Macroinvertebrates and peat nutrient mineralization on a sub-Antarctic island

Abstract

Moth larvae, earthworms and weevil larvae significantly enhance rates of nitrogen, phosphorus and potassium mineralization from peat on Marion Island (47°S, 38°E), as indicated by the amounts of inorganic forms of these elements released into solution in microcosms. Sodium release was unaffected by the animals and magnesium release enhanced by moth larvae only. Lower release rates of calcium and magnesium occurred in the presence of weevil larvae, indicating immobilization. The other two species had no influence on calcium release. These results, together with those of a previously reported investigation of the role of invertebrates in litter nutrient release, show that macroinvertebrates are crucial agents of nutrient cycling. Studies in isolasiehouers (mikrokosmosse) op Marion-eiland (47°S, 38°E) het getoon dat motlarwes, erdwurms en kalanderlarwes die mineralisasietempo’s van stikstof, fosfor en kalium uit veen (soos aangedui deur die vrystelling van anorganiese vorms van die voedingstowwe) beduidend verhoog. Die vrystelling van natrium is nie deur die diere beinvloed nie, terwyl alleen motlarwes magnesiumvrystelling verhoog het. In die teenwoordigheid van kalanderlarwes was die vrystelling van magnesium en kalsium laer as die van die kontrole, wat aan immobilisering toegeskryf word. Die ander twee spesies het geen invloed op kalsiumvrystelling gehad nie. Hierdie en ander resultate toon dat makroïnvertebrate belangrik is vir voedingstofsiklusse op die eiland.