Publisher : University of the Philippines Visayas
Place of publication : Miagao,Iloilo,Philippines
Publication year : 2008
Thematic : Natural Sciences
Language : English
Note
This study was conducted to evaluate the diversity of free-living marine nematodes. This investigate the density and diversity of nematodes in the mangrove forest of Kopiat Island, Compostela Valley Province, Philippines.
Sediment samples were collected from three different sites of the intertidal zone. These were subdivided into five vertical depths (0-1, 1-2, 2-3, 3-4, and 4-5 cm) using 3.4 cm internal diameter sampling corer. Meiobenthos taxa were extracted through decantation and sieving technique. Meiobenthic taxa were examined under a stereomicroscope and the most abundant metazoan taxon was picked out and fixed in De Grisse solution and mounted. Nematodes were identified into the lowest possible level.
Nematodes were the most abundant metazoan taxon comprising 93.90% in all sediments sampled. Other dominant groups lower than 5% were copepods, polychaetes, olygochaetes, and ostracods.
Forty five (45) free-living nematode genera belonging to 14 families and orders were identified. Spirinia (Desmodoridae) has the highest relative density of the identified genera in all sites and layers accounting to 27.9% of the total population. This was followed by Paracanthoncus (Cyatholaimidae) and Paramonohysteria (Xyalidae) with percentage population of 16.5% and 10.7%, respectively. Other abundant taxa were unknown genera 2, unknown genera 1, Eumorpholaimus (Linhominidae) and Graphonema (Chromadoridae) account to 8.33%, 3.61%, 3.30%, and 3.25% respectively. Other genera were less than 3%.
Nematode communities in terms of density and diversity showed that it does not vary significantly in all sampling sites. However, sediment depth or vertical distribution was determined to have significant differences. A sharp decline in density and diversity with depth was observed from the surface sediment down to the 3 cm depth. In deeper sediments, nematode communities were different. Spatial distance in meter scale between sites set in this study was not enough to cause significant differences on the nematode density and diversity.
The study of nematode diversity in this mangrove area can offer relevant information on the current status of the island as well as its mangrove areas in terms of free-living nematodes and results of this study may be useful in formulating management guidelines for this habitat.
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Encoded by : Mae Belen Llanza
