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
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
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
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
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
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
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
Glider tracks
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
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)
Oceanographic Sensors
Frontal crossings Spatial difference in surface and bottom
front
Subsurface chlorophyll maximum Change from stratified to mixed Storm event
Glider echosounder
Glider echosounder
Ship-based echosounder
Hydrophone
291 dives Total of 2413 recordings over 194 dives 2 Harbour porpoise clicks
49 Dolphin whistles 145 Dolphin clicks 42 Clicks and whistles
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)
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
Acknowledgements
MARS staff: David White, Sam Ward, James Burris CEFAS Endeavour crew and scientists IFCA Isles of Scilly James Bowcott (PML) DEFRA JERICO
