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pCO2 gradients

Sara G Shen, Andrew R Thompson, Jonathan Correa, Peer Fietzek, Patricia Ayón, David M Checkley
Large and productive fisheries occur in regions experiencing or projected to experience ocean acidification. Anchoveta (Engraulis ringens) constitute the world's largest single-species fishery and live in one of the ocean's highest pCO2 regions. We investigated the relationship of the distribution and abundance of Anchoveta eggs and larvae to natural gradients in pCO2 in the Peruvian upwelling system. Eggs and larvae, zooplankton, and data on temperature, salinity, chlorophyll a and pCO2 were collected during a cruise off Peru in 2013...
May 31, 2017: Proceedings. Biological Sciences
Marius N Müller, Thomas W Trull, Gustaaf M Hallegraeff
Future oceanic conditions induced by anthropogenic greenhouse gas emissions include warming, acidification and reduced nutrient supply due to increased stratification. Some parts of the Southern Ocean are expected to show rapid changes, especially for carbonate mineral saturation. Here we compare the physiological response of the model coccolithophore Emiliania huxleyi (strain EHSO 5.14, originating from 50(o)S, 149(o)E) with pH/CO2 gradients (mimicking ocean acidification ranging from 1 to 4 × current pCO2 levels) under nutrient-limited (nitrogen and phosphorus) and -replete conditions...
April 21, 2017: ISME Journal
Arnaldo Dubin, Mario Omar Pozo
No abstract text is available yet for this article.
December 2017: Annals of Intensive Care
Meri J Eichner, Isabell Klawonn, Samuel T Wilson, Sten Littmann, Martin J Whitehouse, Matthew J Church, Marcel Mm Kuypers, David M Karl, Helle Ploug
Gradients of oxygen (O2) and pH, as well as small-scale fluxes of carbon (C), nitrogen (N) and O2 were investigated under different partial pressures of carbon dioxide (pCO2) in field-collected colonies of the marine dinitrogen (N2)-fixing cyanobacterium Trichodesmium. Microsensor measurements indicated that cells within colonies experienced large fluctuations in O2, pH and CO2 concentrations over a day-night cycle. O2 concentrations varied with light intensity and time of day, yet colonies exposed to light were supersaturated with O2 (up to ~200%) throughout the light period and anoxia was not detected...
June 2017: ISME Journal
Juan Diego Gaitán-Espitia, Dustin Marshall, Sam Dupont, Leonardo D Bacigalupe, Levente Bodrossy, Alistair J Hobday
Geographical gradients in selection can shape different genetic architectures in natural populations, reflecting potential genetic constraints for adaptive evolution under climate change. Investigation of natural pH/pCO2 variation in upwelling regions reveals different spatio-temporal patterns of natural selection, generating genetic and phenotypic clines in populations, and potentially leading to local adaptation, relevant to understanding effects of ocean acidification (OA). Strong directional selection, associated with intense and continuous upwellings, may have depleted genetic variation in populations within these upwelling regions, favouring increased tolerances to low pH but with an associated cost in other traits...
February 2017: Biology Letters
Erinn M Muller, Maoz Fine, Kim B Ritchie
Increasing levels of pCO2 within the oceans will select for resistant organisms such as anemones, which may thrive under ocean acidification conditions. However, increasing pCO2 may alter the bacterial community of marine organisms, significantly affecting the health status of the host. A pH gradient associated with a natural volcanic vent system within Levante Bay, Vulcano Island, Italy, was used to test the effects of ocean acidification on the bacterial community of two anemone species in situ, Anemonia viridis and Actinia equina using 16 S rDNA pyrosequencing...
November 23, 2016: Scientific Reports
J G Toffaletti, C R Rackley
Although part of a common "blood gas" test panel with pH and pCO2, the pO2, %O2Hb, and related parameters are independently used to detect and monitor oxygen deficits from a variety of causes. Measurement of blood gases and cooximetry may be done by laboratory analyzers, point of care testing, noninvasive pulse oximetry, and transcutaneous blood gases. The specimen type and mode of monitoring oxygenation that are chosen may be based on a combination of urgency, practicality, clinical need, and therapeutic objectives...
