Effects of marine oil pollution on microbial diversity in coastal waters and stimulating indigenous microorganism bioremediation with nutrients

Abstract

Marine oil spill brings disaster to coastal waters, whereas indigenous microorganisms remedy oil pollution. Nutrients such as nitrogen and phosphorus are necessary for the biodegradation of oil pollution. This study investigates the effects of different concentrations of marine oil spill on indigenous microorganisms in coastal waters under different nutrient concentrations. The degradation efficiency of 10.00 g/L crude oil with 0.02 and 2.00 g/L of nutrients added increased by 76.92% and 115.38%, respectively, compared with that of 10.00 g/L crude oil without nutrients added. The degradation efficiency of 0.01 g/L crude oil with 0.02 and 2.00 g/L of nutrients added increased by 20.39% and 23.99%, respectively, compared with that of 0.01 g/L crude oil without nutrients added. Sequencing results showed that 10.00 g/L crude oil reduced bacterial and fungal richness as well as fungal diversity, but increased bacterial diversity. The 0.01 g/L crude oil increased the richness and diversity of bacteria but decreased those of fungi. In addition, the dominant genera in 0.01 g/L crude oil were no-rank Methylophagaceae and unclassified fungi. The dominant genera after adding 0.02 g/L of nutrients were Ralstonia and Alternaria, and unclassified fungi was the dominant genus after adding 2.00 g/L of nutrients. Fungi played a major role in 0.01 g/L crude oil degradation with 2.00 g/L of nutrients added. The dominant genera in 10.00 g/L crude oil were Marivita and unclassified fungi, whereas the dominant genera after adding 0.02 and 2.00 g/L of nutrients were Litoribacillus and unclassified fungi, and Parvibaculum and unclassified Ophiostomataceae, respectively. Parvibaculum was mostly abundant in 10.00 g/L crude oil degradation with 2.00 g/L of nutrients added. The abundance of unclassified fungi in the 10.00 g/L crude oil decreased with the increase in nutrient concentration. Fungi mainly populated the crude oil with 2.00 g/L of nutrients after 14 days of cultivation.