International Journal of Agriculture and Crop Sciences.
Available online at www.ijagcs.com
IJACS/2013/5-12/1269-1275
ISSN 2227-670X ©2013 IJACS Journal
Temporal changes of surface chlorophyll in south of
Caspian Sea based on data gained by MODIS of Aqua
satellite
M.Jamalomidi
Department of Biology, Payame Noor University, Tehran, IRAN
Corresponding author email: [email protected]
ABSTRACT: Caspian Sea is the largest continental water body on earth that is situated in west Asia,
east of the Caucasus and north of the Elburz Mountains. In this aquatic ecosystem, food chain
beginning with phytoplankton and carnivorous occupying higher tropic levels. Plankton study carried
out regularly in north of Caspian Sea but information from south of Caspian is very limitted.The base
of food pyramid are phytoplankton, that they have chlorophyll pigments and they could capture some
radiant energy and make starch, fat and protein. In this study, surface chlorophyll content in south of
Caspian obtained from 2003 until 2009, with use of satellite data (MODIS, Aqua). The results showed
that, yearly mean surface chlorophyll content was increased from 2003 until 2009, and there was not
any relation between chlorophyll concentration and latitude and altitude. Summer has the highest
chlorophyll content and spring has the lowest.
Keywords: South of Caspian, surface chlorophyll, MODIS, Aqua satellite
INTRODUCTION
The Caspian Sea is largest inland water in the world, with an area of 386,400 km2 and a coastline of 7250
km. The Caspian is under intense pressure from environmental threats such as changes in sea water level,
excessive fishing is allowed, risk striker marine, infected industrial and agriculture and the urban most of the
Caspian countries are developing (Nouri et al, 2008).
The photosynthetic processes of phytoplankton convert the energy entering marine ecosystems as sunlight
into bio-chemical energy, which propagates through the food web, as a function of inter-relationships among
organisms and environmental factors. Hence, knowledge of the space and time heterogeneity of phytoplankton
growth is critical to understand basic marine ecosystem dynamics. A sensible assessment of phytoplankton growth
patterns, over basin scales and for multi-annual periods, can only be achieved by means of optical remote sensing.
Measuring the level of chlorophyll in marine ecosystems due to its effects on biological organisms is regarded by
experts. It closed in lakes that make up the environment is more important (Barale, 2010).
Barbiero and Tuchman (2004) the deep chlorophyll maximum (DCM) in Lake Superior in 1996 and 2001
were reviewed. The DCM was usually observed in the upper hypolimnium between 23 and 35 m, a region lacking a
pronounced density gradient. Nezlin (2005) investigated pattern of seasonal and interannual variability of remotely
sensed chlorophyll. He observed that the chlorophyll concentration in the surface layer was especially high in the
shallow northern Caspian Sea. Seasonal variability in all Caspian Sea regions except the Kara- Bogaz- Gol Bay
was characterized by a seasonal maximum in August to September, related to the period of maximum sea surface
temperature and wind stress. Zhao and Tang (2006) investigated the spatial distribution of chlorophyll- and its
responses to oceanographic environments in the South China Sea. The results show that Chl- concentration are
higher in the west than in the east of the SCS. Kneubuhler and et al (2007), determined mapping chlorophyll- in
Intl J Agri Crop Sci. Vol., 5 (12), 1269-1275, 2013
Lake Kivu with remote sensing methods. The result from 2003 through 2005 showed increased chlorophyll
concentration to high algae bloom during the dry season from July to September.
The present study aims at assessing heterogeneity of chlorophyll concentration in surface waters in Caspian
Sea to increase knowledge about primary production and annual cycling in the catchment.
