scholarly journals Differences in the spatial distribution and shell morphology of Thylacodes adamsii (Gastropoda: Vermetidae) distributed in the Pacific and the Sea of Japan coastal areas of Japan

2021 ◽  
Vol 46 ◽  
pp. 42-54
Author(s):  
YUTA KUSAMA ◽  
TOMOYUKI NAKANO ◽  
AKIRA ASAKURA
2014 ◽  
Vol 11 (9) ◽  
pp. 10903-10930
Author(s):  
M. Katsuyama ◽  
T. Yoshioka ◽  
E. Konohira

Abstract. The spatial distribution of oxygen and hydrogen isotopic composition (δ18O and δ2H) of stream waters across Japan was clarified with a data set compiling sample data obtained from 1278 forest catchments during the summer of 2003. Both δ18O and δ2H values showed positive correlations with the mean annual air temperature and annual evapotranspiration, and negative correlations with latitude and elevation. Deuterium excess (d excess) values in stream waters were higher on the Sea of Japan side, and lower on the Pacific Ocean side, of the Japanese archipelago. The d excess in precipitation was generally higher in winter and lower in summer in Japan. The Sea of Japan side experiences a great deal of snowfall, and seasonal changes in monthly precipitation are rather small. In contrast, the Pacific Ocean side experiences a large amount of rainfall during summer with low levels of precipitation during the winter. Therefore, the lower d excess in stream waters on the Pacific Ocean side reflects summer precipitation, and the higher values on the Sea of Japan side are affected by delayed recharge from snowmelt. The isoscapes of stream water connote not only spatially integrated but also temporally integrated isotope signals of precipitation, and provide a framework for addressing applied hydrological, ecological, or meteorological research questions at regional scales, such as the effects of climate change.


2015 ◽  
Vol 19 (3) ◽  
pp. 1577-1588 ◽  
Author(s):  
M. Katsuyama ◽  
T. Yoshioka ◽  
E. Konohira

Abstract. The spatial distribution of oxygen and hydrogen isotopic composition (δ18O and δ2H) of stream waters across Japan was clarified with a data set by compiling sample data obtained from 1278 forest catchments during the summer of 2003. Both δ18O and δ2H values showed positive correlations with the mean annual air temperature and annual evapotranspiration, and negative correlations with latitude and elevation. Deuterium excess (d-excess) values in stream waters were higher on the Sea of Japan side, and lower on the Pacific Ocean side, of the Japanese archipelago. The d-excess in precipitation was generally higher in winter and lower in summer in Japan. The Sea of Japan side experiences a great deal of snowfall, and seasonal changes in monthly precipitation are rather small. In contrast, the Pacific Ocean side experiences a large amount of rainfall during summer with low levels of precipitation during the winter. Therefore, the lower d-excess in stream waters on the Pacific Ocean side reflects summer precipitation, and the higher values on the Sea of Japan side are affected by delayed recharge from snowmelt. The isoscapes of stream water connote not only spatially integrated but also temporally integrated isotope signals of precipitation and provide a framework for addressing applied hydrological, ecological, or meteorological research questions at regional scales, such as the effects of climate change.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hiroshi Ishida ◽  
Ryosuke S. Isono ◽  
Jun Kita ◽  
Yutaka W. Watanabe

AbstractThis study examines long-term ocean pH data to evaluate ocean acidification (OA) trends at two coastal research institutions located on the Sea of Japan and the Pacific Ocean. These laboratories are located away from the influences of large rivers and major industrial activity. Measurements were performed daily for the past 30 years (1980s–2010s). The average annual ocean pH for both sites showed generally negative trends. These trends were – 0.0032 and – 0.0068 year–1 (p < 0.001) at the Sea of Japan and Pacific Ocean sites, respectively. The trends were superimposed onto approximately 10-year oscillations, which appear to synchronize with the ocean current periodicity. At the Sea of Japan site, the ocean pH in the summer was higher, and the rate of OA was higher than during other seasons. Our results suggest that seasonality and ocean currents influence OA in the coastal areas of open oceans and can affect the coastal regions of marginal seas.


PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e2863 ◽  
Author(s):  
Anton Chichvarkhin

A new sea star species,H. djakonovisp.n., was discovered in Rudnaya Bay in the Sea of Japan. This is a sympatric species of the well-known and common speciesHenricia pseudoleviusculaDjakonov, 1958. Both species are similar in body size and proportions, shape of skeletal plates, and life coloration, which distinguishes them from the otherHenriciaspecies inhabiting the Sea of Japan. Nevertheless, these species can be distinguished by their abactinal spines: in both species, they are short and barrel-like, but the new species is the onlyHenriciaspecies in Russian waters of the Pacific that possesses such spines with a massive, smooth, bullet-like tip. The spines inH. pseudoleviusculaare crowned with a variable number of well-developed thorns. About half (<50%) of the abactinal pseudopaxillae in the new species are oval, not crescent-shaped as inH. pseudoleviuscula.


1993 ◽  
Vol 18 ◽  
pp. 227-233 ◽  
Author(s):  
Kazuhide Satow

The amount of acidity in precipitation has been measured in heavy-snowfall regions facing the Sea of Japan. The average pH value of precipitation measured throughout the year at Nagaoka was 4.80 during 4.5 years, 1987–92. During winter the pH value is lower and electric conductivity higher. The spatial distribution of chemical components in new-fallen snow was studied along a 55 km-long sampling route. Results from four surveys showed that acidic snows have average pH values of 4.63–4.90. From the distribution of anion and cation concentration in new-fallen snow, it is concluded that strong northwest monsoons during winter bring an abundance of snow with salt components and many non-salt components from the Sea of Japan and also, possibly, from the Asian continent.


1985 ◽  
Vol 7 (3) ◽  
pp. 379-387 ◽  
Author(s):  
A. G. Rodnikov ◽  
A. G. Gainanov ◽  
B. V. Yermakov ◽  
V. M. Kovylin ◽  
V. A. Seliverstov ◽  
...  

2017 ◽  
Vol 18 (11) ◽  
pp. 2893-2906 ◽  
Author(s):  
Kazuaki Yasunaga ◽  
Masashi Tomochika

Abstract Long-term changes in the monthly precipitation along the coastal areas of the Sea of Japan are examined using monthly operational observation data from the Japan Meteorological Agency. The monthly precipitation in December significantly increased from the mid-1980s to 2015, even though no remarkable changes were found in January, February, or November. Significant positive trends in the December precipitation extend widely over the coastal areas of the Sea of Japan, and the amounts increase to approximately 50% of the climatological precipitation in December at most observational stations. The interannual variations in other variables, including the monthly accumulated actual sunshine duration, days with lightning detection, and satellite-retrieved outgoing longwave radiation, also show significant trends that are consistent with the precipitation increase in December. The effect of the sea surface temperature (SST) on precipitation change is discussed based on correlation and regression analyses. The interannual variations in the December precipitation averaged over the observational stations near the Sea of Japan are significantly correlated with the SSTs in the prior month (November). However, the SST increase in November is insufficient to account for the increase in precipitation. In addition, it was found that the satellite-retrieved surface wind speed in December has grown stronger in recent years over the Sea of Japan. It is suggested that the stronger wind corresponds to the enhanced monsoonal flow and is the primary cause of the precipitation increase in December.


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