Award: OCE-0826254

Award Number: 0826254 Award Title: Collaborative Research: Structure, Function and Evolution of Authigenic, Methane-Derived Carbonate Ecosystems Public Statement. The deep ocean is vast and much of it remains unexplored. While there are parts of the deep ocean we have never visited, detailed study of areas previously visited can reveal new secrets and lessons of great value in understanding life in the ocean. This project explored the life forms associated with carbonate rocks in two regions with methane seepage on the continental margins: one off Costa Rica (400-1850 m) and one off Oregon (500-900m water depth). We used the submersible ALVIN and the remotely operated vehicle JASON to observe, sample and conduct manipulative experiments intended to examine the roles of seepage activity, ocean conditions, and substrate type in shaping microbial and animal communities. In the process we discovered that carbonate rocks, themselves created by an exotic consortium of microbes, host a wealth of previously unknown bacteria, archaea, and small animals – effectively forming their own distinct, dynamic ecosystem. These communities are greatly influenced by proximity to methane seepage. In the processes of conducting these studies we discovered (a) the first animal known to derive nutrition primarily from the kingdom archaea, (b) the first yeti crab representative from methane seeps and only the second member of this family known (Kiwa puravida), (c) the first evidence of a dimorphic (two stage) lifestyle for the largest known bacteria, Thiomargarita, (d) the first (fungal-like) microsporidia ever reported from the deep sea, found in nematodes on seep carbonates and (e) new-found examples of animals and protists living in symbiosis with methane eating microbes. We discovered a novel deep-sea habitat type at 1800 m off Costa Rica that blends attributes of a hydrothermal vent and methane seep; we called this a hydrothermal seep. This study has yielded the first description of active and abundant microbes (methane-oxidizing archaea and sulfate-reducing bacterial partners) living inside methane seep carbonates. It has also yielded a wealth of new biodiversity, with over forty undescribed animals species. Descriptions of new worms, clams, mussels, snails, brittle stars and crabs are made or in progress. What is so remarkable is that our two study regions had been visited numerous times by other scientists before we got there. Taken together our findings reveal exquisite biological communities on margins of the E. Pacific Ocean, living in tight dependence on their environment and other organisms, and vulnerable to disturbance from human activities. Equally important, we have managed introduce a large number of undergraduates, graduate students, postdoctoral scientists, and a rural science teacher, to the wonders of deep- sea science, contributing to the next generation of deep-ocean explorers and researchers. Last Modified: 10/26/2012 Submitted by: Lisa A Levin