Interannual to Decadal Variations of Submesoscale Motions around the North Pacific Subtropical Countercurrent

The outputs from a submesoscale permitting hindcast simulation from 1990 to 2016 are used to investigate the interannual to decadal variations of submesoscale motions. The region we focus on is the subtropical Northwestern Pacific including the subtropical countercurrent. The submesoscale kinetic energy (KE) is characterized by strong interannual and decadal variability, displaying larger magnitudes in 1996, 2003, and 2015, and smaller magnitudes in 1999, 2009, 2010, and 2016. These variations are partially explained by those of the available potential energy (APE) release at submesoscale driven by mixed layer instability in winter. Indeed, this APE release depends on the mixed layer depth and horizontal buoyancy gradient, both of them modulated with the Pacific Decadal Oscillation (PDO). As a result of the inverse KE cascade, the submesoscale KE variability possibly leads to interannual to decadal variations of the mesoscale KE (eddy KE (EKE)). These results show that submesoscale motions are a possible pathway to explain the impact associated with the PDO on the decadal EKE variability. The winter APE release estimated from the Argo float observations varies synchronously with that in the simulation on the interannual time scales, which suggests the observation capability to diagnose the submesoscale KE variability

Climate precursors of satellite water marker index for spring cholera outbreak in Northern Bay of Bengal coastal regions

Cholera is a water-borne infectious disease that affects 1.3 to 4 million people, with 21,000 to 143,000 reported fatalities each year worldwide. Outbreaks are devastating to affected communities and their prospects for development. The key to support preparedness and public health response is the ability to forecast cholera outbreaks with sufficient lead time. How Vibrio cholerae survives in the environment outside a human host is an important route of disease transmission. Thus, identifying the environmental and climate drivers of these pathogens is highly desirable. Here, we elucidate for the first time a mechanistic link between climate variability and cholera (Satellite Water Marker; SWM) index in the Bengal Delta, which allows us to predict cholera outbreaks up to two seasons earlier. High values of the SWM index in fall were associated with above-normal summer monsoon rainfalls over northern India. In turn, these correlated with the La Niña climate pattern that was traced back to the summer monsoon and previous spring seasons. We present a new multi-linear regression model that can explain 50% of the SWM variability over the Bengal Delta based on the relationship with climatic indices of the El Niño Southern Oscillation, Indian Ocean Dipole, and summer monsoon rainfall during the decades 1997–2016. Interestingly, we further found that these relationships were non-stationary over the multi-decadal period 1948–2018. These results bear novel implications for developing outbreak-risk forecasts, demonstrating a crucial need to account for multi-decadal variations in climate interactions and underscoring to better understand how the south Asian summer monsoon responds to climate variability

North Pacific climate and ecosystem predictability on seasonal to decadal timescales

The present Research Topic aims to collect studies on all aspects contributing to marine ecosystem predictability and prediction, including observational and numerical studies, with a focus on the North Pacific Ocean north of 30&deg;N. The scope of this Research Topic includes studies of climate predictability and climate-marine ecosystem relationships as the basis of marine ecosystem predictability. This Research Topic is organized by the Working Group on &ldquo;Climate and Ecosystem Predictability&rdquo;, a joint working group between the North Pacific Marine Science Organization (PICES) and Climate and Oceans, Variability, Predictability and Change (CLIVAR). PICES is an intergovernmental organization for marine science over the North Pacific, that includes the countries along the North Pacific rim, i.e., the United States of America, Japan, People's Republic of China, Canada, Republic of Korea, and the Russian Federation. CLIVAR is one of six global core projects of the World Climate Research Programme. These international science organizations and projects have played important roles in the ocean and climate sciences. This working group is the first joint working group between PICES and CLIVAR, demonstrating the increasing need for collaboration between physical ocean/climate studies, the main area of CLIVAR, and marine biological studies, the major focus of PICES. &nbsp;</p

Examining the impact of multiple climate forcings on simulated Southern Hemisphere climate variability

