Identification of Novel Methane-, Ethane-, and Propane-Oxidizing Bacteria at Marine Hydrocarbon Seeps by Stable Isotope Probing

Marine hydrocarbon seeps supply oil and gas to microorganisms in sediments and overlying water. We used stable isotope probing (SIP) to identify aerobic bacteria oxidizing gaseous hydrocarbons in surface sediment from the Coal Oil Point seep field located offshore of Santa Barbara, California. After incubating sediment with ^(13)C-labeled methane, ethane, or propane, we confirmed the incorporation of ^(13)C into fatty acids and DNA. Terminal restriction fragment length polymorphism (T-RFLP) analysis and sequencing of the 16S rRNA and particulate methane monooxygenase (pmoA) genes in ^(13)C-DNA revealed groups of microbes not previously thought to contribute to methane, ethane, or propane oxidation. First, ^(13)C methane was primarily assimilated by Gammaproteobacteria species from the family Methylococcaceae, Gammaproteobacteria related to Methylophaga, and Betaproteobacteria from the family Methylophilaceae. Species of the latter two genera have not been previously shown to oxidize methane and may have been cross-feeding on methanol, but species of both genera were heavily labeled after just 3 days. pmoA sequences were affiliated with species of Methylococcaceae, but most were not closely related to cultured methanotrophs. Second, ^(13)C ethane was consumed by members of a novel group of Methylococcaceae. Growth with ethane as the major carbon source has not previously been observed in members of the Methylococcaceae; a highly divergent pmoA-like gene detected in the ^(13)C-labeled DNA may encode an ethane monooxygenase. Third, ^(13)C propane was consumed by members of a group of unclassified Gammaproteobacteria species not previously linked to propane oxidation. This study identifies several bacterial lineages as participants in the oxidation of gaseous hydrocarbons in marine seeps and supports the idea of an alternate function for some pmoA-like genes

Light Rare Earth Element Depletion During Deepwater Horizon Blowout Methanotrophy

Rare earth elements have generally not been thought to have a biological role. However, recent work has demonstrated that the light REEs (LREEs: La, Ce, Pr, and Nd) are essential for at least some methanotrophs, being co-factors in the XoxF type of methanol dehydrogenase (MDH). We show here that dissolved LREEs were significantly removed in a submerged plume of methane-rich water during the Deepwater Horizon (DWH) well blowout. Furthermore, incubation experiments conducted with naturally methane-enriched waters from hydrocarbon seeps in the vicinity of the DWH wellhead also showed LREE removal concurrent with methane consumption. Metagenomic sequencing of incubation samples revealed that LREE-containing MDHs were present. Our field and laboratory observations provide further insight into the biochemical pathways of methanotrophy during the DWH blowout. Additionally, our results are the first observations of direct biological alteration of REE distributions in oceanic systems. In view of the ubiquity of LREE-containing MDHs in oceanic systems, our results suggest that biological uptake of LREEs is an overlooked aspect of the oceanic geochemistry of this group of elements previously thought to be biologically inactive and an unresolved factor in the flux of methane, a potent greenhouse gas, from the ocean

Light Rare Earth Element Depletion During Deepwater Horizon Blowout Methanotrophy

Rare earth elements have generally not been thought to have a biological role. However, recent work has demonstrated that the light REEs (LREEs: La, Ce, Pr, and Nd) are essential for at least some methanotrophs, being co-factors in the XoxF type of methanol dehydrogenase (MDH). We show here that dissolved LREEs were significantly removed in a submerged plume of methane-rich water during the Deepwater Horizon (DWH) well blowout. Furthermore, incubation experiments conducted with naturally methane-enriched waters from hydrocarbon seeps in the vicinity of the DWH wellhead also showed LREE removal concurrent with methane consumption. Metagenomic sequencing of incubation samples revealed that LREE-containing MDHs were present. Our field and laboratory observations provide further insight into the biochemical pathways of methanotrophy during the DWH blowout. Additionally, our results are the first observations of direct biological alteration of REE distributions in oceanic systems. In view of the ubiquity of LREE-containing MDHs in oceanic systems, our results suggest that biological uptake of LREEs is an overlooked aspect of the oceanic geochemistry of this group of elements previously thought to be biologically inactive and an unresolved factor in the flux of methane, a potent greenhouse gas, from the ocean

