Hans Staaland

Fungi : a major source of radiocesium contamination of grazing ruminants in Norway

Transfer of radiocesium from vegetation to milk was studied in dairy goats grazing heavily contaminated mountain pasture in southern Norway in the years following the Chernobyl accident. Radiocesium activity in milk and green vegetation remained stable throughout 1986 and 1987. In 1988, a sudden three- to fivefold increase in milk radioactivity occurred during the second half of the summer. Whole-body content of radioactivity in sheep and reindeer also increased rapidly. This coincided with an abundant growth of fungal fruit bodies with radiocesium levels up to 100 times higher than green vegetation. Fungal radiocesium was found to be highly available in a digestibility study with goats. Milk radioactivity levels in the field could be accounted for by consumption of as little as 20-100 g d-1 of fungal dry matter (DM). The importance of fungal fruit bodies in transferring radiocesium to ruminants was further substantiated by comparing meat activities in grazing ruminants in 1988 and 1989. Fungal fruit bodies were present in minor quantities in 1989, and radioactivity levels in sheep and reindeer in August-September were only 28-35% of those in 1988. This ability of fungi to mobilize radiocesium from natural soils and transfer the isotopes into the human food chain greatly enhances the vulnerability of food production in natural ecosystems to radiocesium pollution.

The effect of salinity and temperature on solubility of oxygen and respiratory rate in oxygen-dependent marine invertebrates

Abstract The diffusion rate of O 2 in sea water has been treated physico-chemically. It is shown that although the activity of oxygen in water remains constant when pO 2 and temperature are constant (equilibrium conditions), the diffusion rate of oxygen will nevertheless vary proportionally to the solubility of oxygen in sea water, which decreases with increasing salinity. The effect on the diffusion rate is due to a salt effect on the activity coefficient, which also implies that Ficks law can not be directly used in systems of varying salinity. It is shown that the respiratory rate of the oxygen-dependent prosobranch, Buccinum undatum L., increases with decreasing salinity when the measurements are made as usual, namely, at constant pO 2 . The respiratory rate is independent of the salinity, however, if the plot is based upon equal O 2 concentrations in water of different salinity. Physico-chemical considerations make it likely that the diffusion rate of O 2 in water is a rate-limiting factor for respiration in Buccinum . The literature shows, however, that further experimental evidence is needed before a general conclusion as to the quantitative role of the diffusion rate of oxygen in sea water on the respiratory rate can be reached. Since the solubility of O 2 in water also varies with temperature, corresponding effects regarding metabolism/temperature curves have been considered. It is shown theoretically that when the respiratory rate depends on the diffusion rate of O 2 in water, the increase of the respiratory rate with temperature is less when measured at constant pO 2 than at constant O 2 concentration. Measurements of the respiratory rate of Buccinum at different temperatures conform to this statement.

Distribution of nutrients and minerals in the alimentary tract of muskoxen, Ovibos moschatus

Abstract 1. 1. Distribution of nutrients in the alimentary tract of muskoxen, Ovibos moschatus. 2. 2. In muskoxen shot on high Arctic ranges in northeast Greenland the alimentary tract was developed in accordance with that of a typical “grazer” or “roughage feeder”. 3. 3. Typical features were a large omasum and a small caecum. 4. 4. The rumen-reticulum was a dominating nutrient pool containing 34–78% of total alimentary contents. 5. 5. In the summer most nutrient concentration in the rumen were lower than in winter, indicating increased demands for extra supplements of e.g. Na in the summer. 6. 6. Although the caecal-colon complex is relatively small it plays an important role in scavenging the digesta for important nutrients.

Forage diversity and nutrition supply of reindeer

This study describes the mineral and nitrogen concentrations of reindeer forage plants from the Elga reindeer herding district of south-eastern Norway. The data are compared with results from 5 other areas in Norway. Emphasis is put on the importance of environmental diversity. Different plant species accumulate Ca, Mg, P, S, Na, K, CI and K to a varying degree but reindeer can meet their nutritional requirements by eating different types of forage. Examples are sodium from aquatic herbs, sulphur and sodium from horsetails etc. Of further importance are variations in soil type, phenological development of plants in relation to differences in time for snowmelting, as well as different levels of nutrients in forage from different geographical.

Muskox and caribou adaptation to grazing on the Angujaartorfiup Nunaa range in West Greenland

In recent years (1970-90) the caribou population of the Angujaartorfiup Nunaa range has decreased from about 40 000 animals to 2000. Overgrazing presumably depleted the lichen resources on the range during the population peak. At the same time altogether 27 muskoxen introduced in 1962 and 1965 have proliferated and the muskox population reached 3000 animals in 1990. At the present monocots dominate the diet for both species. The alimentary tract of both muskox and caribou collected in the fall of 1990 had characteristics of grazing ruminants, e.g. relatively small caecum-colon compared to total alimentary size and large alimentary fill relative to body weight. Caribou had an omasum comparable in size to the grazing Svalbard reindeer whereas the omasum of the muskoxen in size, resembled that of domestic cattle. Both winter and summer samples showed highest ruminal hemicellulose and cellulose concentrations in the muskoxen, whereas lignin and nitrogen were equal in the two species. Conclusively our data suggest adaptation to grazing in both species, but more so in muskoxen than in caribou.

