The aim of this study was to investigate the patterns of nematode diversity and community structure in San Jorge Gulf, Argentina, in order to improve knowledge of this key group of organisms. Free-living marine nematodes were sampled at 13 stations in February 2014 during an expedition aboard R/V Coriolis II. We found a total of 188 species (101 of which were new to science) belonging to 98 genera. The statistical results indicated the presence of three different assemblages of free-living marine nematodes distributed spatially in three distinct zones in the gulf: the central part, the outer thermal front at both sides of the entrance, and the south thermal front area. Diversity increased from the coast to the entrance of the gulf, and the highest diversity was found in areas with coarser sediment. Sediment and salinity were the environmental parameters that best matched nematode community distribution.

Pastor de Ward, C.T., V. Lo Russo, and M. Varisco. 2018. Free-living marine nematode communities in San Jorge Gulf, Argentina. Oceanography 31(4):113–121, https://doi.org/10.5670/oceanog.2018.415.

Supplementary Materials (1.2 MB pdf)

Acha, E.M., H.W. Mianzan, R.A. Guerreroa, M. Favero, and J. Bava. 2004. Marine fronts at the continental shelves of austral South America: Physical and ecological processes. Journal of Marine Systems 44:83– 105, https://doi.org/10.1016/​j.jmarsys.2003.09.005.
1. Akselman, R. 1996. Estudios ecológicos en el Golfo San Jorge y adyacencias (Atlántico sudoccidental). Distribución, abundancia y variación estacional del fitoplancton en relación a factores físico-químicos y la dinámica hidrológica. PhD thesis, Universidad de Buenos Aires, Buenos Aires, Argentina.
2. Albertó, E., R.A. Scrosati, and G.A. Díaz. 1993. Feeding of the shrimp Pleoticus muelleri (Crustacea, Decapoda) from the Gulf of San Jorge, Argentina. Gayana Zoología 57:279–284.
3. Balech, E., and M.D. Ehrlich. 2008. Esquema biogeográfico del Mar Argentino. Revista de Investigación y Desarrollo Pesquero 19:45–75.
4. Bett, B.J., A. Vanreusel, M. Vincx, T. Soltwedel, O. Pfannkuche, P.J.D. Lambshead, A.J. Gooday, T. Ferrero, and A. Dinet. 1994. Sampler bias in the quantitative study of deep-sea meiobenthos. Marine Ecology Progress Series 104:197–203, https://doi.org/10.3354/meps104197.
5. Bezerra, T.N., W. Decraemer, U. Eisendle-Flöckner, O. Holovachov, D. Leduc, D. Miljutin, J. Sharma, N. Smol, A. Tchesunov, V. Mokievsky, and others. 2018. NeMys: World Database of Free-Living Marine Nematodes. http://nemys.ugent.be/.
6. Bonaglia, S., F.J.A. Nascimento, M. Bartoli, I. Klawonn, and V. Brüchert. 2014. Meiofauna increases bacterial denitrification in marine sediments. Nature Communications 5:5133, https://doi.org/10.1038/ncomms6133.
7. Boschi, E.E. 1989. Biología Pesquera del Langostino del Litoral Patagónico de Argentina (Pleoticus muelleri). Instituto Nacional de Desarrollo Pesquero (INIDEP), Mar del Plata (Argentina), 72 pp.
8. Clarke, K.R., R.N. Gorley, P.J. Somerfield, and R.M. Warwick. 2014. Change in Marine Communities: An Approach to Statistical Analysis and Interpretation, 3rd ed. PRIMER-E Ltd., Plymouth Marine Laboratory, UK, 176 pp.
9. Danovaro, R., A. Tselepides, A. Otegui, and N. Della Croce. 2000. Dynamics of meiofaunal assemblages on the continental shelf and deep-sea sediments of the Cretan Sea (NE Mediterranean): Relationships with seasonal changes in food supply. Progress in Oceanography 46:367–400, https://doi.org/10.1016/S0079-6611(00)00026-4.
10. Diez, M.J., F. Tapella, M.C. Romero, A. Madirolas, and G.A. Lovrich. 2016. La langostilla Munida gregaria en el Mar Argentino: Biología e interés económico. El Mar Argentino y sus recursos pesqueros 6:213–228.
