Seasonal variations in primary production (PP) in the Kara Sea are underresearched. Previous studies only collected data during autumn or in late summer. However, the middle of summer is close to the ...beginning of the growing season, when PP can contribute significantly to annual water column integrated primary production (IPP). In addition, differences can be expected in the spatial and vertical distribution of phytoplankton communities in this period. This gap in midsummer data was addressed within the framework of a multidisciplinary research cruise by the R/V “Akademik Mstislav Keldysh” (from 15 July to 18 August 2016). High values of IPP (> 200 mgC m
−2
day
−1
) and surface chlorophyll
a
(Chl
a
) concentration (Chl
0
> 1 mg m
−3
) were associated with the Ob–Yenisey river plume, located in the central part of the Kara Sea. Beyond the influence of the plume, in the western and southwestern regions of the Kara Sea, well-pronounced subsurface chlorophyll maxima (SCM) were observed. In some cases, the Chl
a
concentration in SCM exceeded Chl
0
by two orders of magnitude. SCM were often accompanied by subsurface PP maxima (SPM). At stations where SCM was pronounced, IPP values reached 500–800 mgC m
−2
day
−1
, and > 30 % of IPP was accounted for by SPM-integrated PP. Thus, in the middle of summer in the Kara Sea, IPP was linked with the chlorophyll-specific phytoplankton biomass and depended on the strength of the SCM.
The interannual (2002–2021) variability of primary production (PP) of the Kara Sea and associated environmental factors was assessed by MODIS-Aqua data and model calculations. Warming in the Kara Sea ...region during the last two decades was characterized by a pronounced positive trend of the sea surface temperature (
T
0
) and weak positive trend of the ice-free area (
S
) averaged for the growing season (April–October). During the investigated period,
T
0
increased by 3.55°C with a trend of 10% y
–1
and
S
increased by 110 × 10
3
km
2
with a trend of 1.4% y
–1
, on average. The values for the water column PP (IPP) averaged over the growing season statistically significantly (
p
< 0.05) decreased in the all Kara Sea regions (
R
2
= 0.22–0.59). For the entire Kara Sea, IPP declined by 38 mgC m
–2
d
–1
with a moderate trend of 1.1% y
–1
(
R
2
= 0.37). The value of photosynthetically active radiation (PAR) averaged over the growing season weakly, but statistically significantly (
p
< 0.05), decreased in the entire Kara Sea areas (
R
2
= 0.20–0.31). Also, in all regions, significant (
R
2
= 0.24 – 0.38) weak or moderate negative trends of surface chlorophyll (chl)
a
were specified. The total annual PP (PP
tot
) increased insignificantly in accordance with an increase in
S
(0.7% y
–1
,
R
2
= 0.08). The most significant decrease in IPP was specified for spring (
R
2
= 0.28). In autumn, a statistically significant positive trend of
S
(
R
2
= 0.24) was observed. Owing to such an increase in
S
, the notable growth of PP
tot
was noted in autumn. This study demonstrates that the decrease of IPP, resulting from the decrease in PAR and chl, in some degree was the reason for moderation of PP
tot
. It should be concluded that in a period of intense warming, the decrease in IPP of the Kara Sea should affect the productivity of higher trophic levels of the food web.
The distribution of primary production (PP), chlorophyll
a
concentration (Chl
a
), and size structure of the phytoplankton community were studied in the Kara Sea during the first-year ice retreat in ...late June 2021. The maximum value of water column PP (IPP) reached 1352 mgC m
–2
day
–1
. The ice-edge phytoplankton bloom was characterized by high averaged of IPP and Chl
a
integrated in the photosynthetic layer (Chl
phs
) values: 740 mgC m
–2
day
–1
and 81.40 mg m
–2
, respectively. The highest IPP values were observed at sites where Chl
a
was concentrated in the upper mixed layer or where the subsurface chlorophyll maximum coincided with the pycnocline. Over the area of phytoplankton bloom, the contribution of microphytoplankton (>20 µm) to the total IPP and Chl
phs
was 92 and 82%, respectively. Contribution of picophytoplankton (<3 µm) to the total PP increased along the depth until reaching the lower margin of layer of photosynthesis, from 3 to 70%, on average. No similar pattern has been observed for vertical distribution of Chl
a
. This pattern was evidenced by an increase in the chlorophyll specific carbon fixation rate (assimilation number) of picophytoplankton with depth under low insolation conditions.
