Marine protists are single-celled planktonic creatures that form the base of the marine food web and perform important ecosystem services, including driving photosynthesis and the carbon and nitrogen cycles. Protist communities include energy-producing organisms, such as phytoplankton, that use sunlight or chemical reactions to generate their own food. Protists also include predators, such as microzooplankton, that eat the energy-producing protists.
Scientists conducted laboratory experiments to learn more about particle emissions when bubbles on an oil slick burst. They observed that bubbles bursting on slicks containing crude oil and dispersant mixtures aerosolize micro-sized droplets (diameter is one thousandth of a millimeter) and nano-sized droplets (diameter is one billionth of a meter). In ambient air, there is a tenfold increase in the concentration of submicron-sized droplets (<one millionth of a meter) when large bubbles (>500 μm) burst on slicks containing dispersants. These results
Interview by Alasdair Matheson, Editor-in-Chief, LCGC Europe
Q. You recently developed a method using ramped pyrolysis-gas chromatography–mass (Py-GC– MS) spectrometry to analyze petroleum pollution related to the Deepwater Horizon oil spill (1). How did this project arise?
A: Understanding the chemical composition of oil residues is essential for the oil-spill community, response team, and decision makers because the chemistry is related to evaluating toxicity of oil in environments and developing the appropriate response and remediation strategies. The traditional
Scientists generated breaking waves in the presence of various dispersant and oil ratios (DOR) using a custom-built wave tank to investigate how subsurface oil droplets evolve in a turbulent environment. The experiments showed that initially (first 10
Scientists isolated bacteria from Gulf of Mexico surface waters and used them in microcosm experiments to identify those that simultaneously degrade oil and produce mucus-like materials (exopolymeric substances or EPS). Using 16S rRNA gene analysis, they identified Alteromonas and Thalassospira as the main bacteria species that produce EPS when consuming oil and/or dispersed oil. When the microbes consumed oil in the presence of Corexit, the EPS they produced had a higher protein-to-carbohydrate ratio (a 5- to 20-fold increase in protein) than oil-
Oil-water interfaces, such as those formed by marine oil spills or natural ocean oil seeps, are teeming with bacterial activity. Some bacterial species in those interfaces form biofilms that help break up oil, which enhances biodegradation. The interfaces themselves can also significantly influence how bacteria behave, often trapping them or altering their natural movements.
Scientists conducted field and laboratory experiments using oil and Corexit dispersant to uncover the reasons harmful algal blooms, also known as Red Tides, can occur after an oil spill. They found that the presence of chemically-dispersed oil reduced the number of large protozoans (tintinnids and oligotrich ciliates that graze on dinoflagellates) which in turn was associated with an increase in bloom-forming dinoflagellates. The disruption in the predator-prey controls that normally function in plankton food webs could allow
Scientists conducted laboratory experiments to investigate if copepod behavior can reshape the size frequency distribution of oil droplets. They observed that copepods directly changed it through the combined movement of their feeding and swimming appendages and by ingesting oil droplets and discharging undigested, smaller-sized oil drops. The animals’ actions created feeding
Scientists developed a platform at environmentally-relevant scales to advance the study of oil-water interface interactions, biofilm formation, and particle dispersion. Their techniques allow one to control the size, shape, and volume of oil micro-drops and then affix them onto a stable substrate where microbes can live and grow. The technology provides an unprecedented capability in investigating complex interactions of bacteria, cells, and interfaces and to study key microbial processes involved in remediation of environmental pollutants,