Person: Olins, Heather
Loading...
Email Address
AA Acceptance Date
Birth Date
Research Projects
Organizational Units
Job Title
Last Name
Olins
First Name
Heather
Name
Olins, Heather
4 results
Search Results
Now showing 1 - 4 of 4
Publication Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley hydrothermal vents(Nature Publishing Group, 2013) Frank, Kiana L; Rogers, Daniel R.; Olins, Heather; Vidoudez, Charles; Girguis, PeterFew studies have directly measured sulfate reduction at hydrothermal vents, and relatively little is known about how environmental or ecological factors influence rates of sulfate reduction in vent environments. A better understanding of microbially mediated sulfate reduction in hydrothermal vent ecosystems may be achieved by integrating ecological and geochemical data with metabolic rate measurements. Here we present rates of microbially mediated sulfate reduction from three distinct hydrothermal vents in the Middle Valley vent field along the Juan de Fuca Ridge, as well as assessments of bacterial and archaeal diversity, estimates of total biomass and the abundance of functional genes related to sulfate reduction, and in situ geochemistry. Maximum rates of sulfate reduction occurred at 90 °C in all three deposits. Pyrosequencing and functional gene abundance data revealed differences in both biomass and community composition among sites, including differences in the abundance of known sulfate-reducing bacteria. The abundance of sequences for Thermodesulfovibro-like organisms and higher sulfate reduction rates at elevated temperatures suggests that Thermodesulfovibro-like organisms may have a role in sulfate reduction in warmer environments. The rates of sulfate reduction presented here suggest that—within anaerobic niches of hydrothermal deposits—heterotrophic sulfate reduction may be quite common and might contribute substantially to secondary productivity, underscoring the potential role of this process in both sulfur and carbon cycling at vents.Publication Co-registered Geochemistry and Metatranscriptomics Reveal Unexpected Distributions of Microbial Activity within a Hydrothermal Vent Field(Frontiers Media SA, 2017) Olins, Heather; Rogers, Daniel R.; Preston, Christina; Ussler, William; Pargett, Douglas; Jensen, Scott; Roman, Brent; Birch, James M.; Scholin, Christopher A.; Haroon, Mohamed; Girguis, PeterDespite years of research into microbial activity at diffuse flow hydrothermal vents, the extent of microbial niche diversity in these settings is not known. To better understand the relationship between microbial activity and the associated physical and geochemical conditions, we obtained co-registered metatranscriptomic and geochemical data from a variety of different fluid regimes within the ASHES vent field on the Juan de Fuca Ridge. Microbial activity in the majority of the cool and warm fluids sampled was dominated by a population of Gammaproteobacteria (likely sulfur oxidizers) that appear to thrive in a variety of chemically distinct fluids. Only the warmest, most hydrothermally-influenced flows were dominated by active populations of canonically vent-endemic Epsilonproteobacteria. These data suggest that the Gammaproteobacteria collected during this study may be generalists, capable of thriving over a broader range of geochemical conditions than the Epsilonproteobacteria. Notably, the apparent metabolic activity of the Gammaproteobacteria—particularly carbon fixation—in the seawater found between discrete fluid flows (the intra-field water) suggests that this area within the Axial caldera is a highly productive, and previously overlooked, habitat. By extension, our findings suggest that analogous, diffuse flow fields may be similarly productive and thus constitute a very important and underappreciated aspect of deep-sea biogeochemical cycling that is occurring at the global scale.Publication Abiotic Influences on Free-Living Microbial Communities in Hydrothermal Vent Ecosystems(2016-05-18) Olins, Heather; Girguis, Peter R.; Knoll, Andrew H.; Cavanaugh, ColleenHydrothermal vent ecosystems are defined by steep thermal and chemical gradients. Chemosynthetic microorganisms are the primary producers in these systems, utilizing the available chemical energy to support substantial animal biomass. The variety of chemical substrates provided by hydrothermal fluid and surrounding seawater enables a metabolically diverse community of microbes. However, our understanding of how abiotic factors such as temperature, geochemistry, and mineral substrate influence the activity of these microbes is limited. The overarching goal of this dissertation is to examine the influence of these abiotic factors on free-living microbial community composition, structure, and function. In this work I first examined the influence of temperature on primary productivity by using radio isotopic tracer studies to measure rates of carbon fixation by epi- and endolithic microbial communities from vent chimney sulfides. I show evidence that these communities fix more carbon at low temperatures, underscoring the importance of low temperature habitats in these environments commonly characterized by high temperature. I then utilized in situ RNA preservation to examine community-wide microbial activity in low temperature vent fluids throughout a vent field. These data show two distinct activity profiles that cross-cut canonical habitat descriptions, and highlight the importance of the intra-field waters among the discrete vents as regions of high primary productivity bearing similarity in microbial activity to plumes emanating from high temperature chimneys. Finally, I designed novel colonization devices to examine the influence of mineral substrate on microbial community composition, structure, and succession. Mineralogy influenced certain taxa. I also identified potential early and late successional taxa. The combination of metabolic rate measurements, metatranscriptomics, and colonization experiments presented here, all with co-registered geochemistry, underscore the substantial heterogeneity of these systems and offer insights into the relative strengths of the abiotic forces that help to govern these ecosystems.Publication Characterizing the Distribution and Rates of Microbial Sulfate Reduction at Middle Valley Hydrothermal Vents(Nature Publishing Group, 2013-02-28) Frank, Kiana Laieikawai; Rogers, Daniel R.; Olins, Heather; Vidoudez, Charles; Girguis, PeterFew studies have directly measured sulfate reduction at hydrothermal vents, and relatively little is known about how environmental or ecological factors influence rates of sulfate reduction in vent environments. A better understanding of microbially mediated sulfate reduction in hydrothermal vent ecosystems may be achieved by integrating ecological and geochemical data with metabolic rate measurements. Here we present rates of microbially mediated sulfate reduction from three distinct hydrothermal vents in the Middle Valley vent field along the Juan de Fuca Ridge, as well as assessments of bacterial and archaeal diversity, estimates of total biomass and the abundance of functional genes related to sulfate reduction, and in situ geochemistry. Maximum rates of sulfate reduction occurred at \(90^{\circ}C\) in all three deposits. Pyrosequencing and functional gene abundance data reveal differences in both biomass and community composition among sites, including differences in the abundance of known sulfate reducing bacteria. The abundance of sequences for Thermodesulfovibro-like organisms and higher sulfate reduction rates at elevated temperatures, suggests that Thermodesulfovibro-like organisms may play a role in sulfate reduction in warmer environments. The rates of sulfate reduction presented here suggest that - within anaerobic niches of hydrothermal deposits - heterotrophic sulfate reduction may be quite common and can contribute to secondary productivity, underscoring the potential role of this process in both sulfur and carbon cycling at vents.