The article presents the results of the analysis of the problem of digitalization of ed-ucation. Interrelations of digitalization of ecological education with noospheric essence of modern ...civilization and realization of the concept of sustainable development are established. Possibilities of use of developments of the Russian and foreign scientists and teachers are con-sidered. The importance and main directions of development of digitalization of environmental education are shown. Attention is drawn to the need for digitalization of environmental educa-tion in the preparation of not only environmental specialists, but also specialists in other areas of training. Digitalization of education should be aimed at the formation of eco-cultural compe-tencies. The article presents the results of an experimental study of the use of modern IT by various participants of the educational process. The studies were conducted by questionnaire method and allow to indicate the current directions of further development of digitalization of education, including environmental education.
Studies of the interannual variability of primary production, surface water temperature, photosynthetically active radiation, and sea ice cover in the Laptev Sea were performed based on MODIS-Aqua ...data (2002–2018). For a 17-year period, a statistically significant positive trend of surface temperature (
R
2
= 0.27) and a negative trend of photosynthetically active radiation (
R
2
= 0.24) were established. For the investigated period, the average annual water temperature in the Laptev Sea increased by 1.38°C and photosynthetically active radiation decreased by 3.4 Ein m
–2
d
–1
. The ice-free water area extended insignificantly (0.15% y
–1
). The total primary production declined by 1.87 TgC or by 1.4% y
–1
. This decline was accompanied by a decrease in area-specific primary production. For the investigated period, the average annual area-specific primary production values declined by 37.4 mgC m
–2
d
–1
or by 1.6% y
–1
. The presented results suggest that changes in Laptev Sea primary productivity for the last 17 years were mainly caused by a decrease in photosynthetically active radiation and area-specific primary production rather than the dynamics of the sea ice cover.
Seasonal variation of the integrated primary production (IPP) and surface chlorophyll (Chl
0
) in different regions of the Kara Sea was studied from satellite data obtained by the MODIS-Aqua colour ...scanner and averaged for 2003–2015. The minimum variation of Chl
0
concentration during the growing season (from April to October) was 1.5 times in southwestern region and 2 times in the northern region of the sea. It was found that the Chl
0
concentration increased slightly in all regions by the end of the growing season. The maximum IPP value recorded in June coincided with the peak level of photosynthetically active radiation (PAR) and maximum river discharge. The IPP value varied in a wider range compared with the Chl
0
concentration. The ratio of the maximum and minimum monthly average IPP values varied from 8.9 times in Southwestern region to 11.7 times in the Northern region of the sea. The average increase in the Chl
0
concentration was 1.7 times (from 0.78 mg/m
3
in April to 1.29 mg/m
3
in October). The IPP value varied by a factor of 10.7 (from 26 mg C/m2 per day in October to 279 mg C/m
2
per day in June). The article also discusses the influence of water column stratification, the concentration of nutrients, the PAR level, and river discharge on the seasonal IPP dynamics in the Kara Sea.
The spatial variability of primary production in the East Siberian Sea over a large-scale aquatic area was characterized for the first time by the data of cruise 69 of R/V
Akademik Mstislav Keldysh
...in September 2017. The value of the water column primary production IPP amounted to 28 ± 13 mg C/m
2
per day, which pointed to extreme oligotrophy of the treated areas during the autumn. The IPP value was limited by low incident and subsurface insolation, as well as by the concentration of nitrates. The shortage of inorganic nitrogen was partially compensated by ammonium, which also constituted the buffer preventing a phytoplankton deficiency in nitrogen.
—
Studies of seasonal variability of the East Siberian Sea (ESS) water column primary production (IPP) and evaluation of its total annual value (PP
tot
) were performed using MODIS-Aqua data ...(2002–2018). Region-specific primary production and chlorophyll algorithms were used for the first time to achieve that result. Northeastern and Southwestern regions were distinguished in ESS based on multiyear average daily primary production. Seasonal variations in IPP in the Northeastern region were characterized by the maximum in June (273 mgC m
–2
d
–1
). The maximum of water column primary production value in the Southwestern region was recorded in May (311 mgC m
–2
d
–1
). The maximum of IPP for the entire ESS was registered in June (273 mgC m
–2
d
–1
). Values of daily primary production and PP
tot
in the Southwestern region were, respectively, 1.8 and 2 fold higher than in the Northeastern region. The multiyear averaged value of ESS IPP was equal to 91 mgC m
–2
d
–1
and PP
tot
value was equal to 9 TgC. Productivity of the Siberian seas decreased eastward.
PDF
