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We explore the potential of the adjoint‐state tsunami inversion method for rapid and accurate near‐field tsunami source characterization using S‐net, an array of ocean bottom pressure gauges. Compared to earthquake‐based methods, this method can obtain more accurate predictions for the initial water elevation of the tsunami source, including potential secondary sources, leading to accurate water height and wave run‐up predictions. Unlike finite‐fault tsunami source inversions, the adjoint method achieves high‐resolution results without requiring densely gridded Green's functions, reducing computation time. However, optimal results require a dense instrument network with sufficient azimuthal coverage. S‐net meets these requirements and reduces data collection time, facilitating the inversion and timely issuance of tsunami warnings. Since the method has not yet been applied to dense, near‐field data, we test it on synthetic waveforms of the 2011 Mw 9.0 Tohoku earthquake and tsunami, including triggered secondary sources. The results indicate that with a static source model without noise, using the first 5 min of the waveforms yields a favorable performance with an average accuracy score of 93%, and the largest error of predicted wave amplitudes ranges between −5.6 and 1.9 m. Using the first 20 min, secondary sources were clearly resolved. We also demonstrate the method's applicability using S‐net recordings of the 2016 Mw 6.9 Fukushima earthquake. The findings suggest that lower‐magnitude events require a longer waveform duration for accurate adjoint inversion. Moreover, the estimated stress drop obtained from inverting our obtained tsunami source, assuming uniform slip, aligns with estimations from recent studies. Plain Language Summary: Issuing timely tsunami warnings is essential in allowing at‐risk populations to have adequate evacuation time. However, traditional frameworks for issuing warnings rely on accurate models for the earthquake that caused the tsunami. These models can be inaccurate in the immediate aftermath of an earthquake and can lead to underestimated wave heights and late wave arrival time predictions. To address this issue, we developed a method that can yield the tsunami source without needing an earthquake model, simply relying on the wave height data recorded by pressure sensors at the bottom of the ocean. This can also be useful when tsunami‐causing events other than earthquakes (e.g., volcanic eruptions) occur. This method has not yet been tested on a dense ocean bottom instrument network, so we tested it on recorded data from the 2016 Fukushima earthquake's associated tsunami and synthetic waveforms from the 2011 Tohoku tsunami. Our results for the former show accurate predictions of wave arrival times and heights when we use the first 25 min of the wave height data. For the latter, predictions are accurate when we use the first 5 min of the data. Key Points: We use an adjoint‐state tsunami inversion method that predicts tsunami sources directly from near‐field pressure gauge recordingsThe pressure gauge recordings of S‐net provide sufficient azimuthal coverage within a short time interval for accurate adjoint inversionsThe results of our applications show that accurate tsunami predictions can be obtained using recordings as short as 5 min [ABSTRACT FROM AUTHOR]

The 2022 volcanic eruption in Tonga caused an unusually large tsunami around the Pacific. It travels with a faster apparent velocity and has larger amplitudes at long distances than what would be expected from a conventional tsunami from the volcanic source. This tsunami was generated by the moving atmospheric Lamb wave and traveled at the speed of the Lamb wave (0.31 km/s). Japanese data showed the amplitude of this first tsunami becomes small when approaching the coast, due to the weaker air‐sea coupling at the shallow depth. This wave split when passing the continental slope, and traveled at the speed of the ocean gravity wave. Therefore, the tsunami observed at the coast is delayed by thousands of seconds from the passage of the Lamb wave. Tsunamis generated by this atmospheric mechanism have not been previously observed by modern digital recording systems and should be considered in the tsunami warning systems. Plain Language Summary: A tsunami is usually generated by the sudden changes of the water heights, and caused by offshore earthquakes, coastal landslides, and submarine volcanic eruptions. The generated vertical displacement of the water propagates as a very long wave, and the tsunami waves become compressed with increased heights as they approach the coast. The 2022 volcanic eruption in Tonga caused an unusually large tsunami, which cannot be explained by conventional sources. The speed and amplitude are very different from theoretical values: the speed is about 0.31 km/s, whereas the average tsunami speed in the Pacific is 0.2 km/s. These data suggest that the tsunami from the Tonga eruption was excited by a pulse of atmospheric pressure as it traveled from the volcano. This source of the tsunami in the atmosphere needs to be considered for the tsunami warning system in the future. Key Points: Lamb wave produced by the volcanic eruption excites the sea surface as it travels across the Pacific and generates a tsunami pulseThe effect of the air‐sea coupling becomes weaker as the Lamb wave approaches the coastThe tsunami wave splits when passing the continental slope of Japan causing more complex waves [ABSTRACT FROM AUTHOR]

