Qualitative sampling of the flowered and fauna composing in a impermanent pool was carried out during the dry and showery seasons for two old ages. The flowered communities consist of Phytoplankton of which Blue-green algae and diatoms were the most prevailing and the macrophytes, which were classified into Emergent. Submerged and drifting workss. The Fauna communities include the Zooplankton with Daphnia na Cypris species being the most abundant, while the neustons, nektons and benthic division were besides sampled. The consequence of deposit, wet and humus contents of the substrate dirt on both workss and carnal life and the tactics employed by these beings to last drouth in the pool were besides investigated. Assorted ways by which resources of impermanent pools can be of benefit are discussed.
The survey of the functional relationship and productiveness of standing ( lentic ) freshwater biotic communities as they are affected by the kineticss of physical, chemical and biotic environmental parametric quantities forms the footing of the ecology of inland H2O otherwise known as limnology. Hydrobiological survey of impermanent H2O such as pools, paddocks and pools or big H2O organic structures such as lakesw, watercourses and rivers most frequently predict the class of biological events in such home grounds and by and large give an penetration into the composing and productiveness of the H2O.
An apprehension of the Community construction of a organic structure of H2O is dependent upon the ability to distinguish between species population alterations and fluctuations in spacial and temporal distribution ( Wetzel and Likens, 1998 ) . Changes in species composing and biomass may impact photosynthetic rates, assimilation efficiencies, rate of alimentary use, croping rates, productiveness and catch per attempt. Thus the cognition of species composing and copiousness in a organic structure of wter is indispensable for sustainable development, preservation and direction of such H2O organic structure. It besides helps for a better apprehension of the ecological interrelatednesss amongst the population of the community.
Several surveies have been conducted on the flowered and zoology of big H2O organic structures in Nigeria. These include Imevbore ( 1970 ) on Lake Kainji, Holden and Green ( 1960 ) on River Sokoto. and Egbore ( 1979 ) on River Oshun. Small attending has been paid to the Limnology and hydrobiology of seasonal impermanent H2O organic structures. This might be attributed to the fact that impermanent H2O occurs for a short clip to back up life and merely during the rainy season.
Biological surveies of beings in the impermanent pools start from the clip when the pool is dry. This is to detect the physiological and behavioral tactics employed by species in the pool to last drouth. Williams ( 1987 ) and Mclachan ( 1983 ) have reported a figure of physiological and behavioral tactics of beings of impermanent pools to last abiotic conditions during the dry season. In the rainy season, the distribution composing and copiousness of these beings is influenced by the temperature and alimentary degrees of the H2O harboring them ( Mulford and Norcross, 1971 ) .
The function of biotic community in Aquatic nutrient rhythm is known, their hurtful consequence on other beings in the H2O organic structure such as inordinate bloom which may do anoxia and mortality is besides known. These biological communities have been used in H2O quality analysis, biological indexs of pollution and to find the mean ecological conditions of H2O organic structures.
This paper hence aims at placing the organisms prevalent in a seasonal impermanent pool and the tactics they employ to last drouth in the pool. The survey besides intends to observe the consequence of dirt on the benthal beings. This will lend to the cognition of the ecology of being populating impermanent Waterss with a position of doing good usage of the species for learning, research and industrial intents.
Materials and Methods
The survey site
The impermanent pool is located on the South-Eastern side of the University of Ilorin, Kwara State. It is a shallow pool with a maximal length and breadth of 11m and 5m severally, 1.5m deep, surface country of 470.5m2 and volume of 611.75cm2.
The pool Si ever dry at the extremum of the dry season i.e. between December to February ; it becomes bit by bit filled with H2O with the oncoming of the rain in March. The pool is surrounded by hornblende biotite gneiss stone.
