cable tension and strumming measurements, as a current strain meter, at the DDL platform, proposed by Lintern (NRCan) • Proposal with Talling (Durham University) and Lintern (NRcan) to use multiple hydrophones on Fraser Delta for areal turbidity current detections (develop turbidity classifier for hydrophone data) • Infrastructure expansion from NRCan-UK collaboration on fibre-optic strain gauge cable (long-term) • Add NOC-Southampton M 3 sonar to DDL and collect 4 D gravity flow data • Install vertical pole of pressure sensors on DDL to measure flow speeds
Delta Dynamics Lab (inshore) – New/Missing Sites and Data • • • West Coast Fjords Douglas Channel Skeena River (up from Prince Rupert; Terrace, BC) Arctic Fraser Delta Expansion Critical Infrastructure Marine Protected Areas Little Estuaries Southern Salish Sea • • • Spatial surveys LIDAR on ships Longer sediment cores and more complete analysis Kitimat current meter Fluorescence and turbidity on more ferries Ingest NRCan Kitimat Arm data to ONC
Barkley Canyon (offshore) – Highlights MODIS Satellite data
Barkley Canyon (offshore) – Future Papers • Committed 1. Site characterization of the canyon axis, and related to the presence of corals (deep sea) and sponges, south of the Canyon Axis. These have not been described yet, and rely on the delivery of particles to that site. There is AUV data to be exploited, covering the coral cliff. Three years of current meter data, focus on that time, and look at the time series of all the platforms over that same time range and use the particle flux measurements over the last year to characterize these environments for the corals and sponges (lead: Claudio Lo Iacono) 2. Off-shelf (canyon head) sediment transport to the mid-canyon axis site. Hoping the sediment trap at the canyon head will collect nice data, same at the axis, and combine data sets. Incorporate data from the Upper Slope if that is possible (lead: Pere Puig) • Potential longer term 1. Changes in the sedimentation rates in the axis associated with fisheries activities; data sediment cores from last cruise, see if sedimentation rates changed post 90’s to see if fishing activities have had an impact. ROV transects on fishing grounds, see if the canyon walls are trawled, etc. , and build the story
Barkley Canyon (offshore) – Open Questions • Physical processes and interconnection of Barkley Canyon and benthic distribution, ecosystem, benthic-pelagic coupling • Linkages between sites inside and outside Barkley Canyon, including food availability • Influence of trawling or storm forcing and seasonality • Oxygen minimum zone changes • Sources of particles (surface water, tides, other water movements, offshore transport)
Barkley Canyon (offshore) – Future Proposals • Acoustic camera to be moved to Barkley Canyon (De Leo) • Seafloor crawler Wally be redeployed; Wally important platform for Barkley Canyon; should consider flying Wally; Recommendation to prioritize Wally as a reliable mobile platform • New proposal for eco-hydrodynamics of cold-water coral habitats (INCISE, De Leo) • Mienis and De Leo to discuss with Kim Juniper potential funding application for Canyon study • Use existing data to prepare a proposal for shiptime (core sample collection, Falkor, 2 -page, coral related project) (short-term or medium-term goal? )
Barkley Canyon (offshore) – New/Missing Sites and Data • Various in and out canyon locations for comparison • Barkley Canyon head • Barkley Upper Slope (different locations) • Barkley Upper Axis (Vertical Profiling System) • Coral locations (e. g. Coral Cliff near Barkley Hydrates) • Nitinat Canyon (next to Barkley) for comparison • Also comparisons with Clayoquot Slope and OOI Hydrate Ridge (Canyon vs non-Canyon) observatory nodes • • • General: sampling database Biological samples Turbidity and fluorescence at all locations Extended water column measurements (VPS inside canyon, gliders, flying Wally) More ROV observations (video transects) and spatial coverage (AUV) More sediment samples (more traps, longer cores, standard analyses)
Summary • Agreement to write at least six peer-reviewed papers in the short-term (1 -2 years) with existing data • Recommendation to rise priority for seafloor crawler Wally • Request to add turbidity as ONC core parameter • Recommendation to move Barkley Canyon Upper Slope and Vertical Profiling System platforms into Barkley Canyon axis at 600 m depth • Recommendation to analyze bottom sediment and sediment trap samples at UVic lab for coherent longterm time series of sample data, and request sample analysis data from previous samples • Agreement to write expedition and research proposal to compare Hydrate Ridge with Barkley Canyon (to Schmidt Ocean Institute and/or National Science Foundation) • Suggestion to consider ONC hosting NRCan observatory data from Kitimat Arm • Established list of future sites of interest
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