Cross-basin differences in the nutrient assimilation characteristics of induced phytoplankton blooms in the subtropical Pacific waters.

To better understand the nutrient assimilation characteristics of subtropical phytoplankton, deep water addition incubation experiments were carried out on surface waters collected at seven stations across the subtropical North and South Pacific Ocean. These deep water additions induced phytoplankton blooms with nutrient drawdown at all stations. The drawdown ratios of dissolved inorganic nitrogen (DIN) to phosphate (PO4) varied from 14.1 to 30.7 at the PO4-replete stations in the central North Pacific (CNP) and eastern South Pacific (ESP). These ratios were similar to the range represented by the canonical Redfield ratio (16) through to typical particulate N:P ratios in the surface subtropical ocean (28). In contrast, lower DIN:PO4 drawdown ratios (7.7-13.3) were observed in induced blooms at the PO4-depleted stations in the western North Pacific (WNP). The DIN:PO4 drawdown ratios in the PO4-replete ESP were associated with eukaryote-dominated blooms, while those in PO4-depleted WNP were associated with eukaryotic and cyanobacterial blooms. The surplus PO4 assimilation, relative to DIN, by phytoplankton in the WNP was not expected based on their typical cellular N:P ratio, and was likely due to the high PO4 uptake capability as induced by low PO4-adapted phytoplankton. The low and high P* (=PO4-DIN/16) regimes geographically corresponded to the low and high DIN:PO4 drawdown ratios in the WNP and the CNP or ESP, respectively. The basin-wide P* distribution in the oligotrophic Pacific surface waters showed a clear regional trend from low in the WNP (100 nM). These results suggest that the subtropical phytoplankton blooms as observed in our experiments could be an important factor controlling P* as well as the commonly recognized dinitrogen fixation and denitrification characteristics

Marine nitrogen fixation as a possible source of atmospheric water-soluble organic nitrogen aerosols in the subtropical North Pacific

Water-soluble organic nitrogen (WSON) in marine atmospheric aerosols affect the water solubility, acidity, and light-absorbing properties of aerosol particles, which are important parameters in assessing both the climate impact and the biogeochemical cycling of bioelements. Size-segregated aerosol and surface seawater (SSW) samples were simultaneously collected over the subtropical North Pacific to investigate the origin of WSON in the marine atmosphere. The fine-mode WSON concentration (7.5 ± 6.6 ngN m−3) at 200–240∘ E along 23∘ N, defined as the eastern North Pacific (ENP), was significantly higher than that (2.4 ± 1.9 ngN m−3) at 135–200∘ E, defined as the western North Pacific (WNP). Analysis of the stable carbon isotope ratio of water-soluble organic carbon (WSOC; δ13CWSOC) together with backward trajectory indicated that most of the observed WSON in the fine particles in the ENP originated from the ocean surface. We found positive relations among nitrogen-fixation rate, dissolved organic nitrogen (DON) in SSW, and the WSON concentrations. The result suggests that reactive nitrogen (DON and ammonium), produced and exuded by nitrogen-fixing microorganisms in SSW, contributed to the formation of WSON aerosols. This study provides new insights into the role of ocean-derived reactive nitrogen aerosols associated with marine microbial activity.</p

New particle formation and precursor gas concentration over the Antarctic and Southern Indian Ocean

第2回極域科学シンポジウム/第34回気水圏シンポジウム 11月15日（火） 統計数理研究所 3階リフレッシュフロ

A global database of dissolved organic matter (DOM) concentration measurements in coastal waters (CoastDOM v1)

