The colonisation and degradation of stranded Macrocystis pyrifera (L.) C. Ag. by the macrofauna of a New Zealand sandy beach Journal Paper
- Author
- Inglis, Graeme
- Year
- 1989
- Journal / Source
- Journal of Experimental Marine Biology and Ecology
- Publisher / Organisation
- Elsevier
- Volume
- 125
- Number
- 3
- Pages
- 203-217
- Species
- Macrocystis pyrifera, giant kelp, giant bladder kelp, Bellorchestia quoyana, sandhopper, Talorchestia quoyana, sandhopper
- Keywords
- sea weed, kelp, macrofauna, decomposition, Litter bag, Macrocystis pyrifera, Talorchestia quoyana
- Summary
- Litter bags of three mesh sizes (5 × 8 mm, 1 mm, 85 μ) were used to assess the role of faunal components in the breakdown of the kelp Macrocystis pyrifera (L.) C. Ag. on a New Zealand sandy beach. The wrack was colonised by the supralittoral fauna in two distinct phases. The macrofauna, including the talitrid amphipod Talorchestia quoyana (Milne-Edwards), adult Diptera and Coleoptera, colonised the kelp within 1 day, with highest numbers recorded after 3 days. Following this, their presence in the samples declined and the meiofauna, which consisted of nematodes, enchytraeids, dipteran larvae, and mites, became increasingly abundant. After 18 days in the field, the meiofauna dominated the kelp surface. This faunal succession did not relate directly to the degradation of the algal tissues, which proceeded linearly for the entire study period. Algal material was lost from the bags at a rapid rate, with only 36–59% of the original dry mass remaining after 18 days in the field. Exclusion of the macrofauna from the kelp, using litter bags of finer mesh sizes (< 1 mm), had no appreciable effect on the rate of dry matter loss. Laboratory experiments revealed no effect of different meshes on breakdown rates in the absence of the fauna. The major macrofaunal kelp consumers, including T. quoyana and Coleoptera, therefore, did not affect the rate of algal disintegration. The effect of meiofaunal nematodes, enchytraeids and dipteran larvae on kelp breakdown could not be accurately determined. Microbial decay, and abiotic leaching and fragmentation processes were likely to be the major causes of kelp weight loss from the litter bags.