162
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
on zooplankton of Buorkhaya Bay (Figure 1) received by the author in various seasons
between 1993-1996.
120' E
7
I
74'
L
I
,
73'
- 25.
2
130'
17 .12
• .13
.14
·15
~ _ _ _ _ -' 1 .... 2"--· _ _ _ _ - ' -
Figure 1: Scheme of hydro biological stations during Transdrift IV.
Results and discussion
Species composition, population structure, development biology
71
1 4 0' E
Quantitative sample analysis has permitted to identify the presence of 2 Rotatoria species, 1
Cladocera, 13 Copepoda and representatives of another 5 types of invertebrates (Table 2).
Calanoida of estuarine-arctic complex was prevailing in the composition of pelagic fauna.
Among them mostly distributed in May-June proved to be Drepanopus bungei, Acartia
longiremis and representatives of Pseudocalanus genus. Two species of Harpacticoida
(Danielssenia sibirica and Ectinosoma arcticum) have not been previously listed among
zooplankton of Laptev Sea. By our evidence, E.arcticum is a species common for summer-time
plankton of major streams mouth in the Lena-Delta with 0-4 salinity range though it may occur
at salinity up to 16. Recorded at station 20 in June D. sibirica proved to be our first finding. In
literature this species is reported from the coast line and mouth of the river on the island B.
Lyakhovsky (Borutsky, 1952). Sexual and age structure of D. bungei population in May (one
of mostly abundant species of the shelf area of Laptev Sea) is shown in Table 3.
At study period the species was in the stage of reproduction. D. bungei seems to have more
than one generation in the Laptev Sea annually (Abramova, 1996). The onset of spawning of
D. bungei in Buorkhaya Bay was observed to fall on February. Mature males and females,
copepodite and nauplii stages of the species in various interrelations occur in plankton till
October. Late in October-November the mass of D. bungei popUlation is represented by
copepodites of 5 - 6th stages containing considerable fat inclusions. In January-February over
70% of recorded males and females again proved to be mature, some females were reported to
have spermatophores and 4-7 large-sized eggs attached to genital segment. Nauplii of new
Land-Ocean Systems in the Siberian Arctic: Dynamics and History
on zooplankton of Buorkhaya Bay (Figure 1) received by the author in various seasons
between 1993-1996.
120' E
7
I
74'
L
I
,
73'
- 25.
2
130'
17 .12
• .13
.14
·15
~ _ _ _ _ -' 1 .... 2"--· _ _ _ _ - ' -
Figure 1: Scheme of hydro biological stations during Transdrift IV.
Results and discussion
Species composition, population structure, development biology
71
1 4 0' E
Quantitative sample analysis has permitted to identify the presence of 2 Rotatoria species, 1
Cladocera, 13 Copepoda and representatives of another 5 types of invertebrates (Table 2).
Calanoida of estuarine-arctic complex was prevailing in the composition of pelagic fauna.
Among them mostly distributed in May-June proved to be Drepanopus bungei, Acartia
longiremis and representatives of Pseudocalanus genus. Two species of Harpacticoida
(Danielssenia sibirica and Ectinosoma arcticum) have not been previously listed among
zooplankton of Laptev Sea. By our evidence, E.arcticum is a species common for summer-time
plankton of major streams mouth in the Lena-Delta with 0-4 salinity range though it may occur
at salinity up to 16. Recorded at station 20 in June D. sibirica proved to be our first finding. In
literature this species is reported from the coast line and mouth of the river on the island B.
Lyakhovsky (Borutsky, 1952). Sexual and age structure of D. bungei population in May (one
of mostly abundant species of the shelf area of Laptev Sea) is shown in Table 3.
At study period the species was in the stage of reproduction. D. bungei seems to have more
than one generation in the Laptev Sea annually (Abramova, 1996). The onset of spawning of
D. bungei in Buorkhaya Bay was observed to fall on February. Mature males and females,
copepodite and nauplii stages of the species in various interrelations occur in plankton till
October. Late in October-November the mass of D. bungei popUlation is represented by
copepodites of 5 - 6th stages containing considerable fat inclusions. In January-February over
70% of recorded males and females again proved to be mature, some females were reported to
have spermatophores and 4-7 large-sized eggs attached to genital segment. Nauplii of new