METHODS
In this study, to determine the concentration of chlorophyll in the South Caspian region is used of
measurement data from Aqua Satellite of MODIS sensor. Data was extracted from the website of Ocean Watch for
the period 2009-20003. Spatial resolution data was 0.05 degrees (approximately 4/4 km) and in terms of mg/m3
have been collected. Because of the data from the satellite will have a good cover, a regular rectangular grid
interval of 0.1 degrees latitude and 0.04 degrees longitude is defined and data collection points in the network at
any point of time series for the whole period was conducted. The statistical software such as SPSS and Excel were
used to analyze the data and display the results graphically, Surfer software was used. Temporal variations of
surface chlorophyll maps of the South Caspian annual, quarterly and monthly determined.
RESULTS
The results showed that the annual variations of surface chlorophyll from years 2003 to 2009, in the course
of this quantity during the 2005, 2006 and 2009 increased, while during 2003 and 2007, its lowest i.e. 1.81 and 1.95
3
mg/m appears (Figure 1).
3.00
2.73
2.47
chl content (mg/m3)
2.50
2.29
2.01
2.00
2.18
1.95
1.81
1.50
1.00
0.50
0.00
2003
2004
2005
2006
2007
2008
2009
Time (year)
Figure 1. changes in mean of annual surface chlorophyll in South of Caspian
Also change the quantity anomaly (Figure 2), showed that during the years 2005, 2006 and 2009, the
average value over the long term (seven years out) and in the years 2003, 2004 and 2007 were below average, if
showed the variation of sea surface temperature (results not presented), which was a relative increase in sea
surface temperature, which can be a significant change in the opposite direction of the two quantities.
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Time (year)
Figure 2. Annual variations of surface chlorophyll anomaly in South of Caspian
The contour lines of the surface chlorophyll in the South Caspian colors indicated (Figure 3) that changes
with the seasons so that the highest values in summer (July, August and September) and lowest valuesin spring
(April, May and June) and winter (January, February and March) can be seen.
The magnitude of the spring range between 0.6 mg/m3 for the central to 5/4 mg/m3 for the western shores
of the lake varies. In the summer 1/5 to 11/5, autumn 1/5 to 10/5 and in winter 1 to 6/1 of the area varies in different
areas.
B
A
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C
D
Figure 3. Long-term changes of surface chlorophyll in South of Caspian
A)Spring, B)Summer, C)Autumn, D)Winter
surface chlorophyll (mg/m3)
The findings showed that the surface chlorophyll means were equal in all longitudes, approximately (Figure
4). Variations of these quantities showed a decreasing trend as a sharp decline during the 49 to 49/4 it can be seen
that with increasing depth in the Caspian sea (Figure 7). Length from 49/6 to 52/8 with the slow decline of
chlorophyll a trend depth was increased. Subsequently, over 52/8 to 53/6 together with a reduction in the depth of
the chlorophyll increase was seen. In Figure 5, the surface chlorophyll changes have been showed with a slight
change in all latitudes.
longitude
Figure 4. Changes of surface chlorophyll mean in south of Caspian with longitude
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4.50
surface chlorophyll (mg/m3)
4.00
3.50
3.00
2.50
2.00
1.50
1.00
0.50
0.00
latitude
Figure 5. Changes of surface chlorophyll mean in south of Caspian with latitude
Monthly variations of surface chlorophyll in South of Sea at different months demonstrated that August and
June had the highest and lowest amount respectively (Figure 6). The magnitude of the maximum values in August
and the lowest in January. The finding confirms the results of the seasonal analysis.
