Energy recovery from lipid extracted,transesterified and glycerol codigested microalgae biomass

The production of methane (CH₄) via the anaerobic digestion of microalgae biomass residues from the biodiesel production process has the potential to meet some of the energy requirements of the primary biomass to fuel conversion process. This paper investigates the practical CH₄ yields achievable from the anaerobic conversion of the microalgae residues (as well as codigestion with glycerol) after biodiesel production using both the conventional and in situ transesterification methods. Results demonstrate that the type of lipid extraction solvent utilized in the conventional transesterification process could inhibit subsequent CH₄ production. On the basis of actual CH₄ production, a recoverable energy of 8.7–10.5 MJ kg^?1 of dry microalgae biomass residue was obtained using the lipid extracted and transesterified microalgae samples. On codigesting the microalgae residues with glycerol, a 4–7% increase in CH₄ production was observed.     

Australia's marine biogeography revisited: Back to the future?

The recognition of broad biogeographic provinces provides an important framework for ecological and conservation biological research. Marine biologists have long recognized distinct biogeographic provinces in southern Australia, primarily on the basis of qualitative differences in intertidal species assemblages. Here we provide an a priori test for these traditional eastern (Peronian), western (Flindersian) and south‐eastern (Maugean) provinces. Specifically, we analyse distributional data for approximately 1500 algal species using the newly available Australian Virtual Herbarium, an online database of herbarium specimens. Our quantitative algal analyses across southern Australia identify three distinct biogeographic assemblages, consistent with traditional qualitative provinces. We argue that these broad provinces provide a highly effective framework for understanding and managing Australia's marine biodiversity. In particular, biogeographic provinces provide a regional framework for integrating the ongoing discovery of biological variation at finer scales. More broadly therefore we recommend that biologists undertake quantitative analyses to test provincial biogeographic boundaries around the globe.     

Is the signal from the mesophyll to the guard cells a vapour‐phase ion?

Previous studies have suggested that the red light and CO₂ responses of stomata are caused by a signal from the mesophyll to the guard cells. Experiments were conducted to test the idea that this signal is a vapour‐phase ion. Stomata in isolated epidermes of Tradescantia pallida were found to respond to air ions created by an electrode that was positioned under the epidermes. Anthocyanins in the epidermes of this species were observed to change colour in response to these air ions, and this change in colour was attributed to changes in pH. A similar change in lower epidermal colour was observed in intact leaves upon illumination and with changes in CO₂ concentration. Based on the change in epidermal colour, the pH of the epidermis was estimated to be approximately 7.0 in darkness and 6.5 in the light. Stomata in isolated epidermes responded to pH when suspended over (but not in contact with) solutions of different pH. We speculate that stomatal responses to CO₂ and light are caused by vapour‐phase ions, possibly hydronium ions that change the pH of the epidermis.     

Estimating Numbers of Black Brant Using Sequential Spring-Staging Sites

Abstract: Estimating total number of birds using a particular staging site during migration is challenging because counts alone do not account for turnover in the local population. Robust statistical methods are needed to more fully assess the conservation value of such sites. We used the multi-strata model in Program MARK to estimate time-dependent transition probabilities between sequential staging sites to estimate lengths of stay for spring-staging Pacific black brant (Branta bernicla nigricans) on the Fraser River delta and Parksville-Qualicum areas in the Strait of Georgia, British Columbia, Canada. Using resightings of marked individuals in combination with ground counts, we estimated the total number of brant, with associated uncertainties, staging at these sites during the spring migrations of 1999 and 2000. We estimated between 28,927 and 33,181 individual brant transited the Fraser River delta and Parksville-Qualicum sites in 1999 and between 21,621 and 25,405 individuals in 2000. These totals correspond to approximately 18–26% of the entire Pacific Flyway brant population, suggesting the need for continued conservation and management efforts at these sites. Given the importance of staging sites to migratory populations, we believe this method could be applied to other species and locations.     

