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Academic Year 2000-2001

Academic Year 2000-2001. BIODIVERSITY OF THE MEIOBENTHOS OF SANDY BEACHES IN ECU AD OR WITH EMPHASIS ON FREE-LIVING MARINE NEMATODES. By ALBA KATHERINE CALLES PROCEL Promotor Prof. Dr. MAGDA VINCX. AIM.

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Academic Year 2000-2001

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  1. Academic Year 2000-2001 BIODIVERSITY OF THE MEIOBENTHOS OF SANDY BEACHES IN ECUADOR WITH EMPHASIS ON FREE-LIVING MARINE NEMATODES ByALBA KATHERINE CALLES PROCELPromotorProf. Dr. MAGDA VINCX

  2. AIM • § To inventory the meiobenthos to higher taxa (Guayas province in Ecuador). • § To identify the nematode communities to genus level. • § To establish a relationship between the nematode and the environmental factors. • § To establish the value of meiofauna (nematodes) as bio-indicator of anthropogenic impact.

  3. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador AREA OF STUDY Position of Ecuador in South America Olon Cenaim Guayas Province San Pablo SanPablo Salinas Salinas Pacific Ocean Artesanal beach Playas Tourist beach Playas N N Tourist/Artesanal beach

  4. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador SANDY BEACHES • Salinas and Playas are recreational beaches, during weekends and holidays. SALINAS • San Pablo and Cenaim are lesser disturbed, except for the ongoing local artisanal fishery activities SAN PABLO

  5. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador METHODOLOGY Sampling: Four replicates; during low tide level; cores of 3.2 diameter. Fixation: 4% formalin. Extraction: Decantation (ten times) and centrifugation (three times) with LUDOX (1.18 density).

  6. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador METHODOLOGY (Laboratory) Paraffin is melted and the slide is sealed (COBB SLIDE, 1917) Glycerol-ethanol (DE GRISSE, 1969b) Counting meiofauna and pick up nematodes COUNTING MOUNTING

  7. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS

  8. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS

  9. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Sediment analysis

  10. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Densities of meiofauna (ind./10 cm2)

  11. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Composition of meiofauna taxa

  12. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS A total of 19 genera belonging to 14 families identified Nematoda Genus diversity-indices (Hill’s numbers)

  13. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS k-dominance curve for the nematode genera

  14. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Relative abundance of nematode feeding type(according to Wieser)per station %

  15. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Relative abundance of nematode structure per station

  16. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS TWINSPAN dendrogram based on the abundance (%) of nematode genera (Cut level: 0, 2, 5, 10 and 20) GENERA Gonionchus Odontanticoma Sabatiera Halalaimus Playas (A) Playas (B) Salinas (A) Salinas (B) Olon I (A) Olon I (B) Cenaim (A) Cenaim (B) San Pablo (A) San Pablo (B)

  17. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS

  18. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador RESULTS Metadesmolaimus plot per station Paracyatholaimus plot per station

  19. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador Gonionchus sp. n. Six lips very high and weakly cuticularized Amphid circular Longitudinal ornamentation (as rod-like structures)

  20. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador Gonionchus sp. n. Longitudinal ornamentation starts at irregular levels in the cervical region and go throughout the whole body length. Protrusion of the spicules

  21. Biodiversity of Meiobenthos with emphasis on Free-Living Marine Nematodes/Ecuador • CONCLUSION • Meiofauna: highest density Cenaim (2226-2544 ind./10 cm2) • lowest density Salinas (349-558 ind./10 cm2) • Chlorophyll a, SPM and POM (Salinas and Olon) meiofauna density • NEMATODES: 312-2398 ind./10cm2 87% of meiofauna • Gastrotricha: second most dominant taxon of meiofauna; mainly in Playas (324-389 ind./10 cm2) • Diversity: higher in Playas B, (N0= 14); lowest in San Pablo, (N0=6) • nematode density (Playas= 614, S. Pablo= 2190 ind./10cm2). • HIGHESTdiversity LOWEST density • Description of one new species of Gonionchus

  22. THE END

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