Collection of samples
Dry dirt samples were collected from two sites designated A and B ( A is on the Western terminal of the pool while B is on the Eastern side ) by delving 10cm into the substrate utilizing a manus trowel during the extremum of the dry season when the pool was devoid of H2O. The samples were collected into two Sns and taken to the research lab. Plankton samples were collected by brushing plankton cyberspace gently across the H2O surface, fixed and preserved in 4 % formol. The benthal beings were collected utilizing the new wave veen & A ; acirc ; ˆ™s bottom grabs. The contents poured on to a dissecting tray. The vascular rooted workss ( emergents ) , the submerged and drifting workss species were all collected by manus and set into a polyethylene bag where they were taken to the University of Ilorin Herbarium for designation.
Analysis of samples
Fixed plankton ( Phytoplankton and Zooplankton ) and fauna ( nektons and neustons ) samples were analyzed qualitatively by dividing them from one another and placing the being to generic degree utilizing the light microscope and appropriate texts. Their comparative copiousness was estimated by numbering the species in 50ml of the sub sample. The benthic division were recovered from the dirt utilizing a forceps, separated and identified up to Generic degree utilizing the binocular microscope and relevant texts. The aquatic macrophytes from different zones were identified to species degree at the University of Ilorin Herbarium.
Dirt analysis in the research lab
Flotation method ( Madge and Sharma, 1969 ) for extraction of works and animate beings life.
Deposit done by set uping a series of ranked screens on top of one another in diminishing order of mesh sizes and shaken exhaustively.
Gravirnetic method ( Brady, 1985 ) for finding of wet and humus contents.
The flotation experiment carried out on the dry dirt sample produced eggs, spores, cysts of assorted beings and seeds of aquatic macrophytes. Insects such as emmets, beetles and touchs were besides observed, while angleworm, nauplius larva and Chironomous larva were collected.
The fluctuation in the atom size composing of the dirt from the two sites is presented in Table 1. Locate A contains much of sand atoms and the type of sand found was the flaxen loamy.
Table 1: Atom size composing of the dirt from survey sites
The moiosture and umus content of the dirt is shown in Table 2. Site B has the higher wet and humus contents than site A. Site B is characterized with loamy sand dirt. A relationship exists between the wet and humus contents of the dirt. As the wet content additions, the humus contents besides increases and vice-versa.
Table 2: Moisture Humus contents of the dirts from survey sites
Features, Composition and copiousness of Zooplankton and zoologies, ( neustons, nektons and benthic division )
The zooplankton and fauna communities weresampled in the showery seasons. The zooplankton consisted chiefly of Daphnia. Bosmina and Cypris. 70 % of the zooplankton was Arthropod, the protozoa 20 % and Rotifers were represented by merely 2 % Genera ( Table 3 ) .
Table 3: Phytoplankton Composition and Abundance
The fauna communities were extremely diverse and consisted of Neustons which are beings associated with the surface movie of H2O, the Nektons are big swimming or glide animate beings and the benthic division which are organisms life on the bottom substrate. The Neustons were chiefly insects that lay their eggs among bunchs of aqutic flora. The Nektons collected were frog Rana sp. and H2O polo-neck Chresmy sp. that feed on the insect and strain in the H2O. The benthic division were extremely diverse and included worms in substrate debris. Table 4 shows the composing and copiousness of the zoology.
Features, Composition and Abundance of Phytoplankton and flowered ( Aquatic macrophytes )
The phytoplankton and flowered communities were sampled during the showery seasons. The Green algae ( Chlorophyceae ) was the most abundant phytoplankton category with 7 Genera while Euglenophyceae had least with 3 Genera. The Bacillariophyceae ( Diatoms ) were the most abundant in footings of figure ( Table 5 ) .
The flowered communities were divided into three based on the zones where they occur in the pool. The Emergents are rooted in the bottom qand grow to bring forth long sinuate foliages and flowers above the H2O surface. Three works species were found in this class. The submerged have their leaf rarely making the surface. They possess long slender stems with foliages.
Two works species occur as submerged and were non really many in the pool. The drifting foliage workss occur on the H2O surface. They were extremely abundant and explosive at certain periods that they cover the full surface of the pool. Eichhornia and pistia species were the lone natation workss identified in the pool ( Table 6 ) .
