Relationships of functioning and formation of hydrobiocenoses in large internal-drainage lakes charactericed by different stady of salinisation the Chany lacustrine system as a case study (Western Siberia)
Novosibirsk Filiation Federation state Siberian science–investigation
and proect–constructor institute of fishery, Novosibirsk, Russia
The Altay state university, Barnaul, Russia, E-mail: firstname.lastname@example.org, email@example.com
The Chany lacustrine system – largest in Western Siberia has not only large economic, but also large ecological importance. It represents unique object for investigation relationships of functioning and formation of hydrobiocenoses in large internal-drainage lakes characterised by different stady of salinisation. Research of the hydrobiological characteristics of system (study of dynamics and revealing of the factors determining the species diversity, structure and the functional characteristics of aquatic communities have begun in the end XIX of century and proceed till now. The large retrospective material in the scientific publications and archives of research establishments allowing is saved to look after process succession of biohydrocenoses in the past and to predict their direction in the future. Researches of functioning in aquatic ecosystems and changes, occurring in them, now in separate lakes of system in comparative-limnological and historical aspect therefore are very important.
Chany lake – largest in this system. It consists of 6 pools: lakes Small Chany and Yarcul, Chinyaichinsky, Tagano-Kazantsevsky, Yarkovsky and Yudinsky (now separated for reduction of evaporation of water), considerably differing by the aquatory and volume of water, level mineralisation, depths and grounds. On classification A. O. Aloekin water of lake the Chany lake – of chlorine class Na-group the third type (Cl Na/III). Smallest observed on Small Chany lake (total salinity about 3–1,2 g/m2), all others pools – mesohalinity (total salinity 5–21 g/m2). Largest mineralisation – on Yudinsky pool (up to 21 g/m2). During last centuries lake dry: in the end XVII centuries it had the aquatory 10–12, in the beginning XIX – 8, presently – 1,0–1,7 thousand km2. Long-term fluctuation of water level with a complex spectrum of the periods reaching 3 m are characteristic for the lacustrine system. In years of low level water of system are more salt: the large coastal spaces are drained, intensify deficit of dissolved oxygen in shallow pools (Tagano-Kazantsevsky and especially in Small Chany lake), the bioefficiency of aquatic ecosystems falls.
The own researches were carried out on zoobenthos in 1974–1983, 2002–2003 on the standard technique (Leadership on hydrobiological monitoring …, 1992). In total is taken and work up 3 000 tests. The literary data on zoobenthos (Berezovsky, 1927; Philatova, 1941; Petkevich, 1959; Bityukov, 1963; Konoplev, 1968; Selezneva, 1997, 1998) and other water communities (Pulsatory Chany lake…, 1982) were in addition analysed. The analysis of the own long-term and literary data allows to make the certain conclusions about the basic laws of formation biohydrocenoses of lakes which are taking place at different stages of salinity, on an example of Chany lake system.
The taxonomy structure of zoobenthos Chany lake is rather poor. In zoobenthos of lake have received distribution eurybiont fresh-water of the form, adapt oneself to conditions salinity, varying in connection with a pulsation of a water mode. The absence endemic of the forms in lake also is connected to character of it mineralisation.
For the period of researches till 1974 in lake 114 forms of zoobenthos (Miseyko etc., 1986) with prevalence of insects (68 forms, including 45 – Chironomidae) are revealed. Further the tendency of reduction the species diversity is observed: in 1974–1978 is marked 87 (Miseyko, 1982), in 1996–1998 – 53 (Selezneva, 1997), in 2002 – 43 forms (Miseyko etc., 2003). Decrease of the species diversity – parameter eutrophic of a reservoir.
In zoobentos per all years of researches in the species diversity prevail chironomidae – representatives of heterotopic complex, that also is characteristic for eutrophic of reservoirs. About significant eutrophic speaks and observed during many years tendency to monodomination chironomidae (mainly representatives of a genus Chironomus).
Parameters of quantitative development zoobenthos, and also of bacterioplankton, phytoplankton and zooplankton (Pulsatory the Chany lake …, 1982; Ecology of Chany lake, 1986) speak about significant eutrophic of Chany lake. By the contents of biogenes (total phosphorus the average on lake – 80 mkg/l and total nitrogen – 3,5 mg/l) waters of Large Chany are polytrophic, and Small Chany lake – hypertrophic. Besides natural the contribution anthropogenous, going with much more speed and consequently most dangerous brings in. Chany lake system is in a zone of intensive economic activity (drains from farmland and fish of the enterprises, herd agricultural animal on coast and islands, washing of motor vehicles, petroleum pollution by fleet, significant recreational load).
The sharp interannual fluctuations of number and bioweight are characteristic for quantitative development of hydrobionts in lakes with a pulsatory water mode. So, average on lake summer bioweight of zoobenthos changed from 1,8 g/m2 in 1971 up to 10,8 in 2002. Therefore monitoring of a biodiversity, bioefficiency and ecological condition large internal – drainage of lakes should be carried out in view of natural pulsation of their water mode. With fall of a level and increase mineralisation is reduce the species diversity of aquatic communities, the number of dominants is reduced and there is their change. So, in zoobenthos the share of a homotopic complex decreases and the role heterotopic (larvae of insects) is increased.
Eutrophic promotes pollution of lake by organic substances. Autochton the organic substance (OS) is formed basically at the expense of macrophity aquatic vegetation, seaweed periphyton and phytoplankton. Allochton OS acts in Small Chany lake with waters of the rivers Chulim and Kargat. Flowing of Small Chany lake are made possible transport of organic substance in others pools. The contents dissolved OS (21,0–52,8 mg/l), making 90–98 % total OS is much than parameters ÐOS for «average» shallow lakes (Stebaev etc., 1993). Under the contents BPK5 (2,2–6,4 mg O2/l) the Chany lake – a-mesosaprobic (Oksiyuk etc., 1993).
Results hydrobiological indication by a method E. V. Balushkina (1989) on a ratio of various groups chironomidae, having various stability to organic pollution, have shown still large (from moderate up to strong) a degree saprobity (factor changed on various pools of lake per different years from 5,6 up to 10,4) (Miseyko, 2002). Most polluted has appeared Tagano-Kazantsevsky pool and oozy ground in comparison with sandy.
The systems indicative organisms and their modern modifications in monitoring salinity of lakes can be used with some restrictions. Are indicative as bioindicators (monitors) larvae of insects, plancton crayfishes and microseaweed. Non indicative olygochaetes, as more than 5 g/l is factor, limiting their development. The summer of 2002 olygochaetes found out only on oozy ground in a Small Chany with relative meaning 8,6 % on number and 2,6 % on bioweight, while in 1974–1975 they made here 20 and 27 % (index Goodnight–Weetley) from total number zoobenthos (Miseyko, 2002). Such indicative group, as Gastropoda, especially now is poorly submitted. In 70-s’ year of the last century they totaled 13 forms, in 2002 – only 4 (about them in the past an abundance are revealed speak only dead bowls, especially numerous in a Small Chany).
The research is financial support by grant RFBR 02-04-50017
Zoocenosis — 2003
Біорізноманіття та роль зооценозу в природних і антропогенних екосистемах: Матеріали ІІ Міжнародної наукової конференції. – Дніпропетровськ: ДНУ, 2003. – C. 95-97.