Located along the Pacific coast of Costa Rica between 8°22' N and 8°45' N, Golfo Dulce is considered one of only four tropical fiords in the world (Toft & Larsen 2009). The curved embayment, situated between the Osa Peninsula and the mainland, is approximately 50 km in length and 10–15 km wide. It receives fresh water discharge from four main rivers: Rincon, Esquinas, Tigre and Coto Colorado (Svendsen et al. 2006). The inner basin, of tectonic origin and occasionally anoxic (Hebbeln & Cortés 2001), reaches 215 m in depth and is contained by a ~60 m sill, which prevents free exchange with the Pacific water masses (Svendsen et al. 2006). Sediments inside the Gulf already show anthropogenic contamination (Spongberg 2004).


Dalsgaard T., D.E. Canfield, J. Petersen, B. Thamdrup, and J. Acuña-González. 2003. N2 production by the anammox reaction in the anoxic water column of Golfo Dulce, Costa Rica. Nature 422:606-608. [link]

Hebbeln, D., and J. Cortés. 2001. Sedimentation in a tropical fiord: Golfo Dulce, Costa Rica. Geo-Marine Letters 20:142–148. [link]

Lei, Z. 2002. Marine coastal dynamics and primary production response in Golfo Dulce, Costa Rica: A multi-sensor satellite approach. Thesis, Master of Science, Geoinformation to Coastal Zone Studies, International Institute for Geoinformation Science and Earth Observation, Enschede, The Netherlands. [link]

Morales-Ramírez, Á., J. Acuña-González, O. Lizano, E. Alfaro, and E. Gómez. 2015. Rasgos oceanográficos en el Golfo Dulce, Pacífico de Costa Rica: una revisión para la toma de decisiones en conservación marina. Revista de Biología Tropical 63(Supl.1):131-160. [link]

Quesada-Alpízar, M.A. and A. Morales-Ramírez. 2004. Comportamiento de las masas de agua en el Golfo Dulce, Costa Rica durante El Niño (1997 - 1998). Revista de Biología Tropical 52: 95–103. [link]

Rincón-Alejos, F., and D. Ballestero-Sakson. 2015. Hidrografía y plumas estuarinas en Golfo Dulce, Pacífico sur de Costa Rica. Revista de Biología Tropical 63(Supl.1):161-181. [link not yet available]

Silva, A.M., and J. Acuña-Gonzáles. 2006. Caracterización físico-química de dos estuarios en la bahía de Golfito, Golfo Dulce, Pacífico de Costa Rica. Revista de Biología Tropical 54:241-256. [link]

Spongberg, A. 2004. PCB contamination in marine sediments from Golfo Dulce, Pacific coast of Costa Rica. Revista de Biología Tropical 52:23–32. [link]

Svendsen, H., R. Rosland, S. Myking, J.A. Vargas, O.G. Lizano, and E.J. Alfaro. 2006. A physical-oceanographic study of Golfo Dulce, Costa Rica. Revista de Biología Tropical 54:147–170. [link]

Thamdrup, B., D.E. Canfield, T.G. Ferdelman, R.N. Glud, and J.K. Gundersen. 1996. A biogeochemical survey of the anoxic basin Golfo Dulce, Costa Rica. Reconocimiento biogeoquímico de la cuenca anóxica del Golfo Dulce, Costa Rica. Revista de Biología Tropical 44:19–33. [link]

Umana V, G. 1998. Characterization of some Golfo Dulce drainage basin rivers (Costa Rica). Revista de Biología Tropical 46(Supl.6):125·135. [link]

Wolff M., H.J. Hartman, and V. Koch. 1996. A pilot trophic model for Golfo Dulce, a tropical fjord-like embayment, Costa Rica. Revista de Biología Tropical 44:215–231. [link]

Scientific Reports & Posters

Molina-Bustamante, C., and L. Crowder. 2014. Dimensión Humana de los Ecosistemas Marinos de la Región de Osa y Golfito. Stanford Woods Institute for the Environment, Iniciativa Osa y Golfito (INOGO). [link]

Other Links

Toft, R., T. Larsen. 2009. Osa: Where the Rainforest Meets the Sea. Zona Tropical Publications, Costa Rica, 222 pp. [link]