A device for the study of salinity preference in mobile marine animals

Abstract A device for the study of salinity preference in mobile marine animals is described. The construction of the device is based on the introduction of discontinuity layers in an aquarium.

Adaptations of the caecum-colon structure of rodents

Abstract 1. 1. The gross anatomy of the caecum-colon structure of some rodents revealed that all Cricetidae examined possess a post-caecal spiral which is absent in the Muridae studied. 2. 2. The length of colon, i.e. from caecum to anus, is longer in the Cricetidae than in the Muridae. 3. 3. The size and appearance of the post-caecal spiral has been related to the ecology of the animals, e.g. the large post-caecal spiral and the long colon in the Norway lemming, Lemmus lemmus (L.), may reflect demands caused by the low ash content of the food preferred by this animal. 4. 4. Sodium, potassium and water absorption, and the relative efficiency of absorption, in the caecum-colon structure of the Norway lemming and the Norway rat, Rattus norvegicus (L.), have been studied. Relatively, the absorption of sodium and potassium is more efficient in the Norway lemming than in the Norway rat. 5. 5. Water is being efficiently absorbed in the caecum-colon structure of both the Norway lemming and the Norway rat, and, apparently, the amount of water absorbed can be accounted for by a “solute-linked” mechanism.

Volume regulation in the common whelk, Buccinum undatum L.

Abstract 1. 1. Based on measurements of inulin space, total water amount and density, cell water was estimated to increase linearly by decreasing salinity. 2. 2. The common whelk was found to be slightly hyperosmotic to sea water, and intracellular concentrations of ninhydrin-positive substances were correlated to salinity. 3. 3. On the basis of the data obtained the volume regulation of cells was calculated to be incomplete, whereas changes in external salinity was adjusted intracellularly by means of ninhydrin-positive substances.

Nutritional Strategies and Winter Survival of European Roe Deer in Norway

The European roe deer (Capreolus capreolus) are the smallest free-ranging cervid in the northern temperate region. Recently, they have expanded their distribution north of the Arctic circle. Due to their low body mass (25 to 35 kg) they depend, presumably, on high quality forage to cover their energy demands. However, in Norway available winter staple is mostly low-quality forage from dwarf shrubs like blueberry (Vaccinum myrtillus), and when snow cover exceeds about 0.5 m the animals are forced to feed on twigs and buds from deciduous and evergreen trees. Apparently the roe deer have developed morphological, physiological, and behavioral traits that enable them to survive winter on such forage. Among these winter adaptations are a 40% increase in alimentary dry matter content, reduced food intake, and increased total mean retention time of gastrointestinal fill. Based on in vitro studies with rumen inoculum from roe deer culled at different seasons, there is apparently little cellulolytic activity during all seasons. Amount of fat deposits, the midsummer rut, and delayed implantations are additional strategies for winter survival.

On the quality of Svalbard reindeer pasture in the summer and autumn

Late summer and autumn reindeer pasture plants from Adventdalen, Svalbard were analyzed for contents of fatty acids, energy content, protein, fibre, ether extract as well as content of macro minerals. Food intake of grazing reindeer in Adventdalen was estimated from fecal production. Large intake of high quality food seems to account for the growth and fattening of Svalbard reindeer during summer. Om kvaliteten pa reinbeite av reinbeite pa Svalbard sommer og host. Abstract in Norwegian / Sammendrag: Innholdet av fettsyrer, energi, protein, fiber, eterekstrakt og makromineraler ble analysert i reinbeiteplanter fra Adventdalen pa Svalbard. Plantene ble samlet pa ettersommeren. Forinntaket hos beitende rein i Adventdalen ble estimert ut fra fecesproduksjonen. Et stort inntak av for med hoy kvalitet synes a kunne forklare vekst og fettlagring hos Svalbard-reinen om sommeren. Huippuvuorten poronlaidunten laadusta kesalla ja syksylla. Abstract in Finnish / Yhteenveto: Rasvahappojen, energian, fiiberin, eetteriuutteen ja makromineraalien sisaltoa analysoitiin poronlaidunkasveissa Huippuvuorten Adventtilaaksosta. Kasvit kerattiin loppukesalla. Adventtilaaksossa laiduntavien porojen rehun kulunki arvioitiin lannan maarasta. Korkealaatuisen rehun suuri kulutus nayttaa vovan selittaa Huippuvuorten porojen kasvun ja rasvakerrostuman kesalla.