Seasonal Variability and Estimation of Annual East Siberian Sea Phytoplankton Primary Production and Comparison with the Other Siberian Seas

Oceanology ◽  
2020 ◽  
Vol 60 (5) ◽  
pp. 603-616
Author(s):  
A. B. Demidov ◽  
V. I. Gagarin ◽  
S. V. Sheberstov
1987 ◽  
Vol 44 (S1) ◽  
pp. s47-s54 ◽  
Author(s):  
J. A. Shearer ◽  
E. J. Fee ◽  
E. R. DeBruyn ◽  
D. R. DeClercq

One basin of a small, double-basin lake was fertilized with carbon, nitrogen, and phosphorus for eight years, and then fertilization was stopped. The other basin was fertilized simultaneously with equivalent amounts of carbon and nitrogen only. Phytoplankton primary production was monitored using an incubator–numerical model technique. Production increased dramatically in the basin receiving artificial additions of C, N, and P. The increase was particularly large in the epilimnion where Cyanophyte blooms occurred during each year of fertilization and production rates averaged 2 to 10 times higher than in nearby, unfertilized reference lakes. Phosphorus, not nitrogen or carbon, was the critical nutrient. The productivity of the other basin also increased, but to a lesser degree and no Cyanophyte blooms were observed in this basin. When all fertilization was terminated, production in both basins immediately decreased. No more surface blooms were observed in either basin. Within 3 yr, the production had dropped to levels typical of reference lakes.


Author(s):  
A. B. Demidov ◽  
S. V. Sheberstov ◽  
V. I. Gagarin

Studies of seasonal variability of Laptev Sea water column primary production and evaluation of its annual values were performed using MODIS-Aqua data (20022018). To reach that result regional-specific primary production and chlorophyll algorithms were used for the first time. Based on multiyear averaged daily primary production Northwestern and Southeastern regions were distinguished in the Laptev Sea. Seasonal variations in water column primary production in the Northwestern region were characterized by the maximum in June (245 mgC m‑2 d‑1). In the Southeastern region and for all Laptev Sea the maximum water column primary production values were denoted from May to July, 273282 mgC m‑2 d‑1 and 256281 mgC m‑2 d‑1, respectively. Daily primary production and annual values of total primary production in the Southeastern region were, respectively, 1.9 and 3 fold higher than in the Northwestern region. Multiyear averaged value of Laptev Sea water column primary production was equal to 125 mgC m‑2 d‑1 and total annual primary production was equal to 8  1012 gC.


Author(s):  
Akira Umehara ◽  
Akira Umehara ◽  
Satoshi Asaoka ◽  
Satoshi Asaoka ◽  
Naoki Fujii ◽  
...  

In enclosed water areas, organic matters are actively produced by phytoplankton due to abundant nutrient supply from the rivers. In our study area of the semi-enclosed Hiroshima Bay, oyster farming consuming high primary production has been developed since the 1950s, and the oyster production of Hiroshima prefecture have had the largest market share (ca. 60%) in Japan. In this study, species composition of phytoplankton, primary production, and secondary production of net zooplanktons and oysters were determined seasonally at seven stations in the bay between November 2014 and August 2015. In the bay, diatoms including Skeletonema costatum dominated during the period of the study. The primary productions markedly increased during summer (August), and its mean values in the northern part of the bay (NB) and the southern part (SB) were 530 and 313 mgC/m2/d, respectively. The productions of net zooplankton and oyster increased during the warm season, and its mean values in the NB were 14 and 1.2 mgC/m2/d, and in SB were 28 and 0.9 mgC/m2/d, respectively. The energy transfer efficiencies from the primary producers to the secondary producers in the NB and SB were 2.8% and 9.1%, respectively. However, the transfer efficiency to the oysters was approximately 0.3% in the bay. This study clearly showed the spatial difference of the productions and transfer efficiencies, and the low contribution of the production of oysters in secondary productions in Hiroshima Bay.


2018 ◽  
Vol 44 (3) ◽  
pp. 240-247 ◽  
Author(s):  
V. N. Egorov ◽  
V. N. Popovichev ◽  
S. B. Gulin ◽  
N. I. Bobko ◽  
N. Yu. Rodionova ◽  
...  

2015 ◽  
Vol 28 (15) ◽  
pp. 6039-6053 ◽  
Author(s):  
Donald M. Lafleur ◽  
Bradford S. Barrett ◽  
Gina R. Henderson

Abstract One of the most commonly used metrics for both locating the Madden–Julian oscillation (MJO) geographically and defining the intensity of MJO convective activity is the real-time multivariate MJO (RMM) index. However, a climatology of the MJO, particularly with respect to the frequency of activity levels or of consecutive days at certain activity thresholds, does not yet exist. Thus, several climatological aspects of the MJO were developed in this study: 1) annual and 2) seasonal variability in MJO intensity, quantified using four defined activity categories (inactive, active, very active, and extremely active); 3) persistence in the above-defined four categories; 4) cycle length; and 5) low-frequency (decadal) variability. On an annual basis, MJO phases 1 and 2 occurred more often, and phase 8 occurred less often, than the other phases throughout the year. Notable seasonality was also found, particularly in the frequency of extremely active MJO in March–May (8% of days) compared with June–August (only 1% of days). The MJO was persistent in time and across intensity categories, and all activity categories the following day had at least an 80% chance of maintaining their amplitudes. Implications of this climatology are discussed, including length of complete MJO cycles (the shortest of which was 17 days) and correlations between MJO amplitude and atmospheric response.


Oceanology ◽  
2020 ◽  
Vol 60 (6) ◽  
pp. 765-777
Author(s):  
A. B. Demidov ◽  
V. I. Gagarin ◽  
S. V. Sheberstov

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