Hindawi Publishing Corporation Advances in Ecology Volume 2014, Article ID 138360, 9 pages http://dx.doi.org/10.1155/2014/138360 Research Article Distribution and Diversity of Oligochaetes in Selected Ponds of Thiruvananthapuram District, Kerala, South India M. S. Ragi and D. S. Jaya Department of Environmental Sciences, University of Kerala, Kariavattom Campus, Thiruvananthapuram, Kerala 695 581, India Correspondence should be addressed to M. S. Ragi; [email protected] Received 4 April 2014; Revised 19 June 2014; Accepted 30 June 2014; Published 17 July 2014 Academic Editor: Junbao Yu Copyright © 2014 M. S. Ragi and D. S. Jaya. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The present study was carried out to evaluate the distribution and diversity of oligochaete fauna in selected pondsof Thiruvananthapuram district in Kerala, South India. The sediment samples were collected from three ponds seasonally during the period December 2006 to November 2008. In the study, 10 oligochaete species which belong to 8 genera were identified in three selected ponds. These include Dero digitata, Dero nivea, Dero obtusa, Pristina longiseta, Aulophorus furcatus, Stylaria fossularis, Chaetogaster spp., Aeolosoma spp., Tubifex tubifex and Limnodrilus hoffmeisteri. Tubifex tubifex and Limnodrilus hoffmeisteri are the pollution-indicator oligochaete species identified in the fresh water ponds, which reveals that the studied ponds are subjected to pollution. 1. Introduction 2. Methods Oligochaetes, a subclass of Clitellata, in phylum Annelida, 2.1. Study Area. The present study was carried out in three have a worldwide distribution and are the most abundant perennial ponds situated at different locations in Thiruvanan- benthic organisms in many fresh water ecosystems [1]. thapuram District, Kerala state, the southern part of India Oligochaetes are used in biodiversity studies, pollution sur- (Figure 1). It include the temple pond (P1) situated near veys, and environmental assessment and they have economic Rishimangalam temple and two public ponds, one situated importance [2]. Oligochaetes in general have wide geograph- in Muttacaud (P2) and the other one in Vilappilsala (P3). ical distribution patterns [3] and their populations can some- The period of study was from December 2006 to November time reach large numbers [1]. Many species prefer eutrophic 2008, in the postmonsoon (PM), premonsoon (PRM), and monsoon (MON) seasons. waters and living on muddy sediments with abundant detrital ∘ Pond1(P1)issituatedin829 46.07 Nlatitudeand organic matter [4]. ∘ The fauna of aquatic oligochaeta from India has been 76 56 28.31 E longitude, 1.5 km away from Thiruvanantha- puram Central Railway station, and is in the premises of studied and identified by many scientists [5–14]. Among the 2 main taxonomic groups present in the most benthic macro Rishimangalam temple, with an area of 1100 m and depth invertebrate communities, the oligochaetes are common and 226cm.Waterinthispondisusedforbathingandwashing abundant, and some species are considered good bioindi- clothes. Also the wastes from nearby hospital and houses areusuallydumpedinthesurroundingsofthispond. cators, particularly for the assessment of trophic state and ∘ ∘ organic pollution in water bodies [15]. Pond 2 (P2) is located in 8 24 5 Nlatitudeand7659 15 E The literature survey shows that the work performed by longitude, 13 km away from Thiruvananthapuram Central 2 various authors on aquatic oligochaeta in water bodies of Railway station and covering an area of 1400 m and depth Kerala state, India, was meager. The major objective of the 230 cm. Residents in the nearby areas use the pond water for present study is to determine the diversity and distribution of irrigation, bathing, and other domestic purposes. Pond 3 (P3) ∘ ∘ oligochaeta fauna and its seasonal variations in three selected is located in 8 31 15 Nlatitudeand7702 43 Elongitude, ponds of Thiruvananthapuram district, South India. 