Southern Ocean Biogeochemical Float Deployment Strategy, With Example From the Greenwich Meridian Line (GO-SHIP A12).

Biogeochemical Argo floats, profiling to 2,000-m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM). The goal is 200 floats by 2020, to provide the first full set of annual cycles of carbon, oxygen, nitrate, and optical properties across multiple oceanographic regimes. Building from no prior coverage to a sparse array, deployments are based on prior knowledge of water mass properties, mean frontal locations, mean circulation and eddy variability, winds, air-sea heat/freshwater/carbon exchange, prior Argo trajectories, and float simulations in the Southern Ocean State Estimate and Hybrid Coordinate Ocean Model (HYCOM). Twelve floats deployed from the 2014-2015 Polarstern cruise from South Africa to Antarctica are used as a test case to evaluate the deployment strategy adopted for SOCCOM's 20 deployment cruises and 126 floats to date. After several years, these floats continue to represent the deployment zones targeted in advance: (1) Weddell Gyre sea ice zone, observing the Antarctic Slope Front, and a decadally-rare polynya over Maud Rise; (2) Antarctic Circumpolar Current (ACC) including the topographically steered Southern Zone chimney where upwelling carbon/nutrient-rich deep waters produce surprisingly large carbon dioxide outgassing; (3) Subantarctic and Subtropical zones between the ACC and Africa; and (4) Cape Basin. Argo floats and eddy-resolving HYCOM simulations were the best predictors of individual SOCCOM float pathways, with uncertainty after 2 years of order 1,000 km in the sea ice zone and more than double that in and north of the ACC.

The Southern Ocean biogeochemical divide.

Modelling studies have demonstrated that the nutrient and carbon cycles in the Southern Ocean play a central role in setting the air-sea balance of CO(2) and global biological production. Box model studies first pointed out that an increase in nutrient utilization in the high latitudes results in a strong decrease in the atmospheric carbon dioxide partial pressure (pCO2). This early research led to two important ideas: high latitude regions are more important in determining atmospheric pCO2 than low latitudes, despite their much smaller area, and nutrient utilization and atmospheric pCO2 are tightly linked. Subsequent general circulation model simulations show that the Southern Ocean is the most important high latitude region in controlling pre-industrial atmospheric CO(2) because it serves as a lid to a larger volume of the deep ocean. Other studies point out the crucial role of the Southern Ocean in the uptake and storage of anthropogenic carbon dioxide and in controlling global biological production. Here we probe the system to determine whether certain regions of the Southern Ocean are more critical than others for air-sea CO(2) balance and the biological export production, by increasing surface nutrient drawdown in an ocean general circulation model. We demonstrate that atmospheric CO(2) and global biological export production are controlled by different regions of the Southern Ocean. The air-sea balance of carbon dioxide is controlled mainly by the biological pump and circulation in the Antarctic deep-water formation region, whereas global export production is controlled mainly by the biological pump and circulation in the Subantarctic intermediate and mode water formation region. The existence of this biogeochemical divide separating the Antarctic from the Subantarctic suggests that it may be possible for climate change or human intervention to modify one of these without greatly altering the other.

High-latitude controls of thermocline nutrients and low latitude biological productivity.

The ocean's biological pump strips nutrients out of the surface waters and exports them into the thermocline and deep waters. If there were no return path of nutrients from deep waters, the biological pump would eventually deplete the surface waters and thermocline of nutrients; surface biological productivity would plummet. Here we make use of the combined distributions of silicic acid and nitrate to trace the main nutrient return path from deep waters by upwelling in the Southern Ocean and subsequent entrainment into subantarctic mode water. We show that the subantarctic mode water, which spreads throughout the entire Southern Hemisphere and North Atlantic Ocean, is the main source of nutrients for the thermocline. We also find that an additional return path exists in the northwest corner of the Pacific Ocean, where enhanced vertical mixing, perhaps driven by tides, brings abyssal nutrients to the surface and supplies them to the thermocline of the North Pacific. Our analysis has important implications for our understanding of large-scale controls on the nature and magnitude of low-latitude biological productivity and its sensitivity to climate change.

Consistent land- and atmosphere-based U.S. carbon sink estimates.

For the period 1980-89, we estimate a carbon sink in the coterminous United States between 0.30 and 0.58 petagrams of carbon per year (petagrams of carbon = 10(15) grams of carbon). The net carbon flux from the atmosphere to the land was higher, 0.37 to 0.71 petagrams of carbon per year, because a net flux of 0.07 to 0.13 petagrams of carbon per year was exported by rivers and commerce and returned to the atmosphere elsewhere. These land-based estimates are larger than those from previous studies (0.08 to 0.35 petagrams of carbon per year) because of the inclusion of additional processes and revised estimates of some component fluxes. Although component estimates are uncertain, about one-half of the total is outside the forest sector. We also estimated the sink using atmospheric models and the atmospheric concentration of carbon dioxide (the tracer-transport inversion method). The range of results from the atmosphere-based inversions contains the land-based estimates. Atmosphere- and land-based estimates are thus consistent, within the large ranges of uncertainty for both methods. Atmosphere-based results for 1980-89 are similar to those for 1985-89 and 1990-94, indicating a relatively stable U.S. sink throughout the period.

