skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Biohalogenation and gut mineralization of invertebrates specialized in deep-sea hydrothermal environments
A central objective in geology is to understand how biological metabolisms contribute to the cycling of redox-sensitive elements in extreme environments within the Earth's oceans and crust, and potentially how life may persist on water-rich exoplanets. In deep-sea hydrothermal vent systems, organisms cope with the presence of toxic chemical compounds (e.g., H2S) and microbial communities facilitate survival in these extreme geochemical conditions by oxidizing H2S for energy. However, it is essential to know how these animals interact with their microbiomes to immobilize, detoxify, and release elements back into the water, which enlightens how life can persist in extreme conditions and how biomass affects the availability of different chemical compounds. To investigate how large invertebrates cope with these extreme conditions and how this sequestration may affect biochemical cycling, we sampled several invertebrate species from the hydrothermal vents at 9°50'N East Pacific Rise. We used first used high resolution μCT-scanning to image the gut of several species of polychaete worms, crabs, and bivalves. Using diffusible iodine contrast-enhanced μCT-scanning, we could then visualize where minerals (if any) are distributed throughout the organism. Next, we used X-ray fluorescence microscopy to image the whole organism of each animal to characterize the elemental distribution throughout the tissue and also implemented pyrolysis gas-chromatography–mass spectrometry to further characterize the compounds. We discovered that sulfide mineralization in the guts of these animals is ubiquitous. Whether this is a byproduct of their surrounding geochemical environments or an adaptive strategy to assist in harnessing energy or trapping toxic metals remains to be determined. We also found that, in addition to widespread zinc and iron (which is highly correlated with sulfur), bromine tends to occur in high concentrations in some tissues as brominated phenolic compounds, particularly in specialized structures on polychaete worms, which may serve as a protective hardening and/or defensive agent. Because these animals process these toxic conditions in such unique ways, their role in the global cycling and bioavailability of elements such as copper, iron, zinc, and even halogens remain to be discovered.  more » « less
Award ID(s):
1812035
PAR ID:
10391502
Author(s) / Creator(s):
; ; ; ;
Date Published:
Journal Name:
Goldshmidt 2022
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; ; ; ; ; ; ; ; ; (, Journal of Advances in Modeling Earth Systems)
    Abstract Redox processes, aqueous and solid‐phase chemistry, and pH dynamics are key drivers of subsurface biogeochemical cycling and methanogenesis in terrestrial and wetland ecosystems but are typically not included in terrestrial carbon cycle models. These omissions may introduce errors when simulating systems where redox interactions and pH fluctuations are important, such as wetlands where saturation of soils can produce anoxic conditions and coastal systems where sulfate inputs from seawater can influence biogeochemistry. Integrating cycling of redox‐sensitive elements could therefore allow models to better represent key elements of carbon cycling and greenhouse gas production. We describe a model framework that couples the Energy Exascale Earth System Model (E3SM) Land Model (ELM) with PFLOTRAN biogeochemistry, allowing geochemical processes and redox interactions to be integrated with land surface model simulations. We implemented a reaction network including aerobic decomposition, fermentation, sulfate reduction, sulfide oxidation, methanogenesis, and methanotrophy as well as pH dynamics along with iron oxide and iron sulfide mineral precipitation and dissolution. We simulated biogeochemical cycling in tidal wetlands subject to either saltwater or freshwater inputs driven by tidal hydrological dynamics. In simulations with saltwater tidal inputs, sulfate reduction led to accumulation of sulfide, higher dissolved inorganic carbon concentrations, lower dissolved organic carbon concentrations, and lower methane emissions than simulations with freshwater tidal inputs. Model simulations compared well with measured porewater concentrations and surface gas emissions from coastal wetlands in the Northeastern United States. These results demonstrate how simulating geochemical reaction networks can improve land surface model simulations of subsurface biogeochemistry and carbon cycling. 
    more » « less
  2. ; ; ; ; (, Frontiers in Microbiology)
    Hydrothermal sediments host phylogenetically diverse and physiologically complex microbial communities. Previous studies of microbial community structure in hydrothermal sediments have typically used short-read sequencing approaches. To improve on these approaches, we use LoopSeq, a high-throughput synthetic long-read sequencing method that has yielded promising results in analyses of microbial ecosystems, such as the human gut microbiome. In this study, LoopSeq is used to obtain near-full length (approximately 1,400–1,500 nucleotides) bacterial 16S rRNA gene sequences from hydrothermal sediments in Guaymas Basin. Based on these sequences, high-quality alignments and phylogenetic analyses provided new insights into previously unrecognized taxonomic diversity of sulfur-cycling microorganisms and their distribution along a lateral hydrothermal gradient. Detailed phylogenies for free-living and syntrophic sulfur-cycling bacterial lineages identified well-supported monophyletic clusters that have implications for the taxonomic classification of these groups. Particularly, we identify clusters withinCandidatusDesulfofervidus that represent unexplored physiological and genomic diversity. In general, LoopSeq-derived 16S rRNA gene sequences aligned consistently with reference sequences in GenBank; however, chimeras were prevalent in sequences as affiliated with the thermophilicCandidatusDesulfofervidus andThermodesulfobacterium, and in smaller numbers within the sulfur-oxidizing familyBeggiatoaceae. Our analysis of sediments along a well-documented thermal and geochemical gradient show how lineages affiliated with different sulfur-cycling taxonomic groups persist throughout surficial hydrothermal sediments in the Guaymas Basin. 
