Luther George W.

Last Name

Luther

First Name

George W.

Full item page

Search Results

Now showing 1 - 11 of 11

Chemistry, temperature, and faunal distributions at diffuse-flow hydrothermal vents : comparison of two geologically distinct ridge systems

(The Oceanography Society, 2012-03) Luther, George W. ; Gartman, Amy ; Yucel, Mustafa ; Madison, Andrew S. ; Moore, Tommy S. ; Nees, Heather A. ; Nuzzio, Donald B. ; Sen, Arunima ; Lutz, Richard A. ; Shank, Timothy M. ; Fisher, Charles R.

Diffuse-flow, low-temperature areas near hydrothermal vents support life via chemosynthesis: hydrogen sulfide (and other reduced chemical compounds) emanating from the subsurface is oxidized with bottom-water oxygen through bacterial mediation to fix carbon dioxide and produce biomass. This article reviews the in situ diffuse-flow chemistry (mainly H2S and O2) and temperature data collected in 2006 and 2009 along the Eastern Lau Spreading Center (ELSC), and from 2004 to 2008 at 9°N along the East Pacific Rise (9 N EPR), predominantly around macrofauna that contain endosymbionts at these two hydrothermal vent regions. More than 48,000 and 20,000 distinct chemical and temperature data points were collected with a multi-analyte electrochemical analyzer in the diffuse-flow waters at 9 N EPR and the ELSC, respectively. Despite their different geological settings and different macrofauna (two different species of snails and mussels at the ELSC versus two different species of tubeworms and mussels at 9 N EPR), there are similarities in the temperature and chemistry data, as well as in the distributions of organisms. The pattern of water chemistry preferred by the provannid snails (Alviniconcha spp., Ifremeria nautilei) and Bathymodiolus brevior at the ELSC is similar to the water chemistry pattern found for the siboglinid tubeworms (Tevnia jerichonana, Riftia pachyptila) and the Bathymodiolus thermophilus mussels at 9 N EPR. The eruptions at 9 N EPR in 2005 and 2006 resulted in increased H2S concentrations, increased H2S/T ratios, and an initial change in the dominant tubeworm species from Riftia pachyptila to Tevnia jerichonana after the eruption created new vent habitats. In 2005, two sites at 9 N EPR showed major increases in the H2S/T ratio from 2004, which suggested a probable eruption in this basalt-dominated system. At the ELSC, there was a decrease in the H2S/T ratio from northern to southern sites, which reflects the change in geological setting from basalt to andesite and the shallower water depths at the southern sites.
Water column data from samples collected on R/V Hugh Sharp cruise HRS1709 in the Chesapeake Bay in August 2017

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-02-19) Luther, George W. ; Tebo, Bradley M.

Water column data from samples collected on R/V Hugh Sharp cruise HRS1709 in the Chesapeake Bay in August 2017. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/840678
CTD data and analyses of bottles from CTD rosette samples collected on R/V Hugh R. Sharp cruise HRS1415 in August 2014

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-01-14) Luther, George W. ; Tebo, Bradley M.

CTD data and analyses of bottles from CTD rosette samples collected on cruise HRS1415. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/717687
Data from in situ pump profiler system collected on R/V Hugh R. Sharp cruise HRS1415 in August 2014

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-01-10) Luther, George W. ; Tebo, Bradley M.

Data from in situ pump profiler system collected on R/V Hugh R. Sharp cruise HRS1415 in August 2014 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/718887
Event Log from R/V Hugh R. Sharp cruise HRS1415 in the Chesapeake Bay and coastal Atlantic Ocean in August 2014

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2020-01-10) Luther, George W. ; Tebo, Bradley M.

Event Log from R/V Hugh R. Sharp cruise HRS1415 in the Chesapeake Bay and coastal Atlantic Ocean in August 2014 For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/717994
Water column data from samples collected on R/V Hugh Sharp cruise HRS1803GL in the Chesapeake Bay during July-August 2018

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-06-11) Luther, George W. ; Tebo, Bradley M.

Water column data from samples collected on R/V Hugh Sharp cruise HRS1803GL in the Chesapeake Bay during July-August 2018. Samples were collected by CTD and from an in situ pump profiler system attached to the CTD rosette. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/853038
Porewater H2S from a multi-core sample taken on R/V Hugh Sharp cruise HRS1709 in the Chesapeake Bay in August 2017

(Biological and Chemical Oceanography Data Management Office (BCO-DMO). Contact: bco-dmo-data@whoi.edu, 2021-02-19) Luther, George W. ; Tebo, Bradley M.