Carbon biogeochemistry and climate change.

The rapid increase of atmospheric CO2 resulting from anthropogenic activites has stimulated a great deal of interest in the carbon cycle. Important decisions need to be made about future tolerable levels of atmospheric CO2 content, as well as the land and fossil fuel use strategies that will permit us to achieve these goals. The vast amount of new data on atmospheric CO2 content and ancillary properties that has become available during the last decade, and the development of models to interpret these data, have led to significant advances in our capacity to deal with such issues. However, a major continuing source of uncertainty is the role of photosynthesis in providing a sink for anthropogenic emissions. It is thus appropriate that a new evaluation of the status of our understanding of this issue should be made at this time.The aim of this paper is to provide a setting for the papers that follow by giving an overview of the role of carbon dioxide in climate, the biogeochemical processes that control its distribution, and the evolution of carbon dioxide through time from the origin of the earth to the present. We begin with a discussion of relevant processes. We then proceed to a more detailed discussion of the time periods that are best documented: the late Pleistocene (during which time large continental ice sheets waxed and waned) and the modern era of anthropogenic impact on the carbon cycle.

Bypass induced liver disease: an experimental study of the effect of post-operative protein supplementation and metronidazole therapy in an animal model.

An animal model of jejuno-ileal bypass (JIB) with post-operative weight loss and liver dysfunction was established in the rat. The role of a protein supplemented diet and post-operative metronidazole was investigated using this model. The use of a protein supplemented diet alone markedly reduced the detrimental effects of JIB. Although a beneficial effect was also noted with post-operative metronidazole, it was less marked and there appeared to be no additive benefit when both were used together. The results of this study would support the routine use of a protein enriched diet post-operatively in patients undergoing JIB.

[Brachmann-De Lange syndrome: Typus degenerativus amstelodamensis. Report of 5 cases and review of the literature]. / Síndrome de Brachmann-De Lange: "Typus degenerativus amstelodamensis". Comunicación de 5 casos y revisión de la leteratura.

Five cases with Brachmann-de Lange's syndrome are reported. The main idea is to point out the most important clinical, radiological, anatomico-pathological and genetic characteristics. The first three cases were studied at the Hospital de Especialidades of the I.M.S.S. at Peubla, Pue, while cases 4 and 5 correspond to the Hospital to de zona of the I.M.S.S., at Acapulco, Gro. With the exception of case 4, karyotype studies were carried out in the rest, including the parents, showing normal results. At present, only cases 3 and 5 are alive, since the rest died due to multiple infectious processes. In the first case, the anatomicopathological studies showed new findings, such as a diverticulum in the first portion of the duodenum with aberrant pancreas, absence of the middle lobe of the right lung and bilateral adrenocortical adenomas. Finally, pertinent literature, where it is shown that the etiology is still in darkness and that the world frequency for this syndrome reaches the figure of 353 cases.

Sindrome de Brachmann-De Lange: "typus degenerativus amstelodamensis". Comunicacion de 5 casos y revision de la literatura. / Brachmann-De Lange's syndrome: typus degenerativus amstelodamensis. Comunication of 5 cases and review of the literature

Se presentan 5 pacientes con sindrome de Brachmann-De Lange con el objeto de senalar las caracteristicas clinicas, radiologicas, anatomopatologicas y geneticas mas importantes. Los primeros 3 casos fueron estudiados en el Hospital de Especialidades del I.M.S.S.de Puebla, Pue., mientras que los casos 4 y 5 en el Hospital de Zona del I.M.S.S. de Acapulco, Gro. Con excepcion del caso 4, en todos los demas se efectuo cariotipo incluyendo a los padres con resultados normales. Actualmente, solo viven los casos 3 y 5, pues los demas fallecieron a consecuencia de proceso infecciosos multiples. En el primer caso se hizo estudio anatomopatologico con nuevos hallazgos tales como diverticulo en la primera porcion de duodeno con pancreas aberrante, ausencia del lobulo medio del pulmon derecho y adenoma en ambas cortezas suprarrenales.Finalmente, se revisa la literatura existente al respecto en la que se encuentra que la etiologia sigue siendo obscura y su frecuencia mundial, hasta la fecha, es de no menos de 353 casos