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The primary production by diatoms, haptophytes and cyanobacteria in the Kuroshio region was evaluated using satellite ocean color remote sensing. We developed a method that estimates bio-optical properties such as the photosynthetic quantum yield index and chlorophyll- a -specific optical absorption coefficient of phytoplankton to derive the group-specific production. In contrast with the previous efforts that assume bio-optical properties to derive the production, our method relaxes the assumption by integrating an image processing of bulk satellite data into bio-optical modeling. Especially, our bio-optical model uses a universal bio-optical principle that we found: i.e., the absorption coefficient of phytoplankton at the wavelength of 510 nm can represent their spectral average. Climatological average of the group-specific primary production in the Kuroshio region showed 134, 72 and 40 mg C m –2  day –1 for diatoms, haptophytes and cyanobacteria, respectively. The quantum yield index of each phytoplankton group varied spatially, resulting in a latitudinal gradient, and diatoms had a higher quantum yield than those of cyanobacteria and haptophytes. Analysis of seasonal variability in the group-specific primary production in the Kuroshio region suggested that the primary production due to diatoms was mainly driven by variability in their chlorophyll-a abundance, whereas that due to cyanobacteria by variability in their quantum yield index or photophysiology. The production due to haptophytes was shown seasonally regulated by variability in both chlorophyll- a abundance and photophysiology.

The Arctic region is experiencing drastic climatic changes bringing about potential ecological shifts. Here, we explored marine biodiversity and potential species associations across eight Arctic marine areas between 2000 and 2019. We compiled species occurrences for a subset of 69 marine taxa (i.e., 26 apex predators and 43 mesopredators) and environmental factors to predict taxon-specific distributions using a multi-model ensemble approach. Arctic-wide temporal trends of species richness increased in the last 20 years and highlighted potential emerging areas of species accrual due to climate-driven species redistribution. Further, regional species associations were dominated by positive co-occurrences among species pairs with high frequencies in the Pacific and Atlantic Arctic areas. Comparative analyses of species richness, community composition, and co-occurrence between high and low summer sea ice concentrations revealed contrasting impacts of and detected areas vulnerable to sea ice changes. In particular, low (high) summer sea ice generally resulted in species gains (loss) in the inflow and loss (gains) in the outflow shelves, accompanied by substantial changes in community composition and therefore potential species associations. Overall, the recent changes in biodiversity and species co-occurrences in the Arctic were driven by pervasive poleward range shifts, especially for wide-ranging apex predators. Our findings highlight the varying regional impacts of warming and sea ice loss on Arctic marine communities and provide important insights into the vulnerability of Arctic marine areas to climate change.

Unraveling the Paleo-Kuril Arc's origins is key to understanding northwest Pacific tectonics. The Paleo-Kuril Arc is viewed as an intraoceanic arc from trench subduction between the Izanagi and Pacific Plates. Alternatively, several studies suggest the Paleo-Kuril Arc as a continental magmatic arc, hypothesizing the existence of a mid-oceanic ridge and Paleogene subduction, placing the Paleo-Kuril Arc near the Okhotsk Block's southern edge. This study clarifies these hypotheses, previously clouded by limited geochronological data on deposits in the Paleo-Kuril Arc. We conducted U–Pb dating to examine the origins of detrital zircons from the Cretaceous–Paleogene Tokoro and Nemuro Belts of the Paleo-Kuril Arc. Cluster analysis, merging new and existing data, identified two unique detrital zircon age clusters. The abundance of Precambrian zircons in Cretaceous–Paleocene Paleo-Kuril Arc sandstones (Type 1 Cluster) suggests a continental magmatic origin, supporting the ridge subduction model. However, an early Eocene shift to a consistent local volcanic source (Type 2 Cluster) highlights a significant provenance change. This geochronological evidence, indicating a separation from continental sources, calls for further research to decode the simultaneous development of sediment sources in different geological belts, potentially tied to the ridge subduction event.

