Atmospheric pollution has become a serious environmental issue in Ulaanbaatar (UB), the capital city of Mongolia, particularly during the winter season. Suspended particulate matter (SPM) samples were collected from January 2014 to January 2018 using a high volume air sampler at the city center. The purpose of this study is to determine the chemical compositions and the possible sources of SPM throughout the year. The concentrations of water-soluble ions and trace metal elements in SPM samples were measured by Ion chromatography and Inductively Coupled Plasma-Mass Spectrometry, respectively.
There are three areas in the world's oceans where low iron concentration limit the primary production and nutrient concentration is kept high even in summer (Antarctic Ocean, Equatorial upwelling region , subarctic Pacific). The iron fertilization experiment is a friel experiment which add iron to the ocean to promote the primary production and enhance the flux of carbon dioxide in the atmosphere to the ocean. In this presentation, we introduce the outline of three experiments led by Japan (SEEDS, SERIES, SEEDS II). Moreover I will tell about recognition and legal restrictions by international communities on the geoengineering methods including iron fertilization after the series of experiments.
Organic complexation of Cu controls the toxicity and bioavailability of Cu for marine microorganism. Therefore, it is important to reveal the speciation and bioavailability of Cu in the ocean. In this study, we determined the concentrations of Cu and its organic ligands in the soluble (＜ 0.03 µm) and dissolved (＜ 0.2 µm) phases in the western (CL-2), central (CL-5) and eastern (CL-16) part of the subarctic North Pacific during the GEOTRACES-Japan cruise GP02 in summer 2017.Concentrations of total dissolved and soluble Cu ranged from 1.28 nM – 4.82 nM, and 0.47 nM – 2.75 nM, respectively. At both CL-2 and CL-16, soluble Cu accounted for 30%-100% of total dissolved Cu. The proportion of the soluble Cu fraction was low in surface waters, increased to maximum in the intermediate waters, and decreased slightly in deep waters. Up to two classes of organic ligands were detected in the surface and intermediate waters, and only one class of ligand was detected in deep waters. Concentrations of the stronger ligands (L1) and weaker ligands (L2) ranged from 1.02 nM – 2.95 nM, and 0.77 nM – 8.78 nM, respectively. The distribution of L1 followed closely that of total dissolved Cu in the surface waters, but no clear trend was observed in the intermediate waters. At CL-2, L1 mainly existed in the soluble phase, whereas for CL-16, soluble L1 accounted for 50% - 100% of total dissolved L1. Concentrations of L2 were relatively constant throughout the water column but elevated concentrations were detected in the surface waters of CL-5 and in the surface and intermediate waters of CL-16. On the other hand, there was a slight depletion of L2 in the intermediate waters of CL-2.
Collagen of human teeth excavated from Jomon and Yayoi sites in Gunma and Nagano was put to carbon and nitrogen stable isotope analysis. There was an average 3.9‰ δ13C increase in the δ13C of Terminal Jomon and Yayoi samples compared to Early-Late Jomon samples. The possible cause of this shift is the consumption of C4 plants with high δ13C such as foxtail and broomcorn millet (C4 millet). Another candidate is marine shellfish with a similarly high δ13C. We built a model to distinguish cereal and marine shellfish consumption based on the difference in the nutrients that collagen and apatite respectively reflect, and the contrasting nutrient makeup of C4 millet and marine shellfish. Carbon isotope values of collagen and the additionally measured apatite were consistent with the mixing model between C3 herbivores and C4 millet, where the contribution of the latter is 20-80%. These results support the archaeological deduction of millet agriculture.