Trichodesmium, a major diazotroph in tropical and subtropical oceans, provides a significant amount of bioavailable nitrogen in oligotrophic oceans. Remarkably, the cyanobacteria carry out nitrogen fixation and photosynthesis simultaneously under high light (HL) conditions. Here, we hypothesize that nickel superoxide dismutase (NiSOD) protects the nitrogen fixation process from oxidative stress generated in photosynthesis under high solar radiation conditions. We found that the variations in nitrogen fixation rates closely corresponded to Ni availability under HL conditions. The expression of NiSOD and two representative photosynthetic proteins also corresponded to variations in both nitrogen fixation rates and Ni availability under HL conditions. Trichodesmium collected in the field had a high Ni quota and elevated SOD activity. The evidence supports the conclusion that NiSOD protects nitrogen fixation in Trichodesmium from oxidative stress. The ability to utilize NiSOD may be a major advantage for Trichodesmium under high solar radiation conditions. [ABSTRACT FROM AUTHOR]

We investigated the effects of Ni concentration on hydrogen (H2) net production and nitrogen (N2) fixation rates in a model unicellular diazotrophic cyanobacterium, Cyanothece. We quantified NiFe uptake hydrogenase of the diazotroph to examine how Ni deficiency affects the expression of hydrogenase and nitrogenase and N2 fixation rates. We found that Ni availability controls its H2 net production and the expression of HupL, the major subunit of the uptake hydrogenase. Low Ni availability induced low HupL expression levels while yielding high H2 net production, and vice versa. We also identified the threshold range of Ni concentrations that may differentiate low and high H2 net production patterns in the diazotroph. However, the substantial variations in Ni availability and H2 net production did not affect nitrogenase expression and N2 fixation rates in Cyanothece. From two independent studies in the Atlantic tropical and subtropical oceans, we found that dissolved Ni concentrations and H2 oversaturation percentage exhibited a statistically significant negative correlation, which is consistent with the findings of this culture study. Overall, these results indicate that Ni availability may affect H2 net production and concentrations in the euphotic zone of the oceanic regions. H2 concentrations may be used as a promising proxy to reflect N2 fixation activities in tropical and subtropical oceans only under Ni‐deficient conditions. [ABSTRACT FROM AUTHOR]

The North Pacific Ocean is located at the end of the thermohaline circulation of deep water. This study reports on basin‐scale full‐depth sectional distributions of total dissolvable (td), dissolved (d), and labile particulate (lp) Cd, Ni, Zn, and Cu along three transects: the GEOTRACES transects GP18 (165°E) and GP02 (47°N), and along 160°W. We find that scavenging is an important factor that significantly affects the distributions of dZn, dNi, and dCu, of which the magnitude of influence increases in the order of Cd < Ni, Zn < Cu. The relationships between the four dissolved metals with Si(OH)4 and PO4 differed considerably from those in other oceans. The spot concentration ratio of dCd/PO4 was 0.34 ± 0.02 nmol/μmol (n = 296) in waters >800 m deep, which is in the range of the phytoplankton Cd/P ratio. This is indicative of the dominant effect of water circulation and biological processes on dCd distribution. The dissolved metals (dMs) to PO4 ratios of other examined metals were either partially or completely outside the range of typical biomass ratios. They generally increased with depth in waters >800 m deep; the magnitude of increase was the highest for Cu and moderate for Ni and Zn. Below 800 m, an increase in the apparent oxygen utilization from 150 to 300 μmol/kg was concurrent with a decrease in the dMs/PO4 ratios: 4 ± 3% for Cd, 21 ± 4% for Zn, 21 ± 3% for Ni, and 69 ± 7% for Cu. Key Points: Basin‐scale distributions of total dissolvable, dissolved, and labile particulate Cd, Ni, Zn, and Cu in the North Pacific are reportedCd is controlled by internal cycling and biological processes, and its stoichiometry with major nutrients is modified via ocean circulationThe distributions of Ni, Zn, and Cu are affected by scavenging and redissolution from sinking particles and sediments [ABSTRACT FROM AUTHOR]

