Conservation by Design

Abstract: Conservation researchers are increasingly aware of the need to conduct interdisciplinary research and to engage nonscientists in practical applications of conservation biology. But so far, industrial designers have been left out of such collaboration and outreach efforts. Conservation of wildlife often depends on products such as nest boxes, feeders, barriers, and corridors, all of which have a designed component that is frequently overlooked. Furthermore, many products are adopted without testing on short or long time scales. We argue that the design of products for conservation, and hence their functionality, effectiveness, and value, can be improved through collaboration with industrial designers. We see four key benefits that can arise from interactions with industrial designers: improvement of product quality and value, innovation and improvement in functionality of products, harmonization of conservation products with local values, and development of a psychological biomimesis approach to design. The role of industrial designers in conservation projects would be to improve factors such as product durability, affordability, functionality, and aesthetic appeal to local people. Designers can also help to create multiple product options whose success can be tested in the field. We propose that collaborations with industrial designers can contribute to the development of improvements to existing products and innovations in the practice of animal conservation.     

Shipboard bilge water treatment by electrocoagulation powered by microbial fuel cells

Reveals the synergy between microbial fuel cells and electrocoagulation. Demonstrates MFC-ECC shipboard wastewater treatment is advantageous. MFC-ECC integration enables energy neutral bilge water treatment. Ships generate large amounts of wastewater including oily bilge water, blackwater and greywater. Traditionally they are treated separately with high energy consumption. In this study we demonstrate the feasibility that these waste streams can be treated using an integrated electrocoagulation cell (ECC) and microbial fuel cell (MFC) process, which not only synergized the contaminants removal but also accomplished energy neutrality by directly powering EC with MFC electricity. Results showed that MFC stack powered ECC removed 93% of oily organics, which is comparable to the performance of an external DC voltage powered ECC. In the meantime, more than 80% of COD was removed from MFCs when fed with either acetate or municipal wastewater. Moreover, the ECC electrode area and distance showed notable effects on current generation and contaminants removal, and further studies should focus on operation optimization to enhance treatment efficiency.     

Products of denitrification by a marine bacterium as revealed by gas chromatography

Gas chromatography was used to analyse the gases released by growing cultures of the denitrifying marine bacterium Pseudomonas perjectomarinus. When nitrate was provided as final oxidant, CO₂ was the first detectable gas released. Following the peak rate of release of CO₂ at approximately 16 h, N₂ liheration began and peaked at 30 h. When N₂O was provided as terminal oxidant, CO₂ and N₂ release began within a few hours and the rate of liberation of both increased for 45 to 50 h before leveling. Cell-free extracts of bacteria from denitrifying cultures of P. perfectomarinus were incubated anaerobically with nitrate, malic acid and electron transfer cofactors provided, and the gases in the atmosphere above the reaction mixtures were analysed. NO was found to be present transiently, and N₂O was discerned after prolonged incubation. The applicability of gas chromatography to analyses of marine ecosystems and the need for better means of sampling the atmosphere above enzymatic reaction mixtures were disoussed.     

Biodeposition by salt-marsh invertebrates

The importance of salt-marsh invertebrate biodeposits in biogeochemical cycles is discussed. Yearly biodeposition rates of nitrogen, phosphorus, potassium, magnesium, maganese, copper, zinc, and molybdenum are reported for 5 invertebrate species. The 5 species (Littorina irrorata, Arcatula demissa, Polymesoda caroliniana, Uca pugnax and U. pugilator) deposit 1709 g dry weight m² year^-1, of which 455 g m² year^-1 is organic material. Calculations suggest that the invertebrates are capable of processing 53% of the marsh's yearly production, but the actual amount utilized is probably substantially less than this.Contribution No. 716 from the Virginia Institute of Marine Science, and Contribution No. 295 from the University of Georgia Marine Institute.     