Porewater H2S from a multi-core sample taken on R/V Hugh Sharp cruise HRS1709 in the Chesapeake Bay in August 2017. For a complete list of measurements, refer to the full dataset description in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: https://www.bco-dmo.org/dataset/840754
Hydrothermal vent mussel habitat chemistry, pre- and post-eruption at 9°50′North on the East Pacific Rise

(National Shellfisheries Association, 2008-03) Nees, Heather A. ; Moore, Tommy S. ; Mullaugh, Katherine M. ; Holyoke, Rebecca R. ; Janzen, Christopher P. ; Ma, Shufen ; Metzger, Edouard ; Waite, Tim J. ; Yucel, Mustafa ; Lutz, Richard A. ; Shank, Timothy M. ; Vetriani, Costantino ; Nuzzio, Donald B. ; Luther, George W.

Between October 2005 and March 2006, a seafloor volcanic eruption occurred at 9°50′N East Pacific Rise (EPR), establishing a “time zero” for characterizing newly-formed hydrothermal vent habitats and comparing them to pre-eruption habitats. Before the eruption, mussels (Bathymodiolus thermophilus) formed large aggregates between 9°49.6′ and 9°50.3′N. After the eruption, the few mussels remaining were in sparsely-distributed individuals and clumps, seemingly transported via lava flows or from mass wasting of the walls of the axial trough. In situ voltammetry with solid state gold-amalgam microelectrodes was used to characterize the chemistry of vent fluids in mussel habitats from 2004 to 2007, providing data sets for comparison of oxygen, sulfide, and temperature. Posteruption fluids contained higher sulfide-to-temperature ratios (i.e., slopes of linear regressions) (10.86 μM °C−1) compared with pre-eruption values in 2004 and 2005 (2.79 μM °C−1 and −0.063 μM °C−1, respectively). These chemical differences can be attributed to the difference in geographic location in which mussels were living and physical factors arising from posteruptive fluid emissions.
Interrelationships between vent fluid chemistry, temperature, seismic activity, and biological community structure at a mussel-dominated, deep-sea hydrothermal vent along the East Pacific Rise

(National Shellfisheries Association, 2008-03) Lutz, Richard A. ; Shank, Timothy M. ; Luther, George W. ; Vetriani, Costantino ; Tolstoy, Maya ; Nuzzio, Donald B. ; Moore, Tommy S. ; Waldhauser, Felix ; Crespo-Medina, Melitza ; Chatziefthimiou, Aspassia D. ; Annis, Eric R. ; Reed, Andrew J.

In April 1991, submarine volcanic eruptions initiated the formation of numerous hydrothermal vents between 9°45′ and 9°52′N along the crest of the East Pacific Rise (EPR). Dramatic changes in biological community structure and vent fluid chemistry have been documented throughout this region since the eruptive event. By April 2004, mussels (Bathymodiolus thermophilus) dominated the faunal assemblages at several of the vent sites formed during of after the 1991 eruptions, whereas other habitats within the region were dominated by the vestimentiferan Riftia pachyptila. In the present paper, we build upon the extensive data sets obtained at these sites over the past decade and describe a manipulative experiment (conducted at 9°49.94′N; 104°14.43′W on the EPR) designed to assess interrelationships between vent fluid chemistry, temperature, biological community structure, and seismic activity. To this end, in situ voltammetric systems and thermal probes were used to measure H2S/HS− and temperature over time in a denuded region of an extensive mussel bed in which an exclusion cage was placed to inhibit the subsequent migration of mussels into the denuded area. Fluid samples were taken from the same locations to characterize the associated microbial constituents. Basalt blocks, which were placed in the cage in April 2004 and subsequently recovered in April 2005, were colonized by more than 25 different species of invertebrates, including numerous vestimentiferans and remarkably few mussels. Recorded temporal changes in vent fluid chemistry and temperature regimes, when coupled with microbiological characterization of the vent fluids and seismic activity data obtained from ocean bottom seismometers, shed considerable light on factors controlling biological community structure in these hydrothermal ecosystems.
Microbial iron mats at the Mid-Atlantic Ridge and evidence that Zetaproteobacteria may be restricted to iron-oxidizing marine systems

