Secondary amyloidosis and renal failure in a captive California sea lion (Zalophus californianus)

A 16-yr-old, captive-born, female California sea lion (Zalophus californianus) was evaluated for intermittent lethargy, partial anorexia, and polydipsia of 2 wk duration. The animal was immobilized for physical examination. It was in thin body condition, with multifocal mucosal ulcerations over the caudal and ventral tongue. Blood was collected for hematology, serum chemistry, and leptospirosis serology. Serum chemistry revealed severe azotemia, mild hyperglycemia, and severe hyperphosphatemia. The animal went into cardiac arrest during recovery from anesthesia and died. On histopathology, abundant amorphous, finely fibrillar, eosinophilic material was deposited in the kidneys, and smaller amounts of the same material were found in the splenic and pancreatic vessels; these findings are consistent with systemic secondary amyloidosis. The animal also had chronic nephritis, which, coupled with renal amyloidosis, resulted in renal failure and death. Systemic amyloidosis should be considered as an additional differential diagnosis for renal failure in California sea lions.     

Effect of parental origin on early life history traits of European eel

Establishment of European eel (Anguilla anguilla) hatchery production will rely on selectively bred individuals that produce progeny with the best traits in successive generations. As such, this study used a quantitative genetic breeding design, between four females and nine males (four wild‐caught and five cultured), to investigate the effect of paternal origin (wild‐caught vs. cultured) and quantify the relative importance of parental effects, including genetic compatibility, on early life history (ELH) performance traits (i.e. fertilization success, embryonic survival at 32 hr post‐fertilization, hatch success and larval deformities at 2 days post‐hatch) of European eel. Wild‐caught males had higher (56%) spermatocrit values than cultured males (45%), while fertilization success, embryonic survival, hatch success and larval deformities were not significantly impacted by paternal origin. This demonstrates that short‐term domestication of male eels does not negatively affect offspring quality and enables the consideration of cultured male broodstock in future breeding programmes. Moreover, paternity significantly explained 9.5% of the variability in embryonic survival, providing further evidence that paternal effects need to be taken into consideration in assisted reproduction protocols. Furthermore, maternity significantly explained 54.8% of the variation for fertilization success, 61.7% for embryonic survival, 88.1% for hatching success and 62.8% for larval deformities, validating that maternity is a major factor influencing these “critical” ELH traits. At last, the parental interaction explained 12.8% of the variation for fertilization success, 8.3% for embryonic survival, 4.5% for hatch success and 20.5% for larval deformities. Thus, we conclude that eggs of one female can develop more successfully when crossed with a compatible male, highlighting the importance of mate choice for successful propagation of high‐quality offspring. Together, this knowledge will improve early offspring performance, leading to future breeding programmes for this critically endangered and economically important species.     

Time series diagnosis of tree hydraulic characteristics

An in vivo method for diagnosing hydraulic characteristics of branches and whole trees is described. The method imposes short-lived perturbations of transpiration and traces the propagation of the hydraulic response through trees. The water uptake response contains the integrated signature of hydraulic resistance and capacitance within trees. The method produces large signal to noise ratios for analysis, but does not cause damage or destruction to tree stems or branches. Based on results with two conifer tree species, we show that the method allows for the simple parameterization of bulk hydraulic resistance and capacitance of trees. Bulk tree parameterization of resistance and capacitance predicted the overall diel shape of water uptake, but did not predict the overshoot water uptake response in trees to shorter-term variations in transpiration, created by step changes in transpiration rate. Stomatal dynamics likely complicated the use of simple resistance-capacitance models of tree water transport on these short time scales. The results provide insight into dominant hydraulic and physiological factors controlling tree water flux on varying time scales, and allow for the practical assessment of necessary tree hydraulic model complexity in relation to the time step of soil- vegetation-atmosphere transport models.     

Estimates of denitrification in soil by remote sensing of thermal infrared emission at different moisture levels

Remote sensing techniques may be one way to narrow the range of uncertainty in extrapolating N₂ emissions from small-scale to large-scale terrestrial ecosystems. In the present work we investigated the correlations between denitrification activity, soil moisture, and soil thermal infrared emissions. A field experiment was performed on two different agricultural soils, one loam and one silty clay. The results indicated that thermal infrared emissions can only be used to estimate the denitrification rate in soil within a limited range of soil moisture levels. Estimates of denitrification activity based on soil texture and moisture are, however, very likely to be a fruitful approach to generating large-scale N fluxes.