AMBIVALENCES OF A CRUDE OIL SPILL ON THE PLANKTONIC COASTAL COMMUNITIES.

Sébastien Putzeys1, Myriam Juárez1, Sonia P Valencia Agami2, Román Ochoa Rosado3, Victor P Ceja4, Luis P Cetina4, Sara P Morales Ojeda1, Ana Aguilar5, Giuliana Cruz5, Israel Medina1, Oswaldo González6, Rosa Canul Puc7, José-Andres Martínez3, Abril Gamboa6, Rubén Raygosa6, Manuel Eduardo Martínez-Cruz8, Yuri B. Okolodkov8, Flor Arcega Cabrera9, Leopoldina Aguirre10, Daniel Pech3 and Jorge Herrera-Silveira11, (1)CINVESTAV-IPN, Recursos del Mar - Primary production Laboratory, Merida, YC, Mexico, (2)CINVESTAV-IPN, Recursos del Mar - Microbiology Laboratory, Merida, YC, Mexico, (3)El Colegio de la Frontera Sur, Laboratorio de Biodiversidad Marina y Cambio Climático, Campeche, CP, Mexico, (4)CINVESTAV-IPN, Biogeoquimica, Merida, YC, Mexico, (5)CINVESTAV-IPN, YC, Mexico, (6)CINVESTAV-IPN, Recursos del Mar, Merida, YC, Mexico, (7)CINVESTAV-IPN, Recursos del mar - Microbiology Laboratory, Merida, YC, Mexico, (8)Universidad Veracruzana, Instituto de Ciencias Marinas y Pesquerías - Laboratorio de Botánica Marina y Planctología, Boca del Río, VL, Mexico, (9)Universidad Autónoma de Mexico, Facultad de Química de la Universidad Autónoma de Mexico (UNAM). Unidad de Química en Sisal, Sisal, YC, Mexico, (10)CINVESTAV Unidad Merida, Recursos Marinos, Merida, YC, Mexico, (11)Centro de Investigacion y de Estudios Avanzados, Unidad Merida, Merida, Yucatan, YC, Mexico
Abstract:
The direct effects of light crude oil on the marine planktonic community were studied using a mesocosm experiment. The experimental design consisted of twelve experimental units (9 treatments and three controls) of 2.5 m3 capacity each, filled up with seawater. The treatments consisted of three different concentrations of light crude oil in triplicate (10, 40 and 80 ppm respectively). Chlorophyll a content, phytoplankton richness, abundance of cultivable bacteria, hydrocarbon concentrations, as well as physicochemical parameters were monitored for ten days. At the beginning of the experiment and without initial fertilization, a phytoplanktonic bloom occurred in the twelve units of the system. Despite the crude oil contamination, the contaminated units showed significantly higher concentrations of chlorophyll a (between 3.6 ± 0.59 and 5.24 ± 0.33 mg·L-1) compared to controls (2.76 ± 0.36 mg·L-1). The relationship between hydrocarbonoclasts and heterotrophic bacteria showed an increase in the relative abundance of hydrocarbonoclast bacteria four days after the oil was added to the units. The rm-ANOVA analyzes showed that the presence of light crude oil has a significant effect on physicochemical parameters such as irradiance, temperature, and salinity. The rm-ANOVA also indicates that the taxonomic composition and size structure of the phytoplankton community is significantly altered in contaminated tanks versus controls. Despite the low concentrations of light crude oil, we observed that the planktonic communities studied are significantly susceptible to the presence of hydrocarbons, being the most notable structural and taxonomic changes.

Acknowledgments: Research funded by the National Council of Science and Technology of Mexico - Secretariat of Energy -Hidrocarbons Trust project 201441. This is a contribution of the Gulf of Mexico Research Consortium (CIGoM).

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