Award: OCE-1536653

Hydrothermal vents are considered to be some of the most hostile and dynamic places for animals -and microbes- to live. With water temperatures soaring past 300° Celsius (hotter than a home oven while in "self-clean" mode"), and concentrations of sulfide, arsenic and other metals that are toxic to many lifeforms, vents seem to be a formidable and terrifying place to live. Yet, vents host some of the most abundant colonies of animals and microbes in the deep sea. They are as productive as the fastest-growing rainforests and support a diversity of animal taxa from "dandelion" jellies to giant clams. Researchers have found that many of these vent ecosystems, in particular those in the Eastern Pacific Ocean, live up to their reputation, growing and collapsing on the order of a decade or so. Many animals and microbes have adapted to this challenge. "Living fast and dying young", they are adept at producing many, many juveniles that can propagate to other vents before their home field dies. It is these rapid and tumultuous vents that have been the "gold standard" models for vent habitats. Their rapid growth and decline have made them a hotbed for research and has also attracted the attention of deep-sea mining companies, who view ephemeral vents a good target for seafloor mining. Indeed, if each community is very short-lived, and these species are adept at populating other vents, then it is understandable to consider mining them to meet humankind?s growing demand for the exotic metals that reside in the vent minerals. That said, the results of our research show that many of these vents are incredibly stable, with animal communities that show little sign of the massive reproductive effort seen elsewhere, and very little evidence of moving from one vent to another. Our observations are robust, and based on our highly multidisciplinary site assessments, in which our team used geological sonar surveys, ecological camera assessments, molecular biological genomic studies, and geochemical fluid measurements to comprehensively assess the state of these sites during our expedition. Most importantly, our research builds upon a decade of studying these exact same sites (they are located in the Southern Pacific Ocean), providing us with an unprecedented opportunity to map the geological, chemical and biological changes over time. Studies such as this provide us with a glimpse into the changes over time that animals exhibit in the deep sea. While this work advances our basic knowledge of marine ecosystems, it also provides us with a deeper understanding of how these unique bacteria and animals "make a living", and how we might leverage that to produce power and high-value commodities from toxins in our own environment. These studies also provide the baseline data that is critical when considering mining activities. In sum, while many vent communities "live fast and die hard", others don?t. As is true in other communities, including humans, population dynamics can shape the attributes of a population, leading to communities with very different features. This is as important in the deep sea as it is on land. Furthermore, the stability of these ecosystems should give us pause as we consider if and how to exploit these mineral resources. Last Modified: 03/14/2018 Submitted by: Peter Girguis