Chloroform is the organic compound with formula CHCl3. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous. Several million tons are produced annually as a precursor to Teflon and refrigerants, but its use for refrigerants is being phased out.
CHCl3 has a multitude of natural sources, both biogenic and abiotic. It is estimated that greater than 90% of atmospheric CHCl3 is of natural origin.
In particular, chloroform is produced by brown seaweeds (Laminaria digitata, Laminaria saccharina, Fucus serratus, Pelvetia canaliculata, Ascophyllum nodosum), red seaweeds (Gigartina stellata, Corallina officinalis, Polysiphonia lanosa), and green seaweeds (Ulva lactuca, Enteromorpha sp., Cladophora albida). Similarly, the macroalga Eucheuma denticulatum, which is cultivated and harvested on a large scale for carrageenan production, produces CHCl3, as do Hypnea spinella, Falkenbergia hillebrandii, and Gracilara cornea along with seven indigenous macroalgae inhabiting a rock pool. These studies show increased CHCl3 production with increased light intensity, presumably when photosynthesis is at a maximum. Chloroform is also produced by the brown alga Fucus vesiculosus, the green algae Cladophora glomerata, Enteromorpha ahlneriana, Enteromorpha flexuosa, and Enteromorpha intestinalis, and the diatom Pleurosira laevis. Other studies observe CHCl3 in Fucus serratus, Fucus vesiculosis, Corallina officinalis, Cladophora pellucida, and Ulva lactuca, and Desmarestia antarctica, Lambia antarctica, Laminaria saccharina, Neuroglossum ligulatum.
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