Measurements of dissolved organic carbon (DOC), nitrogen (DON), and phosphorus (DOP) con-centrations are used to characterize the dissolved organic matter (DOM) pool and are important components ofbiogeochemical cycling in the coastal ocean. Here, we present the first edition of a global database (CoastDOMv1; available at https://doi.org/10.1594/PANGAEA.964012, L\uf8nborg et al., 2023) compiling previously pub-lished and unpublished measurements of DOC, DON, and DOP in coastal waters. These data are complementedby hydrographic data such as temperature and salinity and, to the extent possible, other biogeochemical variables(e.g. chlorophyll a, inorganic nutrients) and the inorganic carbon system (e.g. dissolved inorganic carbon andtotal alkalinity). Overall, CoastDOM v1 includes observations of concentrations from all continents. However,most data were collected in the Northern Hemisphere, with a clear gap in DOM measurements from the SouthernHemisphere. The data included were collected from 1978 to 2022 and consist of 62 338 data points for DOC,20 356 for DON, and 13 533 for DOP. The number of measurements decreases progressively in the sequenceDOC &gt; DON &gt; DOP, reflecting both differences in the maturity of the analytical methods and the greater focuson carbon cycling by the aquatic science community. The global database shows that the average DOC concen-tration in coastal waters (average \ub1 standard deviation (SD): 182 \ub1 314 μmol C L−1; median: 103 μmol C L−1) is13-fold higher than the average coastal DON concentration (13.6 \ub1 30.4 μmol N L−1; median: 8.0 μmol N L−1),which is itself 39-fold higher than the average coastal DOP concentration (0.34 \ub1 1.11 μmol P L−1; median:0.18 μmol P L−1). This dataset will be useful for identifying global spatial and temporal patterns in DOM and willhelp facilitate the reuse of DOC, DON, and DOP data in studies aimed at better characterizing local biogeochem-ical processes; closing nutrient budgets; estimating carbon, nitrogen, and phosphorous pools; and establishing abaseline for modelling future changes in coastal waters

Western Pacific Air-Sea Interaction Study

A01: Dynamics of Atmospheric CompositionA Study on the Production and Emission of Marine-Derived Volatile Halocarbons / Y. Yokouchi, A. Ooki, S. Hashimoto and N. Itoh : 05w-pass_001.pdfMeasurements of Gaseous Peroxides in the Oceanic Lower Atmosphere / S. Hatakeyama and T. Akatsuka : 06w-pass_027.pdfPhase Partitioning of NH3 and Gas to Particle Conversion / K. Osada : 07w-pass_033.pdfNew Particle Formation of Marine Aerosols / K. Miura, H. Furutani, Y. Iwamoto, K. Nagano, H. Kobayashi, M. Mochida, H. Mukai, S. Hashimoto, M. Takami and M. Uematsu : 08w-pass_037.pdfA Study of the Chemical Processes in Aerosols and Their Impacts on the Environment Using X-ray Absorption Fine Structure Spectroscopy / Y. Takahashi, M. Higashi, T. Furukawa, T. Miyoshi, M. Fujiwara and M. Uematsu : 09w-pass_043.pdfVariability in Mineral Dust Deposition over the North Pacific and Its Potential Impact on the Ocean Productivity / H. Fukushima : 10w-pass_051.pdfAtmosphere-Ocean Interaction through Atmospheric Aerosol Particles Observed in a Single Nanoparticle Aspect / H. Furutani, J. Jinyoung and M. Uematsu : 11w-pass_061.pdfSimultaneous Measurements of Hygroscopic Property and Cloud Condensation Nucleus Activity of Aerosol Particles of Marine Biogenic Origin / M. Mochida : 12w-pass_071.pdfEruption of Mt. Kilauea Impacted Cloud Droplet and Radiation Budget over North Pacific / I. Uno, K. Eguchi and K. Yumimoto : 13w-pass_083.pdfA02: Variability of Gas Exchanges at the Air-Sea InterfaceHigh-Resolution Measurement of Volatile Organic Compounds Dissolved in Seawater Using Equilibrator Inlet-Proton Transfer Reaction-Mass Spectrometry (EI-PTR-MS) / H. Tanimoto, S. Kameyama, Y. Omori, S. Inomata and U. Tsunogai : 14w-pass_089.pdfStudy of the Production Processes of Marine Biogenic Methane and Carbonyl Sulfide Using Stable Isotope Analysis / S. Toyoda, K. Yamada, Y. Ueno, K. Koba and O. Yoshida : 15w-pass_117.pdfLong-Term Changes of Greenhouse Gases in the Ocean and Their Feedback Effects on the Climate / Y. W. Watanabe, I. Yasuda and N. Tsurushima : 16w-pass_123.pdfTemporal and Spatial Variations in Carbonate System and Air-Sea CO2 Flux in the Kuroshio and Kuroshio Extension / H. Yoshikawa-Inoue, T. Midorikawa and T. R. Takamura : 17w-pass_151.pdfA03: Dynamics of the Marine EcosystemBioavailability and Biogeochemical Processes of Trace Metals in the Surface Ocean / S. Takeda, H. Obata, A. Okubo, M. Sato and Y. Kondo : 18w-pass_163.pdfDetailed Variations in Bioactive Elements in the Surface Ocean and Their Interaction with Microbiological Processes / H. Ogawa, K. Kogure, J. Kanda, F. Hashihama and M. Suzumura : 19w-pass_177.pdfPhotoheterotrophic Process in Surface Seawater Environments / K. Hamasaki, Y. Sato-Takabe, A. Taniguchi and Y. Tada : 20w-pass_199.pdfEcological Study of Bacterial Populations Related to Biogenic Gas Transformation in Marine Environments / K. Hamasaki, R. Kaneko, A. Mouri, Y. Tada, N. Kasamatsu-Takasawa and I. Nagao : 21w-pass_203.pdfA04: Modelling of the Interaction between the Ocean and the AtmosphereModeling for Evaluation and Prediction of Effects of Short-Term Atmospheric Disturbance on Air-Sea Material Cycling / M. Fujii and A. Tanaka : 22w-pass_211.pdfRelating Phytoplankton Pnysiology to North Pacific Biogeochemistry / S. L. Smith, M. N. Aita, M. Shigemitsu and Y. Yamanaka : 23w-pass_223.pdfCoupling of Physical and Bio-Geochemical Process and Monitoring Ocean Circulation Using Data Assimilation System / Y. Ishikawa, T. Awaji, M. Ikeda and T. Toyoda : 24w-pass_237.pdfPart of "Western Pacific Air-Sea Interaction Study