11. Fernández, M. 2006. Características físico-químicas de los sedimentos del Golfo San Jorge y su relación con los organismos bentónicos del sector. PhD Thesis, Universidad de Mar del Plata, Mar del Plata.
12. Fernández, M., J.I. Carreto, J. Mora, and A. Roux. 2006. Physico-chemical characterization of the benthic environment of the Golfo San Jorge, Argentina. Journal of the Marine Biological Association of the United Kingdom 85:1,317–1,328, https://doi.org/10.4067/S0718-19572007000200005.
13. Findlay, S., and K.R. Tenore. 1982. Effect of free-living marine nematode (Diplollaimella chitwoodi) on detrital carbon mineralization. Marine Ecology Progress Series 8:161–166, https://doi.org/10.3354/meps008161.
14. Galéron, J., M. Sibuet, M.L. Mahaut, and A. Dinet. 2000. Variation in structure and biomass of the benthic communities at three contrasting sites in the tropical Northeast Atlantic. Marine Ecology Progress Series 197:121–137, https://doi.org/​10.3354/meps197121.
15. Glembocki, N.G., G.N. Williams, M.E. Góngora, D.A. Gagliardini, and J.M. Orensanz. 2015. Synoptic oceanography of San Jorge Gulf (Argentina): A template for Patagonian red shrimp (Pleoticus muelleri) spatial dynamics. Journal of Sea Research 95:22–35, https://doi.org/10.1016/​j.seares.2014.10.011.
16. Góngora, M.E., D. González-Zevallos, A. Pettovello, and L. Mendía. 2012. Caracterización de las principales pesquerías del golfo San Jorge Patagonia, Argentina. Latin American Journal of Aquatic Research 40:1–11.
17. Kaminsky, J., M. Varisco, M. Fernández, R. Sahade, and P. Archambault. 2018. Spatial analysis of benthic functional biodiversity in San Jorge Gulf, Argentina. Oceanography 31(4):104–112, https://doi.org/10.5670/oceanog.2018.414.
18. Krock, B., C.M. Borel, F. Barrera, U. Tillmann, E. Fabro, G.O. Almandoz, M. Ferrario, J.E. Garzón Cardona, B.P. Koch, C. Alonso, and others. 2015. Analysis of the hydrographic conditions and cyst beds in the San Jorge Gulf, Argentina, that favor dinoflagellate population development including toxigenic species and their toxins. Journal of Marine Systems 148:86–100, https://doi.org/10.1016/​j.jmarsys.2015.01.006.
19. Leduc, D. 2013. Mudwigglus gen. n. (Nematoda: Diplopeltidae) from the continental slope of New Zealand, with description of three new species and notes on their distribution. Zootaxa 3682:351–370.
20. Lorenzen, S. 1994. The Phylogenetic Systematics of Free-living Nematodes. The Ray Society, Surrey, 383 pp.
21. Lovrich, G.A., and M. Thiel. 2011. Ecology, physiology, feeding and trophic role of squat lobsters. Pp. 183–222 in The Biology of Squat Lobsters. G.C.B. Poore, S.T. Ahyong, and J. Taylor, eds, CSIRO Publishing. Australia.
22. Moens, T., and M. Vincx. 1997. Observations on the feeding ecology of estuarine nematodes. Journal of the Marine Biological Association of the United Kingdom 77:211–227, https://doi.org/10.1017/S0025315400033889.
23. Moens, T., and M. Vincx. 2000. Temperature, salinity and food thresholds in two brackishwater bacterivorous nematode species: Assessing niches from food absorption and respiration experiments. Journal of Experimental Marine Biology and Ecology 243:137–154, https://doi.org/10.1016/S0022-0981(99)00114-8.
24. Mokievskii, V.O., A.A. Udalov, and A.I. Azovskii. 2007. Quantitative distribution of meiobenthos in deep-water zones of the World Ocean. Oceanology 47:797–813, https://doi.org/10.1134/S0001437007060057.
25. Montagna, P.A. 1995. Rates of metazoan meiofaunal microbivory: A review. Vie et Millieu 45:1–9.
26. Montagna, P.A., J.G. Baguley, C.-Y. Hsiang, and M.G. Reuscher. 2017. Comparison of sampling methods for deep-sea infauna. Limnology and Oceanography: Methods 15:166–183, https://doi.org/​10.1002/​lom3.10150.
