Seasonal variation in lipid content and composition was studied in deposit-feeding amphipods from a Baltic archipelago. In Monoporeia afinis, which is more active and has a higher respiration rate, lipid levels were low in winter and early spring, rose to 27% of the dry mass in late summer, then declined in autumn. In Pontoporeia femorata, which regulates its oxygen consumption, lipid levels were 20-23% of the dry mass. In October, maturing male P. fimorata had a significantly lower lipid content than females. Triacylglyccrol and phospholipid accounted for -90% of lipids. Phospholipid dominated in M. afinis in March, but triacylglycerol accumulated and became the main lipid after the spring bloom. Triacylglycerol was always the main lipid in P. femorata, but also accumulated after the spring diatom bloom. Both species seem to assimilate and store food resources from the diatom bloom. The higher feeding rate of M. afinis may explain its greater accumulation of lipid. Lower metabolic costs in P. femorata may allow it to maintain steady lipid levels for most of the year.

Benthic surveys were conducted in the southern basin of Lake Michigan and throughout the lake to assess trends in benthic populations, emphasizing recent changes in densities of the benthic amphipod Diporeia spp. and dreissenid mussels. In the southern basin, Diporeia populations declined 89%, 91%, and 45% between 1993 and 2002 at sites <30, 31–50, and 51–90 m, respectively. Lakewide, the population declined 65% between 1994–1995 and 2000. Over the same time period, dreissenid densities, particularly Dreissena bugensis, increased. Intensive studies at 45 m sites in the southeastern region examined changes in lipid content, age structure, and benthic food inputs relative to the hypothesis that food limitation was a factor in Diporeia's disappearance. As Diporeia densities declined to zero, length–weight remained unchanged, and lipid content generally increased. Recruitment still occurred, but the young did not survive to become adults. Based on organic carbon, biogenic silica, and chlorophyll collected in sediment traps and found in the upper sediments, pelagic inputs to the benthic region still occurred. Our field observations and laboratory experiments did not disprove the hypothesis that food limitation from dreissenid filtering activities was the cause of the decline, but direct relationships between the loss of Diporeia and indicators of food availability were difficult to establish.

Background:Lateral ligament ankle sprains are the single most common sports injury.Objective:To determine the functional outcome of the ankle joint after a moderate or severe inversion injury, comparing standard treatment with an elastic support bandage against an Aircast ankle brace.Design:Prospective, randomised controlled trial.Setting:Two accident and emergency departments.Method:Fifty patients presenting consecutively were randomised into two equal groups: one group was treated with an elastic support bandage and the other with an Aircast ankle brace. All patients were given a standardised advice sheet referring to rest, ice, compression, and elevation. Patients were reviewed after 48–72 hours, 10 days, and one month.Primary outcome measure:Ankle joint function assessed at 10 days and one month using the modified Karlsson scoring method (maximum score 90).Secondary outcome measure:The difference in ankle girth (swelling) and pain score at 10 days.Results:Seventeen patients in the elastic support bandage group (six defaulted, two excluded) and 18 patients in the Aircast ankle brace group (six defaulted, one excluded) completed the study. There were no significant differences between the two groups at presentation in terms of age (mean 35.3 and 32.6 years respectively), sex, dominant leg, left or right ankle injured, previous injury, time to presentation (median three and four hours respectively), difference in ankle girth (mean 14.5 and 14.3 mm respectively), and pain scores (mean 6.2 and 5.8 respectively). The Karlsson score was significantly higher in the Aircast ankle cast group than in the elastic bandage group at 10 days (mean 50v35, p  =  0.028, 95% confidence interval (CI) 1.7 to 27.7) and one month (mean 68v55, p  =  0.029, 95% CI 1.4 to 24.8) (Student’sttest). There was no difference between the groups in the secondary outcome measures (swelling, p  =  0.09; pain, p  =  0.07). When hierarchical multiple regression analysis was used to correct for possible baseline confounding factors, the Aircast ankle brace group was significantly associated with higher Karlsson scores at 10 days (p  =  0.009) and one month (p  =  0.024).Conclusion:The use of an Aircast ankle brace for the treatment of lateral ligament ankle sprains produces a significant improvement in ankle joint function at both 10 days and one month compared with standard management with an elastic support bandage.

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Phosphate release rates by Stylodrilus heringianus, tubificids, and Chironomus spp. were quantified in laboratory experiments by incubating the animals in wet sand under two temperature regimes (5 and 20 °C) and under two nutritional states (full and empty guts). Inorganic phosphorus release rates (± SE) for animals incubated 24 h ranged from 0.12 ± 0.02 (n = 5) nmol phosphorus (P)∙(mg ash-free dry weight)−1∙h−1 for S. heringianus beginning with cleared guts at 5 °C to 0.81 ± 0.09 (n = 5) nmol P∙(mg ash-free dry weight)−1∙h−1 for chironomids beginning with full guts at 20 °C. Calculations based on total invertebrate bio-mass and mean basal release rate suggest that benthic invertebrate excretion could account for most P released from aerobic Lake Michigan sediments.Key words: phosphorus, benthic invertebrates, macroinvertebrates, excretion, nutrients, sediments, nutrient release

Pontoporeia hoyi, the dominant benthic invertebrate in the upper Great Lakes, appears to be well adapted to environments with seasonal inputs of high-quality food such as those supplied by the spring diatom bloom. Ammonium and phosphate excretion rates and lipid content were examined in P. hoyi under the following conditions: (1) field animals sampled seasonally, (2) food-deprived animals in filtered lake water, and (3) control animals held in native sediments without new food inputs. Nutrient excretion rates for P. hoyi (0.5 to 2 nmole NH4 (milligrams dry weight)−1∙h−1 and 0 to 0.15 nmole PO4 (milligrams dry weight)−1∙h−1) were low relative to rates previously reported for other benthic and pelagic invertebrates and varied little among the three treatment groups. In contrast to the animals held in the laboratory without new food inputs, field-collected P. hoyi accumulated increased levels of lipids following the spring diatom bloom. However, after lipid levels in field animals peaked in May, they decreased during the rest of the season at rates similar to those of starved and control animals. P. hoyi's low nutrient-excretion rates, and its ability to accumulate and store energy as lipids, for periods when food is not abundant, appear to be important factors allowing this animal to thrive in temperate lakes with spring diatom blooms.

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