2016: Advances in Clinical Chemistry
Maxime Tremblin, Michaël Hermoso, Fabrice Minoletti
Growth of the first permanent Antarctic ice sheets at the Eocene-Oligocene Transition (EOT), ∼33.7 million years ago, indicates a major climate shift within long-term Cenozoic cooling. The driving mechanisms that set the stage for this glaciation event are not well constrained, however, owing to large uncertainties in temperature reconstructions during the Eocene, especially at lower latitudes. To address this deficiency, we used recent developments in coccolith biogeochemistry to reconstruct equatorial Atlantic sea surface temperature (SST) and atmospheric pCO2 values from pelagic sequences preceding and spanning the EOT...
October 18, 2016: Proceedings of the National Academy of Sciences of the United States of America
Jennifer Cunniff, Michael Charles, Glynis Jones, Colin P Osborne
BACKGROUND AND AIMS: The reduction of plant productivity by low atmospheric CO2 partial pressure (pCO2) during the last glacial period is proposed as a limiting factor for the establishment of agriculture. Supporting this hypothesis, previous work has shown that glacial pCO2 limits biomass in the wild progenitors of C3 and C4 founder crops, in part due to the direct effects of glacial pCO2 on photosynthesis. Here, we investigate the indirect role of pCO2 mediated via water status, hypothesizing that faster soil water depletion at glacial (18 Pa) compared to post-glacial (27 Pa) pCO2, due to greater stomatal conductance, feeds back to limit photosynthesis during drying cycles...
November 2016: Annals of Botany
H Iroja U Caldera, W A Janendra M De Costa, F Ian Woodward, Janice A Lake, Sudheera M W Ranwala
Stomatal functioning regulates the fluxes of CO2 and water vapor between vegetation and atmosphere and thereby influences plant adaptation to their habitats. Stomatal traits are controlled by external environmental and internal cellular signaling. The objective of this study was to quantify the effects of CO2 enrichment (CE) on stomatal density (SD)-related properties, guard cell length (GCL) and carbon isotope ratio (δ(13) C) of a range of Arabidopsis thaliana ecotypes originating from a wide altitudinal range [50-1260 m above sea level (asl)], and grown at 400 and 800 ppm [CO2 ], and thereby elucidate the possible adaptation and acclimation responses controlling stomatal traits and water use efficiency (WUE)...
January 2017: Physiologia Plantarum
M Wall, J Fietzke, G M Schmidt, A Fink, L C Hofmann, D de Beer, K E Fabricius
The resilience of tropical corals to ocean acidification depends on their ability to regulate the pH within their calcifying fluid (pHcf). Recent work suggests pHcf homeostasis under short-term exposure to pCO2 conditions predicted for 2100, but it is still unclear if pHcf homeostasis can be maintained throughout a corals lifetime. At CO2 seeps in Papua New Guinea, massive Porites corals have grown along a natural seawater pH gradient for decades. This natural gradient, ranging from pH 8.1-7.4, provides an ideal platform to determine corals' pHcf (using boron isotopes)...
2016: Scientific Reports
Renzhong Wang, Linna Ma
There have been debates on the driving factors of C4 plant expansion, such as PCO2 decline in the late Micocene and warmer climate and precipitation at large-scale modern ecosystems. These disputes are mainly due to the lack of direct evidence and extensive data analysis. Here we use mass flora data to explore the driving factors of C4 distribution and divergent patterns for different C4 taxa at continental scale in China. The results display that it is mean annual climate variables driving C4 distribution at present-day vegetation...
2016: Scientific Reports
Carlo Cattano, Folco Giomi, Marco Milazzo
Volcanic CO2 seeps provide opportunities to investigate the effects of ocean acidification on organisms in the wild. To understand the influence of increasing CO2 concentrations on the metabolic rate (oxygen consumption) and the development of ocellated wrasse early life stages, we ran two field experiments, collecting embryos from nesting sites with different partial pressures of CO2 [pCO2; ambient (∼400 µatm) and high (800-1000 µatm)] and reciprocally transplanting embryos from ambient- to high-CO2 sites for 30 h...
2016: Conservation Physiology
Erik A Sperling, Christina A Frieder, Lisa A Levin
Sharp increases in atmospheric CO2 are resulting in ocean warming, acidification and deoxygenation that threaten marine organisms on continental margins and their ecological functions and resulting ecosystem services. The relative influence of these stressors on biodiversity remains unclear, as well as the threshold levels for change and when secondary stressors become important. One strategy to interpret adaptation potential and predict future faunal change is to examine ecological shifts along natural gradients in the modern ocean...
