Shift in ectomycorrhizal community composition in Scots pine (Pinus sylvestris L.) seedling roots as a response to nickel deposition and removal of lichen cover

Scots pine seedlings were exposed to wet-deposited nickel (Ni) and removal of lichen cover in a dry heath Scots pine forest. Ni deposition affected the colonization of roots by indigenous ectomycorrhizal fungi in contrasting ways in intact and skimmed quadrats. Highest frequencies of tubercle morphotypes of ectomycorrhiza were found in quadrats exposed to 100 mg m⁻² year⁻¹ Ni in lichen covered treatment, while in skimmed quadrats these peaked after the treatment with 10 mg Ni m⁻² year⁻¹. Removal of the lichen layer increased the value of diversity index (H′) of ectomycorrhizal fungal community, probably due to the increase in the evenness of the morphotype distribution. Lichen removal seemed also to improve the condition of the short roots, as the frequencies of poor and senescent short roots were decreased by the removal.     

Determination of toxaphenes in fish and marine mammals

An analytical method for the determination of toxaphene in biological materials using gas chromatography with an electron capture detector (GC-ECD) has been established and validated for three single congeners (chlorinated bornanes (CHB) 26, 50 and 62). The analytical method was based on a method for determination of PCB, DDT and other chlorinated pesticides. To include toxaphene congeners an extra step, adsorption chromatography on silica columns, was introduced to separate the pesticides from PCB. The recovery of CHB-26, 50 and 62 were 97+/-11%, 94+/-10% and 99+/-12%, respectively. Samples from cod, ringed seal and polar bear from the Norwegian arctic environment have been analysed. The levels of CHB-26 and 50 found were 13-55 ng/g fat in cod, 1.3-7.7 ng/g fat in ringed seal and 0.4-119 ng/g fat in polar bear. The levels of CHB-62 were 2.0-13, 0.8-3.4, 0.2-11 ng/g fat in cod, ringed seal and polar bear, respectively.     

An improved automatic recording apparatus for determining the filtration rate of Mytilus edulis as a function of size and algal concentration

An automatic recording apparatus for measuring the filtration rate in suspension-feeding bivalves is described. The concentration of algae in the experimental medium is kept constant throughout each experiment by addition of Phaeodactylum tricornutum from a chemostat. Within the range of body size 5.7 to 283 mg (W=dry weight of tissues), the filtration rate (F=ml min^-1) at 15°C in Mytilus edulis L. follows the allometric equation F=0.85 W ^0.72. Within the concentrations 0.18 to 0.70 mg algal dry weight l^-1, the filtration rate in mussels of 132 mg dry flesh weight ranges from 33.1 to 41.0 ml min^-1. At 0.18 mg algal dry weight l^-1 the mussels filter continuously for 20 h, with a high constant rate that presumably represents the water transport capacity under optimal laboratory conditions.     

Ultrastructure and histochemistry of the integument of air-breathing polychaetes from mangrove swamps of sumatra

The integument of S.E. Asian air-breathing polychaetes exhibits a variable ultrastructure with regard to cuticle and epithelial cells. The cuticle varies in thickness, contents of regularly arranged collagen fibrils, and structure of the epicuticle. The basal portion of the epithelium is either of smooth outline, or consists of slender processes of the epidermal cells separated by wide intercellular spaces which are invaded by a loose system of glia cells and nerve fibres. Extracellular spaces within the epidermis of the gills of Dendronereides heteropoda are transformed into blood lacunae. The enzyme content of the epithelial cells is relatively low.Supported by the Deutsche Forschungsgemeinschaft (Sto 75/2, We 380/4).     

Sex ratio manipulation and decreased growth of male offspring of undernourished golden hamsters (Mesocricetus auratus)

