Phytoplanktonic Diversity and Its Relation to Physico-chemical Parameters of Water at Dogarwada Ghat of River Narmada

abStRact Present study was undertaken to assess the spatial and temporal distribution of phytoplanktons with respect to the changes in various physico-chemical parameters of Dongarwada ghat of river Narmada Madhya Pradesh. The study was carried for a year from March 2010 to February 2011.The results revealed presence of total 27 taxa of phytoplanktons belonging to 4 families were found in order of Chlorophyceae (47%) >Cyanophyceae (27%) >Bacillariophyceae (23%)>Euglenophyceae (3%).Diversity parameters Shannon index ranged from 1.092-0.37, Simpson index from 0.6622-0.6202, evenness diversity index from 0.9932-0.7288and Margelef index between 0.5459-0.2951. Various physico-chemical parameters of water analyzed depicted a positive correlation with diversity and distribution of Phytoplankton.


INtRoDuctIoN
Plankton occupies the first link in the food chain and hence forms an important source of food for large aquatic animals.The primary producers are known to contribute significantly to the biological productivity of a water body besides mitigating the carbon cycle by photosynthesis and help to regulate temperature of the area of their prevalence.These are very sensitive to environment they live in and any alteration in the water system leads to the change in their communities in terms of tolerance, abundance, diversity and dominance in the habitat (Amarsinghe and Viverberg, 2002).Phytoplankton are possibly the most important group of organisms on earth generating most of the oxygen and also produce vegetative matter required at various links in a food chain.Wu (1984) has described a relation between aquatic organisms to the degree of pollution and introduced the concept of bio-indicators of pollution in their saprobic system.However, excessive growth and accumulation of phytoplankton as blooms lead to destruction of any water body resulting in dire consequences.
Over the last few decades, there has been much interest in the processes influencing the diversity, distribution and development of phytoplankton communities (Bhosale, et al., 2010;Achary, et al., 2010;Negi and Rajput, 2011) primarily in relation to physico-chemical factors (Akbayet al., 1999 andAchary, et al., 2010).Study of physicochemical parameters is basic tool that contributes in making up of the ecosystems and determine the tropic dynamics of the water body.The change in water quality tends to change the living conditions especially in the number, diversity and distribution of the biota of the ecosystem (Sharma and Singh, 2013).Phytoplankton are the productive base of the food chain in freshwater ecosystems and healthy aquatic ecosystem is dependent on its physical, chemical and biological characteristics (Venkatesharaju et al., 2010).Therefore, the present study was undertaken to assess the spatial diversity of phytoplankton community of river Narmada at Dongarwada and its correlation with the physiochemical parameters of the water body.

Study area
Narmada originates from Amarkantak hill in shahdol district of Madhya Pradesh is known for crystal clear water.Biological production in any aquatic body gives a direct correlation with its physico-chemical status.Hoshangabad town earlier called Narmadapur falls within the geographical coordinates of +22 0 44'40'17" and +77 0 40 ' 52.66 " is famous for its beautiful ghats and is situated about 100 km away from capital city, Bhopal.Water samples were collected at Dongarwada site in Hoshangabad from March 2010 to February 2011.The investigation period was divided into four seasons i.e. summer, monsoon, post-monsoon and winters.

Physico-chemical analysis
Water samples were collected in the morning hours between 9 to 11 AM, in polythene bottle.The samples were immediately brought to laboratory for the estimation of various physicochemical parameters.Water temperature, pH and turbidity were recorded on spot at the time of sample collection, by using thermometer, pocket digital pH meter and turbidity meter.The samples were stored in 4 o C. Total hardness (TH) and alkalinity was analysed using standard procedures in the laboratory by using methods as prescribed by APHA (2002) and Trivedy and Goel (1986).

biological analysis of phytoplanktons
Samples for plankton analysis were collected once in a month from for a period of one year from March 2010 to February 2011.The samples were collected following Welch (1952), Wetzel (1975) and Adoni (1985) as close to the water surface as possible.100 l of water filtered through plankton net having mesh size of 60 microns and allowed to settle down for 24-48 hours.The samples were preserved in Lugol's Iodine solution and further concentrated to approximately 30 ml with 4% formalin.The phytoplankton were identified with the help of keys given by Prescott (1982), Agarkar (1975) and Desikachary (1959) .Counting of the individual plankton was done by "Lac Keys" dropping method (1935) using the formula:-Plankton units/l = N x C x 100 Y N= No. of plankton counted in 0.1 ml concentrate.C= Total volume of concentrate in ml.Y= Total volume of water filtered for sample in litres.
The data generated in present study was subjected to quantitative analysis of parameters using Microsoft past software version 3.0.2.

