Phosphorus and nitrogen sorption to soils in the presence of poultry litter-derived dissolved organic matter

Two environmental aspects associated with land application of poultry litter that have not been comprehensively evaluated are (i) the competition of dissolved organic matter (DOM) and P for soil sorption sites, and (ii) the sorption of dissolved organic nitrogen (DON) relative to inorganic nitrogen species (e.g., NO(3)(-) and NH(4)(+)) and dissolved organic carbon (DOC). The competition between DOM and P for sorption sites has often been assumed to increase the amount of P available for plant growth; however, elevating DOM concentrations may also increase P available for transport to water resources. Batch sorption experiments were conducted to (i) evaluate soil properties governing P sorption to benchmark soils of Southwestern Missouri, (ii) elucidate the impact of poultry litter-derived DOM on P sorption, and (iii) investigate DON retention relative to inorganic N species and DOC. Soils were reacted for 24 h with inorganic P (0-60 mg L(-1)) in the presence and absence of DOM (145 mg C L(-1)) using a background electrolyte solution comparable to DOM extracts (I = 10.8 mmol L(-1); pH 7.7). Soil P sorption was positively correlated with metal oxide (r(2) = 0.70) and clay content (r(2) = 0.79) and negatively correlated with Bray-1 extractable P (r(2) = 0.79). Poultry litter-derived DOM had no significant negative impact on P sorption. Dissolved organic nitrogen was preferentially removed from solution relative to (NO(3)(-)-N + NO(2)(-)-N), NH(4)(+)-N, and DOC. This research indicates that poultry litter-derived DOM is not likely to enhance inorganic P transport which contradicts the assumption that DOM released from organic wastes increases plant-available P when organic amendments and fertilizer P are co-applied. Additionally, this work demonstrates the need to further evaluate the fate and transport of DON in agroecosystem soils receiving poultry litter applications.     

Complexation of plasmid DNA and poly(ethylene oxide)/poly(propylene oxide) polymers for safe gene delivery

Environmental Chemistry Letters - Gene delivery is the process of introducing foreign genetic material, such as DNA or RNA, into host cells. Gene...     

Late season pharmaceutical fate in wetland mesocosms with and without phosphorous addition

The fate of six human-use drugs was assessed and predicted in mesocosms designed to mimic shallow constructed wetlands during the onset of fall and senescence. Mesocosms were monitored for 28 days after the addition of carbamazepine, clofibric acid, fluoxetine and naproxen (nominal initial concentrations of 5 μg/L each), sulfamethoxazole, and sulfapyridine (nominal initial concentrations of 150 μg/L each), with and without phosphorous (P) addition at 1.6 mg/L. We hypothesized that addition of P would stimulate primary productivity and enhance removal of pharmaceuticals from the water column. Carbamazepine, clofibric acid, fluoxetine, and naproxen had half-lives of 8.7, 11, 1.5, and 2.5, and 8.6, 11.0, 1.4, and 2.5 days in treatments with and without P amendment, respectively. Sulfamethoxazole and sulfapyridine had half-lives of 17 and 4.9 days in mesocosms with P amendment and 17 and 4.7 days without amendment. A concurrent pulse of P with pharmaceuticals did not significantly enhance the removal of these compounds. Predicted half-lives from modeling efforts were consistent with observed values, with photolysis the greatest contributor to chemical attenuation.

     

Did the movie Finding Dory increase demand for blue tang fish?

Representations of wildlife in television and films have long been hypothesized to shape human-wildlife interactions. A recent example is Pixar’s film Finding Dory, which featured a blue tang fish (Paracanthurus hepatus) as the main character and was widely reported in the popular press to have increased the number of such fish in the pet trade. We use Bayesian posterior predictive counterfactual models to evaluate the movie’s effect on three metrics of societal behaviour. Although there was an increase in global online searches for the blue tang 2–3 weeks after the movie, we find no substantial evidence for an increase in imports of blue tang fish into the US, or in number of visitors to US aquaria compared to counterfactual expectations. It is vital that an evidence-based discourse is used when communicating potential impacts of popular culture on human-wildlife relationships to avoid loss of credibility and misdirection of conservation resources.

