A5027625709- Marine and coastal ecosystems
- Microbial Community Ecology and Physiology
- Methane Hydrates and Related Phenomena
- Marine Biology and Ecology Research
- Ocean Acidification Effects and Responses
- Isotope Analysis in Ecology
- Geology and Paleoclimatology Research
- Protist diversity and phylogeny
- Genomics and Phylogenetic Studies
- Radioactive contamination and transfer
- Atmospheric and Environmental Gas Dynamics
- Radioactivity and Radon Measurements
- Radioactive element chemistry and processing
- Epigenetics and DNA Methylation
- Geological and Tectonic Studies in Latin America
- Geological and Geophysical Studies
- Maritime and Coastal Archaeology
- Botany and Geology in Latin America and Caribbean
- Marine Bivalve and Aquaculture Studies
- Pacific and Southeast Asian Studies
- Archaeology and ancient environmental studies
- Estrogen and related hormone effects
- Oceanographic and Atmospheric Processes
- Effects and risks of endocrine disrupting chemicals
- Hydrocarbon exploration and reservoir analysis
Woods Hole Oceanographic Institution
2022-2024
International University of Monaco
2016-2020
University of Vienna
2013-2019
International Atomic Energy Agency
2019
Scripps Institution of Oceanography
2006-2016
California Institute of Technology
2010-2015
University of California, San Diego
2013
National Institutes of Health
2003
National Cancer Institute
2003
An ammonia-oxidizing, carbon-fixing archaeon, Candidatus “ Nitrosopumilus maritimus ,” recently was isolated from a salt-water aquarium, definitively confirming that chemoautotrophy exists among the marine archaea. However, in other incubation studies, pelagic archaea also were capable of using organic carbon. It has remained unknown what fraction total archaeal community is autotrophic situ . If live primarily as autotrophs natural environment, large ammonia-oxidizing population would play...
Abstract. The deep sea is often viewed as a vast, dark, remote, and inhospitable environment, yet the ocean seafloor are crucial to our lives through services that they provide. Our understanding of how functions remains limited, but when treated synoptically, diversity supporting, provisioning, regulating cultural becomes apparent. biological pump transports carbon from atmosphere into deep-ocean water masses separated over prolonged periods, reducing impact anthropogenic release. Microbial...
Dilution solves the recalcitrance question The deep ocean is full of dissolved organic carbon, some which has remained unchanged for thousands years. What makes these compounds so resistant to microbial degradation? Perhaps their chemical structures make them intrinsically difficult metabolize? In contrast, Arrieta et al. show that they are simply too dilute be viable sources energy microorganisms (see Perspective by Middleburg). Further experiments if seemingly recalcitrant molecules...
Perinatal exposure to diethylstilbestrol (DES) induces reproductive tract cancers later in life both humans and animals. Because there is no clear evidence that perinatal DES gene mutation, we proposed causes epigenetic methylation changes result persistent alterations expression, leading tumorigenesis. The proto-oncogene c-fos one of the immediately induced genes uterine epithelium after estrogen simulation a key player carcinogenesis. Here, investigated expression mice neonatally exposed...
Several lines of evidence indicate that microorganisms in the meso- and bathypelagic ocean are metabolically active respiring carbon. In addition, growing suggests archaea fixing inorganic carbon this environment. However, direct quantification contribution from deep sources to community production dark remains a challenge. study, flow through microbial at 2 depths mesopelagic zone North Pacific Subtropical Gyre was examined by exploiting unique radiocarbon signatures (Delta(14)C) 3 major...
Summary Ammonia‐oxidizing archaea (AOA) constitute a considerable fraction of microbial biomass in the global ocean, comprising 20%–40% ocean's prokaryotic plankton. However, it remains enigmatic to what extent these chemolithoautotrophic release dissolved organic carbon (DOC). A combination targeted and untargeted metabolomics was used characterize exometabolomes three model AOA strains Nitrosopumilus genus. Our results indicate that marine exude suite compounds with potentially varying...
The vast majority of freshly produced oceanic dissolved organic carbon (DOC) is derived from marine phytoplankton, then rapidly recycled by heterotrophic microbes. A small fraction this DOC survives long enough to be routed the interior ocean, which houses largest and oldest reservoir. reactivity depends upon its intrinsic chemical composition extrinsic environmental conditions. Therefore, recalcitrance an emergent property that analytically difficult constrain. New isotopic techniques track...