Organisms populating seasonal pools are known to last dry periods with the assistance of some versions ( Mclachan, 1983 ) . The presence of emmets, beetles, touchs and angleworm proved that these beings live active lives during the period of drouth in the pool. The formation of spores, eggs, cysts, and seeds is a mechanism employed by beings of the pool to last dry season. The presence of good loamy sand dirt particularly on site B, must hold promoted the endurance of the insects, angleworms, spores, cysts, eggs, and seeds. Edward ( 1968 ) and Amos ( 1969 ) reported that larvae of chironomous, Rotifers and protozoons survive in encystment phase and Algae survive in signifier of spores in dried-out stone pools and pools. Both moisture an humus contents of the dirt have a major consequence on the distribution and copiousness of benthal beings like Earthworm and beetles. The wet prevents dehydration and the organic affair ( humus ) serves as nutrient.
With the oncoming of the rains and subsequent implosion therapy of the pool, the spores, eggs, cysts and seeds either germinate, hatch or turn to give rise to the phytoplankton, zooplankton and flowered communities severally. The phytoplankton in this pool is extremely diverse and composed chiefly of algae. This agrees with Round ( 1973 ) who reported that pools frequently have a rich phytoplankton of mastigophorans such as Euglena Phacus and Scenedesmus. The eutrophic nature of the pool supported many of these mastigophorans. The stableness of the H2O column during the rains and conditions for commixture of H2O might besides be responsible for the high species diverseness of the phytoplankton as observed by Calijuri and Dos Santos ( 1996 ) in a little reservoir.
Table 4: Zooplankton Composition and Abundance
Table 5: The Fauna Communities in the Pond
Table 6: The Floral Communities in the Pond
There is a positive relationship between zooplankton and phytoplankton biomass as evident from the laterality of cladocerans amongst the zooplankton. McCauley and Kalff ( 1981 ) had already reported this type of relationship. The phytoplankton like diatoms which are the primary nutrient manufacturer in plankton rhythms, were extremely abundant, and they served as the primary nutrient beginning for the Zooplankton. Pizzolon et Al ( 1995 ) had already reported such laterality of Diatoms in Lake Futalanquen, Argentina during the rainy season. The absence of fish and the presence of big figure of phytoplankton contributed to the high population of Zooplankton particularly Daphnia. This has an advantage of assisting to command the algal biomass. Therefore predator-prey relationship exists in the pool.
The nature of the substrate and the handiness of nutrient supported a great figure of benthal species such as Libyodrilus and Tubifex. The high population of chironomous larva is typical of the features of benthal zoology of dead Waterss. The lentic and dead nature of the H2O provided a good genteelness and gliding surface for mosquitoes and neustons, like darning needle, pool skaters and H2O boat adult male. The nektons, toad and H2O polo-neck strain in the pool during the rains, while insects and the larvae service as nutrient for them.
The aquatic macrophytes are sites for egg laying by insects. The submersed frozen workss are beginnings of dissolved and organic compounds into the H2O as reported by Wetzel ( 1996 ) and Allen ( 1971 ) , while the parts of emergent flora such as Typha to productiveness is mostly indirect as debris. The natation works Eichhornia and Pistia frequently lead to deoxygenation and turbidness as a consequence of their explosiveness. Aquatic macrophytes can besides be used as indexs of H2O quality ( Urtans, 1995 ) .
The survey of the biotic communities of this seasonal pool, have shown that the pool is a microcosm that supported a big and diverse species of beings. The pool could be developed to a degree whereby the being in it are harvested and put into economic use.For illustration, diatomaceous earth used in industrial filtration, sugar refinement and brewing industries could be obtained from diatoms which are extremely abundant in the pool. Organic fertilisers, Agar, corrageenin and antibiotics could be obtained from Algae ( Round, 1973 ) . Water jacinth, Eichhornia can be formulated into carnal fresh fish while Zooplankton can be turned into fish pellets.