Studies on the Algal Distribution in Various Salt-Pans of Kanyakumari District, Tamilnadu, India

 

S. Betsy Bai ¹, C. Vaithyanathan ²

Department of Chemistry, S.T. Hindu College, Nagercoil-629002(T.N), India.

*Corresponding Author E-mail: betsy.betsyjoe@gmail.com, cvaithyn@gmail.com

Aquaculture is a popular food producing sector with the target of farming useful organisms in water for food production. Microalgae are one of the many organisms cultured as live feed recently in India. Majority of the algal species can adopt themselves physiologically to a very wide range of salinity. Algae are efficient bio accumulators of inorganic nutrients. Microalgae grow efficiently in a medium having a variety of substances and nutrients in low concentrations instead of a single nutrient in high concentration. Recently, the utilization of salt-works for the production of artemia has increased considerably as it is an indispensable source of food for a number of fish and shrimp larvae. Salt-pans have a ruling temperature of around  24⁰ to 35⁰C and a temperature of 25⁰ to 30⁰C is sufficiently favoured to have an increase in biomass content of microalgae. The high nutritive value and adaptability to various environment with a wide range of pH, nutrients and other physical conditions make the microalgae an ideal feed in marine aquaculture enterprise and also a supplement item in human and animal nutrition. The cultivation of these algae with a proper scientific know-how, will improve not only the hatchery need of culture of fishes and shrimps, but also develop the socio-economic status of the coastal people. So, a study was conducted and it unfolds the distribution of algae in different stages of various salt-pans.

 

 

INTRODUCTION:

Aquaculture provides the necessary food for the growing  population.¹.  More care is given to aquaculture as it improves rural economy and also for the productive utilization of vast and varied water resources.² The inter-relationship between the aquatic sources and the plant and animal life in the various water bodies gain more importance in the increased production of protein rich food..³ The gradual decrease in the natural harvest indicates the trend of increasing dependence of aquaculture. This is because of the fact that a large quantity of food is derived through aquaculture. Throughout the globe, India is the seventh largest fish producing country.⁴ The intensity of aquaculture is being geared up because of the availability of the natural facilities and also suitable coastal brackish waters.⁵ In aquaculture, the utility of different feeds has dimensionally increased the production and in turn the profits considerably.⁶ 

 

The formulated feeds are having lesser importance than the live feeds. The organisms that are being cultured, prefer live feeds because it provides essential growth factors, prevents diseases, promotes higher survival etc⁷. Of the various organisms which can act as a potential live feed, phytoplankton (algae) gains more importance. Micro algae is considered as a potential feed to diverse group of organisms because of their small size and higher growth rate.⁸ Microalgae like Dunaliella, Chlorella, Nitzchia, Navicula etc have been cultured for commercial aquaculture.⁹ Algae are rich in proteins, amino acids and also poly unsaturated fally acids (PUFA). India is having a moderately rich marine algal resource and it was reported that a total of 650 marine algal species have been identified in Indian waters.¹⁰ Some algal species require inorganic fertilizers for their growth. Unicellular algae are efficient bio-concentrating agents and can grow rapidly utilizing inorganic nutrients. However, any element can be toxic to algae if supplied more than the permissible limit. Various parameters concentrating on the growth like light, temperature, salinity and dissolved nutrient concentrations are the deciding factors in influencing the chemical composition of microalgae.¹¹

 

MATERIALS AND METHODS:

The algal study was carried out in the various stages of different salt-pans like Swamithoppu, Puthalam and Kovalam, which use back water, sub soil brine and sea brine respectively. Monthly samples were collected from various stages of the above three different salt-pans for a period of one year. The five stages from which samples were collected are source, reservoir, condenser, crystallizer and bittern named I to V respectively. Algal count at various stages of the different salt-pans were carried out according to standard procedures. ¹² It was carried out by collecting 10 litres of brine from each stage of various salt-pans and filtering it through a bolting silk net (50 mesh per linear cm) and the contents were preserved in 5% formalin for subsequent studies.

