Thermal reaction norms for growth vary among cohorts of Pacific cod (Gadus macrocephalus)

While much effort has been directed at determining the spatial scales of adaptation in thermal reaction norms for growth, it is widely assumed that these reaction norms have high temporal stability. Water temperatures in the Gulf of Alaska in 2007 were the coldest on record since the mid-1970s and we present evidence that the thermal reaction norm for growth of age-0 Pacific cod (Gadus macrocephalus) in this cohort differed significantly from two adjacent cohorts. In addition to exhibiting higher growth potential at low temperatures, the 2007 cohort had a higher mean vertebral count, consistent with the widespread thermal effect known as “Jordan’s Rule.” Variation among cohorts in these physiological and morphological traits suggests a persistent response to environmental history (epigenetic effect). Temperature-induced phenotypic plasticity in the reaction norm for growth has significant implications for using growth rates to evaluate habitat quality and illustrates the complex responses of fishes to climate variability.     

Predation affects alarm call usage in female Diana monkeys (Cercopithecus diana diana)

Diana monkeys produce acoustically distinct calls to a number of external events, including different types of predators. In a previous study, we found population-wide differences in male alarm call production in Taï Forest, Ivory Coast, and on Tiwai Island, Sierra Leone, mostly likely originating from differences in predator experience. In Taï Forest, leopards (Panthera pardus) are common but on Tiwai Island they have been absent for decades, while the predation pressure from crowned eagles (Stephanoaetus coronatus) has been similar. To further evaluate the impact of predator experience, we here analyse the vocal behaviour of female Diana monkeys in both habitats. Female Diana monkeys produce predator-specific alarm calls, alert calls and contact calls in response to predators, suggesting that their calls serve in a broader range of functions compared to males. Results showed that females produced the same call types at both sites, despite the differences in predator fauna. Regarding call usage, leopard alarm calls were extremely rare on Tiwai Island, but not in Taï Forest, whereas we found no differences in eagle alarm call production. When comparing response latencies, Tiwai females were slower to respond to both predators compared to Taï females. Finally, we found no habitat-specific acoustic differences in the alert and predator-specific alarm calls, but significant differences in frequency-based parameters of contact calls. Overall, our results suggest that ontogenetic experience can affect primate vocal behaviour in both usage and acoustic structure but that the way in which particular call types are affected may be closely linked to function.     

Nitrogen and nature

Anthropogenic changes to the global N cycle are important in part because added N alters the composition, productivity, and other properties of many natural ecosystems substantially. Why does added N have such a large impact? Why is N in short supply in so many natural ecosystems? Processes that slow the cycling of N relative to other elements and processes that control ecosystem-level inputs and outputs of N could cause N supply to limit the dynamics of ecosystems. We discuss stoichiometric differences between terrestrial plants and other organisms, the abundance of protein-precipitating plant defenses, and the nature of the C-N bond in soil organic matter as factors that can slow N cycling. For inputs, the energetic costs of N fixation and their consequences, the supply of nutrients other than N, and preferential grazing on N-fixers all could constrain the abundance and/or activity of biological N-fixers. Together these processes drive and sustain N limitation in many natural terrestrial ecosystems.     

Reclamation of high-elevation,acidic mine waste with organic amendments and topsoil

The Summitville Mine was a high-elevation (3500 m) gold mine in southwestern Colorado. The mine was abandoned in 1992, leaving approximately 200 ha of disturbance comprised partially of an open pit, a cyanide heap leach pad, and two large waste rock piles. Reclamation of these mine facilities is challenging due to extreme climatic conditions in conjunction with high acid-production potential and low organic matter content of waste materials on site. In addition, stockpiled topsoil at the site is acidic and biologically inactive due to long-term storage, and may not be suitable for plant growth. The purpose of this study was to evaluate the effects of organic amendments (mushroom compost vs. biosolids) and topsoil (stockpiled vs. nonstockpiled) on aboveground biomass and plant trace element uptake. An on-site field study was established in 1995 to identify the most effective combination of treatments for successful reclamation of on-site waste rock materials. Incorporation of organic matter significantly increased aboveground biomass, with mushroom compost being more effective than biosolids, but did not significantly influence trace element uptake. Conversely, the use of topsoil did not affect aboveground biomass, but did influence trace element uptake. Treatments that received topsoil supported plant growth with significantly higher trace element tissue concentrations than treatments that did not receive topsoil. In general, it was found that waste rock could be directly revegetated when properly neutralized, fertilized, and amended with organic matter. Additionally, stockpiled topsoil, when neutralized with lime, supported plant growth equivalent to that on nonstockpiled topsoil.     

Comparison of atrazine losses in three small headwater catchments

Understanding the processes causing herbicide transport to surface waters is crucial to determine mitigation options to reduce these losses. To this end, we investigated the atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) transport in three agricultural catchments (1.1-2.1 km2) in the watershed of Lake "Greifensee" (Switzerland). In 1999, atrazine application data were recorded for all three catchments. Time proportional samples were taken at a high temporal resolution at the catchment outlets. Extremely wet conditions caused large relative losses from the catchments, ranging between 0.6 and 3.5% of the amount applied. Most of the atrazine load was due to event-driven diffuse losses from the fields. Farmyard runoff contributed less but caused the highest concentrations (up to 31 microg L(-1)) in the brooks. The maximum concentrations due to diffuse losses varied between 1.2 and 8.2 microg L(-1) among the catchments. Despite different absolute concentration levels, the concentration time-series were very similar. It seems that the travel-times within the catchments were mainly controlled by the rainfall pattern with little influence of the catchment properties. These properties, however, caused the relative losses to vary by a factor of 6 between the catchments. This variability could be partly explained by differences in the connectivity of the fields to the brooks and by their hydrological soil properties. A comparison of the losses from the three catchments with those from the entire watershed of Lake Greifensee demonstrated that they were representative for the larger area. Hence, the study results provide a good data set to evaluate distributed models predicting herbicide losses.     

Vertical and horizontal distribution of sub-littoral meiofauna in Algoa Bay,South Africa

Meiofauna was sampled using SCUBA along 4 transects from 5 to 30 m depth in Algoa Bay, South Africa. Substrates were well-sorted medium to fine sands with traces of sewage pollution in some areas. Meiofauna numbers recorded in the upper 10 cm of sediment were 55 to 584 10 cm^-2, but total numbers, including deeper-living animals, were 680 to 2090 10 cm^-2 at 6 stations. Longer cores showed meiofauna to be abundant down to at least 35 cm, and samples of interstitial water taken from this depth in the sediment were 7% saturated with oxygen. This is the first detailed record of meiofauna penetration into sub-littoral sand and stresses the need for long cores for quantitative work. Nematode numbers were found to be significantly related to nitrogen in the sand while interstitial harpacticoid numbers were related to median particle diameters, which determine pore space. Effects of sewage were slight and only one station showed notable enrichment, increased meiofaunal numbers and extreme dominance by nematodes.     

ALTERNATIVE STRATEGIES FOR STORMWATER DETENTION1

ABSTRACT: In a simulation experiment, stormwater flows are partially diverted, at various levels, to a detention basin in order to compare the recombined (i.e., undiverted flows and basin discharges) hydrograph to the response of the traditional, in-line design. The use of off-line detention basins is shown to be an effective technique for reducing peak flows from developed watersheds to pre-development levels with lower storage requirements. In addition, the discharge hydrographs produced by off-line detention are significantly different from those produced by the traditional design and may be more suited to certain stormwater management situations.