Initial assessment of fungal population at various sites in Guimaras after the Solar I Oil Spill


by: *Resurreccion B. Sadaba, Erl Flores and Andrea Panilla


Many tropical environments areas are being heavily disturbed by human activity such as the marine environment. They have been a subject to contamination by organic pollutants from a variety of sources including accidental oil spills. On August 11,2006, M/T Solar I chartered by Petron sunk off the coast of Southern Guimaras released more than two million liters of Bunker C oil into the sea and affected diverse coastal habitats and ecosystems with considerable environmental damage. There is a little information on the effect of disturbance on fungi in tropical coastal ecosystems such as sandy beaches and mangroves which are habitats distinctive to the tropics. This study, therefore, examined the effects of the oil spill on the fungal diversity and density among the contaminated sites in the southern part of the island of Guimaras, Philippines within two months after the spill. The initial assessment was conducted on October 11, 2006 at eight sites were selected composed of six oil-contaminated sites and two from in-contaminated areas that served as control. Samples obtained were composed of one beach water sample and three soil samples. Yeasts and filamentous fungi were examined by macroscopic and microscopic observation of colonies. Identification was based on available keys and monographs. Majority of species isolated were mitosporic and typical soil fungi which are terrestrial in origin but are considered as facultative marine fungi. There are more fungal isolates at oil-contaminated sites than un-contaminated sites at 23 and 13 species, respectively as well as a higher Shannon Index of Diversity (H`) at 1.248 and 1.039, respectively. Among the filamentous fungi, nine genera were represented by Aspergillus, Aureobasidium, Cladosporium, Memnoniella, Monilia, Mucor, Penicillium, Pestalotia and Sporothrix. There was allow index of similarity of species composition between oil-contaminated and un-contaminated sites as shown by Jaccard’s coefficient of similarity (J = 0.40) and Sorensen coefficient of similarity: C = 0.57. All samples from oil-contaminated sites yielded a higher diversity and evenness of fungi compared with un-contaminated sites based on the Index of Diversity consistent with the overall trend of fungal occurrences. It appears that most of the oil-contaminated sites particularly beach and mangrove surface soil samples at Taklong Island exhibited a much higher fungal load compared with the un-contaminated sites that could possibly be attributed to the presence of oil in areas that favored their growth. This study provided some evidences on the short-term impacts in terms of change in fungal assemblages and density. Although the report is not conclusive considering the absence of pre-spill data and variability between months or year, the evidence indicates that there was disturbance brought about by the oil. Thus, the need for a long-term monitoring program to examine the effects of oil in these areas to determine recovery and re-instatement of normal fungal flora.

Keywords:Oil spill, marine fungi, bioremediation