HR: 1400h
AN: OS23B-14    [Abstracts]
TI: Morphological Phytoplankton Groups and Trophic State of Topolobampo-Santa Maria-Ohuira, Sinaloa, México
AU: * Ayala, G
EM: gayalar0500@ipn.mx
AF: Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Av. Instituto Politécnico Nacional s/n Col. Playa Palo de Santa Rita, La Paz, BCS 23096, Mexico
AU: Martínez-López, A
EM: amartin@ipn.mx
AF: Centro Interdisciplinario de Ciencias Marinas (CICIMAR-IPN), Av. Instituto Politécnico Nacional s/n Col. Playa Palo de Santa Rita, La Paz, BCS 23096, Mexico
AU: Escobedo-Urías, D C
EM: durias@ipn.mx
AF: Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional Unidad Sinaloa (IPN-CIIDIR Sinaloa), Juan de Dios Bátiz Paredes No. 250, Guasave, SIN 81101, Mexico
AB: Topolobampo-Santa Maria-Ohuira Lagoon Complex in the Gulf of California presents intense anthropogenic activities, such as agricultural with the drainage of nutrient enriched waters into the system, which affects on its health and integrity have been not evaluated before. Monthly data of physical-chemical variables and phytoplankton from November 2004 to February 2006 were used to define the actual trophic state of the lagoons by means of a trophic index (TRIX), and its imprint on the Morphological Phytoplankton Groups. From the analysis of data distinctive responses were observed for each lagoon. Trophic state and phytoplankton dynamic apparently were determinate by differences in hydrodynamics in each lagoon. Santa Maria lagoon showed higher trophic index values followed by Ohuira and Topolobampo. The phytoplankton community dominated for nannophytoplankton was regulated by nitrogen along the year in the entire lagoon system. However, the relationship between phytoplankton and physical-chemical variables examined by multivariate analysis indicated that in Santa Maria, nutrients from the runoff of fertilizers at the beginning of the fall/winter agriculture cycle influenced the occurrence of diatoms Harmful Algae Blooms (HABs), while in Ohuira higher water residence times have major regulatory effects on a large number of HABs of cyanobacteria and dinoflagellates and a lower Trophic state. A minor grade of affectation in Topolobampo lagoon is suggested by a dominance of the seasonality, a lower water residence times, and non HABs incidence during the period of this study.
DE: 0470 Nutrients and nutrient cycling (4845, 4850)
DE: 4845 Nutrients and nutrient cycling (0470, 1050)
DE: 4850 Marine organic chemistry (0470, 1050)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly