The Pentland Firth is an area with a very strong and highly turbulent tidal current, offering excellent potential for the generation of tidal energy. However the environment is, as yet, poorly documented or understood. The focus of this project is to better understand the relation of benthic habitats and extreme flow environments. Specifically this project seeks to develop a core understanding of densities, distributions and diversities of benthic assemblages of epifauna in relation to extreme flow environments, and determine predictions on possible ecological impacts due to the installation of tidal energy devices (TED)

1. Benthic habitats in extreme flow
environments of the Pentland Firth
A presentation by Astrid Harendza
UHI Research and Postgraduate Conference 2010
Communities, Coast and Mountains
Morray College, Elgin

2. Introduction
BUT environment is, as yet, poorly documented or understood
Pentland Firth:
• excellent potential for the generation of tidal energy
• area with very strong and highly turbulent tidal
current
Project focus:
Predictions on possible ecological impacts due
to the installation of tidal energy devices (TED)
Relation of benthic habitats and extreme flow environments
core understanding of densities, distributions and
diversities of benthic assemblages of epifauna in
relation to extreme flow environments
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth

3. Key requirements
Information on:
● physical environment
bathymetry and topography
tidal currents / boundary layer
substratum
● benthic organisms
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
density
distribution
diversity
Methods:
monthly surveys of the Inner Sound
using ERI’s survey boat “ERI Aurora”

4. Survey area
Thurso
Inner Sound of the Pentland Firth
Stroma
Swona
Duncansby
Head
Dunnet Head
Thurso
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth

5. Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
Survey area

6. Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
Survey area

7. Methods
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
Sidescan sonar
● high-resolution, CHIRP
● pole-mounted
information on composition of seabed / substratum

8. Methods
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
Acoustic Doppler Current Profiler (ADCP)
current velocities and direction over
water column
• pole - mounted
© Nortek
current velocities and direction
close to the seabed
• bottom - mounted
different locations

9. Methods
Remote Operated Vehicle (ROV)
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
groundtruthing habitats (SSS)
identification of benthic species
● video footage
● still images

10. Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth
Thank you for your
attention!
Acknowledgements:
Supervisors: Dr Angus Jackson, Environmental Research Institute
Dr Mark Shields, University of Aberdeen, Oceanlab
Prof. Jonathan Side, ICIT
Skipper: William Simpson
Technicians: Soeren Hoejlund, Jason McIlvenny, Hester Jackson
and Lonneke Goddijen-Murphy

11. Methods
Sidescan sonar
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth

12. Methods
Acoustic Doppler Current Profiler (ADCP)
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth

13. Methods
Sidescan sonar
Astrid Harendza: Benthic habitats in extreme flow environments of the Pentland Firth