Sensors and Systems for in situ Observations of Marine Carbon Dioxide System Variables

Autonomous chemical sensors are required to document the marine carbon dioxide system's evolving response to anthropogenic CO2 inputs, as well as impacts on short- and long-term carbon cycling. Observations will be required over a wide range of spatial and temporal scales, and measurements will likely need to be maintained for decades. Measurable CO2 system variables currently include total dissolved inorganic carbon (DIC), total alkalinity (AT), CO2 fugacity (fCO2), and pH, with comprehensive characterization requiring measurement of at least two variables. These four parameters are amenable to in situ analysis, but sustained deployment remains a challenge. Available methods encompass a broad range of analytical techniques, including potentiometry, spectrophotometry, conductimetry, and mass spectrometry. Instrument capabilities (precision, accuracy, endurance, reliability, etc.) are diverse and will evolve substantially over the time that the marine CO2 system undergoes dramatic changes. Different suites of measurements/parameters will be appropriate for different sampling platforms and measurement objectives

Sea surface pCO2 and O2 in the Southern Ocean during the austral fall, 2008

The physical and biological processes controlling surface mixed layer pCO2 and O2 were evaluated using in situ sensors mounted on a Lagrangian drifter deployed in the Atlantic sector of the Southern Ocean (∼50°S, ∼37°W) during the austral fall of 2008. The drifter was deployed three times during different phases of the study. The surface ocean pCO2 was always less than atmospheric pCO2 (−50.4 to −76.1 μatm), and the ocean was a net sink for CO2 with fluxes averaging between 16.2 and 17.8 mmol C m−2 d−1. Vertical entrainment was the dominant process controlling mixed layer CO2, with fluxes that were 1.8 to 2.2 times greater than the gas exchange fluxes during the first two drifter deployments, and was 1.7 times greater during the third deployment. In contrast, during the first two deployments the surface mixed layer was always a source of O2 to the atmosphere, and air-sea gas exchange was the dominant process occurring, with fluxes that were 2.0 to 4.1 times greater than the vertical entrainment flux. During the third deployment O2 was near saturation the entire deployment and was a small source of O2 to the atmosphere. Net community production (NCP) was low during this study, with mean fluxes of 3.2 to 6.4 mmol C m−2 d−1 during the first deployment and nondetectable (within uncertainty) in the third. During the second deployment the NCP was not separable from lateral advection. Overall, this study indicates that in the early fall the area is a significant sink for atmospheric CO2

Sapling size influences shade tolerance ranking among southern boreal tree species

1 Traditional rankings of shade tolerance of trees make little reference to individual size. However, greater respiratory loads with increasing sapling size imply that larger individuals will be less able to tolerate shade than smaller individuals of the same species and that there may be shifts among species in shade tolerance with size. 2 We tested this hypothesis using maximum likelihood estimation to develop individual-tree-based models of the probability of mortality as a function of recent growth rate for seven species: trembling aspen, paper birch, yellow birch, mountain maple, white spruce, balsam fir and eastern white cedar. 3 Shade tolerance of small individuals, as quantified by risk of mortality at low growth, was mostly consistent with traditional shade tolerance rankings such that cedar > balsam fir > white spruce > yellow birch > mountain maple = paper birch > aspen. 4 Differences in growth-dependent mortality were greatest between species in the smallest size classes. With increasing size, a reduced tolerance to shade was observed for all species except trembling aspen and thus species tended to converge in shade tolerance with size. At a given level of radial growth larger trees, apart from aspen, had a higher probability of mortality than smaller trees. 5 Successional processes associated with shade tolerance may thus be most important in the seedling stage and decrease with ontogeny

Psychodynamik medikalisierter Beziehungen

Konsensuskonferenzen in der Medizin tragen das zu einem bestimmten Zeitpunkt verfügbare Wissen über eine Krankheit zusammen, um Empfehlungen zu formulieren, wie sie erfolgreich diagnostiziert und therapiert werden kann. Für die Aufmerksamkeits und/oder Hyperaktivitätsstörung bei Kindern und Jugendlichen haben entsprechende Bemühungen dazu geführt, einen aufwendigen Diagnoseprozess zu verlangen, der die gesamte Lebenswelt der auffälligen Kinder und Jugendlichen in die Beobachtung einbezieht und Vorsicht walten lässt, um Unaufmerksamkeit, Impulsivität und Hyperaktivität nicht vorschnell als Symptome einer psychischen Störung zu beurteilen (Remschmidt, 2005). Ein solcher Aufwand ist nicht zuletzt deshalb notwendig, weil die Symptomdiagnose einer AD(H)S auf Urteilen sozialer Wahrnehmung beruht, die immer Normalitätsvorstellungen enthalten, die unterschiedlich ausfallen können. Eine andere Möglichkeit der Objektivierung gibt es nicht. Was die Therapie der AD(H)S betrifft, so gilt es inzwischen als Behandlungsstandard, sich nicht auf die Verordnung von Medikamenten zu beschränken, weil eine solche Beschränkung die Ätiologie der Symptome ignoriert. Wenn eine Medikation nach sorgfältiger Prüfung indiziert erscheint, sollte sie gegebenenfalls von psychotherapeutischen, psychoedukativen, ergotherapeutischen, logopädischen, pädagogischen oder anderen geeigneten nichtmedikamentösen Unterstützungen flankiert werden. Ohne eine solche Flankierung wird den Betroffenen die Entwicklung eines angemessenen Selbstverständnisses vorenthalten

Fiber optic chemical sensors for characterizing the carbon cycle in ocean margin regions

The overall objective of our DOE-Ocean Margins Programs grant is to develop a pCO[sub 2] sensor for long-term monitoring of pCO[sub 2] in the ocean margins and to establish a proving ground for the development of other chemical sensors for characterizing the carbon cycle in these regions. We have succeeded in keeping with the approximate timeline outlined in the original proposal, which, for year 1 included the following objectives: Continue sensor optimization, test response characteristics (reagent and sample flow rates, temperature), introduce position sensitive photodiode and photodiode array spectrophotometers and evaluate, develop reliable and reproducible fabrication techniques, develop sensor based on preliminary studies optimized for field measurements (minimize size and power requirements), test long-term stability of the sensor in the laboratory, determine susceptibility to fouling and corrosion. This work is summarized below along with a brief review of the sensor's operating principle