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A Study of Phytoplankton
Communities and Related
Environmental Factors of Ratnagiri
sea coast
Madhura Mukadam and Arvind Kulkarni
Department of Zoology,
Gogate Jogalekar College, Ratnagiri, (MS), India.
INTRODUCTION• Phytoplankton is a vital and important organism as a
producer of the primary food supply of the sea.
• Its study includes a variety of taxonomic groups
(cyanobacteria, diatoms, dinoflagellates, silicoflagelates,
coccolithophorids, and many other flagellates) that inhabit
the water column.the water column.
• Marine phytoplankton of the world may include as many as
17 classes and an estimated number of 498 ± 15 genera and
3,910 ± 465 species (Sournia et al. 1991).
• Through the process of photosynthesis, also extract carbon
dioxide from the atmosphere, and play an important role in
the balance of greenhouse gases that control global
climate(Alles, 2011).
• These are the skeletons of food web dynamics, which
control many ecological processes such as carbon budget,
modulation of sea surface temperature(SST) affecting
global climate.
• They are very efficient and easily detectable indicators of
ecological alteration.
• Presence of certain species of phytoplankton can trigger
the fishery or deplete it also resulting in toxicity.
• The most important factors determining the values of the
photosynthetic parameters in natural phytoplankton
populations are - light, temperature, nutrient concentration,
and pigment content in algae.
Importance of Phytoplankton in Food Chain :
• Predominantly autotrophic or holophytic organisms (they build
organic matter from inorganic materials present in their
environment).
• Marine phytoplankton is the most important producer of organic
substances and determine the basic primary productivity of the
ecosystem.
• Under favourable conditions, phytoplankton is capable of
remarkably rapid growth, sometimes producing new organic
materials equalling its own weight within 24 hours, a rate greater
than that achievable by terrestrial plants.
• All other living forms of higher trophic levels are directly or
indirectly dependant on phytoplankton for energy supply and
hence perform vital functions (Chandy et al.1991).
Factors Affecting Primary Production
• Physico-chemical factors like Light, temperature and availability
of nutrients.
• Biomass of phytoplankton and consequently primary production,
display strong seasonal variation in accordance with climatic
conditions and other oceanic phenomena such as upwelling and
turbulence (Eddy diffusion) in addition to the grazing rate of
herbivorous zooplankton of the local habitat.herbivorous zooplankton of the local habitat.
• Since primary production depends on the ability of plants to
absorb and utilize light in photochemical reactions, it is confined
to the illuminated surface zone of the sea (euphotic zone).
• Seasonal variations in light intensity and other factors that affect
light penetration influence photosynthesis to a great extent.
• Rate of photosynthesis increases with rising temperature up to
a maximum, but then diminishes sharply with further rise in
temperature.
• Ability of organisms to perform photosynthesis depends on their
adaptability to ambient conditions and different species are
suited to different range of temperature.
• In addition to its direct effect on rate of photosynthesis,• In addition to its direct effect on rate of photosynthesis,
temperature also influences production through its effects on
movement and mixing of the water, and hence on the supply of
nutrients to the euphotic levels.
• Availability of biolimiting elements such as nitrogen,
phosphorous and silica is an important factor affecting primary
production.
Significance of Phytoplankton
• Diatoms are the important group of phytoplankton engaged in
primary production.
• Distribution and abundance of diatoms indicate a conducive
environment for active growth and survival of other forms of life.
• Population density of marine animals and their reproductive cycle
are related to the abundance of phytoplankton.are related to the abundance of phytoplankton.
• This is because those animals themselves and/or their
metamorphosing young ones (larvae) are dependent on diatoms,
dinoflagellates etc. for nutrition.
• High plankton density is associated with similar increase in
bacterial population mainly involved in decomposition of
particulate organic matter from fecal pallets and the bodies of
dead organisms.