Human carcinogenesis by arsenic

Arsenic is one of the few human carcinogens for which there is not yet a reliable animal cancer model. As such, the classification of arsenic as a carcinogen is based upon data derived from human epidemiologic studies. Although the mechanisms of action of arsenic as a toxic agent have been known for many years, the inability to produce cancer with arsenic in laboratory animals has confounded the operational characterisation of arsenic as initiator, promoter, complete carcinogen, or cocarcinogen for humans. Arsenic is clearly a genotoxic agent that induces chromosomal aberrations, micronuclei and sister chromatid exchange in mammalian cells as well as neoplastically transforms Syrian hamster embryo cells; however, it is not a classical point mutagen. This paper reviews some of the scientifically based issues relating to arsenic and risk assessment.     

Echolocation by cave swiftlets

Summary The ability of cave dwelling swiftlets (Collocalia spodiopygius) to detect small cylindrical obstacles by echolocation was tested in a 3x9 m flight chamber. Although there was great individual variability, 6.3 mm obstacles were avoided much more often in total darkness than 1.5 wires (P<0.001). Flash photographs showed that the latter were avoided only by chance (about 50% misses). Obstacles 3.0 mm in diameter were avoided only slightly more often than 1.5 mm wires.Even in the light these swiftlets avoided the obstacles in only about 75% of the trials, probably because gentle touches with the primary feathers caused little discomfort.The 3.0 and 6.3 mm obstacles tended to be avoided more often on first encounters after they had been shifted horizontally by 10–30 cm, probably because the birds became more attentive.     

Direct measurement of dissolved organic carbon release by phytoplankton and incorporation by microheterotrophs

It is now possible to divide particulate primary production into algal and heterotrophic components without physical separation. This depends on two innovations, the introduction of isotope in the form of labelled dissolved product(s) of primary production and the employment of a data analysis specifically designed for tracer kinetic incorporation experiments. The ¹⁴C technique described by Steemann Nielsen (1952) is inapplicable in the analyses of certain classes of systems and kinetic tracer incorporation experiments must be employed instead. We show that measurement of PDOC production rate requires such kinetic tracer analyses. Measurements made in the laboratory on water taken from 2 m depth in South West Arm of the Port Hacking estuary showed that: (1) the steady-state rate of PDOC production was 0.10 to 0.13 mg C.m^-3.h^-1; (2) the rate of PDOC incorporation into microheterotroph particulate organic carbon was 0.10 to 0.12 mg C.m^-3.h^-1; (3) the rate at which PDOC was respired to CO₂ was 0.001 to 0.003 mg C.m^-3.h^-1. (4) the PDOC makes up only about 0.1% of the total dissolved organic carbon. The size class of particles associated with PDOC production differed from the size class responsible for uptake of PDOC. More than 50% of the PDOC production was associated with particles having a nominal diameter range of 20 to 63 m, while this fraction was responsible for <10% of the incorporation.     

Rapid degradation of carbon tetrachloride by commercial micro-scale zinc powder assisted by citric acid

We developed an effective method for degradation of carbon tetrachloride (CT) in contaminated water. Zinc metal as a reducing agent for CT in aqueous solutions has been previously studied in some detail, but the rapid corrosion of zinc surface usually reduces its efficiency in removing CT. We assumed that citric acid could enhance the degradation of CT by zinc powder due to the elimination of a passivation layer of Zn(II) (hydr)oxides on the surface of zinc powder through chelating of organic ligands with Zn(II) produced from the reaction and keeping the exposure of active sites to targets. Here the influence of citric acid on the decomposing of CT by commercial micro-scale zinc powder was investigated in a pH range of 3.5–7.5 at 25°C in batch experiments. Reaction mixtures were analysed by gas chromatography/headspace analysis, and Cl⁻ concentration was determined by turbidimetry. The results demonstrate that the degradation of CT by zinc metal alone is very weak, but the addition of citric acid can assist zinc powder to decompose CT more completely and rapidly at all pHs. Degradation of CT took place mainly in the first 10 min of reaction, coupled with 75–95% of CT removal. Maximum dechlorination percentage (82.4%) of CT was obtained at pH 5.5. In that case, chloroform and dichloromethane, as main intermediates, were found at low levels during the whole reaction, suggesting that CT may be sequentially and multiply degraded so quickly that methane is yielded before the intermediates can be desorbed and released to aqueous solution. When compared with the current methods of nano-scale zinc and bimetallic systems, the application of commercial micro-scale zinc particles assisted by organic ligands is of environmental significance since it allows decontamination of aqueous chlorinated organic compounds at low cost and with high efficiency.     