(Public Library of Science, 2015-03-11) Scott, Jarrod J. ; Breier, John A. ; Luther, George W. ; Emerson, David

Chemolithoautotrophic iron-oxidizing bacteria play an essential role in the global iron cycle. Thus far, the majority of marine iron-oxidizing bacteria have been identified as Zetaproteobacteria, a novel class within the phylum Proteobacteria. Marine iron-oxidizing microbial communities have been found associated with volcanically active seamounts, crustal spreading centers, and coastal waters. However, little is known about the presence and diversity of iron-oxidizing communities at hydrothermal systems along the slow crustal spreading center of the Mid-Atlantic Ridge. From October to November 2012, samples were collected from rust-colored mats at three well-known hydrothermal vent systems on the Mid-Atlantic Ridge (Rainbow, Trans-Atlantic Geotraverse, and Snake Pit) using the ROV Jason II. The goal of these efforts was to determine if iron-oxidizing Zetaproteobacteria were present at sites proximal to black smoker vent fields. Small, diffuse flow venting areas with high iron(II) concentrations and rust-colored microbial mats were observed at all three sites proximal to black smoker chimneys. A novel, syringe-based precision sampler was used to collect discrete microbial iron mat samples at the three sites. The presence of Zetaproteobacteria was confirmed using a combination of 16S rRNA pyrosequencing and single-cell sorting, while light micros-copy revealed a variety of iron-oxyhydroxide structures, indicating that active iron-oxidizing communities exist along the Mid-Atlantic Ridge. Sequencing analysis suggests that these iron mats contain cosmopolitan representatives of Zetaproteobacteria, but also exhibit diversity that may be uncommon at other iron-rich marine sites studied to date. A meta-analysis of publically available data encompassing a variety of aquatic habitats indicates that Zetaproteobacteria are rare if an iron source is not readily available. This work adds to the growing understanding of Zetaproteobacteria ecology and suggests that this organism is likely locally restricted to iron-rich marine environments but may exhibit wide-scale geographic distribution, further underscoring the importance of Zetaproteobacteria in global iron cycling.
Oxidative formation and removal of complexed Mn(III) by Pseudomonas species

(Frontiers Media, 2018-04-12) Wright, Mitchell H. ; Geszvain, Kati ; Oldham, Véronique E. ; Luther, George W. ; Tebo, Bradley M.

The observation of significant concentrations of soluble Mn(III) complexes in oxic, suboxic, and some anoxic waters has triggered a re-evaluation of the previous Mn paradigm which focused on the cycling between soluble Mn(II) and insoluble Mn(III,IV) species as operationally defined by filtration. Though Mn(II) oxidation in aquatic environments is primarily bacterially-mediated, little is known about the effect of Mn(III)-binding ligands on Mn(II) oxidation nor on the formation and removal of Mn(III). Pseudomonas putida GB-1 is one of the most extensively investigated of all Mn(II) oxidizing bacteria, encoding genes for three Mn oxidases (McoA, MnxG, and MopA). P. putida GB-1 and associated Mn oxidase mutants were tested alongside environmental isolates Pseudomonas hunanensis GSL-007 and Pseudomonas sp. GSL-010 for their ability to both directly oxidize weakly and strongly bound Mn(III), and to form these complexes through the oxidation of Mn(II). Using Mn(III)-citrate (weak complex) and Mn(III)-DFOB (strong complex), it was observed that P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 and mutants expressing only MnxG and McoA were able to directly oxidize both species at varying levels; however, no oxidation was detected in cultures of a P. putida mutant expressing only MopA. During cultivation in the presence of Mn(II) and citrate or DFOB, P. putida GB-1, P. hunanensis GSL-007 and Pseudomonas sp. GSL-010 formed Mn(III) complexes transiently as an intermediate before forming Mn(III/IV) oxides with the overall rates and extents of Mn(III,IV) oxide formation being greater for Mn(III)-citrate than for Mn(III)-DFOB. These data highlight the role of bacteria in the oxidative portion of the Mn cycle and suggest that the oxidation of strong Mn(III) complexes can occur through enzymatic mechanisms involving multicopper oxidases. The results support the observations from field studies and further emphasize the complexity of the geochemical cycling of manganese.

Luther George W.

Last Name

First Name

ORCID

Filters

Author

Subject

Date

Type

Has files

Settings

Sort By

Results per page

Search Results