USING ARTIFICIAL SUBSTRATA TO MONITOR HOW CRYPTOFAUNAL ACARI COLONIZELITTORAL ALGAE ON SUB-ANTARCTIC SOUTH GEORGIA

The colonization of littoral macroalgae by meiofaunal Acari on the sub -Antarctic island of South Georgia was studied using spun-Nylon pan sc ourers as artificial substrata. A total of twelve species of littoral Acari, including two Rhodacaridae, four Halacaridae, three Podacaridae and three Hyadesiidae, were collected from the scourers. Rhombognathu s auster, R. plumifer (Halacaridae), Halozetes littoralis, H. marinus (Podacaridae) and Hyadesia subantarctica (Hyadesiidae) rapidly establi sh their dominance in spring and remain ascendant throughout the summe r. Predation and competition have minimal impact on the mite populatio ns compared with abiotic (climatic) influences. Low winter temperature s exert an indirect pressure by killing most of the algal substrata, w hile storms have a more direct effect by removing both mites and algae from the shore. Surviving mites over-winter in the shelter afforded b y crevices and among the basal portions of enduring algae.