Environmental Consequences of Invasive Species: Greenhouse Gas Emissions of Insecticide Use and the Role of Biological Control in Reducing Emissions

Greenhouse gas emissions associated with pesticide applications against invasive species constitute an environmental cost of species invasions that has remained largely unrecognized. Here we calculate greenhouse gas emissions associated with the invasion of an agricultural pest from Asia to North America. The soybean aphid, Aphis glycines, was first discovered in North America in 2000, and has led to a substantial increase in insecticide use in soybeans. We estimate that the manufacture, transport, and application of insecticides against soybean aphid results in approximately 10.6 kg of carbon dioxide (CO₂) equivalent greenhouse gasses being emitted per hectare of soybeans treated. Given the acreage sprayed, this has led to annual emissions of between 6 and 40 million kg of CO₂ equivalent greenhouse gasses in the United States since the invasion of soybean aphid, depending on pest population size. Emissions would be higher were it not for the development of a threshold aphid density below which farmers are advised not to spray. Without a threshold, farmers tend to spray preemptively and the threshold allows farmers to take advantage of naturally occurring biological control of the soybean aphid, which can be substantial. We find that adoption of the soybean aphid economic threshold can lead to emission reductions of approximately 300 million kg of CO₂ equivalent greenhouse gases per year in the United States. Previous studies have documented that biological control agents such as lady beetles are capable of suppressing aphid densities below this threshold in over half of the soybean acreage in the U.S. Given the acreages involved this suggests that biological control results in annual emission reductions of over 200 million kg of CO₂ equivalents. These analyses show how interactions between invasive species and organisms that suppress them can interact to affect greenhouse gas emissions.     

Haloperoxidases and their role in biotransformation reactions

The past year has seen further structural characterisation of both nonmetal and vanadium haloperoxidase enzymes to add to that already known for the haem- and vanadium-containing enzymes. Exploitation of these enzymes for halogenation, sulfoxidation, epoxidation, oxidation of indoles and other biotransformations has increased as more information on their catalytic mechanism has been obtained.     

Monetary Valuation of Emissions in Implementing Environmental Policy

At various levels of environmental policy making there is a demand to translate polluting emissions into monetary units. In the so-called reduction cost approach, based upon policy targets, polluting emissions are expressed in monetary terms by determination of the marginal unit reduction cost at the emission target level. This approach provides shadow prices for emissions by which it can be established whether a certain measure or technology belongs to the most efficient set of measures by which the policy targets can be reached. This article argues that, if clear (generic) government targets such as national emission reduction targets exist for an emission, shadow prices derived by this method are to be preferred to shadow prices derived by other methods for decisions at the project (implementation) level. By application of the reduction cost approach, implementation decisions can be made that are both cost-effective and consistent with government policy.     

Exploring the Chemistry and Biology of Vanadium-dependent Haloperoxidases

Nature has developed an exquisite array of methods to introduce halogen atoms into organic compounds. Most of these enzymes are oxidative and require either hydrogen peroxide or molecular oxygen as a cosubstrate to generate a reactive halogen atom for catalysis. Vanadium-dependent haloperoxidases contain a vanadate prosthetic group and utilize hydrogen peroxide to oxidize a halide ion into a reactive electrophilic intermediate. These metalloenzymes have a large distribution in nature, where they are present in macroalgae, fungi, and bacteria, but have been exclusively characterized in eukaryotes. In this minireview, we highlight the chemistry and biology of vanadium-dependent haloperoxidases from fungi and marine algae and the emergence of new bacterial members that extend the biological function of these poorly understood halogenating enzymes.     

Chemical and Physical Environmental Conditions Underneath Mat- and Canopy-Forming Macroalgae,and Their Effects on Understorey Corals

Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m⁻² dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.     

Detection of a Phytochrome-like Protein in Macroalgae

A phytochrome-like protein was detected in extracts from the red algae Corallina elongata and Gelidium sp., from the brown algae Cystoseira abiesmarina and Cystoseira tamariscifolia, and from the green algae Ulva rigida, Enteromorpha compressa and Chara hispida. Relative amounts of the photoreversible protein were determined by measurement of Δ (ΔA) values of the crude extract. SDS gel electrophoresis and immunoblotting with monoclonal antibodies directed to phytochrome from etiolated maize and oat seedlings revealed only one phytochrome-related band with apparent molecular weight of 130 kDa. The absorption difference spectrum after partial purification showed a “normal” absorption band (λ_max = 670 nm) for the Pr form but only a very weak band (λ_max = 705 nm) for the “Pfr form”.     