 

The collected samples were allowed to settle for 24 hours. Sedimentation technique was used to determine the numerical abundance of the algae. After sedimentation, the supernatant solution was siphoned out in two to three successive days until the volume was reduced to 5ml. The concentrated volume was diluted exactly to 50ml and the enumeration of the phytoplankton were made using a light microscope.

 

The total algal count and the algal genus were identified according to the method of Desikachary (1959)¹³ and Fritzch ¹⁴ and the values are presented in Tables.

 

RESULTS AND DISCUSSION:

Three classes of algae were identified namely Cyanophyceae, Chlorophyceae and Bacillariophyceae. Cyanophyceae includes blue-green algae and the genus identified were Oscillatoria, Spirulina, Nostoc, Lyngbya and Anabaena. Under chlorophyceae class, Volvox and chlorella were identified. Bacillariophyceae class contained Diatoms, Nitzchia and Navicula. The total algal count and genus were identified and presented in Table.1.

 

The present study included  the algal distribution at the various stages viz source, reservoir, condenser, crystallizer and bittern of the different salt-pans of Kanyakumari district like Kovalam, Puthalam and Swamithoppu, which exclusively use sea brine, subsoil, brine   and back waters respectively for salt making. Generally, it was observed that during the premonsoon period (i.e) January, February and  March and also in between the south-west and north –east monsoons (i.e) August and also to some extent in July, the total algal  count was maximum and as monsoon proceeded, the count went on decreasing. As the north east monsoon became active during the period of October to December the total algal count was even lower. This was in accordance with earlier works that phytoplankton was maximum in summer season and was negligible in rainy season¹⁵.

 

 

Table-1-Total Algal Count at various stages of the different salt pans

Salt Pans	Nature of the brine	Stages	Months
			January	February	March	April	May	June	July	August	September	October	November	December
Swamithoppu	Back water	I	23	23	26	12	7	10	16	23	8	7	4	3
		II	20	18	19	9	4	7	10	18	7	5	3	1
		III	17	16	15	7	3	5	7	14	5	4	1	1
		IV	9	9	7	3	1	4	5	6	2	1	ND	ND
		V	4	4	5	ND	ND	X	2	2	ND	ND	X	ND
Puthalam	Subsoil brine	I	24	27	23	10	8	9	18	23	10	9	5	2
		II	20	21	19	7	5	7	15	20	9	5	3	1
		III	17	15	16	6	4	5	12	17	6	2	2	ND
		IV	11	9	12	4	2	2	9	9	3	1	1	ND
		V	5	6	4	ND	ND	X	4	5	ND	ND	X	ND
Kovalam	Sea brine	I	20	21	20	12	9	9	15	22	9	6	5	3
		II	16	17	17	10	6	8	12	19	7	5	4	1
		III	12	13	11	5	6	7	9	16	5	3	2	1
		IV	8	9	7	4	4	4	4	11	2	1	1	ND
		V	2	4	3	ND	2	X	2	4	1	ND	X	X

 

STAGES I- SOURCE                              II-RESERVOIR                        III-CONDENSER     ND-NOT  DETECTED

                IV- CRYSTALLIZER              V-BITTERN                            X-NO SAMPLE AVAILABLE DUE TO RAIN

 

he total algal count was found to decrease from source to bittern stage through reservoir, condenser and crystallizer stages. This decrease in  the total algal count was assumed on the fact that as the concentration of the brine gradually increases and reaches the maximum in the bittern stage and as a result there is a dimensional increase in salinity. This was in accordance with the earlier work that the phytoplankton crop was more when salinity was low¹⁶.

 

Different class of algae belonging to chlorophycease were identified in almost all the stages of the different salt-pans. Various genus of algae like Spirogyra, Clamydomonas and Dunaliella of Chlorophyceae; Oscillatoria, Spirulina and Nostoc of Cyanophyceae and Nitzchia, Navicula and Diatom of Bacillariophyceae were identified in marked numbers. But a marginal count of Volvox and Ulothrix of Chlorophyceae; Lyngbya and Anabena of Cyanophyceae were also identified.

