University of Southampton Research Repository ePrints Soton Copyright © and Moral Rights for this thesis are retained by the author and/or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder/s. The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given e.g. AUTHOR (year of submission) "Full thesis title", University of Southampton, name of the University School or Department, PhD Thesis, pagination http://eprints.soton.ac.uk University of Southampton North Atlantic octocorals: Distribution, Ecology and Phylogenetics. By Kirsty Janet Morris A thesis submitted in partial fulfilment for the degree of Doctor of Philosophy in the Faculty of Natural and Environmental Science School of Ocean and Earth Sciences. October 2011 1 Declaration of Authorship I, Kirsty Janet Morris, declare that this thesis titled, “North Atlantic octocorals: Distribution, Ecology and Phylogenetics” and the work presented in it are my own. I confirm that: This work was done wholly or mainly while in candidature for a research degree at this University. Where any part of this thesis has previously been submitted for a degree or any other qualification at this University or any other institution, this has been clearly stated. Where I have consulted the published work of others, this is always clearly attributed. Where I have quoted from the work of others, the source is always given. With the exception of such quotations, this thesis is entirely my own work. I have acknowledged all main sources of help. Where the thesis is based on work done by myself jointly with others, I have made clear exactly what was done by others and what I have contributed myself. Signed: Date: 2 “Nothing in this world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent. The slogan Press On! has solved and always will solve the problems of the human race” Calvin Coolidge 3 UNIVERSITY OF SOUTHAMPTON Abstract Faculty of Natural and Environmental Sciences School of Ocean and Earth Science Doctor of Philosophy North Atlantic octocorals: Distribution, Ecology and Phylogenetics by Kirsty Janet Morris Most studies of deep-sea benthic fauna have concentrated on soft sediments with little sampling in rocky areas and even less on non-vent mid-ocean ridges and within submarine canyons, mainly as a result of difficulty accessing them. To assess the distribution and abundance of cold-water corals along an Axial Volcanic Ridges along the Mid-Atlantic ridge at 45oN 27oW, and within the Whittard Canyon along the Irish Margin video footage from the ROV Isis taken during a three scientific cruises was analysed. Samples were also taken to allow taxonomic and phylogentic work to be completed. Abundance of octocorals per 100 m transect were calculated and mapped using Arc GIS, with a maximum of 59 in the AVR compared to 855 within the Whittard Canyon. Thirty-one putative species were identified within the Whittard Canyon including some scleractinians, Eleven more than were found in along the AVR. Both locations indicated differences in coral assemblages dependent on substratum type with sedimented areas having increased occurrence of Pennatulidae and Chrysogorgiidae within the AVR and an increased abundance of Acanella and Radicipes upon sediment in comparison to rock within the Whittard Canyon. It is suggested that these differences in abundance and assemblage structure, both within and between the AVR and Whittard Canyon sites, reflects higher food availability as well as differences in substratum type on which coral larvae settle. Taxononomic investigations identified 4 new species from samples taken along the AVR, and are described within the thesis. Phylogenetic analysis of novel sequences obtained throughout this study, as well as published sequences, showed the presence of 3 clades A) Calcaxonia and some Alcyoniidae B) Holoaxonia and Pennatulacea C) some Alcyoniidae, Corallium and Paragorgia. When individual MSH1 and ND2 genes were combined the Pennatulacea separated out as a fourth clade. This was attributed to an increase in resolution when two or more genes are used for analysis. Results indicate that morphological taxonomy and molecular analysis are not in agreement and there is a requirement for some taxonomic revisions using molecular data to confirm species boundaries and help guide taxonomic decisions. 4 Acknowledgements I would like to thank my supervisors Paul Tyler and Alex Rogers without whom I would not be where I am today. I would particularly like to thank Paul for his support and listening ear, his quick feedback and for not giving up on me. Thank you also to my panel chair for your unwavering support and guidance. I would also like to thank my funding body NERC for my studentship NE/F009097/1. Thanks also go to Les Watling, Scott France, Catherine McFadden and Phil Alderslade for stimulating chats, thought provoking emails, helpful guidance and data provisions. I would like to give some special thank you for people at NOC who have gone above and beyond their duty to help me with this project; Chrysoula Gubili without who I would still be in a state of phylogenetic confusion, Chris Hauton for help and advice, Tim Le bas and Simon Dodds for technical assistance. Bramley Murton for allowing me to go on JC24 without which my data would be severely depleted. I would like to thank my friends. Joanne for long phone calls and always being there to help, officemates especially Sarah Taws and Verity Nye for helpful distractions, and my friends at NOC for much needed social interactions and fun times especially, Ellen, Sally, John P, Mary, Jo and Rose. A special thank you to Gerard for your support and putting up with me. Finally I would like to thank my family who have also given me unwavering support and belief. You have given me strength when I needed it and have always been on the other end of the phone. Although you were never really sure what my project was about you have always made me feel like you were proud of me for pursuing my goal. Thank you. 5 Contents Chapter 1: General Introduction 1.1General Introduction ................................................................................................ 1 1.1.1 Cold-water corals ............................................................................................. 3 1.1.2 Coral structure .................................................................................................. 4 1.1.3 Subclass Octocorallia ....................................................................................... 6 1.1.4 Octocorallia Taxonomy and Systematics ...................................................... 12 1.1.5 Cold-water octocoral reproduction ................................................................ 14 1.1.6 Cold-water octocoral growth ......................................................................... 17 1.1.7 Cold-water octocoral distribution. ................................................................. 18 1.1.8 Why study cold-water octocoral?...................................................................19 1.2 Aims of thesis....................................................................................................21 Chapter 2. Lower Bathyal and abyssal distribution of coral in the Axial Volcanic Ridge of the Mid-Atlantic Ridge at 45 oN 2.1 Introduction .......................................................................................................... 23 2.1.1 Mid-Atlantic Ridge ........................................................................................ 25 2.1.2 Axial Volcanic ridge at 45 oN ........................................................................ 26 2.1.2 Water masses at 45oN .................................................................................... 27 2.1.3 Aims ............................................................................................................... 29 2.2 Materials and methods .......................................................................................... 30 2.2.1 Data collection ............................................................................................... 30 2.2.2 Image analysis ................................................................................................ 30 2.2.3 Data analysis .................................................................................................. 33 2.2.3.2 Random sampling ....................................................................................... 34 2.2.3.3 Multivariate analysis ................................................................................... 35 2.2.3.4 Cumulative frequencies .............................................................................. 35 2.3 Results .................................................................................................................. 36 2.3.1 Environmental setting ...................................................................................