MATERIALS AND METHODS
• Samples are being collected from one location (Mirkarwada) on
fortnightly basis (30m/50m) and from two other locations (Dabhol
and Burondi) samples are being collected quarterly.
• Phytoplankton collection was done using conical nylon bags
(30cm diameter) made up of 30 no. bolting silk cloth is used for
filtering 100 L of surface water with a bucket of 25 liters volumefiltering 100 L of surface water with a bucket of 25 liters volume
and the plankton was thus concentrated.
• The net was washed again with sea water and concentrated
plankton was collected in 100 ml volume screw capped airtight
plastic bottles.
• The samples were preserved on site by adding 1 ml of Lugol’s
iodine. The sample was allowed to settle prior to analysis.
• The enumeration of phytoplankton was carried out by obtaining 1 ml of
plankton sample from the stock through the Stampel pipette. This volume
was transferred to a Sedgwick Rafter counting cell.
• Counting of the individual plankton was done by using the formula.
Plankton units/Liter = N x C x 10
Y
• The species-wise phytoplankton were counted. This was repeated by
taking one ml of sample twice and from average of the three samplestaking one ml of sample twice and from average of the three samples
data was calculated.
• Thus, average number of phytoplankton present in a liter of water sample
was then calculated and final results are expressed as no. of cells.
• For chlorophyll analysis samples are filtered on board and other samples
for nutrient analysis are analyzed in the laboratory on the next day.
SAMPLING
Mirkarwada Station GPS
MIRKARWADA SAMPLING STATIONSTUDY AREA
MIRKARWADA SAMPLING STATION
Mirkarwada Station GPS
position
17°.00.210N
72°.58.920E
DABHOL AND BURONDI SAMPLING STATION
Burondi Station GPS
Position
170.36’10.99N
720.48‘29.72E
Dabhol Station GPS
Position
170.32'32.11"N
720.48'0.80"E
RESULTS AND DISCUSSION
22
24
26
28
30
32
34
12
.10
.13
M
26
.10
.13
M
9.1
1.1
3M
26
.11
.13
M
11
.12
.13
M
27
.12
.13
M
11
.01
.14
M
25
.01
.14
M
09
.02
.14
M
15
.2.1
4D
20
.2.1
4D
21
.02
.14
B
03
.03
.14
M
17
.04
.14
D
18
.04
14
B
Te
mp
era
ture
0C
Date
Average Variations in Temperature
11:00 AM
1:00 PM
3:00 PM
Min 27 Max 29.5
22
24
26
28
30
32
34
12
.10
.13
M
26
.10
.13
M
9.1
1.1
3M
26
.11
.13
M
11
.12
.13
M
27
.12
.13
M
11
.01
.14
M
25
.01
.14
M
09
.02
.14
M
15
.2.1
4D
20
.2.1
4D
21
.02
.14
B
03
.03
14
M
17
.04
.14
D
18
.04
.14
B
Te
mp
era
ture
0C
Date
Average Variations in pH
11:00 AM
1:00 PM
3:00 PM
Min 5.4 Max 8.7
Temperature showed decreasing trend while pH, Salinity and DO Showed increasing trend
from October to March,2014
Min 0.58 Max 4.32
30
32
34
36
38
40
42
44
12
.10
.13
M
26
.10
.13
M