Fate of dispersants associated with the Deepwater Horizon oil spill

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of American Chemical Society for personal use, not for redistribution. The definitive version was published in Environmental Science & Technology 45 (2011):1298–1306, doi:10.1021/es103838p.Response actions to the Deepwater Horizon oil spill included the injection of ~771,000 gallons (2,900,000 L) of chemical dispersant into the flow of oil near the seafloor. Prior to this incident, no deepwater applications of dispersant had been conducted and thus no data exists on the environmental fate of dispersants in deepwater. We used ultrahigh resolution mass spectrometry and liquid chromatography with tandem mass spectrometry (LC/MS/MS) to identify and quantify one key ingredient of the dispersant, the anionic surfactant DOSS (dioctyl sodium sulfosuccinate), in the Gulf of Mexico deepwater during active flow and again after flow had ceased. Here we show that DOSS was sequestered in deepwater hydrocarbon plumes at 1000-1200m water depth and did not intermingle with surface dispersant applications. Further, its concentration distribution was consistent with conservative transport and dilution at depth and it persisted up to 300 km from the well, 64 days after deepwater dispersant applications ceased. We conclude that DOSS was selectively associated with the oil and gas phases in the deepwater plume, yet underwent negligible, or slow, rates of biodegradation in the affected waters. These results provide important constraints on accurate modeling of the deepwater plume and critical geochemical contexts for future toxicological studies.The authors gratefully acknowledge funding from the National Science Foundation’s RAPID program (OCE-1045811 to EBK, OCE-1042097 to DLV, OCE-1042650 to J. D. Kessler for R/V Cape Hatteras cruise) and from the WHOI Director of Research. Instrumentation in the WHOI FT-MS facility was funded by the National Science Foundation MRI program (OCE-0619608) and by the Gordon and Betty T. Moore Foundation. Stipend support for A. Boysen was provided by the WHOI Summer Student Fellow Program

The Ursinus Weekly, October 21, 1971

Nat. opinion poll indicates approval of legal abortion • President Pettit approves 3rd U.S.G.A. open dorm proposal • Action-packed Homecoming slated for Saturday, October 30 • Andrew Wyeth to receive degree on Founder\u27s Day • Ursinus professors present history forum October 20th • Editorial: Sign out • Focus: Rich Hofferman • Enforced adolescence: Place on the college community? • I.R. Club hosts to model U.N. • Probable parable • Spotlight: Pauline D. Pearson • Evening School enrolls 745; Numbers down • Women enjoy freedom with extended curfew • Soccer undefeated; 2-0-2 record • Third team rolls • Feiger\u27s field goal wins for Ursinushttps://digitalcommons.ursinus.edu/weekly/1109/thumbnail.jp

The Ursinus Weekly, June 2, 1972

Campus Chest presents: You can\u27t take it with you • New gym named Helfferich Hall • U.C. receives $100,000 grant from Kresge Foundation • Ursinus to confer 261 degrees at June 4 commencement • Ursinus suffers blackout; Transformer explodes • Scrounge Lounge opens; Provides place for chat • Editorial: The year of optimism • U.C. arts festival attracts hundreds • ProTheatre presents: Marat / Sade • President presents Ronnie Hollyman • Object d\u27art appears; Graces Library steps • President Pettit approves 3rd U.S.G.A. open dorm proposal • Kevin Akey elected new USGA president • Renovations: a new look for Pfahler • Ursinus Meistersingers plan 34th annual tour • WRUC-FM presents Jaime Brockett concert • Ursinus math team ranked in top 20 • I.R.C. welcomes 120 students to M.U.N.C. on U.C. campus • A. Wyeth, H.C. Pitz, and J.W. Merriam receive honorary degrees • Obituaries: Dr. John Jacob Heilemann, professor of physics, dies; Dr. Helen T. Garrett dies; Mrs. Dorothy A. Towers dies; Longtime Paisley resident head • Swimmers, Snellbelles off to regionals • Snellbelles undefeated • Bears close season with 4-4 record • Messiah sung tonight; Annual U.C. tradition • Women enjoy freedom with extended curfew • Ursinus Harriers place second in Middle Atlantic Conferencehttps://digitalcommons.ursinus.edu/weekly/1125/thumbnail.jp