不同阳离子影响下小麦根吸收镉的动力学过程

生物配体模型(BLM)是基于稳定态假设的一个平衡模型,能够较准确地运用于预测重金属的毒性及其生物有效性.根据BLM模型的假设条件模拟土壤溶液,研究了Ca2+、Mg2+、Cu2+和Ni2+对小麦根吸收Cd2+动力学的影响,阐述了BLM在应用中存在的局限性.结果表明:在8h内的短期动力学吸收实验中,小麦根对Cd的吸收及吸附量呈线性增加,但未达到稳定值,这说明Cd2+在根-液界面未达到稳定平衡;并且小麦根对Cd的吸收是受溶液中Cd2+扩散速率影响的.小麦根对Cd的吸收通量与Cd2+浓度[Cd2+]和Cd与小麦根表上的配体结合浓度{Cd-Rcel}l都具有较好的线性关系,但随着Cd2+浓度的增加稳定常数KM-Rcell、渗透常数p和同化速率常数kint均呈降低趋势.Ca2+、Mg2+和Cu2+降低了小麦根对Cd2+的吸收通量,而Ni2+对Cd2+的竞争作用不显著.由于Cd与Ca、Ni有共同的吸收通道,Ca通道吸收达到饱和后可降低小麦根对Cd的吸收,但是Ca2+、Mg2+和Cu2+通过降低内化速率常数也可使小麦根对Cd的内化通量减少,因此不能完全用竞争效应解释其结果.另外,阳离子的存在会改变小麦根表的性质,Ca2+、Mg2+的存在会增加亨利系数KCd,即生物配体浓度{Rcel}l和(或)离子与生物配体结合稳定常数KCd-Rcell会增加,同时这些离子的存在还会降低渗透常数p和kint;Cu2+、Ni2+的存在会降低KCd;且p和k在低浓度Cd(0.01～0.05μM)条件下增加,在高浓度Cd条件下降低.     

Pollutant removal by an integrated vertical-flow constructed wetland treating simulated river water by reoxygenation

The effects and mechanism of chemical oxygen demand (COD), nitrogen, and phosphorus concentration removal by an integrated vertical-flow constructed wetland were studied in the wetland system during one inlet–outlet operating period, in two typical stages (each stage is connective 24 h, sampled once every 4 h). The concentration of ammonia decreased along the flow direction in the system, while levels of nitrate (NO₃^?-N) increased. In one operating period, total nitrogen (TN) concentration fell with rising operation time due to evacuative reoxygenation. The TN and NH₃-N removal rates in the system were 26.6% and 97.5%, respectively. COD decreased rapidly in the early stages and more gradually in the direction of water flow of the wetland system. Average total phosphorus (TP) removal rate was 20.71%. TN and NO₃^?-N levels in water of the wetland had a tendency to decline gradually with increasing operation time. Ammonia concentrations displayed only a small variation with operation time. The results also indicated that the wetland was able to maintain its temperature. The oxygen content differed during the various operating stages and exerted a marked influence on COD, TP, and TN removal.     

Vinasse biodegradation by Phanerochaete chrysosporium

Vinasse is a colored recalcitrant wastewater of the distillery industry. The aim of this work was to study the use of Phanerochaete chrysosporium for the vinasse degradation under two different growth conditions. Vinasse was treated by P. chrysosporium in a liquid inoculum form, during 32 days at room temperature (approximately 25 degrees C) and at 39 degres C. Chemical oxygen demand (COD), total phenol concentration and color removal were measured and there8 was a decrease in COD, phenolic concentration and color of 47.48%, 54.72% and 45.10% respectively, at room temperature and a decrease in 54.21%, 59.41% and 56.8 1% respectively at 39 degrees C.     