Physico-chemical parameters
In present investigation, the mean temperature of the water body ranged from 26.183 ± 3.720.Water temperature is of enormous significance as it regulates various abiotic characteristics and biotic activities of an aquatic ecosystem (Ishaq et al., 2013).The lowest water temperature was recorded in the month of February (20.1°C) and highest in May (31.2°C).pH marked a fluctuation from 7.3 in January to 8.9 in June with lower value of pH was observed during winters because of low temperature and photosynthetic activities.Change in pH concentrations have a definite impact on aquatic life by altering other aspects of water chemistry e.g.low pH levels can increase the solubility of certain heavy metals.This allows the metals to be more easily absorbed by aquatic organisms.The mean pH values ranged from 7.831 ± 0.490.
Turbidity concentration was highest in monsoon with 30.2 NTU in August and lowest 15.2 NTU in January.Turbidity was highest in monsoon and low in winters with mean values ranging from 19.617 ± 4.113.It is attributed to the addition of sand particles in river waters due to monsoon rains.Similar findings were also recorded by Tali et al., 2012 who also observed fluctuations of turbidity in river Narmada at Maheshwar dam.
Alkalinity of water is its capacity to neutralize a strong acid and is characterized by presence of all hydroxyl ions capable of combining with hydrogen ions (Koshy and Nayar, 2000).Alkalinity ranged      The temporal succession of phytoplankton groups were noticed as Chlorophyceae>Cyanop hyceae>Bacillariophyceae>Euglenophyceae.27 species were identified of which Chlorophyceae were found most dominating having 2,827(47 %) taxa followed by Bacillariophyceae with 1400 (23 %) taxa, Cyanophyceae having 1658 (27 %) taxa and Euglenophyceae with 169 (3 %).(Fig. 2) shows percentage compositions of phytoplankton in river Narmada.The result indicated that phytoplankton was more during summers and low in winters and rainy seasons but no regular trend was observed.Our findings are in agreement to Dhimdhime et 1) and (Fig. 3) showing monthly variation in phytoplankton in river Narmada.Sharma et al., 2011 concluded the same results seasonal fluctuation in abundance of phytoplankton in river Narmada.Jafari and Alavi, 2010 observed similar result from Talar River Iran and concluded that phytoplankton appears and disappears without regularity.Murugesan and Sivasubramanian, 2008 observed enhanced growth of Chlorophytes during summer months.Rise in temperature during summers increase the rate of decomposition and also due to evaporation water becomes nutrient rich resulting in higher concentration of phytoplankton while low density during monsoon season can be attributed to heavy floods.

biotic Indices
Quantifying biodiversity is one of the most complicated aspects of biodiversity (Gaston and Spicer, 1998).The goal of using multiple indices is an attempt to describe the diversity of an ecosystem as accurately as possible.These indices attempt to define biodiversity in many different ways though most indices use a combination of number of species and the degree of difference between those species (Gaston and Spicer, 1998).The various diversity index used in present study gives species diversity of area studied.Diversity indices used in study provide important information about rarity and commonness of species in the area studied.The Shannon index gives information on statistic index, which means it assumes that all species are represented in a sample and that they are randomly sampled whereas Simpson index is a dominance index that are used mainly to quantify the biodiversity of habitat and gives more weight to common or dominant species.Margalef index is used to estimate the number of species to calculate diversity.The ability to quantify diversity in this way is an important tool to understand diversity of studied area.

the relationships between phytoplankton and physico-chemical parameters
Abiotic factors exer t a considerable influence on phytoplankton abundance and diversity (Das et al., 1996).
The study of correlation between water parameters and phytoplankton is useful in gaining basic knowledge of trophic status of a water body.In present study,the correlation between the phytoplankton and the physico-chemical variables in the surface water at the station was explored.The factors correlating with the composition of phytoplankton were water temperature, pH, turbidity, alkalinity and total hardness.Our result showed that there exist a positive correlation between phytoplankton and different water parameters thus indicating that the density of phyto-plankton is dependent on different abiotic factors either directly or indirectly.(Table 3) showing co-relation matrix of physico-chemical parameters and phytoplanktons of river Narmada at Hoshangabad from March 2010 to February 2012.
There are many detailed descriptions of phytoplankton succession being correlated with changes in environmental parameters particularly temperature, light, nutrients availability and mortality factors such as grazing and parasitism (Roelke and Buyukates, 2002).

table 1 :
monthly variation in phytoplankton density (units/l) in river Narmada, hoshangabad during march 2010

Fig. 1 :Fig. 2 :Fig. 3 :
Fig. 1: Showing monthly variation in water-parameters of river Narmada at hoshangabad (march 2010-February 2011) According toCabecadas and Brogueira, 1987 the growth and photosynthesis of algae are influenced by the pH and alkalinity of water.Pandey et al., 1995 observed a positive correlation between pH, dissolved oxygen, bicarbonate, phosphate and transparency.They reported a positive correlation between pH, dissolved oxygen, transparency and Chlorophyceae.Bhat and Pandit, 2005 found a close relationship between physico-chemical characters of water with growth and abundance of phytoplanktons.Senapati et al., 2001 also observed positive correlation between certain water parameters and phytoplankton from a semi-lentic water body at Burdwan West Bengal.Sharma and Singh, 2013 observed positive correlation of phytoplankton with water parameters.Suresh et al., 2013 studied a co-relation between physico-chemical parameters with phytoplankton and observed significant results.The diversity index used in present study for phytoplankton analysis would be an important step towards study of stress on biological data due to water parameters of the selected area of study.

table 3 : co-relation matrix of physico-chemical parameters and phytoplanktons of river Narmada at hoshangabad from march 2010-February 2012.
al., 2012; Suresh et al., 2013 and Chergui et al., 2013 who observed the highest phytoplankton concentration during summer months.The dominant group in each family are listed in (Table