The spatial distribution of the methane fluxes on the water–atmosphere boundary in the Sea of Okhotsk

2019 ◽  
Vol 3 (1) ◽  
pp. 107-123
Author(s):  
R.B. Shakirov ◽  
◽  
O.V. Mishukova ◽  
2012 ◽  
Vol 25 (7) ◽  
pp. 2261-2278 ◽  
Author(s):  
Sohey Nihashi ◽  
Kay I. Ohshima ◽  
Noriaki Kimura

Abstract Sea ice formation, its transport, and its melting cause the redistribution of heat and salt, which plays an important role in the climate and biogeochemical systems. In the Sea of Okhotsk, a heat and salt flux dataset is created in which such sea ice processes are included, with a spatial resolution of ~12.5 km. The dataset is based on a heat budget analysis using ice concentration, thickness, and drift speed from satellite observations and the ECMWF Interim Re-Analysis (ERA-Interim) data. The salt flux calculation considers both salt supplied to the ocean from sea ice production and freshwater supplied when the ice melts. This dataset will be useful for the validation and boundary conditions of modeling studies. The spatial distribution of the annual fluxes shows a distinct contrast between north and south: significant ocean cooling with salt supply is shown in the northern coastal polynya region, while ocean heating with freshwater supply is shown in the south. This contrast suggests a transport of freshwater and negative heat by ice advection. The annual fluxes also show ocean cooling with freshwater supply in the Kashevarov Bank (KB) region and the central and eastern Sea of Okhotsk, suggesting the effect of warm water advection. In the ice melt season, relatively prominent ice melting is shown in the coastal polynya region, probably due to large solar heating of the upper ocean. This indicates that the polynya works as a “meltwater factory” in spring, contrasting with its role as an “ice factory” in winter. In the coastal polynya region, the spatial distribution of phytoplankton bloom roughly corresponds with the ice melt region.


2017 ◽  
Vol 475 (2) ◽  
pp. 963-967 ◽  
Author(s):  
G. I. Mishukova ◽  
R. B. Shakirov ◽  
A. I. Obzhirov

2019 ◽  
Vol 59 (6) ◽  
pp. 944-951
Author(s):  
A. I. Obzhirov ◽  
G. I. Mishukova ◽  
R. B. Shakirov ◽  
V. F. Mishukov ◽  
E. V. Maltseva ◽  
...  

For the first time subannual variability of methane fluxes on the water-atmosphere border in the water area of the Sea of Okhotsk, located eastward to Sakhalin Island, is shown. Variability of methane fluxes is determined by the presence and activity of submarine methane sources and is connected to the seasonal changes in hydrological and hydrochemical parameters of the sea water and the structure of of currents in the region under study. In spring and autumn the average fluxes are higher, than in the summer period. Within the summer modification of water and increase of stratification, the methane flux from the sea surface is reduced. In autumn, as a result of the autumnal convection of water and high average wind speed, methane, accumulated in transitional waters, is emitted into the atmosphere.


2021 ◽  
Vol 43 (3) ◽  
Author(s):  
N.L. Sokolova ◽  
Yu. A. Telegin ◽  
A.I. Obzhirov

Methane is one of the important representatives of the organic substances in the atmosphere (for example, an increase of methane content in the atmosphere can affect enhancing the greenhouse effect). Gas hydrates are an essential part of links in the methane cycle and the accompanying fluxes of other gases. The research object in this paper is the Sea of Okhotsk, where gas hydrate fields and active submarine gas discharge areas were found. The study of methane fluxes is relevant both for the Sea of Okhotsk and the World Ocean. From 1984 to 2015, the background and anomalous methane fields were explored in the Sea of Okhotsk as a result of gas geochemical research carried out by scientists of the Gasgeochemistry Laboratory (POI FEB RAS). The flux of natural gas became stronger from the sources to the seafloor, from the seafloor to the water, and, finally, to the atmosphere due to renew of fault zones. Moreover, the amount of methane vents on the Sakhalin slope has increased from 2-3 vents to more than 400. The most representative hydroacoustic anomalies “flares” mapped direct methods study methane hydrates. The received outcomes indicate the urgency of the study of methane fluxes and the formation-dissociation mechanism of gas hydrates, and the influence of natural gas from hydrocarbon sources on the environment.


2018 ◽  
Vol 52 (1) ◽  
pp. 63-73
Author(s):  
N. V. Evseeva

The revision of the herbarium material, collected in the northern part of the Sea of Okhotsk in 1965–1966 and stored in VNIRO, allowed to expand the taxonomic list of macrophyte algae of the coastal zone of this area. The locations of discovery of 24 previously unmentioned species are described. Myrionema balticum, Ulvella repens, Syncoryne reinkei, Acrochaetium arcuatum were found in the Sea of Okhotsk for the first time. Most species new for the Sea of Okhotsk is represented by epiphytes of the family Ulvellaceae (Chlorophyta). The final taxonomic list of this region, including literature data, consists of 169 species.


Author(s):  
Alexandra Romanova ◽  
Alexandra Romanova ◽  
Vladimir Anin ◽  
Vladimir Anin ◽  
Sergey Pletnev ◽  
...  

80 sediment stations collected along the meridian transect across the Sea of Okhotsk were studied in order to reveal patterns of dissolution based on planktonic foraminifera. The degree of calcite dissolution intensity from planktonic foraminifera determined by different indices (degree of fragmentation, presence of susceptible to dissolution species, benthos/ plankton ratio). The highest degree of dissolution evidenced by a large number of shell fragments and corroding walls were found in sediments from the area of the Kuril Islands. The most revealing measure of probable dissolution of foraminiferal shells in the central part of the sea is a low number and lack of thin-walled species. The effects of dissolution on foraminiferal shells were studied for dominated species Neogloboquadrina pachyderma sin and Globigerina bulloides using a scanning electron microscope. The results are important for understanding processes of sedimentation, the paleo-oceanologial reconstructions and for obtaining reliable results in isotope analyzes.


Sign in / Sign up

Export Citation Format

Share Document