An unusual devastating tsunami occurred on September 28, 2018 after a strike‐slip faulting earthquake in Sulawesi, Indonesia. The induced tsunami struck Palu city with ∼4‐m flow depth. We performed two analyses to investigate the source of the tsunami. We first conducted the teleseismic source inversion and obtained the overall slip distribution of the strike‐slip fault. Our tsunami simulation from the coseismic deformation of the seismically estimated strike‐slip faulting produced a tsunami comparable to the leading part of the observation at Pantoloan. In order to reconstruct the detailed slip distribution on the fault plane, we then jointly utilized the tsunami waveform and Synthetic Aperture Radar (SAR) data. Because of the lack of SAR data in the bay, the tsunami data is necessary to constrain the offshore slip distribution, which directly induces the tsunami. The inverted source model shows a strike‐slip fault which consists of three segments extending from the epicenter to the south of 1.4°S with two bends and two asperities around Palu city. The joint inversion model accurately reconstructs the observed surface displacements and the leading part of the tsunami waveform. Our result exhibits the significant contribution of the strike‐slip faulting to the tsunami, but it also suggests additional tsunami sources, such as landslides, for the high inundations near Palu bay. The result also indicates that regional devastating tsunamis can be generated by an onshore strike‐slip fault with localized large dip slip. Plain Language Summary: The Palu, Indonesia, earthquake of September 28, 2018 produced tsunami flooding and damage in Palu city. Because of its strike‐slip mechanism, which is typically not efficient to produce tsunamis, multiple submarine landslides have been speculated as a tsunami source. We found that the fault model estimated by teleseismic waves (recorded globally outside Indonesia) can reproduce the tsunami recorded at the Pantoloan station in Palu bay. This indicates that the source of tsunami recoded at Pantoloan is mostly the fault motion due to the earthquake. We then combined the displacements measured by Synthetic Aperture Radar images and the Pantoloan tsunami waveform to estimate the detailed slip distribution on the fault. The slip model shows a strike‐slip fault with two large slip areas located near Palu city between two bends. This model well reproduces the Pantoloan tsunami but fails to fully reproduce the inundations in Palu city, suggesting that additional tsunami sources, such as landslides, should be responsible for the large inundations in Palu city. Our result suggests that a strike‐slip fault can induce a devastating local tsunami. Key Points: Two analyses utilizing teleseismic, Synthetic Aperture Radar, and tsunami data retrieve an earthquake source model that explains the observed tsunamiA strike‐slip fault with localized large dip slip of the 2018 Palu earthquake induced the devastating regional tsunamiOnshore strike‐slip faults should also be regarded as a potential source of tsunamis for regional areas [ABSTRACT FROM AUTHOR]

Warming and nutrient limitation are stressors known to weaken the health of microalgae. In situations of stress, access to energy reserves can minimize physiological damage. Because of its widespread requirements in biochemical processes, iron is an important trace metal, especially for photosynthetic organisms. Lowered iron availability in oceans experiencing rising temperatures may contribute to the thermal sensitivity of reef‐building corals, which rely on mutualisms with dinoflagellates to survive. To test the influence of iron concentration on thermal sensitivity, the physiological responses of cultured symbiotic dinoflagellates (genus Breviolum; family Symbiodiniaceae) were evaluated when exposed to increasing temperatures (26 to 30°C) and iron concentrations ranging from replete (500 pM Fe') to limiting (50 pM Fe') under a diurnal light cycle with saturating radiance. Declines in photosynthetic efficiency at elevated temperatures indicated sensitivity to heat stress. Furthermore, five times the amount of iron was needed to reach exponential growth during heat stress (50 pM Fe′ at 26–28°C vs. 250 pM Fe′ at 30°C). In treatments where exponential growth was reached, Breviolum psygmophilum grew faster than B.minutum, possibly due to greater cellular contents of iron and other trace metals. The metal composition of B.psygmophilum shifted only at the highest temperature (30°C), whereas changes in B.minutum were observed at lower temperatures (28°C). The influence of iron availability in modulating each alga's response to thermal stress suggests the importance of trace metals to the health of coral‐algal mutualisms. Ultimately, a greater ability to acquire scarce metals may improve the tolerance of corals to physiological stressors and contribute to the differences in performance associated with hosting one symbiont species over another. [ABSTRACT FROM AUTHOR]