Superoxide production by marine microalgae

A survey was conducted for production of the reactive oxygen species superoxide by 37 species (65 strains) of microalgae including dinoflagellates, raphidophytes, chlorophytes, prasinophytes, eustigmatophytes and prymnesiophytes. Ichthyotoxic raphidophyte species of Chattonella were found to produce the highest environmental levels of superoxide (177×10⁴ total chemiluminescence units). However, ichthyotoxic dinoflagellates (Karenia, Alexandrium) and the prymnesiophyte Prymnesium were also found to produce significant levels of superoxide (4×10⁴, 3×10⁴ and 5×10⁴ chemiluminescence units, respectively), equivalent to that of other raphidophyte species of Heterosigma and Fibrocapsa (6×10⁴ and 2×10⁴, respectively). A direct relationship between cell size and superoxide production was observed (r²=0.94), with larger cells producing more superoxide per cell. Chattonella produced the most superoxide per cell (expressed as cellular chemiluminescence units), followed by the dinoflagellate species Karenia, Alexandrium, Takayama and Gymnodinium. Small cells, such as the raphidophyte Heterosigma and the prymnesiophyte Prymnesium produced very little superoxide per cell (cellular chemiluminescence units), but potentially could still produce high total levels of superoxide if present at high biomass levels. Species commonly used as aquaculture bivalve feeds such as Dunaliella, Tetraselmis, Nannochloropsis and Pavlova produced negligible levels of superoxide, even at high biomass. We speculate that superoxide, while not the sole ichthyotoxic principle, may play a wider role in algal toxicity than previously considered, and propose a broad classification of microalgae based upon superoxide production.Communicated by M.S. Johnson, Crawley     

石油污染物的微生物降解研究

以炼油厂污水池底泥中分离的3株细菌和3株真菌为供试微生物,陕北黄土(0～20 cm)制备的土壤悬浮液为土壤微生物对照,灭菌培养基为非生物降解对照,研究不同组合微生物的生长动态及对石油烃的降解率.将不同组合的微生物接种到石油烃质量浓度为10000 mg·L-1的液体培养基中,29 ℃±1 ℃,摇床连续培养50 d.于0 ～72 h内取样,进行微生物生长动态检测;于5～50 d定期取样,考察培养基中石油烃降解率的动态变化.结果表明:单独外源菌降解效果优于混合外源菌和土著微生物,25 d后土著微生物生物降解率超过混合外源菌.外源细菌、外源真菌、混合外源菌和土著微生物50 d生物降解率分别为71.54 %,60.13 %,47.26 %和51.49 %.土壤细菌对石油污染物具有较强的生长适应性,外源细菌降解效果最好.     

Heavy-metal adsorption by non-living biomass

The adsorption of some heavy metals onto the walls of harvested, washed, and dried non-living biomass cells of different Pseudomonas strains was studied at optimum experimental conditions using a simplified single component system. The Langmuir adsorption model was found to be a suitable approach to describe the system via multi-step processes. Isotherms measured at 30.0°C and pH 5.5 with [M]_total?=?10–100 mM for tight, reversible Cr⁶⁺(aq), Ni²⁺(aq), Cu²⁺(aq) and Cd²⁺(aq) binding by the cell walls of the investigated biomass fit the Langmuir model and give the pH-independent stoichiometric site capacities ν _i and equilibrium constants K _i for metal binding at specific biomass sites i?=?A, B, C, and D. Tight binding sites A, B, and D of the non-living biomass are occupied by Cr^VI, sites A and C by Ni^II, sites A and D by Cd^II, and only site B by Cu^II. It is concluded that ν _i is a stoichiometric parameter that is independent of the magnitude of K _i for binding site i and that the studied heavy metals selectively and tightly bind at different biomass sites.     

二甲亚砜作探针试剂研究Fenton反应条件

随着高级氧化技术成为废水处理的研究热点,羟基自由基的产生、测定及测定条件等相关问题的探索,成为发展高级氧化技术的重要条件及其重要组成部分。以分光光度法为主要分析方法,以二甲亚砜作为·OH的探针试剂,对Fenton反应及其反应的最佳条件进行研究。结果表明,在实验条件下,H2O2初始浓度为11.5mmol/L,Fe2+/H2O2的浓度比值在1:23左右,pH范围为3～4时,·OH产率最高。     

Biogas upgrading by cryogenic techniques

Environmental Chemistry Letters - The scarcity of fossil fuels and the worldwide pollution have led the scientific community to seek renewable energy alternatives. In particular, biogas has become...