Publications by authors named "Takuma Miyakawa"
Iron availability limits marine ecosystem activities in large areas of the ocean. However, the sources and seasonal supply of iron, critically important for controlling surface ocean biogeochemistry and carbon cycling, are poorly understood. The western subarctic Pacific is a high-nutrient and low-chlorophyll region, and despite high concentrations of macronutrients, iron limits phytoplankton production in summer.
View Article and Find Full Text PDFAerosol Iron from Metal Production as a Secondary Source of Bioaccessible Iron.
Environ Sci Technol
March 2023
Atmospheric iron (Fe) from anthropogenic, lithogenic, and pyrogenic sources contributes to ocean fertilization, climate change, and human health risk. However, significant uncertainties remain in the source apportionment due to a lack of source-specific evaluation of Fe-laden aerosols. Here, the large uncertainties in the model estimates are investigated using different Fe emissions from metal production.
View Article and Find Full Text PDFArticle Synopsis
- Researchers measured marine aerosol particles and trace gases during a cruise on the R/V Mirai in the Arctic and Northwest Pacific regions from August to October 2016, finding average black carbon concentrations consistent with previous studies.
- The study highlighted that black carbon levels in the Arctic Ocean provide important benchmarks for testing atmospheric transport models, and these levels were lower than those observed at nearby ground-based stations like Barrow.
- Elevated black carbon and carbon monoxide levels were linked to biomass burning events, particularly from Siberian forest fires, with model simulations suggesting that fire plumes traveled significant distances, but the observed ratios indicated potential influences from wet removal and smoldering emissions.
Article Synopsis
- * It finds that the residential sector was responsible for 64% of black carbon emissions in China in 2019, using data collected during the COVID-19 pandemic when human activities were limited.
- * The research also highlights the need for mitigation policies focused on reducing residential black carbon emissions, presenting evidence for economic feasibility through marginal abatement cost curves.
Article Synopsis
- Brown carbon (BrC) aerosols play a significant role in warming Earth's atmosphere, but their light-absorption properties in the Asian outflow region are not well understood.
- This study, conducted on Fukue Island in Japan, used filter measurements and remote sensing to analyze BrC's light-absorption coefficient, finding a correlation with black carbon (BC) due to shared combustion sources.
- The research identified a high-BrC event linked to air masses from fossil fuel combustion and biomass burning in East China, aiding in understanding the climatic impacts of BrC aerosols in East Asia.