27. Mureşan, M. 2012. Assessment of free-living marine nematodes community from the NW Romanian Black Sea shelf. Geo-Eco-Marina 18:133–145, https://doi.org/10.5281/zenodo.56876.
28. Nascimento, F.J.A., J. Näslund, and R. Elmgren. 2012. Meiofauna enhances organic matter mineralization in soft sediment ecosystems. Limnology and Oceanography 57:338–346, https://doi.org/​10.4319/lo.2012.57.1.0338.
29. Paparazzo, F.E., G.N. Williams, J.P. Pisoni, M. Solís, J.L. Esteves, and D.E. Varela. 2017. Linking phytoplankton nitrogen uptake, macronutrients and chlorophyll-a in SW Atlantic waters: The case of the Gulf of San Jorge, Argentina. Journal of Marine Systems 172:43–50, https://doi.org/10.1016/​j.jmarsys.2017.02.007.
30. Pape, E., T.N. Bezerra, D.O.B. Jones, and A. Vanreusel. 2013. Unravelling the environmental drivers of deep-sea nematode biodiversity and its relation with carbon mineralisation along a longitudinal primary productivity gradient. Biogeosciences 10:3,127–3,143, https://doi.org/​10.5194/bg-10-3127-2013.
31. Pastor de Ward, C.T. 1987. Aporte al conocimiento de los nematodos marinos libres de la Ría Deseado y áreas vecinas, provincia de Santa Cruz, Argentina. PhD Thesis. Universidad Nacional de Buenos Aires, Buenos Aires.
32. Pastor de Ward, C.T. 1998. Distribución espacial de nemátodos marinos libres de la ría Deseado, Santa Cruz (Patagonia, Argentina). Revista de Biología Marina y Oceanografía 33:291–311.
33. Pastor de Ward, C.T. 2003. Two new species of Sabatieria (Nematoda, Comesomatidae) from Golfo Nuevo, Chubut (Argentina). Zootaxa 172:1–12, https://doi.org/10.11646/zootaxa.172.1.1.
34. Pastor de Ward, C.T. 2004. New species of Hopperia (Nematoda, Comesomatidae) and Metachromadora (Nematoda, Desmodoridae) from Patagonia, Chubut, Argentina. Zootaxa 542:1–15, https://doi.org/10.11646/zootaxa.542.1.1.
35. Pastor de Ward, C.T., and V. Lo Russo. 2007. A review of the genus Richtersia (Nematoda: Selachinematidae): New species from Golfo San José and Golfo San Matías, Chubut (Argentina). Journal of the Marine Biological Association of the United Kingdom 87:1,153–1,160, https://doi.org/​10.1017/​S0025315407056755.
36. Pastor de Ward, C., V. Lo Russo, G. Villares, V. Milano, L. Miyashiro, and R. Mazzanti. 2015. Free-living marine nematodes from San Julián Bay (Santa Cruz, Argentina). ZooKeys 489:133–144, https://doi.org/​10.3897/​zookeys.489.7311.
37. Piola, A.R., and A.L. Rivas. 1997. Corrientes en la plataforma continental. Pp. 119–132 in El Mar Argentino y sus Recursos Pesqueros. E.E. Boschi, ed., Instituto Nacional de Investigaciones y Desarrollo Pesquero, Mar del Plata, República Argentina.
38. Platt, H.M., and R.M. Warwick. 1983. Freeliving Marine Nematodes: Part I. British Enoplids. The Linnean Society of London and the Estuarine & Brackish-Water Sciences Association, Bath, 316 pp.
39. Platt, H.M., and R.M. Warwick. 1988. Freeliving Marine Nematodes: Part II. British Chromadorids. The Linnean Society of London and the Estuarine & Brackish-Water Sciences Association, Avon, 502 pp.
40. Roux, A., R. Piñero, P. Moriondo, and M. Fernández. 2009. Diet of the red shrimp Pleoticus muelleri (Bate, 1888) in Patagonian fishing grounds, Argentine. Revista de Biología Marina y Oceanografía 44:775–781.
