Thus the climate change observed from 1964 to 2005 was
relatively favourable
for the marine biota: 60-70's period was favourable for the deep water sea part,
and in the following period (up to 2005) - for the North Caspian. The period start-
ing from 2006 to 2015 was generally unfavourable for the marine bioproductivity.
There is a growing concern that climate warming, if it occurs in future, will raise
the occurrence of warm and dry years and thus will lead to the reduction in the
marine bioproductivity.
Summarizing the
facts stated above, we can say that Caspian Sea sensitivity to
climate change is determined by its isolation, geomorphology, homogeneous ver-
tical salinity distribution and other factors. The bioproductivity
of the Caspian Sea
is in direct proportion to the Volga runoff, and the bioproductivity of the Middle
and the South Caspian is related to vertical water circulation, and in particular to
the depth of the autumn-winter convection. On this basis, one can single out four
kinds of climate status affecting the marine biota: "cool and dry", "cool and wet",
"warm and dry", "warm and wet".
Using CASPCOM data catalogues, one can
trace all the above mentioned statuses in the Caspian Sea climate change
throughout the past 50 years. The objective of further research is to determine
biological indicators of different statuses of the Caspian Sea climate.
References
Caspian Sea: Ichthyofauna and
commercial resources / V.N.Belyaeva,
E.N.Kaznacheev, V.M. Paspopov et al. M.:Nauka, - 1989. 236 p.
Hydrometeorology and hydrochemistry of the seas in the USSR. "Seas"Project.
V.6 Caspian Sea. Issue 1: Hydrometeorological conditions/ Edited by F.S.
Teziev, A.N.Kosarev, A.A. Kerimov. - Spb. Gidrometeoizdat, 1992. - 359 p.
Hydrometeorology and hydrochemistry of the seas in the USSR. "Seas"Project.
V.6 Caspian Sea. Issue 2: Hydrochemial conditions and oceanological back-
ground for the formatin of biological productivity. - Spb. Gidrometeoizdat,
1996. - 322 p.
Katunin D.N. Hydroecological background for ecosystem processes in the Caspian
Sea and the Volga delta. Astrakhan. KaspNIRKh Publishers, 2014. 478 p.
Kosarev A.N. Physico-Geographical Conditions of the Caspian Sea // The Caspian
Sea Environment / Eds. A.G. Kostianoy, A.N. Kosarev. – Hdb. Env. Chem. V.
5. Part P. – Berlin, Heidelberg, New York: Springer–Verlag, 2005. – Р. 59–81
Tuzhilkin V.S., Goncharov A.V. On ventilation of the Caspian Sea deep water//
Proceedings of SOI. - 2008. - Issue 211. - PP 27-39
Yablonskaya E.A. Biology of the Caspian Sea. - M.: VNIRO. 2007. - 142 p.
9
Fatty acid composition of sponges as biomarkers of stress factors
Bazarsadueva
1
, S.V., L.D. Radnaeva
1
& V.V. Taraskin
1
1
Baikal Institute of Nature Management of Siberian Branch of Russian Academy of Sciences,
Ulan-Ude, Russia
Key words: sponges, fatty acids, biomarkers
Introduction
Understanding of the mechanisms responsible for adaptation of living
organisms to changing
environmental conditions has always been one of the main tasks of ecology and systematic
biology. As our knowledge of the complex processes that determine evolution, speciation and
species adaptation continues to grow, need to study the mechanisms underlying resistance of
living organisms to stress factors becomes more and more evident (Hoffmann & Parsons,
1997). The life of organisms is limited to a specific temperature range in which, theoretically,
increasing on 10°C leads to a two- to fourfold increase in the response time of metabolic
processes. Numerous physical and chemical studies show that the mechanisms of survival at
abnormally high temperatures include changes in the lipid components of cell membranes.
The degree of involving of lipids in the adaptation processes depends on
biological features of
various species, including marine and freshwater sponges (Temperature…, 1994; Velansky &
Kostetsky, 2009; Gladyshev et al., 2011).
Because of increasing anthropogenic impact on natural ecosystems, adaptations developed by
various organisms have recently received growing attention from researchers, but adaptive
biochemical characteristics of organisms representing taxa of lower phylogenetic ranks are still
poorly studied. Sponges as a symbiotic community of various microorganisms are a unique
object for such studies.
During millions of years, Baikal sponges have adapted to living in a
narrow temperature range from 0.5 to 11.5°C (at depths of 4 m and below).
The aim of the research is comparative analysis of the fatty acid composition of the Baikal
freshwater sponge
Baicalospongia bacillifera from different depth and upon a rise of
temperature in its natural habitat by 6°C.
Materials and methods
Field sampling
Deep water sponges
B. bacilifera were collected from the depth of 750 m from Barguzin Bay
(Lake Baikal) in July-August by using manned submersible “MIR” (during the International
Research Expedition «MIRs on Lake Baikal», 2008-2010). Shallow sponges
B. bacilifera were
collected from a depth of 15 m in the southern part of Lake Baikal in August. The collected
samples were stored at -18
o
C for less than seven days prior to laboratory analyses.
A living sponge colony was adapted for 14 days to the artificial conditions of glass aquariums
with flowing Baikal water at 10.5°C and 12-h photoperiod without additional feeding. The
water to the aquariums was supplied from a homemade refrigeration unit (Glyzina et al.,
2016).
After adaptation, sponge samples were taken for biochemical analysis.
10