Concentrations and controls of dissolved organic matter in a constricted-channel region of the Ohio River

A 12-month study was conducted to measure the concentrations ofdissolved organic matter (DOC, TDN, TDP) in four sites within a119 km long reach of the Ohio River, near Louisville, KY. In thisstudy we test whether specific geomorphological and biologicalfactors influenced variations in dissolved organic matter.Concentrations of DOC in the river averaged 1200mol/L, and varied by nearly two orders of magnitudeseasonally (mean DOC during base flow 620 mol/L).Peak periods for DOC at all sites were during April–May. Thesite nearest a navigation dam (deeper, lower current velocities)had significantly lower concentrations of TDN and greater C:Nratios than upstream sites. The largest tributary entering thisreach (Kentucky River) had no significant effect on levels of DOMin the main river, despite having significantly greaterconcentrations of TDN and lower levels of DOC during most monthsof the year. Concentrations of DOC, TDN, and TDP were notsignificantly different in littoral and pelagic habitats at allsites studied, suggesting little floodplain influence on DOM inthis constricted-channel section of the Ohio River. C:N ratios ofDOM in the Ohio were significantly different among seasons; C:Nexceeded or equaled Redfield ratios in summer and fall (6 to 10),but were below Redfield (1.8 to 3.0) during winter and spring.Regression models suggest that total phytoplankton densities andflow conditions are the two most important factors regulating DOMin this very large river.     

Quantifying the costs and benefits of protective egg coating in a Chrysomelid beetle

Abstract.  1. The costs and benefits of behavioural care of offspring can often be easily quantified through observations and experiments. Other forms of parental investment, on the other hand, are usually less amenable to cost–benefit analysis.
2. Here, the costs and benefits are estimated for protective egg coating by a chrysomelid beetle, Cryptocephalus hypochaeridis , where the female spends a considerable amount of time adding extra structural components to each of the eggs after laying them.
3. Adding this protective coating was very costly, both in terms of material and energy used: the mass of the extrachorion is equivalent to half the mass of the egg, and water loss and energy expenditure while coating the egg is equivalent to half what would be lost while laying a further egg.
4. Choice tests with egg predators demonstrated that these high costs are offset by benefits in terms of protection against predation: whereas uncoated eggs are readily eaten by predators, coated eggs are always rejected.     

The functional response of Toxorhynchites rutilus rutilus to changes in the population density of its prey Aedes aegypti

We present an analysis of the functional response of the predator Toxorhynchites rutilus rutilus (Coquillett) to changes in the density of the larvae of Aedes aegypti (L.) (Diptera: Culicidae). The experiment was replicated for five different ages, and at three different densities of the predator. The data were fitted to Rogers' (1972) random predator equation by non-linear least-squares in order to estimate searching efficiency and handling time for each experimental treatment. The data show that estimated searching efficiencies are highest at intermediate ages of the predator for all predator densities tested. Handling time declines exponentially with increasing predator age. There is a marked interference effect; searching efficiency decreases with increased predator density, and this is most pronounced at intermediate prey ages. Estimated handling times increase with predator density at a rate which declines with increasing predator age.     

Species and site differences in Neotropical army ant emigration behaviour

Abstract 1. Along with large wingless queens and group foraging raids, periodic colony movements or emigrations are a defining feature of army ant behaviour. Emigrations are important because they regulate spacing among colonies, and provide access to new foraging sites. 2. Raid and emigration activity of army ant communities was measured at four Neotropical sites using a standardised sampling protocol. Sampling of emigration activity was carried out throughout the diel cycle. 3. Both raid and emigration activity occurred throughout the day and night. Emigration activity was highest under cover of darkness, but sites and species differed in the diel timing of emigrations. These site and species differences have implications for the evolution of emigration behaviour, as well as for the community ecology of army ants.     

Identification and functional characterization of effectors in expressed sequence tags from various life cycle stages of the potato cyst nematode Globodera pallida

In this article, we describe the analysis of over 9000 expressed sequence tags (ESTs) from cDNA libraries obtained from various life cycle stages of Globodera pallida . We have identified over 50 G. pallida effectors from this dataset using bioinformatics analysis, by screening clones in order to identify secreted proteins up-regulated after the onset of parasitism and using in situ hybridization to confirm the expression in pharyngeal gland cells. A substantial gene family encoding G. pallida SPRYSEC proteins has been identified. The expression of these genes is restricted to the dorsal pharyngeal gland cell. Different members of the SPRYSEC family of proteins from G. pallida show different subcellular localization patterns in plants, with some localized to the cytoplasm and others to the nucleus and nucleolus. Differences in subcellular localization may reflect diverse functional roles for each individual protein or, more likely, variety in the compartmentalization of plant proteins targeted by the nematode. Our data are therefore consistent with the suggestion that the SPRYSEC proteins suppress host defences, as suggested previously, and that they achieve this through interaction with a range of host targets.