41. Sajan, S., T.V. Joydas, and R. Damodaran. 2010. Meiofauna of the western continental shelf of India, Arabian Sea. Estuarine, Coastal and Shelf Science 86:665–674, https://doi.org/10.1016/​j.ecss.2009.11.034.
42. Sargent, J.R., C.C.E. Hopkins, J.V. Seiring, and A. Youngson. 1983. Partial characterization of organic material in surface sediments from Balsfjorden, northern Norway, in relation to its origin and nutritional value for sediment-​ingesting animals. Marine Biology 76:87–94, https://doi.org/​10.1007/​BF00393059.
43. Schiemer, F., 1985. Bioenergetic niche differentiation of aquatic invertebrates. SIL Proceedings, 1922–2010 22(5):3,014–3,018, https://doi.org/10.1080/​03680770.1983.11897823.
44. Schiemer, F. 1987. Nematoda. Pp. 185–215 in Animal Energetics, vol. 1. J.F. Vernberg, and T.J. Pandian, eds, Academic Press, New York, London.
45. Smol, N., and A. Coomans. 2006. Order Enoplida. Pp. 225–292 in Freshwater Nematodes: Ecology and Taxonomy. E. Abebe, I. Andrássy, and W. Traunspurger, eds, CABI Publishing, Wallingford. United Kingdom.
46. Somerfield, P.F., and R.M. Warwick. 1996. Meiofauna in Marine Pollution Monitoring Programmes: A Laboratory Manual. Directorate of Fisheries Research (MAFF), Lowestoft, UK, 71 pp.
47. Tonini, M., E. Palma, and A. Rivas. 2006. Modelo de alta resolución de los golfos patagónicos. Mecánica Computacional 25:1,441–1,460.
48. Trett, M.W., B. Calvo Urbano, S.J. Forster, and S.P. Trett. 2009. Commercial aspects of the use of nematodes as bioindicators. Pp. 275–314 in Nematodes as Environmental Indicators. M.J. Wilson and T. Kakouli-Duarte, eds, CABI, Cornwall.
49. Vanaverbeke, J., M. Steyaert, K. Soetaert, V. Rousseau, D. Van Gansbeke, J.Y. Parent, and M. Vincx. 2004. Changes in structural and functional diversity of nematode communities during a spring phytoplankton bloom in the southern North Sea. Journal of Sea Research 52:281–292, https://doi.org/10.1016/j.seares.2004.02.004.
50. Varisco, M., and J.H. Vinuesa. 2007. La alimentación de Munida gregaria (Fabricius, 1793) (Crustacea: Anomura: Galatheidae) en fondos de pesca del Golfo San Jorge, Argentina. Revista de Biología Marina y Oceanografía 42(3):221–229.
51. Villares, G., V. Lo Russo, C. Pastor de Ward, V. Milano, L. Miyashiro, and R. Mazzanti. 2016. Free-living marine nematodes from San Antonio Bay (Río Negro, Argentina). ZooKeys 574:43–55, https://doi.org/​10.3897/​zookeys.574.7222.
52. Vinuesa J., and M. Varisco. 2007. Trophic ecology of the lobster krill Munida gregaria in San Jorge Gulf, Argentina. Investigaciones Marinas 35(2):25–34, https://doi.org/10.4067/S0717-71782007000200003.
53. Warwick, R.M., H.M. Platt, and P.J. Somerfield. 1998. Freeliving Marine Nematodes: Part III. Monhysterids. The Linnean Society of London and The Estuarine & Brackish-Water Sciences Association, Dorchester, 302 pp.
54. Wentworth, C.K. 1922. A scale of grade and class terms of clastic sediments. The Journal of Geology 30:377–392.
55. Wieser, W. 1953. Free-living marine nematodes I. Enoploidea. Acta Universitatis Lundensis N.F. 49:1–155.

This is an open access article made available under the terms of the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/), which permits use, sharing, adaptation, distribution, and reproduction in any medium or format as long as users cite the materials appropriately, provide a link to the Creative Commons license, and indicate the changes that were made to the original content. Images, animations, videos, or other third-party material used in articles are included in the Creative Commons license unless indicated otherwise in a credit line to the material. If the material is not included in the article’s Creative Commons license, users will need to obtain permission directly from the license holder to reproduce the material.