Western Pacific Air-Sea Interaction Study

A01: Dynamics of Atmospheric CompositionA Study on the Production and Emission of Marine-Derived Volatile Halocarbons / Y. Yokouchi, A. Ooki, S. Hashimoto and N. Itoh : 05w-pass_001.pdfMeasurements of Gaseous Peroxides in the Oceanic Lower Atmosphere / S. Hatakeyama and T. Akatsuka : 06w-pass_027.pdfPhase Partitioning of NH3 and Gas to Particle Conversion / K. Osada : 07w-pass_033.pdfNew Particle Formation of Marine Aerosols / K. Miura, H. Furutani, Y. Iwamoto, K. Nagano, H. Kobayashi, M. Mochida, H. Mukai, S. Hashimoto, M. Takami and M. Uematsu : 08w-pass_037.pdfA Study of the Chemical Processes in Aerosols and Their Impacts on the Environment Using X-ray Absorption Fine Structure Spectroscopy / Y. Takahashi, M. Higashi, T. Furukawa, T. Miyoshi, M. Fujiwara and M. Uematsu : 09w-pass_043.pdfVariability in Mineral Dust Deposition over the North Pacific and Its Potential Impact on the Ocean Productivity / H. Fukushima : 10w-pass_051.pdfAtmosphere-Ocean Interaction through Atmospheric Aerosol Particles Observed in a Single Nanoparticle Aspect / H. Furutani, J. Jinyoung and M. Uematsu : 11w-pass_061.pdfSimultaneous Measurements of Hygroscopic Property and Cloud Condensation Nucleus Activity of Aerosol Particles of Marine Biogenic Origin / M. Mochida : 12w-pass_071.pdfEruption of Mt. Kilauea Impacted Cloud Droplet and Radiation Budget over North Pacific / I. Uno, K. Eguchi and K. Yumimoto : 13w-pass_083.pdfA02: Variability of Gas Exchanges at the Air-Sea InterfaceHigh-Resolution Measurement of Volatile Organic Compounds Dissolved in Seawater Using Equilibrator Inlet-Proton Transfer Reaction-Mass Spectrometry (EI-PTR-MS) / H. Tanimoto, S. Kameyama, Y. Omori, S. Inomata and U. Tsunogai : 14w-pass_089.pdfStudy of the Production Processes of Marine Biogenic Methane and Carbonyl Sulfide Using Stable Isotope Analysis / S. Toyoda, K. Yamada, Y. Ueno, K. Koba and O. Yoshida : 15w-pass_117.pdfLong-Term Changes of Greenhouse Gases in the Ocean and Their Feedback Effects on the Climate / Y. W. Watanabe, I. Yasuda and N. Tsurushima : 16w-pass_123.pdfTemporal and Spatial Variations in Carbonate System and Air-Sea CO2 Flux in the Kuroshio and Kuroshio Extension / H. Yoshikawa-Inoue, T. Midorikawa and T. R. Takamura : 17w-pass_151.pdfA03: Dynamics of the Marine EcosystemBioavailability and Biogeochemical Processes of Trace Metals in the Surface Ocean / S. Takeda, H. Obata, A. Okubo, M. Sato and Y. Kondo : 18w-pass_163.pdfDetailed Variations in Bioactive Elements in the Surface Ocean and Their Interaction with Microbiological Processes / H. Ogawa, K. Kogure, J. Kanda, F. Hashihama and M. Suzumura : 19w-pass_177.pdfPhotoheterotrophic Process in Surface Seawater Environments / K. Hamasaki, Y. Sato-Takabe, A. Taniguchi and Y. Tada : 20w-pass_199.pdfEcological Study of Bacterial Populations Related to Biogenic Gas Transformation in Marine Environments / K. Hamasaki, R. Kaneko, A. Mouri, Y. Tada, N. Kasamatsu-Takasawa and I. Nagao : 21w-pass_203.pdfA04: Modelling of the Interaction between the Ocean and the AtmosphereModeling for Evaluation and Prediction of Effects of Short-Term Atmospheric Disturbance on Air-Sea Material Cycling / M. Fujii and A. Tanaka : 22w-pass_211.pdfRelating Phytoplankton Pnysiology to North Pacific Biogeochemistry / S. L. Smith, M. N. Aita, M. Shigemitsu and Y. Yamanaka : 23w-pass_223.pdfCoupling of Physical and Bio-Geochemical Process and Monitoring Ocean Circulation Using Data Assimilation System / Y. Ishikawa, T. Awaji, M. Ikeda and T. Toyoda : 24w-pass_237.pdfPart of "Western Pacific Air-Sea Interaction Study