9.1
1.1
3M
26
.11
.13
M
11
.12
.13
M
27
.12
.13
M
11
.01
.14
M
25
.01
.14
M
09
.02
.14
M
15
.2.1
4D
20
.2.1
4D
21
.02
.14
B
03
.03
14
M
17
.03
.14
D
18
.03
.14
B
Sa
lin
ity
Date
Average Variaions in Salinity
11:00 AM
1:00 PM
3:00 PM
Min 33 Max 40
0
1
2
3
4
5
6
7
DO
mg
.l-1
Date
Average variations in DO
11:00 AM
1:00 PM
3:00 PM
Chlorophyll a was found to be higher at
1:00 PM than 11:00 AM and 3:00 PM
Secchi Depth showed decreasing
0
5
10
15
20
25
30
Ch
loro
ph
yll
a m
g.m
-3
Date
Average Variations in Chlorophyll a
11:00 AM
1:00 PM
3:00 PM
Min 0.5 Max 5.53
0
5
10
15
20
25
30
11
:00
AM
3:0
0 P
M
1:0
0 P
M
11
:00
AM
3:0
0 P
M
1:0
0 P
M
11
:00
AM
3:0
0 P
M
1:0
0 P
M
11
:00
AM
3:0
0 P
M
1:0
0 P
M
11
:00
AM
3:0
0 P
M
1:0
0 P
M
9.11.13M26.11.13M11.12.13M27..12.13M11.01.14M25.01.14M9.02.14M15.02.14 D22.02.14D23.02.14B
Se
cch
i D
ep
th (
m)
Date
Secchi Depth (m)
Secchi Depth (m)
Secchi Depth showed decreasing
trend, and low values of Secchi
depth correlates with low
concentration of chlorophyll from
27 Dec 13 till 3 March,14 at
Mirkarwada station
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
6.0
6.5
0m 5m 10m 20m 30m
Ph
yto
pla
nk
ton
Lo
g N
o.-1
Depth
Phytoplankton variations on
26 Oct 13
11:00am 11:00am 3:45pm 3:45pm
Ranked graphs shows phytoplankton
variations which have been
plotted showing species present at all
6/5 or 4 depths with time series
3
3.5
4
4.5
5
5.5
6
0m 5m 10m 20m 30m
Ph
yto
pla
nk
ton
Lo
g.N
o.l
-1
Depth
Phytoplankton variation on
9 Nov 13
10am 10am 12pm 12pm
12pm 12pm 2pm 2pm
2
2.5
3
3.5
4
4.5
5
5.5
6
0m 5m 10m 20m 30m 50m
Phytoplankton Variations on
26 Dec 13
11:00AM 11:00AM 11:00AM 1:00 PM 1:00 PM
1:00 PM 3:00 PM 3:00 PM 3:00 PM
2
2.5
3
3.5
4
4.5
5
5.5
6
0m 5m 10m 20m 30m 50m
Ph
yto
pla
nk
ton
Lo
g N
O.l
-1
Depth
Phytoplankton Variations on
17 March 14
11:00 AM 11:00 AM 11:00 AM 11:00 AM 11:00 AM
11:00 AM 11:00 AM 11:00 AM 1:00 PM 1:00 PM
2
2.5
3
3.5
4
4.5
5
5.5
0m 5m 10m 20m 30m 50m
Ph
yto
pla
nk
ton
Lo
g N
O.l
-1
Axis Title
Phytoplankton Variations on
11 Feb 14
1:00 PM 1:00 PM 1:00 PM 1:00 PM 3:00 PM
3:00 PM 3:00 PM 3:00 PM
�As a general feature, Phytoplankton density was higher at
1:00 PM than at 3:00 PM
�Coscinodiscus was most prominent genus followed by
Fragillaryopsis, Nitzschia, Pleurosigma, Chaetoceros and
Thallasionema
11:00AM 11:00AM 1:00PM 1:00PM
1:00PM 1:00PM 1:00 PM 1:00 PM
1:00 PM 1:00 PM 1:00 PM 1:00 PM
The Identified
Genera are 60
16 genera comprised
of 66 species
Genus No of
Species
Asterionella 2
Ceratium 18
Dictiocha 2
Dinophysis 2
Ditylum 2
Gonyaulux 2
Gunardia 2Gunardia 2
Miniduscus 2
Nitzschia 5
Ornithoceros 3
Peridinium 5
Pleurosigma 5
Prorocentrum 5
Rhizosolenia 6
Thallasionema 2
Thallasiothrix 3