dimethylsulfide

Dimethylsulfide (DMS) is an organic compound with the formula (CH3)2S. It is a colorless liquid that boils at 38°C and has a characteristic smell of decayed cabbage or cooked corn. DMS is a significant component of the global sulfur cycle and plays a crucial role in atmospheric chemistry.

DMS is naturally produced by marine algae and phytoplankton as a byproduct of their metabolism. It is the most abundant biogenic sulfur compound emitted from the ocean, with an estimated annual emission of 15 to 30 teragrams. The enzyme DMSP lyase catalyzes the breakdown of dimethylsulfoniopropionate (DMSP), a compatible solute produced by marine algae, into DMS and acrylate.

In the atmosphere, DMS is oxidized to form sulfur dioxide (SO2), methane sulfonic acid (MSA), and other sulfur oxides. These compounds can act as cloud condensation nuclei, influencing cloud formation and albedo. This process is part of the so-called CLAW hypothesis, which suggests a feedback loop between oceanic DMS production, cloud formation, and climate regulation.

DMS is also produced anthropogenically through the decomposition of organic matter and industrial processes. It is used in the synthesis of various chemicals, including pesticides and pharmaceuticals. However, its strong odor makes it an indicator of spoilage in foods like beer, milk, and seafood.

Exposure to DMS can cause irritation to the eyes, skin, and respiratory tract. The Occupational Safety and Health Administration (OSHA) has set a permissible exposure limit of 100 parts per million (ppm) for DMS in the workplace. In the environment, DMS can contribute to acid rain formation and has been linked to coral bleaching events.