April 27, 2016: Proceedings. Biological Sciences
Norma E Guerra-Hernández, Karen V Ordaz-López, Laura Escobar-Pérez, Circe Gómez-Tenorio, Víctor M García-Nieto
BACKGROUND: Primary distal renal tubular acidosis is a clinical disorder characterized by hyperchloremic metabolic acidosis, hypercalciuria, hypocitraturia, urinary acidification impairment, hypokalemia, metabolic bone disease, and nephrocalcinosis. Urinary acidification ability may be evaluated by an acidification test or maximum urinary pCO2 assessment with alkaline urine. The maximum urinary pCO2 test using acetazolamide and sodium bicarbonate is an easy test to confirm the lack of urine acidification in distal renal tubular acidosis in children...
May 2015: Revista de Investigación Clínica; Organo del Hospital de Enfermedades de la Nutrición
Jonathon H Stillman, Adam W Paganini
The change in oceanic carbonate chemistry due to increased atmospheric PCO2  has caused pH to decline in marine surface waters, a phenomenon known as ocean acidification (OA). The effects of OA on organisms have been shown to be widespread among diverse taxa from a wide range of habitats. The majority of studies of organismal response to OA are in short-term exposures to future levels of PCO2 . From such studies, much information has been gathered on plastic responses organisms may make in the future that are beneficial or harmful to fitness...
June 2015: Journal of Experimental Biology
Jörn O Streefkerk, Albertus Beishuizen, A B Johan Groeneveld
BACKGROUND: Gastric mucosal ischemia may be a risk factor for gastrointestinal intolerance to early feeding in the critically ill. AIMS: To study intragastric PCO2 air tonometry and gastric residual volumes (GRV) before and after the start of gastric feeding. METHODS: This is a two-center study in intensive care units of a university and teaching hospital. Twenty-nine critically ill, consecutive and consenting patients scheduled to start gastric feeding were studied after insertion of a gastric tonometry catheter and prior to and after start of gastric feeding (500 ml over 1 h), when clinically indicated...
June 2016: Clinical Nutrition: Official Journal of the European Society of Parenteral and Enteral Nutrition
K E Fabricius, A Kluibenschedl, L Harrington, S Noonan, G De'ath
Crustose coralline algae (CCA) fulfill important ecosystem functions in coral reefs, including reef framework stabilization and induction of larval settlement. To investigate in situ the effects of high carbon dioxide on CCA communities, we deployed settlement tiles at three tropical volcanic CO2 seeps in Papua New Guinea along gradients spanning from 8.1 to 7.4 pH. After 5 and 13 months deployment, there was a steep transition from CCA presence to absence around pH 7.8 (660 μatm pCO2): 98% of tiles had CCA at pH > 7...
April 2, 2015: Scientific Reports
Rafael M Almeida, Fábio Roland, Simone J Cardoso, Vinícius F Farjalla, Reinaldo L Bozelli, Nathan O Barros
In response to the massive volume of water along the Amazon River, the Amazon tributaries have their water backed up by 100s of kilometers upstream their mouth. This backwater effect is part of the complex hydrodynamics of Amazonian surface waters, which in turn drives the variation in concentrations of organic matter and nutrients, and also regulates planktonic communities such as viruses and bacteria. Viruses and bacteria are commonly tightly coupled to each other, and their ecological role in aquatic food webs has been increasingly recognized...
2015: Frontiers in Microbiology
Benjamin D Fox, Dominique Joyal, Robert D Schlesinger, Mark J Eisenberg, David Langleben
Physicians often need to measure arterial PCO2 in clinical practice. Arterial blood gas sampling is typically available only in hospitals and may be unpleasant for patients. Minimally invasive techniques for measuring PCO2 offer the potential for overcoming these limitations. The MicroStat monitor non-invasively measures PCO2 in the sublingual tissues, which should track arterial PCO2 in hemodynamically stable patients. This was a prospective observational study. Patients undergoing routine cardiac catheterization were recruited...
February 2016: Journal of Clinical Monitoring and Computing
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