 

Clamydomonas of Chlorophyceae, Nostoc of Cyanophyceae and Nitzchia and Navicula of Bacillariophyceae were identified in almost all the stages of various salt-pans, irrespective of the nature of the brine used for salt-making. During the pre-monsoon period, the count was maximum and as the onset of the monsoon, the algal count went on decreasing and reached the minimum.

 

 

Table-2-Algal distribution of Cyanophyceae at Swamithoppu (Back water)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

OSCILLATORIA

I

+

+

+

+

+

-

-

+

+

+

+

-

II

+

+

-

-

-

-

-

+

-

-

-

-

III

-

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

SPIRULINA

I

+

+

+

-

-

-

-

+

-

-

-

-

II

+

+

+

-

-

-

-

+

-

-

-

-

III

-

-

-

-

-

-

-

+

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

NOSTOC

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

-

-

-

-

+

+

-

-

-

III

+

+

+

-

-

+

-

+

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

STAGES     I-SOURCE                            II-RESERVOIR        III-CONDENSER

                     IV-CRYSTALLIZER          V-BITTERN            X-NO SAMPLE AVAILABLE DUE TO RAIN

   (+) PRESENT                            (-) ABSENT

 

 

Similarly, algae like Dunaliella of Chlorophyceae and Spirulina of  Cyanophyceae were identified maximum at various stages of Kovalam salt-pans, where seabrine is the only source of water for salt production. In these pans, these algae were found maximum during the

 

premonsoon period viz-January, February and March and also in August. The count of these algal cells went

 

on decreasing and almost minimum was recorded during the month of December which was in accordance with earlier works.¹⁷ But regarding the other two salt-pans like Puthalam and Swamithoppu, these genus like Dunaliella and Spirulina were found in marginal numbers as  these salt- pans use subsoil brine and backwaters respectively  for salt production.

 

The predominance of Spirulina and Dunaliella in the various stages of Kovalam salt pans indicated that these are exclusively marine based, extremophilic and also due to the P^H of the brine. Such an existence of these marine based algal cells in Kovalam salt-pans were in accordance with earlier observations that P^H of the brine favoured the phytoplankton growth.

 

Clamydomonas of Chlorophceae and Nostoc of Cyanophyceae were found in notable numbers in various stages of the salt-pans of Swamithoppu. But these were found minimum in the different stages of Puthalam and Kovalam which use subsoil brine and sea brine respectively for salt production. As the monsoon proceeded, these algal count went on decreasing and became very marginal during the month of December. This was in accordance with earlier works.

 

Table-3-Algal distribution of Chlorophyceae at Swamithoppu (Back water)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

SPIROGYRA

I

+

+

+

+

+

+

-

+

+

+

+

+

II

+

+

+

-

-

-

-

+

+

+

-

-

III

+

+

+

-

-

-

-

+

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

DUNALIELLA

I

+

+

+

+

-

-

+

+

-

-

-

-

II

+

+

+

-

-

-

+

+

-

-

-

-

III

-

+

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

CLAMYDOMONAS

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

-

-

+

+

-

-

-

-

III

+

+

+

-

-

-

+

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

STAGES       I-SOURCE                           II-RESERVOIR                        III-CONDENSER

                     IV-CRYSTALLIZER          V-BITTERN                            X-NO SAMPLE AVAILABLE DUE TO RAIN

                     (+) PRESENT (-) ABSENT

 

 

 

Spirogyra belonging to Chlorophyceae, being an underground spring habitat was found maximum in the various stages of Puthalam salt-pans which use subsoil brine for salt making. Also found to some extent in the various stages of Swamithoppu salt- pans which uses back water for salt production .But a minimum count of Spirogyra was recorded in the stages of Kovalam salt-pans as it uses sea brine. The distribution of this algae is found to be maximum during the premonsoon period viz. January, February and March and also in between monsoons (i.e) July and August. But as monsoon commenced , the algal count went on decreasing and reached the minimum.

