Showing papers on "Driftwood published in 1994"

From the Forest to the Sea: The Ecology of Wood in Streams, Rivers, Estuaries and Oceans

Abstract: From the Forest to the Sea: The Ecology of Wood in Streams, Rivers, Estuaries and Oceans is a fascinating new scientific work that discusses the role wood plays in very complex and diverse aquatic ecosystems. Until now almost nothing has been published on this little understood topic. 1. Wood in streams and rivers is a source of food energy for invertebrate organisms; habitat for vertebrate organisms, such as fish; and a structural component that shapes, diversifies, and stabilizes channels while helping to dissipate the water's energy before it can scour channels.2. Wood in estuaries is a major source of food and habitat for obligatory, wood boring, marine invertebrates that in their feeding, break it down and pass usable carbon into the water's current where it enters the detrital based marine food web.3. Wood along the coastline stabilizes sand spits, beaches, and dune complexes, as well as battering rocky shores where it creates new habitats for intertidal organisms and provides small splinters of wood to the coastal food chain.4. Driftwood floating in the open ocean attracts a variety of marine invertebrates and fishes, forming a floating surface community that help organisms colonize new areas. Large fishes, such as tuna, not only feed on smaller fishes attracted to the wood but also drift with it because its movement is controlled by wind and current; thus tuna find the best feeding areas-current interfaces rich in food species. 5. A common textbook perception on marine biology is that, while communities of bacteria can use sulfur compounds as energy and animals can and do live around deep-sea hydrothermal vents through which hot water issues in the ocean's floor, the rest of the oceans bottom is almost devoid of life. But as driftwood becomes waterlogged and sinks, it represents terrestrially-fixed carbon in the energy poor deep-sea where at least three species of wood-borers convert it into a readily available source of detritus that in turn supports the development of complex communities of bottom-dwelling organisms.6. The loss of wood to aquatic ecosystems means destabilization of streams, estuaries, dunes and beaches as well as food chains in the oceans of the world. Sooner or later it may mean the loss of jobs and unique cultural ways of life such as the commercial fishing of certain species.

Mackenzie River Driftwood - A Dendrochronological Study

Abstract: As part of a general study of arctic driftwood, 206 samples of driftwood logs from the Mackenzie delta area were analyzed by dendrochronological methods (tree-ring studies). The aim was to detect the origin of the wood. Three forest stands in the delta were also sampled, and tree-ring chronologies were constructed. The Mackenzie driftwood can be divided into four groups: 1) driftwood originating from the upper Mackenzie delta with individual logs having up to 600 tree rings, 2) driftwood originating near the southern limit of the delta, 3) wood with relatively few tree rings with possible origin in the Liard River drainage area, and 4) driftwood samples not datable with any available chronologies. Three driftwood samples from the coast of Greenland could be correlated with tree-ring chronologies from the Mackenzie delta area and another three were correlated with chronologies from Alaska. American driftwood has not been detected in collections from Svalbard and Iceland, although more than 200 samples have been analyzed from each area. Key words: Mackenzie River, driftwod, dendrochronology, Arctic Ocean, East Greenland Current, surface currents, drift ice, Canada, Alaska

Driftwood as an indicator of relative changes in the influx of Arctic and Atlantic water into the coastal areas of Svalbard

Abstract: A total of 276 driftwood samples from Wijdefjorden on the northern coast of Spitsbergen were den-drochronologically analysed and compared with results from a similar study on driftwood from Isfjorden. The composition and origin of the driftwood from the two places differ. Whereas Larix is almost absent in the Isfjorden driftwood, it comprises 25% of the Wijdefjorden collection. The Isfjorden driftwood has its main origin in the White Sea region and the dates of the driftwood concentrate around the period from 1950 to 1979, with only a few dates from the period 1910 to 1950. The Wijdefjorden driftwood has two main origins: Siberia and the White Sea region. The dates of the White Sea components of the Wijdefjorden driftwood are concentrated mainly in the period 1910-1950. The dates of the Siberian (Yenisey) components of the Wijdefjorden driftwood are concentrated in the period 1950–1979. It can be argued that during the time period from ca. 1910 to 1950 the activity of a warm northerly flowing current along the western coast of Spitsbergen was stronger, transporting White Sea driftwood all the way to the Wijdefjorden area. However, after ca. 1950 the input of White Sea driftwood decreased, and the relative importance of the Siberian component increased. These results fit well with the climatic records from Svalbard, showing a warm regime during the first half of this century due to increased activity of the warm West Spitsbergen Current along the western coast of Spitsbergen. After ca. 1950, the influx of Atlantic Water became weaker, the climate became colder and the relative occurrences of Siberian driftwood transported by the Transpolar Current increased on the northern coast of the Svalbard archipelago.

Exploitation of Local, Drifted and Imported Wood by the Vikings on the Faroe Islands

Abstract: Summary Two hundred wood samples have been examined from the Viking settlement at Argisbrekka on Eysturoydated to AD 770–1015. They fall into three categories:-1. local wood: Juniperus. Betula pubescens Ehrh., Corylus, Salix and heathland dwarf shrubs; 2. driftwood: Picea, Larix and Pinus section strobus; and 3. imported wood: Quercus, Pinus section sylvestris, Alnus and Fraxinus. The local tree vegetation was over-exploited and Betula became extinct in the course of the Viking Age. Driftwood, mainly of Siberian origin, seems to be the most important tree resource and was used for houses and utensils. Imported wood probably mostly comprised ships and finished products made in Scandinavia. The detection of tree Betula growth between 2,460 BC and AD 770 is a new contribution to the vegetational history of the Faroe Islands.

Permeable driftwood occurrence control device

Abstract: PURPOSE:To provide a permeable driftwood occurrence control device, to reduce the corrosion of a cliff in the case of a flood while keeping a scene of the cliff or natural environment and, at the same time, to make it possible to prevent earth and driftwood from flowing out to the course of a river. CONSTITUTION:Excavated spaces are formed in cliffs, etc., to arrange base frames 3 and 3, and base members 4 and 4 at right angles to them are mounted. Column members 6 and 6 are fixed on them to form triangular frame bodies 5 and 5, adjacent triangular frame bodies 5 and 5 are connected to each other with beam members 7 and, at the same time, batten members 13 and 13 are mounted between adjacent column members 6 and 6. Bedding cages 18 are used to construct a driftwood accurrence control device 1. Even if a river rises to have running water rolling in, the driftwood occurrence control device 1 displays energy dissipation effect to ease the corrosion of the cliffs. While, even if the flow of earth or driftwood occurs by an earthquake, etc., driftwood, etc., are caught by the driftwood occurrence control device 1 to prevent them from flowing out to the course of the river, so that bridges carried away by the flood can be reduced. The installation of the driftwood occurrence control device 1 is not accompanied by any natural destruction, and living environment of plants and animals is also maitained.