Carbohydrases of some marine invertebrates with notes on their food and on the natural occurrence of the carbohydrates studied

Extracts of 22 marine invertebrates were incubated with 29 different carbohydrates, and enzyme spectra estimated from chromatograms. Enzymatic activities were quantified as reducing sugar in 14 of these species. Significant hydrolysis of laminaran, glycogen, and amylose was found in nearly all species, while hydrolysis of oligosaccharides and structural polysaccharides in most cases was weak or absent. The strongest overall degradation of carbohydrates was found among crustaceans. Enzymatic degradation of laminaran shows some relation to food, but the spectra of carbohydrases are not directly predictable from knowledge of natural food sources. Some carbohydrases (sucrase, cellobiase, lactase) could not be explained by ecological considerations. The results indicate that structural polysaccharides are utilized only to a small extent.     

Effects of different management strategies on long-term trends of Australian threatened and near-threatened mammals

Monitoring is critical to assess management effectiveness, but broadscale systematic assessments of monitoring to evaluate and improve recovery efforts are lacking. We compiled 1808 time series from 71 threatened and near-threatened terrestrial and volant mammal species and subspecies in Australia (48% of all threatened mammal taxa) to compare relative trends of populations subject to different management strategies. We adapted the Living Planet Index to develop the Threatened Species Index for Australian Mammals and track aggregate trends for all sampled threatened mammal populations and for small (<35 g), medium (35–5500 g), and large mammals (>5500 g) from 2000 to 2017. Unmanaged populations (42 taxa) declined by 63% on average; unmanaged small mammals exhibited the greatest declines (96%). Populations of 17 taxa in havens (islands and fenced areas that excluded or eliminated introduced red foxes [Vulpes vulpes] and domestic cats [Felis catus]) increased by 680%. Outside havens, populations undergoing sustained predator baiting initially declined by 75% but subsequently increased to 47% of their abundance in 2000. At sites where predators were not excluded or baited but other actions (e.g., fire management, introduced herbivore control) occurred, populations of small and medium mammals declined faster, but large mammals declined more slowly, than unmanaged populations. Only 13% of taxa had data for both unmanaged and managed populations; index comparisons for this subset showed that taxa with populations increasing inside havens declined outside havens but taxa with populations subject to predator baiting outside havens declined more slowly than populations with no management and then increased, whereas unmanaged populations continued to decline. More comprehensive and improved monitoring (particularly encompassing poorly represented management actions and taxonomic groups like bats and small mammals) is required to understand whether and where management has worked. Improved implementation of management for threats other than predation is critical to recover Australia's threatened mammals.     

Decision-support tools for dynamic management

Spatial management is a valuable strategy to advance regional goals for nature conservation, economic development, and human health. One challenge of spatial management is navigating the prioritization of multiple features. This challenge becomes more pronounced in dynamic management scenarios, in which boundaries are flexible in space and time in response to changing biological, environmental, or socioeconomic conditions. To implement dynamic management, decision-support tools are needed to guide spatial prioritization as feature distributions shift under changing conditions. Marxan is a widely applied decision-support tool designed for static management scenarios, but its utility in dynamic management has not been evaluated. EcoCast is a new decision-support tool developed explicitly for the dynamic management of multiple features, but it lacks some of Marxan's functionality. We used a hindcast analysis to compare the capacity of these 2 tools to prioritize 4 marine species in a dynamic management scenario for fisheries sustainability. We successfully configured Marxan to operate dynamically on a daily time scale to resemble EcoCast. The relationship between EcoCast solutions and the underlying species distributions was more linear and less noisy, whereas Marxan solutions had more contrast between waters that were good and poor to fish. Neither decision-support tool clearly outperformed the other; the appropriateness of each depends on management purpose, resource-manager preference, and technological capacity of tool developers. Article impact statement: Marxan can function as a decision-support tool for dynamic management scenarios in which boundaries are flexible in space and time.     

Sodium bisulfate and a sodium bisulfate/tannin mixture decreases pH when added to an in vitro incubated poultry cecal or fecal contents while reducing Salmonella Typhimurium marker strain survival and altering the microbiome

The objective of the present study was to investigate the ability of animal feed-grade sodium bisulfate (SBS) and a mixture of sodium bisulfate/tannin to inhibit the growth of Salmonella using an anerobic in vitro mixed cecal culture to mimic the conditions within the chicken cecum. An initial inoculum of Salmonella Typhimurium was introduced to an anerobic dilution solution containing 1/3000 diluted cecal bacteria and solids consisting of ground chicken feed and different percentages of solid SBS or SBS/tannin, and surviving organisms were enumerated. Two different experimental designs were employed. In the “unadapted” treatment, the S. Typhimurium was added at the beginning of the culture incubation along with cecal bacteria and chicken feed/SBS or chicken feed/SBS/tannin. In the “adapted” treatment, S. Typhimurium was added after a 24 hour pre-incubation of the cecal bacteria with the chicken feed/SBS or chicken feed/SBS/tannin. Adding SBS resulted in reduction of pH in the cultures which paralleled with the reduction of S. Typhimurium. The SBS alone was found to be inhibitory to S. Typhimurium in the adapted treatment at all concentrations tested (0.25, 0.5, and 0.75%), and the degree of inhibition was concentration-dependent. Salmonella Typhimurium was completely killed in the adapted culture with 0.5% SBS after 24 and 48 h. The SBS/tannin mixture was less inhibitory than SBS alone at the same concentrations in side-by-side comparisons. Testing at a 0.5% SBS concentration, chicken age had little or no effect on log reduction of S. Typhimurium relative to age-matched control cultures without SBS, but age did affect the absolute number of S. Typhimurium surviving, with the greatest decreases occurring at 2 and 4 weeks of age (approx. 10³ S. Typhimurium surviving) compared to 6 weeks of age (approx. 10⁵ Salmonella surviving). Microbiome analysis with an Illumina MiSeq platform was conducted to investigate bacterial compositional changes related to the addition of SBS. The relative abundance of Firmicutes (at the phylum level) was decreased, and genera Lactobacillus and Faecalibacterium were increased when SBS was added to the anaerobic mixed culture containing either fecal or cecal material. The antimicrobial action of feed-grade SBS may represent a potential pre-harvest control measure for Salmonella in poultry production.     