 

Oscillatoria of Cyanophyceae class was normally found maximum in Puthalam salt- pans which exclusively use subsoil brine for salt making. But is was observed earlier that some species like Oscillatoria  limnetica are purely  marine based and are commonly   found  in salt –pans which use sea brine for salt production. Regarding the Kovalam salt-pans which use sea brine, no such species of  Oscillatoria was observed. The count of Oscillatoria in the various stages of  Puthalam salt-pans were maximum during the pre monsoon period and as north east monsoon became active, almost  very few algal cells were indentified in December.

 

Regarding Diatoms of Bacillariophyceae class, as it is both marine as well as fresh water habitat, they were indentified maximum in almost all the stages of the different salt-pans. The algal count was found to decrease from source to bittern as concentration in turn salinity increases. Nitzchia of the same class was found maximum in  Kovalam salt-pans when compared to the other two salt- pans as it uses sea brine exclusively.

 

 

 

Table-4-Algal distribution of Bacillariophyceae at Swamithoppu  (Back water)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

NITZCHIA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

-

-

+

+

+

+

+

-

-

III

+

+

+

-

-

+

+

+

-

-

-

-

IV

+

+

+

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

NAVICULA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

-

-

+

+

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

DIATOM

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

-

-

+

+

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

STAGES        I-SOURCE                         II-RESERVOIR                        III-CONDENSER

                       IV-CRYSTALLIZER        V-BITTERN                            X-NO SAMPLE AVAILABLE DUE TO RAIN

                       (+) PRESENT (-) ABSENT

 

Similarly, Navicula of the same class (i.e) Bacillariophyceae was found in large numbers in the various stages of Puthalam  salt-pans as subsoil brine is normally used for salt production. Irrespective of the presence of different algae in the various stages of the different salt-pans, they went on decreasing from source to bittern stage and also as monsoon proceeded, the algal count also decreases and reached the minimum in December.

 

 

Table-5-Algal distribution of Chlorophyceae at Puthalam (Subsoil brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

SPIROGYRA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

-

+

+

-

-

-

-

IV

+

+

+

-

-

-

-

+

-

-

-

-

V

+

-

-

-

-

x

-

-

-

-

x

-

DUNALIELLA

I

+

+

+

-

-

+

+

+

-

-

-

-

II

+

+

+

-

-

-

-

+

-

-

-

-

III

+

+

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

CLAMYDOMONAS

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

-

-

-

-

+

+

-

-

-

III

+

+

-

-

-

-

-

-

-

-

-

-

IV

+

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

STAGES     I-SOURCE                            II-RESERVOIR                        III-CONDENSER

                    IV-CRYSTALLIZER           V-BITTERN                            X-NO SAMPLE AVAILABLE DUE TO RAIN

                    (+) PRESENT (-) ABSENT

 

Table-6- Algal distribution of Bacillariophyceae at Puthalam (Subsoil brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

NITZCHIA

I

+

+

+

+

-

+

+

+

+

+

+

+

II

+

+

+

-

-

-

-

+

-

-

-

-

III

+

+

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

NAVICULA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

+

+

+

+

-

-

-

IV

+

+

-

-

-

-

-

+

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

DIATOM

I

+

+

+

+

-

-

+

+

+

+

-

-

II

+

+

+

+

-

-

+

-

-

-

-

-

III

+

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

STAGES       I-SOURCE                          II-RESERVOIR                        III-CONDENSER

                      IV-CRYSTALLIZER         V-BITTERN                            X-NO SAMPLE AVAILABLE DUE TO RAIN

                      (+) PRESENT (-) ABSENT

 

Table-7-  Algal distribution of Bacillariophyceae at Puthalam (Subsoil brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

