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