The Ursinus Weekly, December 9, 1971

Gulf Oil Corporation awards scholarships to U.C. science scholars • Scrounge Lounge opens; Provides place for chat • Traditional banquet takes on a new look • Seven Ursinus seniors named to Who\u27s who • Memorial service: Dr. John Vorrath • Ecological concern group sponsors recycling project • Editorial: False alarm; Scrounge! • Focus: Stan Talley • Messiah sung tonight; Annual U.C. tradition • Faculty portrait: Mr. Walter Marsteller • Administration answers • Ursinus presents gift of $1,500 to Collegeville • Francis Davis speaks at Sigma Xi meeting • Slumming it • Critic\u27s choice: Thanksgiving, Marcus Welby M.D., Jamie Brockett and hayrides • Spotlight: Mr. Philip Harvey • Bears even record; Future looks good • Their work is never done • Letter to the editor • Soccer season closes: 4 wins, 7 losses, 3 ties • USGA notes • Outing Club braves cold • Ursinus Harriers place second in Middle Atlantic Conferencehttps://digitalcommons.ursinus.edu/weekly/1114/thumbnail.jp

Investigations of Aerobic Methane Oxidation in Two Marine Seep Environments: Part 1—Chemical Kinetics

Microbial aerobic oxidation is known to be a significant sink of marine methane (CH4), contributing to the relatively minor atmospheric release of this greenhouse gas over vast stretches of the ocean. However, the chemical kinetics of aerobic CH4 oxidation are not well established, making it difficult to predict and assess the extent that CH4 is oxidized in seawater following seafloor release. Here we investigate the kinetics of aerobic CH4 oxidation using mesocosm incubations of fresh seawater samples collected from seep fields in Hudson Canyon, U.S. Atlantic Margin and MC118, Gulf of Mexico to gain a fundamental chemical understanding of this CH4 sink. The goals of this investigation were to determine the response or lag time following CH4 release until more rapid oxidation begins, the reaction order, and the stoichiometry of reactants utilized (i.e., CH4, oxygen, nitrate, phosphate, trace metals) during CH4 oxidation. The results for both Hudson Canyon and MC118 environments show that CH4 oxidation rates sharply increased within less than one month following the CH4 inoculation of seawater. However, the exact temporal characteristics of this more rapid CH4 oxidation varied based on location, possibly dependent on the local circulation and biogeochemical conditions at the point of seawater collection. The data further suggest that methane oxidation behaves as a first‐order kinetic process and that the reaction rate constant remains constant once rapid CH4 oxidation begins

Investigations of Aerobic Methane Oxidation in Two Marine Seep Environments: Part 2—Isotopic Kinetics

During aerobic oxidation of methane (CH4) in seawater, a process which mitigates atmospheric emissions, the 12C‐isotopologue reacts with a slightly greater rate constant than the 13C‐isotopologue, leaving the residual CH4 isotopically fractionated. Prior studies have attempted to exploit this systematic isotopic fractionation from methane oxidation to quantify the extent that a CH4 pool has been oxidized in seawater. However, cultivation‐based studies have suggested that isotopic fractionation fundamentally changes as a microbial population blooms in response to an influx of reactive substrates. Using a systematic mesocosm incubation study with recently collected seawater, here we investigate the fundamental isotopic kinetics of aerobic CH4 oxidation during a microbial bloom. As detailed in a companion paper, seawater samples were collected from seep fields in Hudson Canyon, U.S. Atlantic Margin, and atop Woolsey Mound (also known as Sleeping Dragon) which is part of lease block MC118 in the northern Gulf of Mexico, and used in these investigations. The results from both Hudson Canyon and MC118 show that in these natural environments isotopic fraction for CH4 oxidation follows a first‐order kinetic process. The results also show that the isotopic fractionation factor remains constant during this methanotrophic bloom once rapid CH4 oxidation begins and that the magnitude of the fractionation factor appears correlated with the first‐order reaction rate constant. These findings greatly simplify the use of natural stable isotope changes in CH4 to assess the extent that CH4 is oxidized in seawater following seafloor release