Motivated by the unwarned tsunami disaster caused by the flank collapse of the Anak Krakatau volcano on 22 December 2018, we used a landslide tsunami model to explore potential tsunami observing and warning systems for the region. With the estimated volume of 0.24 km3 and the relatively short duration (~3 to 5 min), the landslide of the volcanic edifice in the southwest sector triggered a tsunami of higher than 40 m in the vicinity. The tsunami, however, attenuated rapidly as it propagated away from the generation area, resulting in lower than 2 m wave heights at tide gauges around the Sunda Strait. Using the tsunami model, we demonstrated the capability of a ship height positioning method to detect the tsunami of amplitude ~20 cm associated with the event. Furthermore, assimilating the tsunami current velocity observed by high‐frequency oceanographic radars can produce accurate forecasts of coastal tsunami heights. Plain Language Summary: The tsunami on 22 December 2018 claimed hundreds of lives across the Sunda Strait regions of Indonesia. Unlike typical tsunamis, this silent tsunami was caused by the activity of Anak Krakatau volcano. This paper proposes new tsunami observation and warning systems for such a tsunami by modeling the generation and propagation processes. Although the source characteristics are constrained using limited data, that is, satellite images, the model can reproduce tsunami waveforms recorded at tide gauges and flow depths measured at specified regions. We then perform numerical experiments to assess the performance of potential tsunami observing systems based on high‐frequency oceanographic radars and ship‐height positioning. The experiment suggests that both systems can be viable future tsunami observations in the region. Key Points: The study models the tsunami generation and propagation processes associated with the Anak Krakatau volcanoWe validate our model against tsunami waveforms at tide gauges and flow depthsBased on the model, tsunami observing systems using oceanographic radars and ship height positioning are suitable for the region [ABSTRACT FROM AUTHOR]

Ni is an essential cofactor in NiFe‐uptake hydrogenase, an enzyme regulating H2 metabolism in diazotrophic cyanobacteria, the major H2 producers in the surface ocean globally. Here, we investigated the effect of Ni supply on H2 production and N2 fixation by using a model marine cyanobacterial diazotroph, Cyanothece. By mediating total dissolved Ni concentrations from 100 to 0.03 nmol L−1 in a trace metal‐defined culture medium, we demonstrated that Ni deficiency results in H2 accumulation, coupled with decreasing Ni quotas, growth rates, and occasionally relatively low N2 fixation rates. These results indicate that Ni deficiency limits the growth of the Cyanothece to some extent, considerably decreases H2 uptake by hydrogenase and leads to H2 accumulation and N2 fixation variation in the diazotroph. The findings show that Ni availability is a critical factor on controlling H2 production and N2 fixation in marine diazotrophic cyanobacteria. The information of Ni bioavailability for diazotrophic cyanobacteria is thus essential to evaluate the importance of Ni for H2 cycling and N2 fixation in oceanic surface waters. [ABSTRACT FROM AUTHOR]

