Emil Ólafsson

Learn More
A survey was conducted to examine spatial variations in the population density of major meiofaunal taxa and the assemblage structure of free-living marine nematodes within 5 mangrove areas on the west and east coast of Zanzibar. Meiofauna densities in surface sediments (0–5 cm) ranged from 205 to 5263 ind. 10 cm2, being on average 1493 ind. 10 cm2. Of the(More)
Twenty stations were sampled in a reef-protected lagoon on the east coast of Zanzibar from a variety of habitats: seagrass beds, fine sand, bare medium sand and coarse sand. Total meiofauna densities ranged from 219 to 3422 ind./10 cm2. Stations in the upper lagoon (< 400 m from shore) had relatively higher densities of meiofauna than those of other(More)
Leaf litter removal by the abundant mangrove decapod crab Neosarmatium meinerti was studied in series of field and laboratory experiments in East Africa. In the high intertidal Avicennia marina zone crabs buried all leaves placed on the forest floor and consumed on average 67% of them within 2 hrs. High shore crabs in Kenya buried 4 g m(-2) leaf-litter in 1(More)
Tropical intertidal sediments often contain porewater of relatively high salinity, especially in areas exposed to longer periods without seawater inundation and high evaporation. Such an area exists on the west coast of Zanzibar: a high intertidal mangrove plateau, flooded only during spring high tides, with sediment porewater salinities commonly exceeding(More)
To evaluate the effects of a deposit-feeding bivalve on meiobenthic assemblage structure in muddy habitats, a laboratory experiment was performed at the Askö Laboratory in the northwestern Baltic proper. Microcosms, surface area 104 cm2, containing a c. 7-cm thick layer of sieved (0.5 mm) sublittoral mud were established in June 1990. Two months later the(More)
The harpacticoid copepod Parathalestris croni, a widespread pelagic species of the northern North Atlantic, was found to be closely associated with seaweed originating in the intertidal zone floating on the surface of the sea around Iceland. The abundance of the copepod increased with distance from the shore and it showed a special affinity for the brown(More)
The distribution and abundance of reef fishes in relation to habitat structure were studied within Bar Reef Marine Sanctuary (BRMS) and on an adjacent reef, disturbed by destructive fishing techniques, in north-western Sri Lanka, by visually censusing 135 species groups using fifty metre belt-transects. Two types of continental shelf patch-reefs are found(More)
The structure of harpacticoid copepod communities of floating detached intertidal algae was studied by surveys and experiments. Seaweed clumps were sampled from Faxaflói, western Iceland, at various distances from the shore (0.2–14 km). Altogether 20 species of harpacticoids were found in these clumps, most of them typical phytal species. Multidimensional(More)
Field surveys were conducted to evaluate the occurrence of the isopod borer Sphaeroma terebrans (Crustacea) in aerial roots (prop roots) of the red mangrove Rhizophora mucronata on several different spatial scales (m to 100 km) in East Africa. In 6 out of 17 sites studied in Kenya and on Zanzibar Island, Tanzania, no signs of the isopods were found. When(More)
A laboratory experiment was performed to quantify the fate of diatom phytodetritus and how this is affected by the presence of benthic amphipods. A Baltic Sea spring bloom sedimentation event was simulated by adding 14C-labeled diatoms (Skeletonema costatum) to microcosms with varying densities of the amphipods Monoporeia affinis and Pontoporeia femorata,(More)