recorded at the minimal rate of water renewal and it decreased with its growth (Fig. 3). If we
consider the difference between X
mean
and Me as an indicator of heterogeneity of zoobenthos
distribution, then this heterogeneity was the most pronounced at the
minimal water renewal
rate and levelled off with its growth.
Fig. 3 - Changes of zoobenthos abundance and biomass in the north-western part of the
Caspian Sea in 1961-2012 depending on the water renewal rate (its values are
plotted along the X axis).
Discussion
Some characteristics of the long-term dynamics of abundance and biomass of plankton and
benthos in the western part of the North Caspian still have no definite explanation (Caspian
Sea..., 1986). Having studied the causes of the long-term changes, we extended a number of
factors which can affect the status of plankton and benthos. One of these
factors is the rate of
North Caspian water renewal.
The results presented above show that this rate obviously does not affect the abundance and
biomass of the phytoplankton in the western part of the North Caspian during the flooding
time. The dependence of zooplankton abundance and biomass on the water renewal rate is of
complicated nature. To look into this nature, zooplankton should be
subdivided into separate
ecological groups.
The direct dependence of zoobenthos abundance on the rate of water renewal proves the fact
that allochthonous organic substance plays an important part in zoobenthos feeding (here, the
abundance and biomass median should be considered). On the contrary, the decrease of
water renewal rate promotes the formation of rare and dense accumulations of zoobenthos.
Thus, the more abundant the benthos is, the poorer are its local accumulations and vice versa.
The abundance and distribution of zoobenthos in the western part of the North Caspian during
the flooding period depend on the water renewal rate.
0
10
20
30
0
3
6
9
12
15
Xmean
Me
Abundance of zoobenthos,
thousand specimen/m2
Me
0
50
100
150
200
250
0
15
30
45
60
75
Xmean
Me
Biomass of zoobenthos, g/m2
Me
55
References
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abundance and biomass of plankton and benthos// Environmental protection
in oil and gas
complex. January 2018. PP. 20-26.
Caspian Sea: Hydrology and hydrochemistry. - M. Nauka, 1986. - 261 p.
Caspian Sea. On the impact of environmental changes on biodiversity and bioproductivity// Edited
by A.F.Sokolsky. - Astrakhan. OOO KPTs "Poligrafkom". - 2009. - 404 p.
Caspian Sea: fauna and biological productivity. - M.: Nauka, 1985 - 276 p.
Kolmykov E.V., Monakhova G.A., Vasilyeva T.V., Asaeva K.I., Kashin D.V. Methodical aspects of fauna
protection in the course of development of the marine oil and gas fields: analysis of spatial
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Environmental protection in the oil and gas complex. June 2016. PP. 55 - 61.
56
Assessment of the changes in average wind speed in the south Caspian Sea, due to
climate change
Alinejhad-Tabrizi, Tahereh
1*
, Hadjizadeh-Zaker, Nasser
2
1
Graduate Faculty of Environment, University of Tehran, Tehran, Iran, t.alinejhad@ut.ac.ir
2
Associate professor, Graduate Faculty of Environment, University of Tehran, Tehran, Iran,
nhzaker@ut.ac.ir
Keywords: CMIP5, CORDEX, RCP, climate change, Caspian Sea
Introduction
Caspian Sea is the biggest enclosed body of water on Earth, with approximately 7000 km coastline, a
surface area of 371,000 km², and a volume of 78,200 km3. It also bordered by five countries including
Iran. The Caspian Sea can be subdivided into three distinct physical parts, the northern, middle and
southern parts. The southern and middle parts are characterized as deep water, with a depth more than
1000 m in the southern region and 500 m in the central region. The Northern part is also known as
shallow water with average depths of less than 5m (Kostianoy et al. 2008; Kroonenberga et al. 2000).
Climate change causes global warming and consequently changes meteorological conditions, wind field
characteristics, wave and ocean currents dynamics, and sea level variations.
The increasing awareness of
the hazards related to climate change impacts on coastal zones and the need for impact assessment,
mitigation and adaptation strategies have been driving the development and implementation of several
climatological modelling efforts at global to regional scale (Slott et al., 2006; Tol et al., 2008; Nicholls,
2011). This allowed to draw some estimates on possible changes in different features, such as
temperature and precipitation patterns (Giorgi et al., 2004), wave storminess, surge hazard (Benetazzo
et al., 2012; Conte et al., 2014) and sea level fluctuations (Ardakanian & Alemohammad, 2008). The
capability of capturing wind climate variability over a decadal time scale is crucial
for providing a realistic
quantification of wave dynamics and coastal sediment transport processes, identifying possible
erosional and depositional hotspots and setting intervention priorities for coastal management (Bonaldo
et al., 2015).
There is a large number of studies within the last few years assessing the impacts of climate change on
wind patterns and sea wave regimes such as Mori et al. (2009), Kamranzad et al. (2013), Alinejhad-
Tabrizi et al. (2017) and Davy et al. (2017), using different global or regional climate models,
which
illustrate increasing or decreasing of wind speed in different areas in the world
. However, the
studies on the effects of climate change on the wind field over the Caspian Sea are limited . In the
context of climate change, this study assesses the impact on the wind field along
the southern part of
the Caspian Sea. For this purpose, wind characteristics obtained based on
CORDEX (a project for World
Climate Research Program) are used based on two greenhouse gas presentative concentration pathways
(
RCP4.5 and
RCP8.5).
Materials and methods
Assessment of the effect of climate change on the wind field over the Caspian Sea was carried out in 3
points in different latitudes and longitudes in the southern part of the Caspian Sea (Fig. 1), these point
are located far from the coastal areas.
57