The slip distribution of the 1960 Chile earthquake was estimated using geodetic data, local tsunami data, and newly usable transoceanic tsunami data. The large slips triggered a significant tsunami which was recorded by the tide gauges around the Pacific Ocean. We performed a two‐step inversion to estimate the slip distribution. In the first step, we jointly inverted the tsunami waveforms and local geodetic data to recover the ground and seafloor vertical displacement. The transoceanic tsunami data could not be used for waveform inversions until the wave phase and arrival time discrepancies were recently reconciled by improving the long‐wave theory with the phase correction method. The random arrival time discrepancy due to inaccurate local bathymetry and/or instrumental problems was considered by the optimal time alignment. In the second step, we estimated the slip distribution on the plate interface by inverting the vertical displacement obtained in the first step. Checkerboard tests showed that our method and data can resolve displacement at a spatial resolution of at least ~100 km but cannot estimate the rupture velocity. The result for actual data shows a rupture extended about 800 km with a width of about 150 km and three asperities. The large slips are concentrated in the offshore shallow plate interface. Our results indicate that the central and south patches contribute to the large coastal elevation changes at southern source area and high tsunami waves at far field. The estimated moment ranges 1.3–1.9 × 1023 Nm (Mw 9.3–9.4) for rake angles of 90–140°. Key Points: The slip distribution of the 1960 Chile earthquake is estimated from transoceanic tsunami data, local tsunami data, and geodetic dataThe seismic moment is 1.4 x 1023 Nm (Mw 9.4) for rake angle of 110°, and the slip consists of three shallow asperitiesLarge central and south asperities are required to reconstruct the southern high coastal uplift and large tsunami waves at far field [ABSTRACT FROM AUTHOR]

The Kuroshio, flowing through the eastern end of the East China Sea, transports terrestrial material to the Northwestern Pacific Ocean. Along the Kuroshio path, we collected size‐fractionated suspended particles in the upper 200 m to investigate the composition and sources of particulate trace metals. Demonstrated by Al‐ and P‐normalized elemental ratios, we found that anthropogenic aerosol deposition was the major source of most particulate trace metals in the Kuroshio region although the impact of bottom resuspension and riverine input may be significant at some specific regions. As seen in our previous studies in the South China Sea and the Western Philippine Sea, this study concluded that anthropogenic aerosol deposition is the dominant particulate trace metal source in the surface water of the Northwestern Pacific Ocean and its marginal seas. Compared to particulate trace metal composition obtained in other open oceans, we found that the distribution patterns of particulate trace metal composition in the surface waters are closely associated with aerosol deposition fluxes. In regions with low deposition, the particulate trace metal concentrations were extremely low and metal to P ratios were all comparable to their intracellular quota previously proposed. In regions with high deposition, metal to P ratios were highly elevated in comparison to their intracellular quota and metal to Al ratios were deviated from lithogenic ratios to various extents. The globally consistent distribution patterns validate trace metal stoichiometry concept in plankton intracellularly and the primary role of aerosol deposition on deciding particulate trace metal composition in oceanic surface water globally. Plain Language Summary: The Kuroshio adjacent to the East China Sea is an ideal region to investigate the material exchange and transport from the marginal sea to the Northwestern Pacific Ocean. Particulate trace metals may serve as useful proxies or tracers for the sources of particulate materials in the Kuroshio and material exchange with the marginal seas and islands. In addition to aerosol transport, both anthropogenic and lithogenic materials carried by riverine or sediment transport may be additional sources of particulate trace metals in the studied region. In this study, we found that anthropogenic aerosol deposition is the dominant particulate trace metal source in the surface water. Compared to the data obtained in other open oceans, we further revealed that the distribution patterns of particulate trace metal composition in the surface waters are closely associated with aerosol deposition globally. The globally consistent distribution patterns also validate that plankton possess relatively constrained trace metal composition intracellularly. Key Points: Anthropogenic aerosol deposition is the dominant source of most particulate trace metals collected in the surface water of the KuroshioThe distribution patterns of particulate metal composition in the global surface water are associated with aerosol deposition fluxesThe distribution patterns of particulate metal composition validate intracellular trace metal stoichiometry concept in plankton [ABSTRACT FROM AUTHOR]

Abstract: Desert dust storms are frequent in the Northern Red Sea region, providing nutrients (i.e., PO4) and trace‐metals (i.e., Fe) that may stimulate dinitrogen (N2) fixation. Dust also carries a high diversity of airborne microbes (bacteria and archaea), including diazotrophs, that may remain viable during transport and upon deposition. Here we evaluate the impact of atmospheric deposition and its associated airborne diazotrophs on N2 fixation in the surface water of the low‐nutrient Northern Red Sea, using mesocosm bioassay experiments. We compared the chemical (nutritional) and sole airborne microbial impact of aerosol additions on N2 fixation using “live‐dust” (release nutrients/trace metals and viable airborne microorganisms) and “UV‐killed dust” (release only chemicals). Airborne diazotrophy accounted for about one third of the measured N2 fixation (0.35 ± 0.06 nmol N · L−1 · day−1 and 0.29 ± 0.06 nmol N · L−1 · day−1, for “February 2017” and “May 2017,” “live‐dust” additions, respectively). Two nifH sequences related to cluster III diazotrophs were amplified from the dust samples, consistent with the N2 fixation measurement results. We postulate that the deposition of viable airborne diazotrophs may enhance N2 fixation, especially in marine provinces subjected to high aerosol loads. We speculate that the relative contribution of airborne N2 fixation may increase in the future with the predicted increase in dust deposition. [ABSTRACT FROM AUTHOR]

