Profiles of stable isotopes of silicon in silicic acid from the US GEOTRACES EPZT cruise (R/V Thomas G. Thompson TN303) in the Eastern Tropical Pacific from October to December 2013

Dataset: delta 30SiThese data include measurements of the stable isotopes of silicon within seawater, silicic acid expressed in del notation relative the standard NBS28, along the section from Peru to Tahiti conducted by US GEOTRACES. Data were generated in the laboratory of Mark Brzezinski at the University of California, Santa Barbara and in the laboratory of Martin Frank in GEOMAR, Kiel, Germany. Intercalibration was also performed between these same two laboratories. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/728819NSF Division of Ocean Sciences (NSF OCE) OCE-12330282020-01-3

Elevated pCO2 enhances bacterioplankton removal of organic carbon.

Factors that affect the removal of organic carbon by heterotrophic bacterioplankton can impact the rate and magnitude of organic carbon loss in the ocean through the conversion of a portion of consumed organic carbon to CO2. Through enhanced rates of consumption, surface bacterioplankton communities can also reduce the amount of dissolved organic carbon (DOC) available for export from the surface ocean. The present study investigated the direct effects of elevated pCO2 on bacterioplankton removal of several forms of DOC ranging from glucose to complex phytoplankton exudate and lysate, and naturally occurring DOC. Elevated pCO2 (1000-1500 ppm) enhanced both the rate and magnitude of organic carbon removal by bacterioplankton communities compared to low (pre-industrial and ambient) pCO2 (250 -~400 ppm). The increased removal was largely due to enhanced respiration, rather than enhanced production of bacterioplankton biomass. The results suggest that elevated pCO2 can increase DOC consumption and decrease bacterioplankton growth efficiency, ultimately decreasing the amount of DOC available for vertical export and increasing the production of CO2 in the surface ocean

Nutrients, pigments, silicate and experimental data collected aboard the OCEANUS during cruise OC1504A in the North Pacific Ocean from 2015-04-19 to 2015-05-06

Dataset: MUSiCC OC1504A - Nutrients, CTD, and silicon biogeochemical dataThese data include nutrient, pigment, silica and experimental data collected aboard the OCEANUS during cruise OC1504A in the North Pacific Ocean along the California Coast from 2015-04-19 to 2015-05-06. The water samples were collected by CTDs. Silica production rates were characterized by delivering incremental increases in silicic acid (Si) along with a radioactive isotope of silicon (32Si). This is an extremely sensitive assay and can determine the maximum production rates of the community being studied and the degree that its growth is being limited by lack of Si. These data were collected by Mark Brzezinski from the University of California at Santa Barbara as part of Linking Physiological and Molecular Aspects of Diatom Silicification. For a complete list of measurements, refer to the supplemental document 'Field_names.pdf', and a full dataset description is included in the supplemental file 'Dataset_description.pdf'. The most current version of this dataset is available at: http://www.bco-dmo.org/dataset/650831NSF Division of Ocean Sciences (NSF OCE) OCE-133438

Controls on the Silicon Isotope Composition of Diatoms in the Peruvian Upwelling

The upwelling area off Peru is characterized by exceptionally high rates of primary productivity, mainly dominated by diatoms, which require dissolved silicic acid (dSi) to construct their frustules. The silicon isotope compositions of dissolved silicic acid (δ 30 Si dSi ) and biogenic silica (δ 30 Si bSi ) in the ocean carry information about dSi utilization, dissolution, and water mass mixing. Diatoms are preserved in the underlying sediments and can serve as archives for past nutrient conditions. However, the factors influencing the Si isotope fractionation between diatoms and seawater are not fully understood. More δ 30 Si bSi data in today’s ocean are required to validate and improve the understanding of paleo records. Here, we present the first δ 30 Si bSi data (together with δ 30 Si dSi ) from the water column in the Peruvian Upwelling region. Samples were taken under strong upwelling conditions and the bSi collected from seawater consisted of more than 98% diatoms. The δ 30 Si dSi signatures in the surface waters were higher (+1.7‰ to +3.0‰) than δ 30 Si bSi (+1.0‰ to +2‰) with offsets between diatoms and seawater (Δ 30 Si) ranging from −0.4‰ to −1.0‰. In contrast, δ 30 Si dSi and δ 30 Si bSi signatures were similar in the subsurface waters of the oxygen minimum zone (OMZ) as a consequence of a decrease in δ 30 Si dSi . A strong relationship between δ 30 Si bSi and [dSi] in surface water samples supports that dSi utilization of the available pool (70 and 98%) is the main driver controlling δ 30 Si bSi . A comparison of δ 30 Si bSi samples from the water column and from underlying core-top sediments (δ 30 Si bSi_ sed. ) in the central upwelling region off Peru (10°S and 15°S) showed good agreement (δ 30 Si bSi_ sed. = +0.9‰ to +1.7‰), although we observed small differences in δ 30 Si bSi depending on the diatom size fraction and diatom assemblage. A detailed analysis of the diatom assemblages highlights apparent variability in fractionation among taxa that has to be taken into account when using δ 30 Si bSi data as a paleo proxy for the reconstruction of dSi utilization in the region

Техніки графіки

Робоча програма навчальної дисципліни «Техніки графіки» для студенів спеціальності 023 «Образотворче мистецтво*, декоративне мистецтво, реставрація». Освітній рівень перший (бакалаврський) (2 курс, 3 семестр

Elliptic Gaudin models and elliptic KZ Equations

The Gaudin models based on the face-type elliptic quantum groups and the $XYZ$ Gaudin models are studied. The Gaudin model Hamiltonians are constructed and are diagonalized by using the algebraic Bethe ansatz method. The corresponding face-type Knizhnik-Zamolodchikov equations and their solutions are given.Comment: LaTex file 18 pages; Errors corrected and references adde

Exact solution of the XXZ Gaudin model with generic open boundaries

The XXZ Gaudin model with {\it generic} integerable boundaries specified by generic {\it non-diagonal} K-matrices is studied. The commuting families of Gaudin operators are diagonalized by the algebraic Bethe ansatz method. The eigenvalues and the corresponding Bethe ansatz equations are obtained.Comment: Latex file, 17 pages;V2:minor typos corrected, references updated and a discussion adde