Heterotrophic prokaryote distribution along a 2300 km transect in the North Pacific subtropical gyre during a strong La Niña conditions: relationship between distribution and hydrological conditions

The spatial distribution of heterotrophic prokaryotes was investigated during the Tokyo–Palau cruise in the western part of the North Pacific subtropical gyre (NPSG) along a north–south transect between 33.60 and 13.25° N. The cruise was conducted in three different hydrological areas identified as the Kuroshio region, the subtropical gyre area and the transition zone. Two eddies were crossed along the transect: one cold-core cyclonic eddy and one warm-core anticyclonic eddy and distributions of the heterotrophic prokaryotes were recorded. By using analytical flow cytometry and a nucleic acid staining protocol, heterotrophic prokaryotes were discriminated into three subgroups depending on their nucleic acid content (low, high and very high nucleic acid contents labelled LNA, HNA and VHNA, respectively). Statistical analyses performed on the data set showed that LNA, mainly associated with low temperature and low salinity, were dominant in all the hydrological regions. In contrast, HNA distribution seemed to be associated with temperature, salinity, Chl <i>a</i> and silicic acid. A latitudinal increase in the HNA / LNA ratio was observed along the north–south transect and was related to higher phosphate and nitrate concentrations. However, the opposite relationship observed for the VHNA / HNA ratio suggested that the link between nucleic acid content and oligotrophic conditions is not linear, underlying the complexity of the biodiversity in the VHNA, HNA and LNA subgroups. In the Kuroshio Current, it is suggested that the high concentration of heterotrophic prokaryotes observed at station 4 was linked to the path of the cold cyclonic eddy core. In contrast, it is thought that low concentrations of heterotrophic prokaryotes in the warm core of the anticyclonic gyre (Sta. 9) are related to the low nutrient concentrations measured in the seawater column. Our results showed that the high variability between the various heterotrophic prokaryote cluster abundances depend both on the mesoscale structures and the oligotrophic gradient