19 km away from the Thiruvananthapuram Central Railway 2 Advances in Ecology ∘ ∘ ∘ ∘ 76 40 0 E 76 50 0 E 77 0 0 E 77 10 0 E N KERALA Thiruvananthapuram district + + + + + N N +++ + + + + + + + + ++ 0 0 50 50 ∘ ∘ 8 8 N N 0 0 40 40 ∘ ∘ 8 8 Vilappilsala (P3) N N 0 0 30 30 ∘ ∘ 8 Rishimangalam (P1) 8 Muttacaud (P2) N N 0 0 20 (km) 20 ∘ ∘ 8 10 50 10 8 ∘ ∘ ∘ ∘ 76 40 0 E 76 50 0 E 77 0 0 E 77 10 0 E ∗ Locations District boundary Figure 1: Map showing location of ponds in study area. 2 station and with an area of 1300 m and depth 218 cm. drops of lactic acid. Photomicrographs of oligochaetes were This pond water is extensively used by public for irrigation, taken using a compound microscope fitted with a digital washing clothes, bathing, and cattle wash. camera. Drawings were made using a camera lucida and identification of oligochaeta to species/genus level was done according to the taxonomic criteria adopted by Brinkhurst 2.2. Methodology. Surface sediment samples were collected [17] and Ward and Whipple [18]. from four different sites of the selected ponds. Sampling The species diversity was calculated using the formula was done between 6.00 am and 9.00 am. Sediment samples provided by Shannon and Weaver [19],whichisasfollows: were collected with a PVC made tubular corer (5 cm in diameter), inserted into the sediment at a depth of about =−Σ ln , (1) 10 cm. Four replicate sediment samples from each pond =1 were also taken, and oligochaete distribution was studied. Thesampleswerewashedthroughasieveof0.2mmmesh where (200 m) in diameter, and the worms were sorted manually by diluting small portions of the sediment residue in a petri is the species diversity index. dish. A subsample of 100 mL was taken and oligochaetes were is the number of species. sorted out using a long dropper with the help of monocular ordinary dissection microscope (Olympus, Japan). Counting is the proportion of individuals of each species. of oligochaetes was done using a Compound microscope (Olympus, Japan). All organisms were counted according to 3. Results the procedure described by Welch [16]. With the help of a dissection microscope, the worms were picked with pincers 3.1. Oligochaeta Identification. In this study, altogether 10 and preserved in 10% formalin in separately labeled vials. The oligochaete species were identified, which include taxa with worms preserved in 10% formalin were cleared with a few wide ecological tolerances. Advances in Ecology 3 20 m 20 m 10 100 m m 20 m 10 m (a) (b) (c) (d) (e) (f) Figure 2: (a–d) Dero digitata: (a) posterior end, (b) ventral anterior chaetae, (c) ventral posterior chaetae, and (d) needle chaetae. (e-f) Dero nivea: (e) ventral chaetae and (f) needle chaetae. Seven species from Naididae, two species from Tubifici- are absent. Prostomium is short and conical; the branchial dae, and one species from Aeolosomatidae were identified fossa prolonged posteriorly. Three pairs of gills are on pos- from the studied ponds. The identified species include Tubifex terior end (usually only 2 pairs seen, 3rd is reduced). Dorsal tubifex Muller,¨ 1774, Limnodrilus hoffmeisteri Claparede, chaetal bundles start in segment VI onwards, consisting 1862, Stylaria fossularis Linnaeus, 1967, Pristina longiseta of one smooth hair and one weakly curved bifid needle. Ehrenberg, 1828, Dero digitata Muller,¨ 1774, Dero nivea Teeth of dorsal chaetae are of equal length. Ventral chaetae Aiyer, 1929, Dero obtusa d’Udekem, 1885, Aulophorus furcatus in segments II–V are different from those of the rest of Muller,¨ 1773, Aeolosoma spp. Ehrenberg, 1828, and Chaeto- segments, with the upper tooth twice being as long as the gaster spp. Von Baer, 1827. lower, while posteriorly the teeth are of about equal length and the lower teeth are slightly thicker, or the upper teeth are slightly shorter than the lower ones. Anterior ventral chaetae 3.2. Taxonomical Description is of 65–84 minlength. Family: Naididae (3) Dero obtusa d’Udekem, 1885 (1) Dero Digitata Muller,¨ 1774 (Figures 2(a)–2(d)) Morphological Observations. Two ventral and one lateral pairs Morphological Observations. D. digitata is one of the most of gills. A single crochet in each dorsal bundle, with the teeth common species of Naididae oligochaetes. It is an elongated, being equal in length, anterior ventral chaetae with extremely segmented worm, ranging in size from 6 to 32 mm, and thin teeth, and posterior ventral chaetae with very short teeth. weighing around 0.06 mg. The anterior part is formed by fiveventralchaetaebearingsegments,plusacone-shaped (4) Aulophorus furcatus Muller,¨ 1774 (Figures 3(e)–3(g) and prostomium and small peristomium. It has no eyes. Dorsal 5(e)) bundles from VI, with 1 hair and 1 needle. The distal tooth of Morphological Observations.Prostomiumisbluntlyconical. the needles are longer than the proximal. Ventral chaetae 4-5 Dorsal chaetae begin from V with 1 hair and 1 bifid needle in II–V with distal teeth are longer than the proximal. From chaetae. Ventral chaetae 3–5 per bundle exist; in anterior VI onwards, ventral chaetae 2–4 with distal and proximal bundles, upper tooth are slightly longer, decreasing to 2- teetharealmostequal.Branchialfossaiswith4pairsofgills. 3 posteriorly. Branchial fossa is cup-shaped with a pair of The presence of 1 hair and 1 needle in the dorsal bundle is a noncontractile palps and 3 pairs of gills. characteristic