    more » « less
  3. ; (, Chemistry)
    Hydrogen sulfide (H2S), once regarded solely as a highly toxic gas, is now recognized as a crucial signaling molecule in plants, bacteria, and mammals. In humans, H2S signaling plays a role in numerous physiological and pathological processes, including vasodilation, neuromodulation, and cytoprotection. To exploit its biological functions and therapeutic potential, a wide range of H2S-releasing compounds, known as H2S donors, have been developed. These donors are designed to release H2S under physiological conditions in a controlled manner. Among them, self-reporting H2S donors are seen as a particularly innovative class, combining therapeutic delivery with real-time fluorescence-based detection. This dual functionality enables spatiotemporal monitoring of H2S release in biological environments, eliminating the need for additional sensors or probes that could disrupt cellular homeostasis. This review summarizes recent advancements in self-reporting H2S donor systems, organizing them based on their activation triggers, such as specific bioanalytes, enzymes, or external stimuli like light. The discussion covers their design strategies, performance in biological applications, and therapeutic potential. Key challenges are also highlighted, including the need for precise control of H2S release kinetics, accurate signal quantification, and improved biocompatibility. With continued refinement, self-reporting H2S donors offer great promise for creating multifunctional platforms that seamlessly integrate diagnostic imaging with therapeutic H2S delivery. 
    more » « less
  4. ; ; ; ; (, The ISME Journal)
    Abstract In principle, iron oxidation can fuel significant primary productivity and nutrient cycling in dark environments such as the deep sea. However, we have an extremely limited understanding of the ecology of iron-based ecosystems, and thus the linkages between iron oxidation, carbon cycling, and nitrate reduction. Here we investigate iron microbial mats from hydrothermal vents at Lōʻihi Seamount, Hawaiʻi, using genome-resolved metagenomics and metatranscriptomics to reconstruct potential microbial roles and interactions. Our results show that the aerobic iron-oxidizing Zetaproteobacteria are the primary producers, concentrated at the oxic mat surface. Their fixed carbon supports heterotrophs deeper in the mat, notably the second most abundant organism, Candidatus Ferristratum sp. (uncultivated gen. nov.) from the uncharacterized DTB120 phylum. Candidatus Ferristratum sp., described using nine high-quality metagenome-assembled genomes with similar distributions of genes, expressed nitrate reduction genes narGH and the iron oxidation gene cyc2 in situ and in response to Fe(II) in a shipboard incubation, suggesting it is an anaerobic nitrate-reducing iron oxidizer. Candidatus Ferristratum sp. lacks a full denitrification pathway, relying on Zetaproteobacteria to remove intermediates like nitrite. Thus, at Lōʻihi, anaerobic iron oxidizers coexist with and are dependent on aerobic iron oxidizers. In total, our work shows how key community members work together to connect iron oxidation with carbon and nitrogen cycling, thus driving the biogeochemistry of exported fluids. 
    more » « less
  5. ; ; ; ; ; (, Geochemistry, Geophysics, Geosystems)
    Abstract Although the serpentinite‐hosted Lost City hydrothermal field (LCHF) was discovered more than 20 years ago, it remains unclear whether and how the presence of microbes affects the mineralogy and textures of the hydrothermal chimney structures. Most chimneys have flow textures comprised of mineral walls bounding paleo‐channels, which are preserved in inactive vent structures to a varying degree. Brucite lines the internal part of these channels, while aragonite dominates the exterior. Calcite is also present locally, mostly associated with brucite. Based on a combination of microscopic and geochemical analyses, we interpret brucite, calcite, and aragonite as primary minerals that precipitate abiotically from mixing seawater and hydrothermal fluids. We also observed local brucite precipitation on microbial filaments and, in some cases, microbial filaments may affect the growth direction of brucite crystals. Brucite is more fluorescent than carbonate minerals, possibly indicating the presence of organic compounds. Our results point to brucite as an important substrate for microbial life in alkaline hydrothermal systems. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Save / Share this Record
  • Send to Email