THE ECOLOGICAL IMPACTS OF MINING AT SEAFLOOR MASSIVE SULFIDE DEPOSITS ON MEGAFAUNAL ASSEMBLAGE STRUCTURE AND POPULATION CONNECTIVITY BY RACHEL ELIZABETH BOSCHEN A thesis submitted to the Victoria University of Wellington in fulfilment of the requirements for the degree of Doctor of Philosophy Victoria University of Wellington 2016 ii This thesis was conducted under the supervision of Prof Jonathan P A Gardner Victoria University of Wellington, New Zealand Dr Ashley A Rowden & Dr Malcolm R Clark National Institute of Water and Atmospheric Research, New Zealand iii iv Abstract Deep-sea mining is rapidly becoming a reality, yet there are considerable gaps in our knowledge of the seabed assemblages that could be affected by mining activities. Seafloor Massive Sulfide (SMS) mining is expected to remove nearly all organisms in the immediate area and alter the remaining habitat, so that mitigation strategies for SMS mining will most likely need to include the establishment of protected areas to preserve the biodiversity that is lost at mine sites. Prospecting licences have been issued previously for SMS deposits within the New Zealand Exclusive Economic Zone (EEZ), however little is known about the seabed assemblages potentially at risk from SMS mining, particularly with respect to their structure (at multiple spatial scales) and the connectivity of assemblages at different sites. Designing studies to provide this information can be aided by turning to terrestrial, freshwater and shallow marine systems, where the fields of ecological theory, environmental management and conservation theory are better developed (Chapter 1). Prior to detailed investigations into the assemblage structure and population connectivity of New Zealand SMS deposits, it is essential to understand the global context of SMS mining. This was undertaken through an extensive literature review of SMS deposits, including their geology, seafloor communities, impacts from mining, international and national regulation, and environmental management (Chapter 2). In order to investigate the large-scale spatial distribution and structure of seafloor assemblages at SMS deposits, three New Zealand seamounts previously licenced for the prospecting phase of SMS mining were surveyed. Video footage from a towed camera was analysed to identify and characterise assemblages, and their association with environmental variation was investigated. Analysis of 249 video samples (each 250 m in length) distributed amongst the three seamounts indicated that SMS deposits support unique assemblages and that there were strong links between assemblage structure and environmental variation at a range of spatial scales. There was also a complex distribution of assemblages amongst the seamounts, suggesting a network of protected areas would be the most effective method for spatial management. Such networks should include sites that support the unique assemblages found in association with SMS deposits (Chapter 3). The fine-scale distribution and structure of assemblages at SMS deposits was investigated by using data from a single SMS deposit, Proteus 1, and comparing it to a Reference Site selected to have similar size and seabed characteristics to the deposit. Video footage from a Remotely Operated Vehicle (ROV) was used to identify and v characterise assemblages, and their association with environmental conditions. Analysis of 153 video samples (each 15 m in length) confirmed the existence of assemblages unique to SMS deposits, and indicated that environmental characteristics specific to the deposit are responsible for the observed patterns of faunal distribution. Although five assemblages were shared between Proteus 1 and the Reference Site, six assemblages were unique to Proteus 1. This suggested that the proposed Reference Site would be inadequate on its own in terms of protecting the biological diversity present at the mine site but could contribute to a network of protected areas (Chapter 4). The issue of connectivity was addressed by examining the genetic connectivity of populations of the endemic hydrothermal vent mussel, Gigantidas gladius. Universal markers, archived material and off-the-shelf DNA extraction kits were used to investigate a cost effective approach. The assessment utilised variation in 586 base pairs of the mitochondrial cytochrome oxidase I subunit (COI) from 150 individuals in seven populations of G. gladius. Small sample sizes limited the recommendations that could be made for environmental management; however interpretation of the available sequences indicated panmixia with limited genetic structure and high connectivity amongst populations. Central Kermadec Volcanic Arc populations had particularly high haplotypic diversity and migrant exchange, suggesting they could be important for maintaining regional genetic connectivity and would merit inclusion in seabed protection measures. (Chapter 5). Establishing protected areas for biodiversity needs to utilise all of the available information. The integrated findings of this thesis highlight the need for a network of protected seabed areas along the Kermadec Volcanic Arc to help mitigate the impacts of any future SMS mining activities. These networks should be highly connected (as determined by genetic connectivity) and include both active and inactive SMS areas to conserve 1) the endemic vent fauna in active areas and 2) the unique assemblages found in both environments (Chapter 6). vi Acknowledgements Specific acknowledgements are made at the end of each chapter; here I would like to acknowledge the help and support from individuals regarding the thesis as a whole. Firstly, I would like to thank my supervisors; Prof Jonathan Gardner at Victoria University of Wellington (VUW) and Dr Ashley Rowden & Dr Malcolm Clark at the National Institute of Water and Atmospheric Research (NIWA). The guidance, support and wealth of knowledge supplied by my supervisors has been essential to the completion of my PhD. I am also exceedingly grateful for the opportunities provided by my supervisors to participate in research voyages and workshops, and to present my work at international conferences. I am very grateful to NIWA and VUW for providing the stipend and tuition fee scholarships to support my PhD. My research was conducted as part of the NIWA project ‘Deep-sea mining of the Kermadec Arc – Geophysical prospectivity and environmental impacts’ funded by the New Zealand Ministry of Business, Innovation and Employment. I am also grateful to the scientists, technicians and support staff at both NIWA and VUW, not only for providing help and guidance, but for making me feel so welcome. Particular thanks go to the NIWA Invertebrate Collection team for helping me locate samples and for allowing me to dissect hundreds of vent mussels, some of which were rather smelly. I would also like to thank the various external colleagues and collaborators who provided pertinent comments on my research during conferences and workshops. My thesis also benefitted from the constructive comments of my examiners, Dr Wayne Linklater, Prof Thomas Schlacher and Prof Verena Tunnicliffe. I am lucky to have met many colourful and talented people on my travels, both within New Zealand and overseas. My eclectic circle of friends have entertained and supported me in a multitude of ways during my PhD, for which I am very grateful. I have had some fantastic office and laboratory mates who have encouraged me and indulged my sense of humour. I would like to thank the medical and healthcare professionals that provided the support needed for me to complete my PhD. In particular I would like to thank the staff at the Wellington Regional Pain Management Service, Victoria University Student Health, and Willis Street Physio. It was a rough ride at times but perseverance paid off. The biggest thank-you goes to my parents, Kate and Andy, and my sister, Hannah. They have supported me every step of the way; my family is my rock and words cannot say how much I appreciate them. Grandma Clark and Grandma Minchin passed away vii whilst I was completing my PhD but I think they would have been proud. My Dad instilled in me a love of nature from an early age, spending many hours with me sampling and classifying the inhabitants of the family pond and local streams. My sister showed me how it was possible to achieve your potential, despite difficulties, and that the journey is just as important as the destination. My mum is the most inspiring person I know, I am in awe of her resilience and determination and I am immensely proud of how far she has come. A thesis is a journey with as many ups and downs as the Wellington landscape. But when you do finally reach the hilltop, the view makes the struggle worthwhile. It also provides a vantage point from which to scout out the next series of hills to investigate… viii Table of Contents Abstract .............................................................................................................................. v Acknowledgements ......................................................................................................... vii Table of Contents.............................................................................................................. ix List of Figures ................................................................................................................. xiii List of Tables .................................................................................................................. xvii