The Tautra Cold-Water Coral Reef Mapping and describing the biodiversity of a cold-water coral reef ecosystem in the Trondheimsfjord by use of multi-beam echo sounding and video mounted on a remotely operated vehicle June Jakobsen Marine Coastal Development Submission date: May 2016 Supervisor: Geir Johnsen, IBI Co-supervisor: Svein Karlsen, Fylkesmannen i Nord-Trøndelag Martin Ludvigsen, IMT Torkild Bakken, NTNU, Vitenskapsmuseet Norwegian University of Science and Technology Department of Biology i Contents Acknowledgements ................................................................................................................................. iii List of Abbreviations: .............................................................................................................................. iv Abstract: ................................................................................................................................................... v Sammendrag ............................................................................................................................................ vi Introduction: ............................................................................................................................................ 1 Theory ..................................................................................................................................................... 2 The geology of the fjord ...................................................................................................................... 2 Current systems in the fjord ................................................................................................................ 3 Lophelia pertusa – an important part of marine habitats and ecology ................................................ 4 Early coral research of the fjord .......................................................................................................... 7 Johan Gunnerus. .............................................................................................................................. 7 Vilhelm Ferdinand Johan Storm ...................................................................................................... 9 Carl Frederik Lindeman Dons ....................................................................................................... 10 Common traditional benthic sampling methods in marine biology .................................................. 11 Dredges, sledges and trawls .......................................................................................................... 11 Grabs and boxcorers. ..................................................................................................................... 12 Seabed mapping ................................................................................................................................ 12 Multi-Beam Echo Sounding .......................................................................................................... 12 Optical sea floor mapping ............................................................................................................. 13 Material and methods ............................................................................................................................ 14 Research platforms ............................................................................................................................ 14 The Research Vessel Gunnerus ..................................................................................................... 14 Multi-beam echo sounder (MBES) ............................................................................................... 14 Remotely operated vehicle ............................................................................................................ 15 Video Camera ................................................................................................................................ 16 Transects ............................................................................................................................................ 16 The Beitstadfjord transect.............................................................................................................. 16 The Tautra sill transect .................................................................................................................. 18 Data processing and analysis for the Hoøyskjæret in Beitstadfjorden .............................................. 19 Data processing for the Tautra sill..................................................................................................... 19 Data analysis for the Tautra sill ..................................................................................................... 23 Results ................................................................................................................................................... 26 The Beitstadfjord – Hoøyskjæret....................................................................................................... 26 The Tautra cold-water coral reef. Mapping and describing the biodiversity of a cold-water coral reef ecosystem in the Trondheimsfjord by the use of multibeam echo sounder and video mounted on a remotely operated vehicle. MSc thesis by June Jakobsen, May 2016, NTNU ii Tautra sill: Total abundance of benthic organisms ............................................................................ 27 Equitability and Shannon’s diversity index ....................................................................................... 31 Tautra sill: The equitability (E) of Shannon diversity index, H’, and depth ..................................... 33 Tautra sill: Live Lophelia pertusa coverage in relation to depth ...................................................... 36 Tautra sill: Live coral coverage and E ............................................................................................... 40 Tautra sill: Live Lophelia pertusa coverage in relation to numbers of sponges ............................... 43 Shannon’s diversity index, H’. .......................................................................................................... 46 Fish associated with live coral cover ................................................................................................. 47 Live L. pertusa gradient .................................................................................................................... 48 Discussion: ............................................................................................................................................ 50 Live Lophelia pertusa coverage ........................................................................................................ 50 Bioturbation ....................................................................................................................................... 51 Biodiversity along the Tautra sill transect. ........................................................................................ 52 Sponges ............................................................................................................................................. 53 Fish .................................................................................................................................................... 54 Data acquisition/performing a survey ............................................................................................... 55 Beitstadfjord – Hoøyskjæret .............................................................................................................. 56 Analysing data ................................................................................................................................... 58 ROV movement and video and image analysis ................................................................................. 59 Concluding remarks .............................................................................................................................. 61 References: ............................................................................................................................................ 62 The Tautra cold-water coral reef. Mapping and describing the biodiversity of a cold-water coral reef ecosystem in the Trondheimsfjord by the use of multibeam echo sounder and video mounted on a remotely operated vehicle. MSc thesis by June Jakobsen, May 2016, NTNU iii Acknowledgements The work of this MSc thesis was carried out at Trondheim Biological Station (TBS), Department of Biology, NTNU, in cooperation with the County Governor of Nord-Trøndelag and NTNU Autonomous Underwater Robotics-lab in the time between August 2014 to June 2016. I would like to express my sincere and utmost gratitude to my supervisor Geir Johnsen for inspiring me to do better and to be creative. Without your enthusiasm for my project, this would never have been as fun and interesting as it truly has been. Thank you. My co-supervisor Torkild Bakken, thank you for your sound and grounded advice and for listening to my thoughts about the work. I am indebted to you for your valuable input to my work and to your positive feedback keeping me on track. To my supervisor Martin Ludvigsen and to Christian Malmquist. Thank you for helping me understand the technological side of seabed mapping. Thank you for