Abstract: Systemic travel time delays of up to 15 min relative to the linear long waves for transoceanic tsunamis have been reported. A phase correction method, which converts the linear long waves into dispersive waves, was previously proposed to consider seawater compressibility, the elasticity of the Earth, and gravitational potential change associated with tsunami motion. In the present study, we improved this method by incorporating the effects of ocean density stratification, actual tsunami raypath, and actual bathymetry. The previously considered effects amounted to approximately 74% for correction of the travel time delay, while the ocean density stratification, actual raypath, and actual bathymetry, contributed to approximately 13%, 4%, and 9% on average, respectively. The improved phase correction method accounted for almost all the travel time delay at far‐field stations. We performed single and multiple time window inversions for the 2011 Tohoku tsunami using the far‐field data (>3 h travel time) to investigate the initial sea surface displacement. The inversion result from only far‐field data was similar to but smoother than that from near‐field data and all stations, including a large sea surface rise increasing toward the trench followed by a migration northward along the trench. For the forward simulation, our results showed good agreement between the observed and computed waveforms at both near‐field and far‐field tsunami gauges, as well as with satellite altimeter data. The present study demonstrates that the improved method provides a more accurate estimate for the waveform inversion and forward prediction of far‐field data. [ABSTRACT FROM AUTHOR]

The surface water of the Western Philippine Sea (WPS) receives a significant amount of anthropogenic aerosols from East Asia, serving as an ideal location to investigate the impact of anthropogenic aerosol deposition on trace metal composition and cycling in the Northwestern Pacific Ocean (NWPO). As part of the Taiwan GEOTRACES process study, we have collected size-fractionated plankton from surface water to investigate their metal composition in the open ocean. Elemental ratios in plankton, P- and Al-normalized, are used to evaluate the sources of trace metals and the relative contribution of different metal components in plankton assemblages. Most of the trace metal quotas in plankton are one to two orders of magnitude higher than their intracellular plankton quota, indicating that the majority of the metals are most likely to be extracellularly adsorbed or aggregated on plankton. The metal to Al ratios for most of the trace metals in plankton are also one to two orders of magnitude higher than their lithogenic composition, but are relatively close to metal composition in aerosols collected in situ. This supports the notion that particulate trace metals associated with plankton mainly originate from anthropogenic aerosols, not lithogenic particles. Compared to plankton metal quotas obtained in other oceanic regions, trace metal quotas observed in the WPS rank among the highest for Fe, Mn, Zn, and Cu globally. Our study demonstrates that anthropogenic aerosol deposition has significantly elevated trace metal concentrations in the size-fractionated plankton in the surface water of the NWPO relative to the biological requirements. [ABSTRACT FROM AUTHOR]

A visible-light-induced hydrogen evolution system based on a CdSe quantum dots (QDs)-TiO2-Ni(OH)2 ternary assembly has been constructed under an ambient environment, and a bifunctional molecular linker, mercaptopropionic acid, is used to facilitate the interaction between CdSe QDs and TiO2. This hydrogen evolution system works effectively in a basic aqueous solution (pH 11.0) to achieve a hydrogen evolution rate of 10.1 mmolg-1h-1 for the assembly and a turnover frequency of 5140 h-1 with respect to CdSe QDs (10 h); the latter is comparable with the highest value reported for QD systems in an acidic environment. X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, and control experiments demonstrate that Ni(OH)2 is an efficient hydrogen evolution catalyst. In addition, inductively coupled plasma optical emission spectroscopy and the emission decay of the assembly combined with the hydrogen evolution experiments show that TiO2 functions mainly as the electron mediator; the vectorial electron transfer from CdSe QDs to TiO2 and then from TiO2 to Ni(OH)2 enhances the efficiency for hydrogen evolution. The assembly comprises light antenna CdSe QDs, electron mediator TiO2, and catalytic Ni(OH)2, which mimics the strategy of photosynthesis exploited in nature and takes us a step further towards artificial photosynthesis. [ABSTRACT FROM AUTHOR]