3.29
Chlorophyll content (mg/m3)
3.50
3.05
2.84
3.00
2.55
2.42
2.50
2.00
1.83
1.65
1.98
1.78
1.73
MAR
APR
1.63
1.61
MAY
JUN
1.50
1.00
0.50
0.00
JAN
FEB
JUL
AUG
SEP
OCT
NOV
DEC
Time (month)
Figure 6. Monthly variations of surface chlorophyll in south of Caspian from 2003 to 2009
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Figure 7. Overview along with the division of the Caspian Sea
DISCUSSION
A time series of chlorophyll-like pigments statistical maps and anomalies, derived from data collected by
MODIS sensor of Aqua satellite. Heterogeneity in the time series of surface chlorophyll concentrations in the
Southern Caspian are also involved Sea surface temperature (SST), wind stress and other factors, including Jelly
Fish reversal (Mnemiopsis leidyi) (Barale, 2010). SST anomalies are negatively correlated with chlorophyll
concentration anomalies in deep Middle and Southern Caspian Sea areas. Indeed, low SST indicates more
intensive upwelling or turbulent mixing, resulting in increased nutrient flux to the upper euphotic layer, an increase
of the phytoplankton growth rate, and more phytoplankton biomass. However, the time lag between the signal (low
SST) and response (high chlorophyll concentration) is as long as 9 months. We expect that more intensive
convection of the water column in winter results in grater phytoplankton biomass during the period of its maximum
in late summer (August to September). We see that the results are perfectly matched, the results also Nezlin
(2005). A similar relationship is observed between the chlorophyll concentration and wind stress. More intensive
wind mixing results in higher phytoplankton biomass in the deep parts of the Caspian Sea 10-11 months later.
Increasing concentrations of jelly fish feeding pressure on the zooplankton, which feed on phytoplankton biomass
and the subsequent pressure decreases, resulting in a major boom in phytoplankton concentrations is observed
(Kideys et al, 2008). As the map in Figure 3 shows the highest amount of chlorophyll in coastal waters and
estuaries in the South Caspian observed. Due to the accumulation of nutrients, low depth and also reduce of wind
stress, the quantity of phytoplankton and chlorophyll concentrations were increased, and when going deep towards
the central regions of Caspian, the surface chlorophyll content decreases. In deep regions of the Caspian Sea, the
process of phytoplankton growth is regulated by vertical stratification of the water column, similar to other deep
open regions of the World Ocean (Rocha et al, 2009). The pycnocline established in summer as a result of the
heating of the surface layer by solar radiation works as a natural boundary separating deep layer rich in nutrients
from the well-illuminated upper mixed layer where phytoplankton is concentrated. This boundary results in a
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nutrient limitation of phytoplankton growth. Wind stress and/or the cooling of the sea surface erode the pycnocline,
resulting in an increase of nutrient flux into the upper layer, which in turn stimulates phytoplankton growth.
REFERENCES
Barale V. 2010. Exploring the Caspian sea basic ecosystem dynamics by means of the sea WIFS historical record (1997-2009). Internatinal
scientific conference “ Climate and water balance changes in the Caspian region”, Astrakhan, Russian Federation, 19-20 October
2010.
Barbiero RP, Tuchman ML. 2004. The deep chlorophyll maximum in Lake Superior. J. Great Lakes Res, Vol. 30 (1),pp. 256-268
Kideys AE, Roohi A, Develi E, Beare D. 2008. Increased chlorophyll in southern Caspian sea following an invasion of jellfish. Hindawi
Publishing Corporation. Research Letters in Ecology.Vol. 185642, 4 pages.
Kneubuhler M, Frank T, Kellenberger TW, Pasche N, Schmid M. 2007. Mapping chlorophyll- in Lake Kivu with remote sensing methods.
Envisat symposium, Montreux, Switzerland.
Nezlin NP. 2005. Pattern of seasonal and interannual variability of remotely sensed chlorophyll. Hdb Env Chem.Vol. 5,pp 143-157.
Nouri J, Karbassi AR, Mirkia S. 2008. Environmental management of coastal region in the Caspian Sea. Int. J. Environ. Sci. Tech. Vol. 5(1),pp
43-52.
Rocha RRA, Thomaz SM, Carvalho P, Gomes LC. 2009. Modelling chlorophyll- and dissolved oxygen concentration in tropical floodplain
Lakes. Braz. J. Biol. Vol, 69(2),pp 491-500.
Zhao H, Tang D. 2006. The spatial distribution of chlorophyll- and its responses to oceanographic environments in the south china sea.
Advances in Geosciences.Vol, 5,pp 7-14.
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