NITZCHIA

I

+

+

+

+

-

+

+

+

+

+

+

+

II

+

+

+

-

-

-

-

+

-

-

-

-

III

+

+

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

NAVICULA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

+

+

+

+

-

-

-

IV

+

+

-

-

-

-

-

+

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

DIATOM

I

+

+

+

+

-

-

+

+

+

+

-

-

II

+

+

+

+

-

-

+

-

-

-

-

-

III

+

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

-

 STAGES     I-SOURCE                           II-RESERVOIR        III-CONDENSER

                      IV-CRYSTALLIZER         V-BITTERN            X-NO SAMPLE AVAILABLE DUE TO RAIN

                      (+) PRESENT (-) ABSENT

 

 

 

 

 

 

 

Table-8- Algal distribution of Cyanophyceae at Kovalam (Sea brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

OSCILLATORIA

I

+

+

-

-

-

-

-

+

-

-

-

-

II

+

+

-

-

-

-

-

-

-

-

-

-

III

-

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

x

SPIRULINA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

+

+

+

+

+

+

+

+

+

IV

+

+

+

-

+

+

-

+

-

-

-

-

V

+

+

+

-

-

x

-

+

-

-

x

x

NOSTOC

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

-

-

-

-

-

+

-

-

-

-

IV

+

+

+

-

-

-

-

+

-

-

-

-

V

+

+

+

-

-

x

-

-

-

-

x

x

STAGES     I-SOURCE                            II-RESERVOIR        III-CONDENSER

                      IV-CRYSTALLIZER         V-BITTERN            X-NO SAMPLE AVAILABLE DUE TO RAIN

                      (+) PRESENT (-) ABSENT

 

 

Table-9- Algal distribution of Chlorophyceae at Kovalam (Sea brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

SPIROGYRA

I

+

+

+

-

-

-

-

+

-

-

-

-

II

+

+

+

-

-

-

-

+

-

-

-

-

III

-

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

x

DUNALIELLA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

+

+

+

+

+

+

+

+

+

IV

+

+

+

-

-

-

-

+

-

-

-

-

V

+

+

+

-

-

x

-

+

-

-

x

x

CLAMYDOMONAS

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

-

-

+

+

+

+

+

-

-

III

+

+

+

-

-

-

-

-

-

-

-

-

IV

+

+

-

-

-

-

-

-

-

-

-

-

V

+

+

-

-

-

x

-

-

-

-

x

x

STAGES     I-SOURCE                            II-RESERVOIR        III-CONDENSER

                      IV-CRYSTALLIZER         V-BITTERN            X-NO SAMPLE AVAILABLE DUE TO RAIN

                      (+) PRESENT (-) ABSENT

 

 

 

 

Table-10- Algal distribution of Bacillariophyceae at Kovalam (Sea brine)

Algal genus

Stages

January

February

March

April

May

June

July

August

September

October

November

December

NITZCHIA

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

+

+

+

+

+

+

+

+

III

+

+

+

-

-

+

+

+

+

-

-

-

IV

+

+

+

-

-

+

+

+

+

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

x

NAVICULA

I

+

+

+

-

-

-

-

+

-

-

-

-

II

+

+

+

-

-

-

-

-

-

-

-

-

III

-

-

-

-

-

-

-

-

-

-

-

-

IV

-

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

x

DIATOM

I

+

+

+

+

+

+

+

+

+

+

+

+

II

+

+

+

+

-

-

-

+

+

-

-

-

III

+

+

+

-

-

-

-

+

-

-

-

-

IV

+

-

-

-

-

-

-

-

-

-

-

-

V

-

-

-

-

-

x

-

-

-

-

x

x

 

STAGES     I-SOURCE                            II-RESERVOIR        III-CONDENSER

                      IV-CRYSTALLIZER         V-BITTERN            X-NO SAMPLE AVAILABLE DUE TO RAIN

                      (+) PRESENT (-) ABSENT