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The fate of photons absorbed by phytoplankton in the global ocean
Lin, Hanzhi,Kuzminov, Fedor I.,Park, Jisoo,Lee, SangHoon,Falkowski, Paul G.,Gorbunov, Maxim Y. American Association for the Advancement of Scienc 2016 Science Vol.351 No.6270
<P>Solar radiation absorbed by marine phytoplankton can follow three possible paths. By simultaneously measuring the quantum yields of photochemistry and chlorophyll fluorescence in situ, we calculate that, on average, similar to 60% of absorbed photons are converted to heat, only 35% are directed toward photochemical water splitting, and the rest are reemitted as fluorescence. The spatial pattern of fluorescence yields and lifetimes strongly suggests that photochemical energy conversion is physiologically limited by nutrients. Comparison of in situ fluorescence lifetimes with satellite retrievals of solar-induced fluorescence yields suggests that the mean values of the latter are generally representative of the photophysiological state of phytoplankton; however, the signal-to-noise ratio is unacceptably low in extremely oligotrophic regions, which constitute 30% of the open ocean.</P>
Park, Jisoo,Kuzminov, Fedor I.,Bailleul, Benjamin,Yang, Eun Jin,Lee, SangHoon,Falkowski, Paul G.,Gorbunov, Maxim Y. Wiley (John WileySons) 2017 Limnology and Oceanography Vol.62 No.5
<P>Amundsen Sea polynyas are among the most productive, yet climate-sensitive ecosystems in the Southern Ocean and host massive annual phytoplankton blooms. These blooms are believed to be controlled by iron fluxes from melting ice and icebergs and by intrusion of nutrient-rich Circumpolar Deep Water, however the interplay between iron effects and other controls, such as light availability, has not yet been quantified. Here, we examine phytoplankton photophysiology in relation to Fe stress and physical forcing in two largest polynyas, Amundsen Sea Polynya (ASP) and Pine Island Polynya (PIP), using the combination of high-resolution variable fluorescence measurements, fluorescence lifetime analysis, photosynthetic rates, and Feenrichment incubations. These analyses revealed strong Fe stress in the ASP, whereas the PIP showed virtually no signatures of Fe limitation. In spite of enhanced iron availability in the PIP, chlorophyll biomass remained similar to 30-50% lower than in the Fe-stressed ASP. This apparent paradox would not have been observed if iron were the main control of phytoplankton bloom in the Amundsen Sea. Long-term satellite-based climatology records revealed that the ASP is exposed to significantly higher solar irradiance levels throughout the summer season, as compared to the PIP region, suggesting that light availability controls the magnitude of phytoplankton blooms in the Amundsen Sea. Our data suggests that higher Fe availability (e.g., due to higher melting rates of ice sheets) would not necessarily increase primary productivity in this region. Furthermore, stronger wind-driven vertical mixing in expanding ice-free areas may lead to reduction in light availability and productivity in the future.</P>
Improvement of the Administration System of Customs Payments in the Modern Conditions
Mishina, Natalya V.,Kuzminov, Vitaly A.,Kuzminova, Olga A.,Konovalova, Elena E.,Gubanova, Natalia V. International Journal of Computer ScienceNetwork S 2022 International journal of computer science and netw Vol.22 No.10
The article is devoted to the formation of approaches to improving the system of administration of customs payments in modern conditions. It is established that important components of the administration of customs payments are customs expertise, customs value assessment, and control over the declaration of goods to ensure the completeness and timeliness of customs duties payments to the budget. It is found that the practice of customs administration shifts the emphasis of foreign trade regulation to the use of the principles of work implying the use of the latest technologies for the preliminary electronic exchange of information, remote customs clearance of goods without the physical presence of an official, and consistent application of risk management. It is established that an important place in the structure of the state authorities regulating the foreign economic activity is given to the customs service. Furthermore, the existing problems in the implementation of international trade operations necessitate the improvement of approaches to the customs regulation of export-import activities of enterprises.