Abstract Radiocarbon ( 14 C) measurements on dissolved inorganic carbon (DIC) are a powerful tool to trace water masses and cycling in the ocean. Existing methodologies determine C content of seawater DIC requires large volumes sample (usually >100 mL) specialized graphitization techniques achieve accuracy precision needed for meaningful data interpretation. The advancement CO 2 gas ionization accelerator mass spectrometry (AMS) technique today allows routine small samples (<100 µgC)...
Sixty percent of the world ocean by area is contained in oligotrophic gyres [Longhurst A (1995) Prog Oceanog 36:77–16], biomass which dominated picophytoplankton, including cyanobacteria and picoeukaryotic algae, as well picoheterotrophs. Despite their recognized importance carbon cycling surface ocean, role small cells detrital remains transfer particulate organic matter (POM) to deep disputed. Because marine conditions are projected expand under current climate trends, a better...
Characterizing the composition of marine dissolved organic matter (DOM) is important for gaining insight into its role in oceanic biogeochemical cycles. Using Fourier transform ion cyclotron resonance mass spectrometry, we analyzed molecular solid phase extracted (SPE) DOM from northeast Atlantic to investigate specificity pool individual major water masses North Atlantic. All 272 measured samples depths ranging 87 5609 m and latitudes 24°N 68°N shared 96% similarity (on a Bray–Curtis scale)...
Abstract The carbon isotope ratio (δ 13 C value) of marine particulates is a potentially useful tracer for elucidating pathways flow in the environment. Different species phytoplankton vary fractionation vs. CO 2 by up to 24‰ laboratory cultures under varying nutrient and growth conditions, signal that should propagate through microbial food web. However, such contrasts have been difficult confirm field measurements due analytical limitations. Here, we combine fluorescence‐activated cell...
Radioisotopes have been used in earth and environmental sciences for over 150 years provide unique tools to study processes great detail from a cellular level through an oceanic basin scale. These nuclear techniques employed understand coastal marine ecosystems via laboratory field studies how aquatic organisms respond stressors including temperature, pH, nutrients, metals, organic anthropogenic compounds biological toxins. Global issues, such as ocean warming, deoxygenation, plastic...
ABSTRACT This note describes improvements of UV oxidation method that is used to measure carbon isotopes dissolved organic (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). The procedural blank reduced 2.6 ± 0.6 μg C, with Fm 0.42 0.10 and δ 13 C –28.43 1.19‰. throughput improved from one sample per day two samples day.
Abstract. The deep sea is often viewed as a vast, dark, remote, and inhospitable environment, yet the ocean seafloor are crucial to our lives through services provisions that they provide. Our understanding of how functions remains limited, but when treated synoptically, diversity provisioning, regulating cultural become apparent. biological pump transports carbon from atmosphere into deep-ocean water masses which separated over prolonged periods, reducing impact anthropogenic release....
ABSTRACT Radiocarbon observations (Δ 14 C) in dissolved inorganic carbon (DIC) of seawater provide useful information about ocean cycling and circulation. To deliver high-quality observations, the Laboratory Ion Beam Physics (LIP) at ETH-Zurich developed a new simplified method allowing rapid analysis radiocarbon DIC small samples, which is continually assessed by following internal quality controls. However, comparison with externally produced C measurements to better establish an...
ABSTRACT Sequential thermal analysis allows for deconvoluting the refractory nature and complexity of carbon mixtures embedded in mineral matrices subsequent offline stable radiocarbon ( 14 C) isotope analyses. Originally developed to separate Holocene from more ancient sedimentary organic matter improve dating marine sediments, Ramped Pyrolysis Oxidation (RPO) apparatus, or informally, “dirt burner” is now used address pressing questions broad field biogeochemistry. The growing interest...
Abstract Ammonia-oxidizing archaea (AOA) constitute a considerable fraction of microbial biomass in the global ocean, comprising 20-40% ocean’s prokaryotic plankton and thus play an important role nitrogen cycle. However, it remains enigmatic to what extent these chemolithoautotrophic are releasing dissolved organic matter (DOM). A combination targeted untargeted metabolomics was used characterise exometabolomes three model AOA strains Nitrosopumilus genus. Furthermore, we compared...
<title>Abstract</title> Anaplerotic carbon fixation is ubiquitous in heterotrophic organisms including those inhabiting the ocean1. Despite its prevalence, drivers of this process and significance ocean cycling remain poorly understood2,3. Here we combined global metatranscriptomic analysis, laboratory experiments on a bacterial model strain, microautoradiography with catalyzed reporter deposition fluorescence situ hybridization (MICRO-CARD-FISH) marine microbial communities, to uncover...
Improving the Application of Radionuclides in Studies Carbon Cycle and Impact Ocean Acidification; Monaco, 19–21 October 2016