Microbial communities in dark oligotrophic volcanic ice cave ecosystems of Mt. Erebus, Antarctica.

The Earth's crust hosts a subsurface, dark, and oligotrophic biosphere that is poorly understood in terms of the energy supporting its biomass production and impact on food webs at the Earth's surface. Dark oligotrophic volcanic ecosystems (DOVEs) are good environments for investigations of life in the absence of sunlight as they are poor in organics, rich in chemical reactants and well known for chemical exchange with Earth's surface systems. Ice caves near the summit of Mt. Erebus (Antarctica) offer DOVEs in a polar alpine environment that is starved in organics and with oxygenated hydrothermal circulation in highly reducing host rock. We surveyed the microbial communities using PCR, cloning, sequencing and analysis of the small subunit (16S) ribosomal and Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (RubisCO) genes in sediment samples from three different caves, two that are completely dark and one that receives snow-filtered sunlight seasonally. The microbial communities in all three caves are composed primarily of Bacteria and fungi; Archaea were not detected. The bacterial communities from these ice caves display low phylogenetic diversity, but with a remarkable diversity of RubisCO genes including new deeply branching Form I clades, implicating the Calvin-Benson-Bassham (CBB) cycle as a pathway of CO2 fixation. The microbial communities in one of the dark caves, Warren Cave, which has a remarkably low phylogenetic diversity, were analyzed in more detail to gain a possible perspective on the energetic basis of the microbial ecosystem in the cave. Atmospheric carbon (CO2 and CO), including from volcanic emissions, likely supplies carbon and/or some of the energy requirements of chemoautotrophic microbial communities in Warren Cave and probably other Mt. Erebus ice caves. Our work casts a first glimpse at Mt. Erebus ice caves as natural laboratories for exploring carbon, energy and nutrient sources in the subsurface biosphere and the nutritional limits on life

Defining the word “seamount”

Author Posting. © Oceanography Society, 2010. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 23, 1 (2010): 20-21.The term seamount has been defined many times (e.g., Menard, 1964; Wessel, 2001; Schmidt and Schmincke, 2000; Pitcher et al., 2007; International Hydrographic Organization, 2008; Wessel et al., 2010) but there is no “generally accepted” definition. Instead, most definitions serve the particular needs of a discipline or a specific paper

Seamount Catalong: Seamount Morphology, Maps, and Data Files

Seamount research, more often than not, is carried out by highly specialized science teams with narrowly focused science objectives. As a result, different seamount science disciplines often do not collaborate or are not even aware of each other. However, it is obvious that interdisciplinary collaboration is the most successful approach to help understand the integrated chemical, physical, and biological systems at seamounts. The Seamount Biogeoscience Network (SBN) was founded to promote the necessary cooperation through workshops, publications, and the development of a database that allows all seamount sciences to share data. Among such data, bathymetric maps are the most fundamental to all disciplines

Vailulu’u Seamount

Author Posting. © Oceanography Society, 2010. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 23, 1 (2010): 164-165.Vailulu’u seamount is an active underwater volcano that marks the end of the Samoan hotspot trail

Scalable models of data sharing in Earth sciences

Many Earth science disciplines are currently experiencing the emergence of new ways of data publication and the establishment of an information technology infrastructure for data archiving and exchange. Building on efforts to standardize data and metadata publication in geochemistry [Staudigel et al., 2002], here we discuss options for data publication, archiving and exchange. All of these options have to be structured to meet some minimum requirements of scholarly publication, in particular reliability of archival, reproducibility and falsifiability. All data publication and archival methods should strive to produce databases that are fully interoperable and this requires an appropriate data and metadata interchange protocol. To accomplish the latter we propose a new Metadata Interchange Format (.mif ) that can be used for more effective sharing of data and metadata across digital libraries, data archives, and research projects. This is not a proposal for a particular set of metadata parameters but rather of a methodology that will enable metadata parameter sets to be easily developed and interchanged between research organizations. Examples are provided for geochemical data as well as map images to illustrate the flexibility of the approach.Keywords: geosciences, metadata, publication, interdisciplinary, data management, data sharingKeywords: geosciences, metadata, publication, interdisciplinary, data management, data sharin

Seamount sciences : quo vadis?

Author Posting. © Oceanography Society, 2010. This article is posted here by permission of Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 23, 1 (2010): 212-213.Seamounts are fascinating natural ocean laboratories that inform us about fundamental planetary and ocean processes, ocean ecology and fisheries, and hazards and metal resources. The more than 100,000 large seamounts are a defining structure of global ocean topography and biogeography, and hundreds of thousands of smaller ones are distributed throughout every ocean on Earth

High-resolution ⁴⁰Ar/³⁹Ar dating of the oldest oceanic basement basalts in the western Pacific basin

We report new ⁴⁰Ar/³⁹Ar ages for the oldest Pacific oceanic floor at Ocean Drilling Program Site 801C in the Pigafetta basin and Site 1149D close to the Izu-Bonin subduction zone in the Nadezhda basin. These ages were determined by applying high-resolution incremental heating experiments (including 15–30 heating steps) to better resolve the primary argon signal from interfering alteration signatures in these low-potassium ocean crust basalts. Combined with previous results from Pringle [1992] for Site 801B and 801C, we arrive at a multistage history for the formation of the Pigafetta ocean crust. The oldest part of the Pacific plate was formed at the spreading ridges at 167.4 ± 1.4/3.4 Ma (n = 2, 2σ internal/absolute error), offering an important calibration point on the Geological Reversal Timescale (GRTS) since it represents the old end of the Mesozoic magnetic anomalies. This mid-ocean ridge basalt sequence, however, is overlain by more tholeiites and alkali basalts that were formed 7.3 ± 1.5 Myr later around 160.1 ± 0.6 Ma (n = 7, 2σ internal error). The older age group is confirmed independently by radiolarian ages ranging from Late Bajocian to Middle Bathonian (167–173 Ma [Bartolini and Larson, 2001]) and by profound differences in the structural characteristics of this basement section [Pockalny and Larson, 2003]. Thin layers comprising hydrothermal deposits separate these sequences, which in addition to the difference in isotopic age show distinct major and trace element compositions. This indicates that key volcanic and hydrothermal activity took place 400–600 km away from the spreading ridges, on the basis of a Jurassic ~66 km/Myr half spreading rate in the Pacific. It remains unclear if these processes were active continuously after the initial formation of the Pacific oceanic crust, but all our observations seem to point to an episodic history. Site 1149D gives another important calibration point on the GRTS of 127.0 ± 1.5/3.6 Ma (n = 1, 2σ internal/absolute error) for anomaly M12 that is slightly younger when compared to current timescale compilations (134.2 ± 2.1 Ma [Gradstein et al., 1995]). This might suggest that the dated basalt from Site 1149D does not represent the age of the ocean crust formed at its ridge axis; it may also be part of the Early Cretaceous intraplate events that have produced dolerite sills in the Pacific crust at Sites 800 and 802 around 114–126 Ma