Summary The theory that female mammals in poor condition may increase individual fitness by skewing the sex ratio of their offspring toward daughters and by investing more resources in daughters than in sons was tested in hamsters. Newly mated experimental females were food-restricted during pregnancy and lactation (RR) or during lactation only (AR). Controls received food ad libitum. Maternal body weights were assessed daily from mating to 25 days postpartum. Litter survival (% litters with at least one pup surviving on any day), litter size, offspring sex ratios (=% males), and pup weights were monitored daily from birth (Day 1) to Day 25. All control and AR dams gave birth 16 days after mating. Gestation was extended by 1–3 days for 35.4% of RR dams. RR dams weighed significantly less at parturition than controls and AR females. During lactation, AR females showed the greatest weight loss and control females the least. AR weight loss exceeded that of RR females, possibly because the former maintained larger litters. Survival was highest for controls, intermediate for AR, and lowest for RR litters. Mean sex ratio at birth was significantly less for RR (40.7%) than for control (49.6%) and AR (48.8%) litters. RR sex ratio did not change significantly postnatally. Sex ratios of control and AR litters never differed statistically from 50%. Control male pups were significantly heavier than their sisters throughout the experiment. No significant gender differences were observed for AR pup weights after Day 2 postpartum. RR female offspring weighed more than their brothers throughout the experiment, and this difference was statistically significant immediately prior to the time that pups began to feed independently (Days 14–17). RR female pup weights were similar to, and sometimes significantly greater than, weights of control daughters during the period of postnatal maternal investment. Control males were always heavier than males from the other treatments. Patterns of weight gain by AR and RR males varied with age. We conclude that underfed female hamsters are able to adjust the sex ratio of offspring prenatally and parental investment postnatally to favor daughters.     

Ecological aspects of deformed chaetognaths and visual observations of their periphytes

Preserved samples of chaetognaths (Sagitta crassa) in Tokyo Bay contained normal specimens and knotty and flabby deformed ones. On the body surfaces of both normal and deformed specimens, three different types of periphyte were observed by a scanning electron microscope (SEM): branch-like growths, large numbers of filaments and protuberances. Some branch-like growths frequently covered almost the entire body of even normal chaetognaths. Bacteria were only observed on the abnormal specimens. Bacterial colonization occurred inside the body rather than on the body surface. Due to the growth of bacteria, muscles degenerated and chaetognaths became abnormally knotty and flabby. Abnormal chaetognaths occurred in Tokyo Bay more frequently in July 1979 (12.4%) than in June 1982 (3.9%). Food containing ratio (FCR) values, an indication of feeding activity, of the abnormal chaetognaths were less than 10% and no feeding rhythm was found, whereas normal chaetognaths had high FCR values with a maximum peak (more than 60%) between 20.000 and 23.000 hrs. Abnormal specimens sometimes had spermatophores on their body surfaces. It is obvious that abnormal chaetognaths had still been alive in the sea and that some of them not only fed on copepods but also copulated. However, feeding activity and reproductive behaviour were far lower in abnormal chaetognaths than in normal ones. Abnormal specimens were not larger than 9.0 mm and their mean body length was smaller than that of normal chaetognaths. This suggests that bacterial infection directly affects the mortality of the chaetognath population.     

Respiration and excretion rates of Calanus glacialis in arctic waters of the Barents Sea

The respiration and excretion rates of Calanus glacialis (Jaschnov) Copepodite Stages III, IV, V, and adult females from the drift-ice area east of Svalbard (Barents Sea) were measured in shipboard experiments during the period from 27 May to 13 June, 1983. The phytoplankton biomass and abundance varied considerably between localities, but these variations were not generally reflected in the respiration and excretion rates of the copepod. The respiration and excretion rates of C. glacialis at the ambient temperature of-1.8°C (average respiration rates of 0.95, 0.73, 0.57, and 0.60 l O₂ mg^-1 dry wt h^-1 for Copepodite Stage III, IV, V, and adult females, respectively) were similar to those previously reported for other large-sized copepods from cold or temperate areas. Average respiration and excretion rates tended to decrease with incubation time or time after capture. Measurements on ten occasions within a period of 27 h after capture revealed excretion rates of ammonium ranging between 2.9 and 16.8 for C III, 3.7 and 21.1 for C IV, 1.3 and 28.4 for C V, and 1.6 and 18.7 for adult females, all expressed as nmol mg^-1 dry wt h^-1. In all experiments, excretion rates of inorganic phosphate varied between 0.7 and 1.5 (C III), 0.5 and 1.1 (C IV), 0.2 and 0.8 (C V), and 0.3 and 1.0 (adult females) nmol mg^-1 dry wt h^-1. Ratios of O:N, O:P, and N:P indicated that much of the metabolic energy was derived from catabolism of proteins. Comparison of the turnover rate of carbon and nitrogen showed, however, that nitrogen turnover was between 2.6 and 8.9 times higher than that of carbon. This may indicate that the copepods deaminate ingested protein, with the carbon skeleton of the amino acids subsequently being used in the synthesis of lipid compounds, possibly wax esters.