The study examines the influence of external climate forcings, and atmosphere–ocean–sea–ice coupled interaction on the Southern Hemisphere (SH) atmospheric circulation variability. We analysed observed and simulated changes in view of Antarctic sea–ice and Southern Ocean surface temperature trends over recent decades. The experiment embraces both idealised and comprehensive methods that involves an Earth System Model (ESM) prototype. The sensitivity experiment is conducted in a manner that decomposes the signatures of sea–ice, sea surface temperature and feedback mechanisms. The results reveal that the Southern Annular Mode (SAM) multidecadal variability is found to be modulated by coupled interactions whereas its sub-seasonal to interannual vacillation seems to follow a random trajectory. The latter may strengthen the notion that its predictability is limited even with the use of ESMs. Most of the atmospheric circulation variability and recent changes may be explained by the ocean thermal forcing and coupled interactions. However, the influence of sea–ice forcing alone is largely indistinguishable and predominantly localised in nature. The result also confirms that the Antarctic dipole-like sea–ice pattern, a leading climate mode in the SH, has intensified in the last three decades irrespective of season. The probable indication is that processes within the Southern Ocean may play a key role, which deserves further investigation.The National Research foundation through the Alliance for Collaboration on Climate & Earth Systems Science (ACCESS). The iDEWS project, which supported the study under the auspices of the Japan Science and Technology Agency/Japan Agency for Medical Research and Development through the Science and Technology Research Partnership for Sustainable Development (SATREPS), and the ACCESS in South Africa.http://link.springer.com/journal/3822021-04-27hj2020Geography, Geoinformatics and Meteorolog

RIM1 confers sustained activity and neurotransmitter vesicle anchoring to presynaptic Ca2+ channels.

International audienceThe molecular organization of presynaptic active zones is important for the neurotransmitter release that is triggered by depolarization-induced Ca2+ influx. Here, we demonstrate a previously unknown interaction between two components of the presynaptic active zone, RIM1 and voltage-dependent Ca2+ channels (VDCCs), that controls neurotransmitter release in mammalian neurons. RIM1 associated with VDCC beta-subunits via its C terminus to markedly suppress voltage-dependent inactivation among different neuronal VDCCs. Consistently, in pheochromocytoma neuroendocrine PC12 cells, acetylcholine release was significantly potentiated by the full-length and C-terminal RIM1 constructs, but membrane docking of vesicles was enhanced only by the full-length RIM1. The beta construct beta-AID dominant negative, which disrupts the RIM1-beta association, accelerated the inactivation of native VDCC currents, suppressed vesicle docking and acetylcholine release in PC12 cells, and inhibited glutamate release in cultured cerebellar neurons. Thus, RIM1 association with beta in the presynaptic active zone supports release via two distinct mechanisms: sustaining Ca2+ influx through inhibition of channel inactivation, and anchoring neurotransmitter-containing vesicles in the vicinity of VDCCs

北太平洋亜寒帯前線の南北変位に対する大気と海洋の応答: 大気海洋結合モデル CFES を用いた実験

近年の観測データを用いた研究から、風成海洋循環の変動に伴う黒潮続流域での海洋前線の南北シフトが、 海洋から大気への熱的な強制の変動を通じて、海盆ス ケールの大気循環変動に影響を与る可能性が示唆され ている (Frankignoul et al. 2011, Taguchi et al. 2012)。 しかし既往研究で採用された診断的な解析手法では、 海洋前線変動の大気への影響の因果関係を直接的に明 らかに出来ないため、大気大循環モデルに海洋前線ス ケールの海面水温 (SST) 偏差を与える感度実験が、国 内外で精力的に実施されている (例えば Okajima et al. 2014)。本研究では、このような海洋前線変動に対する 大気応答実験を大気海洋結合モデルを用いて行うこと により、より現実的な条件の下での海洋前線変動に対 する大気応答を調べ、究極的には、そのような大気応 答の海洋への再影響を評価することを目的とする。要旨 ; 2014年度日本海洋学会春季大会（2014年3月26日～3月30日, 東京海洋大学

Biochemical classification of tauopathies by immunoblot, protein sequence and mass spectrometric analyses of sarkosyl-insoluble and trypsin-resistant tau

Intracellular filamentous tau pathology is the defining feature of tauopathies, which form a subset of neurodegenerative diseases. We have analyzed pathological tau in Alzheimer’s disease, and in frontotemporal lobar degeneration associated with tauopathy to include cases with Pick bodies, corticobasal degeneration, progressive supranuclear palsy, and ones due to intronic mutations in MAPT. We found that the C-terminal band pattern of the pathological tau species is distinct for each disease. Immunoblot analysis of trypsin-resistant tau indicated that the different band patterns of the 7–18 kDa fragments in these diseases likely reflect different conformations of tau molecular species. Protein sequence and mass spectrometric analyses revealed the carboxyl-terminal region (residues 243–406) of tau comprises the protease-resistant core units of the tau aggregates, and the sequence lengths and precise regions involved are different among the diseases. These unique assembled tau cores may be used to classify and diagnose disease strains. Based on these results, we propose a new clinicopathological classification of tauopathies based on the biochemical properties of tau