This study applied a regional air quality model, incorporated with an emission module, to quantitatively differentiate the atmospheric iron sources originating from lithogenic dusts or coal-burning fly ashes deposited in the Northwestern Pacific Ocean and its marginal seas. Particular attention was paid to the high iron content of fly ashes emitted from steel and iron plants burning coals. Using the year 2007 as an example, the modeling results exhibit large seasonal variations in iron deposition, with highest deposition fluxes occurred during spring and autumn, which are comparable to the seasonal fluctuation of chlorophyll a concentrations estimated by satellite images in the oceanic regions. Fly ash from coal burning accounted for 7.2% of the total iron deposited over the northwestern Pacific Ocean and 15% of that over the northern South China Sea. After considering the difference of iron solubility in the aerosols, anthropogenic aerosol associated with coal burning would be the major bioavailable iron source in the surface water of the oceanic regions. [ABSTRACT FROM AUTHOR]

Nanocomposites from a polyether-type waterborne polyurethane (PU) and 0.1 wt % of silicate materials were prepared. The individual silicate materials were natural clays (montmorillonite and mica), their exfoliated clays [nano silicate platelets (NSP) and nano mica platelets], and NSP modified with C18 fatty amine (NSP-S). The physico-chemcical properties and antimicrobial activity of the nanocomposites were characterized in vitro. The biostability and biocompatibility of the nanocomposites were evaluated in vivo. The nanocomposites exhibited various surface morphologies with phase separation of hard and soft domains in nanometric scales. The nanocomposite containing NSP (PU-NSP) showed better endothelial cell attachment and gene expression. The better biocompatibility of PU-NSP and PU-NSP-S was evidenced by the lower thickness of foreign body capsules in rat subcutaneous implantation. PU-NSP had the least surface degradation in vivo as demonstrated by the electron microscopy and infrared spectroscopy. This may be associated with the different surface structure. PU-NSP and PU-NSP-S showed strong bacteriostatic effects, which suggested that the nano clay in the polymer matrix may still interact with the microbes. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. [ABSTRACT FROM AUTHOR]

We determined Zn isotope composition (δ66Zn) in the water column of the Northwestern Pacific Ocean (NWPO) and its marginal seas to investigate the processes driving vertical and spatial variations. Comparable to previous studies, dissolved δ66Zn was relatively low in the top 200 m, ranging from −0.91 to +0.24‰ and increased with depth toward an averaged value, +0.38±0.10‰, in deep water. We found that δ66Zn observed in the deep water of the NWPO was much lower than the Northeastern Pacific Ocean. Box model approaches suggest that spatial variations in the deep water may be attributed to isotopically light Zn originating from sedimentary input or anthropogenic aerosols. In the surface water, the fractionation factors derived from both closed or open system fractionation models are all less than one in the NWPO. However, both closed and open system models show a relatively poor fit to the measured data. We thus propose that external input is a major factor causing the variations of [Zn] and δ66Zn values in surface water, in addition to the effects of scavenging, physical mixing, and biological uptake. As elevated [Zn] and relatively light δ66Zn in the surface water were observed in high aerosol input regions, aerosol deposition may play a dominant role in regulating Zn elemental and isotopic composition in the surface ocean. Key Points: We observed spatial variations of δ66Zn in the deep water of the NWPO and found considerably lighter δ66Zn than the NEPOThe sedimentary input may be a major cause of relatively light dissolved δ66Zn in the deep water of the NWPOAerosol Zn input is a major cause of the variations of [Zn] and δ66Zn in the surface water of the NWPO [ABSTRACT FROM AUTHOR]

The title compound, C18H16N2O, contains a phthalonitrile ring lying on a crystallographic mirror plane and a 4- tert-butyl­phen­oxy substituent oriented exactly perpendicular to that plane. [ABSTRACT FROM AUTHOR]