Serpentinization along subducting plates induces mechanical mixing of diverse rocks and interaction with compositionally distinct fluids, which is often accompanied by the formation of rare mineral species. In this study, newly discovered baddeleyites in the Higuchi serpentinite body (HSB), Japan, are described. The HSB occurs as a 15 × 8 m outcrop surrounded by high-P/T metapelite, and baddeleyite was collected from only one serpentinite block. The baddeleyite appear as aggregates exhibiting angular or subrounded shapes with sizes of up to 2 mm in length. The aggregates are composed of acicular baddeleyite surrounded by porous zircon rims. Both the baddeleyite and the zircon yielded U–Pb ages of ca. 96 Ma, corresponding to the peak metamorphic age of the region. Within the aggregates, Th-enriched areas with sizes of less than 20 μm were observed. The baddeleyite aggregates show enrichment of light rare earth elements with positive Eu anomalies. Based on thermodynamic stability relationships, the baddeleyite aggregates are inferred to have originated as zircon megacrysts, which were mechanically incorporated into the ultramafic rock and subsequently metamorphosed during serpentinization. Subsequent metasomatism associated with carbonation and pervasive silicification led to the formation of the zircon rim and trace-elemental maldistribution. This study demonstrates significant high field strength elements (HFSE) heterogeneity on scales ranging from millimeters to micrometers within serpentinite along subduction zones.

[This corrects the article DOI: 10.1371/journal.pone.0304718.].

The biennial review of atomic-weight determinations and other cognate data has resulted in changes for the standard atomic weights of five elements. The atomic weight of bromine has changed from 79.904(1) to the interval [79.901, 79.907], germanium from 72.63(1) to 72.630(8), indium from 114.818(3) to 114.818(1), magnesium from 24.3050(6) to the interval [24.304, 24.307], and mercury from 200.59(2) to 200.592(3). For bromine and magnesium, assignment of intervals for the new standard atomic weights reflects the common occurrence of variations in the atomic weights of those elements in normal terrestrial materials. © 2013 IUPAC.

Spectrally resolved water-leaving radiances (ocean colour) and inferred chlorophyll concentration are key to studying phytoplankton dynamics at seasonal and inter-annual scales, for a better understanding of the role of phytoplankton in marine biogeochemistry; the global carbon cycle; and the response of marine ecosystems to climate variability, change and feedback processes. Ocean colour data also have a critical role in operational observation systems monitoring coastal eutrophication, harmful algal blooms, and sediment plumes. The contiguous ocean-colour record reached 21 years in 2018; however, it is comprised of a number of one-off missions such that creating a consistent time-series of ocean-colour data requires merging of the individual sensors (including MERIS, Aqua-MODIS, SeaWiFS, VIIRS, and OLCI) with differing sensor characteristics, without introducing artefacts. By contrast, the next decade will see consistent observations from operational ocean colour series with sensors of similar design and with a replacement strategy. Also, by 2029 the record will start to be of sufficient duration to discriminate climate change impacts from natural variability, at least in some regions. This paper describes the current status and future prospects in the field of ocean colour focusing on large to medium resolution observations of oceans and coastal seas. It reviews the user requirements in terms of products and uncertainty characteristics and then describes features of current and future satellite ocean-colour sensors, both operational and innovative. The key role of in situ validation and calibration is highlighted as are ground segments that process the data received from the ocean-colour sensors and deliver analysis-ready products to end-users. Example applications of the ocean-colour data are presented, focusing on the climate data record and operational applications including water quality and assimilation into numerical models. Current capacity building and training activities pertinent to ocean colour are described and finally a summary of future perspectives is provided.