Human maternal and umbilical cord blood concentrations of polybrominated diphenyl ethers

Polybrominated diphenyl ethers (PBDEs), widely used as flame retardants in commercial products, have become ubiquitous environmental contaminants. Although adult human exposure to PBDEs is well documented, developmental exposure is less well characterized. The objectives of this study were to measure maternal and fetal exposure to nine PBDE congeners and to investigate potential associations with birth weight. PBDE congeners were quantified in maternal serum at 24-28 weeks of pregnancy, delivery, and umbilical cord serum (UCS) by gas chromatography-mass spectrometry (GC/MS/MS). Complete blood sample sets were obtained from 97 pregnant women (mean age 33.1 ± 0.5 years). PBDE-28, -47 and -99 were quantified in all samples tested and PBDE-47 was the most abundant congener measured in both maternal (mid-pregnancy and delivery samples geometric mean = 26.9 and 26.9, respectively) and UCS (GM = 56.0 ng g⁻¹ lipid). The UCS concentration for all congeners with the exception of PBDE-153 was higher vs. maternal delivery samples (p < 0.001). Only the UCS concentration of PBDE-17 and -99 were significantly associated (β = −49.860, p = 0.032, and β = −3.645, p = 0.05) with birth weight. However, after adjustment for potential confounders only the association between PBDE-99 and birth weight remained significant (β = −3.951 and p = 0.016). We conclude that: the fetus is exposed to PBDEs from at least the second trimester of pregnancy onward; PBDE congeners are higher in UCS compared to maternal serum samples collected at delivery; and that developmental PBDE exposure is potentially associated with lower birth weight.     

Animal Welfare and Organic Aquaculture in Open Systems

The principles of organic farming espouse a holistic approach to agriculture that promotes sustainable and harmonious relationships amongst the natural environment, plants, and animals, as well as regard for animals’ physiological and behavioral needs. However, open aquaculture systems—both organic and conventional—present unresolved and significant challenges to the welfare of farmed and wild fish, as well as other wildlife, and to environmental integrity, due to water quality issues, escapes, parasites, predator control, and feed-source sustainability. Without addressing these issues, it is unlikely that open net-pen aquaculture production can be compatible with the principles inherent to organic farming.     

Decentralized Groundwater Recharge Systems Using Roofwater and Stormwater Runoff1

Stephens, Daniel B., Mark Miller, Stephanie J. Moore, Todd Umstot, and Deborah J. Salvato, 2011. Decentralized Groundwater Recharge Systems Using Roofwater and Stormwater Runoff. Journal of the American Water Resources Association (JAWRA) 48(1): 134‐144. DOI: 10.1111/j.1752‐1688.2011.00600.x Abstract: Stormwater capture for groundwater recharge in urban areas is usually conducted at the regional level by water agencies. Field and modeling studies in New Mexico indicate that stormwater diverted to retention basins may recharge about 50% of precipitation that falls on the developed area, even in dry climates. Comparable volumes of recharge may be expected at homes, subdivisions, or commercial properties with low‐impact development (LID) technologies for stormwater control that promote recharge over evapotranspiration. Groundwater quality has not been significantly impacted at sites that have been recharging stormwater to aquifers for decades. Distributed recharge systems may be a good alternative to centralized regional facilities where there is limited land for constructing spreading basins or little funding for new infrastructure. LID technologies borrowed from stormwater managers are important tools for groundwater managers to consider to enhance recharge.     

Long-term copper partitioning of metal-spiked sediments used in outdoor mesocosms

Understanding the effects of sediment contaminants is pivotal to reducing their impact in aquatic environments. Outdoor mesocosms enable us to decipher the effects of these contaminants in environmentally realistic scenarios, providing a valuable link between laboratory and field experiments. However, because of their scale, mesocosm experiments are often complex to set up and manage. The creation of environmentally realistic conditions, particularly when using artificially contaminated sediment, is one issue. Here, we describe changes in geochemistry over 1.5 years of a sediment spiked with four different concentrations of copper, within a large freshwater mesocosm facility. The spiking procedure included proportional amendments with garden lime to counteract the decreases in pH caused by the copper additions. The majority of copper within the spiked mesocosm sediments partitioned to the particulate phase with low microgram per liter concentrations measured in the pore waters and overlying waters. The minimum partition coefficient following equilibration between pore waters and sediments was 1.5?×?10⁴ L/kg, which is well within the range observed for field-contaminated sediments (1?×?10⁴ to 1?×?10⁶ L/kg). Recommendations are made for the in situ spiking of sediments with metals in large outdoor mesocosms. These include selecting an appropriate sediment type, adjusting the pH, allowing sufficient equilibration time, and regular mixing and monitoring of metal partitioning throughout the experimental period.