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Assessing the potential of autonomous submarine gliders for ecosystem monitoring
Damien Guihen (BAS)
Lavinia Suberg; Russell B Wynn; Jeroen van der Kooij; Liam Fernand; Sophie Fielding; Damien Guihen; Douglas Gillespie; Mark Johnson; Kalliopi C Gkikopoulo; Ian J Allan; Vrana Branislav; Peter I Miller; David Smeed; Alice R Jones
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Shallow-water Slocum glider
Autonomous
Buoyancy-driven
Optimized for shallow-water
operations (~200m)
GPS/dead-reckoning
Iridium communication
horizontal speed: 20-40cm/sec
vertical speed: 10-20cm/sec
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Shallow-water Slocum glider
Autonomous
Buoyancy-driven
Optimized for shallow-water
operations (~200m)
GPS/dead-reckoning
Iridium communication
horizontal speed: 20-40cm/sec
vertical speed: 10-20cm/sec dailywireless.org
Cost-efficient Samples entire water column Simultaneous measurements of multiple parameters High frequency data few weather constraints
Slow moving Limited sensor load/ quality Data validation
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Large spatio-temporal datasets
Low resolution Surface only Cloud cover
Satellite
High resolution and quality
Multitude of sensors QAed Low spatio-temporal
extend Expensive
Vessel
High resolution Time series Spatial extend
Mooring
Cost-efficient Samples entire water column Simultaneous measurements of multiple parameters High frequency data few weather constraints
Slow moving Limited sensor load/ quality Data validation
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Need for high resolution data across multiple parameters
Implementation of the EU Marine Strategy Framework Directive (MSFD)
Establishment of Marine Protected Areas (MPAs)
Understanding ecosystem functioning, predator-prey interactions
JNCC oceanlink
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Simultaneous deployment of two gliders equipped with sensors measuring: Water-column properties chlorophyll Zooplankton and fish cetacean
Survey area: Isles of Scilly tidal mixing front Productive Cetacean and seabird abundance Marine Conservation Area Physically heterogeneous environment
Assessing the potential of submarine gliders for cost-efficient ecosystem monitoring
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Zephyr
CTD + fluorometer: temperature, salinity, chlorophyll fluorescence
Hydrophone (dtag): passive acoustic monitoring (cetacean)
Passive sampling sheets: contaminants
U194
CTD + fluorometer: temperature, salinity, chlorophyll fluorescence
ES853 Echosounder: Fish and zooplankton
Zephyr
U194 Deployment Autumn 2013
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Glider tracks
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U194 CTD + fluorometer
U194 echo-sounder
Zephyr DTAG
1 6 5 4 3 2 8 7 9
Memory full No recordings, broken cable
DEPLOYMENT
SENSORS
Zephyr
U194
Zephyr CTD + fluorometer
Deployment week
Repairs
No recordings, software problem
Repairs
Repairs
Deployment: 12th September 2013 Retrieval Zephyr : 21st October (38 days) Retrieval U194: 13th November (60 days)
Mission summary
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U194 CTD + fluorometer
U194 echo-sounder
Zephyr DTAG
1 6 5 4 3 2 8 7 9
Memory full No recordings, broken cable
DEPLOYMENT
SENSORS
Zephyr
U194
Zephyr CTD + fluorometer
Deployment week
Repairs
No recordings, software problem
Repairs
Repairs
Statistic Zephyr U194
No. of dives 2654 2821
Total distance (km) 1080 1309
Mean dist b/w GPS fixes (km) 0.9 0.85
Max dist b/w GPS fixes (km) 13.7 10.3
Mean dive depth (m) 44.55 40
Max dive depth (m) 101.49 103.89
Deployment: 12th September 2013 Retrieval Zephyr : 21st October (38 days) Retrieval U194: 13th November (60/39 days)
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Oceanographic Sensors
Frontal crossings Spatial difference in surface and bottom
front
Subsurface chlorophyll maximum Change from stratified to mixed Storm event
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Glider echosounder
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Glider echosounder
Ship-based echosounder
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Hydrophone
291 dives Total of 2413 recordings over 194 dives 2 Harbour porpoise clicks
49 Dolphin whistles 145 Dolphin clicks 42 Clicks and whistles
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Flight control Currents, tides, sensor effect Possible solutions: Changing flight settings Extended trials prior to survey Less challenging environments Alignment of glider trajectories
Positives Sensors provided useful data Entire water-column sampled High resolution data Few weather constraints Long term Limitations Sensor technology Level of information: distribution
or relative abundance, not biomass or species composition
Calibration and validation of data Monitoring networks
Glider operations Sensors/technology
Ohman et al. (2013)
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Early stages Great potential Will not be able to substitute vessel surveys Can significantly contribute to ecosystem monitoring
in conjunction with other platforms monitoring networks
Conclusions
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Acknowledgements
MARS staff: David White, Sam Ward, James Burris CEFAS Endeavour crew and scientists IFCA Isles of Scilly James Bowcott (PML) DEFRA JERICO