Strike-slip faults on the plate tectonic scale in arc settings significantly contribute to the movement of crustal blocks, crustal deformation, and orogeny associated with back-arc spreading, arc–arc collisions, and the subsequent evolution of arcs. The Tanakura Fault Zone, which was active during and after the opening of the Sea of Japan, is one of the main strike-slip faults in Japan. An understanding of the kinematic history of the Tanakura Fault Zone would provide insights into the tectonics of the opening of the Sea of Japan, the ensuing collision of the Honshu and Izu–Ogasawara (Bonin)–Mariana arcs, and the subsequent evolution of the Japanese island arc system. We investigated the activity of the Tanakura Fault Zone during the Miocene based on a field study along the Tanakura Western Marginal Fault in the Tanakura Fault Zone, analysis of deformed Miocene conglomerates, and provenance analysis of detrital zircon in Miocene strata. These results indicate that dextral faulting has occurred in the Tanakura Fault Zone since ~ 16 Ma. We obtained evidence of dextral movement along the Tanakura Western Marginal Fault from fault outcrops. This movement resulted in the formation of elongated granitic clasts in the deformed conglomerate through cataclastic deformation related to the faulting. In addition, cataclasite samples contain Paleozoic zircon grains, suggesting that some clasts were derived from the Paleozoic Hitachi Metamorphic Rocks. Paleozoic clasts were probably supplied as gravel to the area west of the southern Abukuma Mountains and were then transported several kilometers to the north-northwest by dextral movement on the Tanakura Eastern Marginal Fault in the Tanakura Fault Zone to reach their present location. Our findings suggest that dextral faulting of the Tanakura Fault Zone occurred due to NE–SW compression resulting from the collision between the Honshu and Izu–Ogasawara (Bonin)–Mariana arcs, which occurred as a result of the initiation of subduction of the Philippine Sea Plate, just after the opening of the Sea of Japan.

Subsurface chlorophyll maxima are widely observed in the ocean, and they often occur at greater depths than maximum phytoplankton biomass. However, a consistent mechanistic explanation for their distribution in the global ocean remains lacking. One possible mechanism is photoacclimation, whereby phytoplankton adjust their cellular chlorophyll content in response to environmental conditions. Here, we incorporate optimality-based photoacclimation theory based on resource allocation trade-off between nutrient uptake and light harvesting capacity into a 3D biogeochemical ocean circulation model to determine the influence of resource allocation strategy on phytoplankton chlorophyll to carbon ratio distributions. We find that photoacclimation is a common driving mechanism that consistently explains observed global scale patterns in the depth and intensity of subsurface chlorophyll maxima across ocean regions. This mechanistic link between cellular-scale physiological responses and the global scale chlorophyll distribution can inform interpretation of ocean observations and projections of phytoplankton responses to climate change.

Aim To investigate the species‐specific exposure and distributional responses of marine fish and invertebrate taxa to rapidly shifting climate in the Pacific Arctic, characterized by warming and cooling episodes, over the last 24 years. Location Pacific Arctic region, eastern Bering Sea and Chukchi Sea. Methods We examined the variations in the summer (June–July) habitat patterns of 21 marine fish and invertebrate taxa in the eastern Bering Sea using multimodel ensemble predictions of species distribution between 1993 and 2016. Using ensemble model outputs, we examined the rates of predicted (biotic velocities) and expected (bioclimatic velocities) distribution shifts across taxa under four consecutive time periods of distinct climatic regimes. We then compared these species‐specific velocity metrics to the rates of local climatic shifts (climatic velocities) and quantified the potential lags in distributional responses relative to changes in climate across taxa and transitions. Results Our analyses showed that individual taxa responded to climatic fluctuations at different paces and generally exhibited lags in their predicted distributional responses. Subarctic species revealed higher habitat sensitivity and exposure to climatic changes than Arctic taxa, as they expand their habitat ranges into suitable regions emerging in the north under warmer conditions. Importantly, the actual rates of climate shifts (climatic velocities) were poorly correlated with both the expected and observed shifts in species distributions across taxa. Main conclusions Our findings underpin the importance of incorporating species‐specific climatic sensitivity and exposure to changes in climatic conditions when predicting range shift responses and evaluating species vulnerability. These insights are critical for conservation and management of fisheries resources in the region.