     

Identification of sex pheromone components of the pea midge, Contarinia pisi (Diptera: Cecidomyiidae)

 Three components in extract of pheromone glands of female pea midges, Contarinia pisi, were found to be active on male pea midge antennae by coupled gas chromatographic-electroantennographic detection. The EAD active components were identified as 2-acetoxytridecane, (2S,11S)-diacetoxytridecane, and (2S,12S)-diacetoxytridecane. A blend of these compounds proved to be highly attractive to males in windtunnel experiments. Received: 12 November 1998 / Accepted in revised form: 26 january 1999     

Migration and habitat of white sharks (<Emphasis Type="Italic">Carcharodon carcharias</Emphasis>) in the eastern Pacific Ocean

Satellite telemetry studies of 20 adult and sub-adult white sharks (360–530 cm estimated total length (TL)) in the eastern North Pacific during 1999–2005 revealed long distance seasonal migrations from the coast of California to an offshore focal area 2,500 km west of the Baja Peninsula, as well as the Hawaii Islands. Three tags were recovered allowing detailed behavioral analyses, including one shark’s migration cycle from the coast to the offshore focal area and back. While near pinniped rookeries in autumn and winter, sharks avoided the surface and used water to 50 m depth, consistent with a silhouette-based hunting strategy. Offshore migrations were initiated during November–March and followed periods of decreasing pinniped abundance. Migrations were highly directed, taking 23 ± 5 days to reach the offshore focal area along similar paths among sharks and years, defining a migration corridor. Sharks exhibited a broad depth distribution (0–644 m) in the offshore focal area, and remained there for up to 167 days during spring and summer, though primary productivity and fishery data suggest that forage resources are scarcer there than in other regions of the eastern North Pacific. Archival data from one shark revealed intensive oscillatory movements while in the offshore focal area, a behavior that may be related to foraging or mating. Sharks traveling to Hawaii remained near the islands up to 122 days, potentially feeding on pelagic fishes and marine mammals that concentrate around the islands. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Effects of suspended and sedimented clays on juvenile hard clams,<Emphasis Type="Italic"> Mercenaria mercenaria</Emphasis>, within the context of harmful algal bloom mitigation

Increased interest in using ecologically inert clays to flocculate, sediment, and thus mitigate harmful algal blooms at nearshore mariculture sites has prompted studies on the effectiveness of this method on prolific blooms, such as those caused by the neurotoxic dinoflagellate Karenia brevis in the Gulf of Mexico. Potential repercussions of this control strategy revolve around the increased flux of suspended particles to the benthos. Juvenile suspension-feeding bivalves are potentially vulnerable as they could suffer burial, a decrease in clearance rates, and/or an increase in pseudofeces production in response to suspended clay, leading to reduced growth and delay in attaining size refuge from predators. Here we assess lethal and sublethal effects on juvenile hard clams, Mercenaria mercenaria, in a 2-week flume application of phosphatic clay to simulated blooms of the nontoxic dinoflagellates Heterocapsa triquetra and Prorocentrum micans. Flow regimes simulated two contrasting, worst-case field conditions where (1) low flow allowed complete sedimentation and formation of a benthic sediment layer, and (2) high flow allowed complete particle suspension. No clam mortalities occurred in either treatment. The sedimentation treatment showed variable growth inhibition in shell and/or tissue, but effects were not apparent compared to controls (no sediment layer), and clams rapidly resumed siphon contact with the overlying water column. In contrast, a strong growth effect (~90% reduction in shell and tissue growth) occurred in particle-suspension trials compared to no-clay controls. These results suggest that repeated clay applications in the field are likely more detrimental to clams in a high-energy environment leading to prolonged in situ resuspension of clay than in an environment favoring sedimentation.Communicated by R.J. Thompson, St. Johns     

Sea otter foraging on deep-burrowing bivalves in a California coastal lagoon

Sea otter, Enhydra lutris, predation had no detectable effect on abundance and size distribution of deep-burrowing bivalve prey in the Elkhorn Slough, California, USA. Up to 23 otters were present for 6 mo of the study period (March 1984 through April 1985). This is in contrast to previous studies of sea otter predation, especially on the shallow-burrowing Pismo clam Tivela stultorum, which can be found along the wave-exposed coast near the slough. The deep-burrowing clams Tresus nuttallii and Saxidomus nuttalli made up 61% of the prey taken in the slough, and are more difficult for otters to excavate than Pismo clams. The occurrence of foraging otters was highest in an area where the two bivalve prey were extremely abundant (18 individuals m^–2). However, the otters did not selectively prey on the largest clams available within the study sight, but foraged preferentially in a patch of smaller individuals where bivalve burrow depth was restricted by the presence of a dense clay layer. This foraging strategy maximized the amount of prey biomass obtained per unit volume of sediment excavated. Our findings suggest that in soft-sediment habitats deep-burrowing bivalves may be more resistant to otter predation than shallower burrowers.