Unprecedented long chain 1-chloroalkenes and 1-chloroalkanes in the Holocene sediments of Lake El Junco, Galلpagos Islands

The occurrence of long chain chloroalkenes and chloroalkanes has not been previously reported in natural sediments. Here we report the presence of long chain (C30–C36) n-chloroalkanes and chloroalkenes in the recent sediments of the only permanent freshwater lake in the Galápagos Islands, El Junco. Both chloroalkanes and chloroalkenes have a chlorine atom at the terminal position. The cis and trans alkenyl chlorides have double bonds near the middle of the hydrocarbon chain (ω15, 16, 17). Alkenes in the lake sediments are typically C23:1 to C27:1, substantially shorter than the chloroalkenes and chloroalkanes. The lipid chain lengths and the positions of functional groups imply a structural relationship between chloroalkenes and some alkenols, diols and (or) hydroxy acids that most likely derive from algae.