62
The Radiocarbon Method to Estimate Primary Production
the trophical status of the basin, calculate its carbon and energy budget, as
well as for the model analysis of its ecosystem. To obtain the whole-basin
and the average values of primary production, the station positions should
be planned for a corresponding cruise to cover basic specific areas. The basin
is divided into a number of sections with comparable daily rates of primary
production measured at the stations. The area of each section is found by
planimetry and its primary production is calculated as this area per day using
the average daily photosynthesis rates. The sum of production in sections
gives its value per whole-basin area per day expressed as gC- 2 day-l. When
divided per area, this gives the average primary production in a given basin
per day.
The estimation of annual primary production in the water basin, especially
in extensive ones like large lakes or reservoirs, presents a rather complicated,
but quite accessible problem. Such research had been successfully accomplished in the Rybinsk reservoir in central Russia, 100 x 60km in size (Sorokin
1972a). Every 2-3 weeks standard cruises were accomplished during whole
seasons for several years (Fig. 2.17). Then the whole-basin daily primary
production was calculated and plotted against the time of season (Fig. 2.18).
The curve thus obtained corresponded to the seasonal course of the wholebasin primary production. With the use of this curve, the annual primary production per whole basin and also the average value per 1 km 2 of its area were
calculated.
To obtain the most adequate curve of the seasonal course of primary
production in a water basin, and consequently the correct numbers of its
annual primary production, the sampling program during the season should
be carefully planned. Sampling missions must cover basic maxima and minima
due to the seasonal succession of the plankton community. The best way
to meet this condition is by permanent monitoring of its state and composition in samples taken at one of the coastal stations at 2-4-day intervals.
To observe the state of phytoplankton, it is sufficient to examine it in the
intact samples of water by the use of a glass chamber 1.0-1.5mm high under
phase contrast microscope magnification - x 150 x 300 (see Fig. 6.3). The
subsequent sampling mission should be carried out when the change in
composition and density of phytoplankton is clearly recorded during this
monitoring (Sorokin and Paveljeva 1972). A usual error during seasonal
observations on primary production occurs by missing late winter-early spring
phytoplankton maxima. In many temperate basins these maxima are the
main ones for the whole season, and create the basic input of autotrophic production which supports the functions of the ecosystem for the whole of the
rest of the season. We have observed such a situation in subarctic and arctic
seas (Okhotsk Sea, Bering Sea), in temperate seas (Black Sea, Japan Sea), and
in subarctic lakes (Dalnee Lake on the Kamchatka Peninsula). Cold weather
and rough seas often make sampling missions during the late winter-early
spring really difficult; but they are necessary for adequate primary production
evaluation.
The Radiocarbon Method to Estimate Primary Production
the trophical status of the basin, calculate its carbon and energy budget, as
well as for the model analysis of its ecosystem. To obtain the whole-basin
and the average values of primary production, the station positions should
be planned for a corresponding cruise to cover basic specific areas. The basin
is divided into a number of sections with comparable daily rates of primary
production measured at the stations. The area of each section is found by
planimetry and its primary production is calculated as this area per day using
the average daily photosynthesis rates. The sum of production in sections
gives its value per whole-basin area per day expressed as gC- 2 day-l. When
divided per area, this gives the average primary production in a given basin
per day.
The estimation of annual primary production in the water basin, especially
in extensive ones like large lakes or reservoirs, presents a rather complicated,
but quite accessible problem. Such research had been successfully accomplished in the Rybinsk reservoir in central Russia, 100 x 60km in size (Sorokin
1972a). Every 2-3 weeks standard cruises were accomplished during whole
seasons for several years (Fig. 2.17). Then the whole-basin daily primary
production was calculated and plotted against the time of season (Fig. 2.18).
The curve thus obtained corresponded to the seasonal course of the wholebasin primary production. With the use of this curve, the annual primary production per whole basin and also the average value per 1 km 2 of its area were
calculated.
To obtain the most adequate curve of the seasonal course of primary
production in a water basin, and consequently the correct numbers of its
annual primary production, the sampling program during the season should
be carefully planned. Sampling missions must cover basic maxima and minima
due to the seasonal succession of the plankton community. The best way
to meet this condition is by permanent monitoring of its state and composition in samples taken at one of the coastal stations at 2-4-day intervals.
To observe the state of phytoplankton, it is sufficient to examine it in the
intact samples of water by the use of a glass chamber 1.0-1.5mm high under
phase contrast microscope magnification - x 150 x 300 (see Fig. 6.3). The
subsequent sampling mission should be carried out when the change in
composition and density of phytoplankton is clearly recorded during this
monitoring (Sorokin and Paveljeva 1972). A usual error during seasonal
observations on primary production occurs by missing late winter-early spring
phytoplankton maxima. In many temperate basins these maxima are the
main ones for the whole season, and create the basic input of autotrophic production which supports the functions of the ecosystem for the whole of the
rest of the season. We have observed such a situation in subarctic and arctic
seas (Okhotsk Sea, Bering Sea), in temperate seas (Black Sea, Japan Sea), and
in subarctic lakes (Dalnee Lake on the Kamchatka Peninsula). Cold weather
and rough seas often make sampling missions during the late winter-early
spring really difficult; but they are necessary for adequate primary production
evaluation.