大型海藻的组织培养及其应用

文章对大型海藻组织培养中愈伤组织和原生质体的获得、除菌效果以及植物生长调节物质的选用的研究进展进行了概述,并对其应用和研究前景作了分析和展望。     

A Preliminary Canadian Environmental Emissions Inventory for Endogenous and Retail Pharmaceutical Estrogens

Pharmaceuticals and personal care products (PPCPs), including estrogen pharmaceuticals, have been an environmental concern for well more than a decade, but no environmental emissions inventory for Canada has yet been published. Endogenous estrogens cannot be distinguished from the equivalent pharmaceutical estrogens in the environment. Therefore, data were compiled to estimate total environmental emissions of endogenous and retail pharmaceutical estrogens by the Canadian population for year 2007. Approximately 1,700 kg of pharmaceutical estrogens were dispensed through retail pharmacies in Canada in 2007. Of this amount, total environmental emissions were estimated to be approximately 730 kg, half to surface water via municipal sewage outfalls (> 90% via sewage treatment plants providing primary, secondary, or tertiary treatment), and half to the soil vadose zone and (potentially) groundwater via in situ sewage treatment systems. Approximately 960 kg of endogenous estrogens were excreted by the Canadian population, with about 420 kg reaching the environment, again approximately half to each of surface water and soil/groundwater. In situ sewage treatment may deliver an equivalent load of estrogens to the environment as do sewage treatment plants, despite servicing only 22% of the Canadian population.     

光生物反应器培养大型海藻细胞或组织

许多大型海藻含有具潜在重要药用价值的次生代谢物质,通常这些物质在藻体中含量极微,大型海藻体本身也不像微藻那样易在短期内大量获取,并且这些物质化学结构复杂,这使得直接提取或者人工合成极为困难。利用光生物反应器培养大型海藻细胞或组织,可以经济、无限量和资源循环再利用的方式,在植物体外合成生产重要的海洋植物次生代谢物质。光生物反应器所提供的可调控和工程优化的培养环境有望成为优化次生代谢物生物合成的有效手段。光生物反应器培养大型海藻细胞或组织也是大型海藻养殖业育苗技术发展的一个重要方向。综述了近10年来光生物反应器培养大型海藻细胞或组织在培养条件以及生长动力学模型方面国内外的研究进展,并对该领域未来可能的研究方向作一展望。     

Palatability and Chemical Defenses of Macroalgae in the Antarctic Peninsula

We examined palatability of 37 species of nonencrusting macroalgae from the Antarctic Peninsula. This represents approximately 30% of the entire antarctic macroalgal flora and 75% of the 49 nonencrusting species we collected. Organic extracts from most species were also prepared and mixed into artificial foods. We examined palatability using feeding bioassays with three common, macroalga‐consuming animals (an omnivorous antarctic rockfish, Notothenia coriiceps; an omnivorous sea star, Odontaster validus; and a herbivorous amphipod, Gondogenia antarctica). Thallus pieces from 23 of 34 macroalgal species tested with the fish (68%) were rejected. Of the 23 species rejected as thallus, organic extracts of 16 were bioassayed using the fish with 9 (56%) unpalatable. Thallus pieces from 21 of 36 macroalgal species tested with the sea star (58%) were rejected. Of the 21 species rejected as thallus, organic extracts of 20 were bioassayed using the sea stars and 14 (70%) were unpalatable. Overall, 28 of the 37 species assayed as thallus (76%) were rejected by either or both the fish and sea stars. The amphipod assay was not suitable for use with thallus but was utilized with organic extracts of 23 macroalgal species that were rejected as thallus by either or both the fish and sea stars. Of these, 14 (61%) of the species' extracts were rejected by the amphipods. Unpalatability was highest among the brown algae examined with only an ephemeral, ectocarpoid species not rejected as thallus out of 10 species tested. Of the remaining nine brown algal species, six of seven tested were also unpalatable as extracts, including all the ecologically dominant, perennial species in the area. We conclude that unpalatability to herbivores is common in antarctic macroalgae and that chemical defenses may play an important role in the unpalatability of many algal species (NSF OPP9814538, OPP9901076).     

Evaluation of the Metals Industry's Position on Recycling and its Implications for Environmental Emissions

A healthy debate on the treatment of metals recycling in the life cycle assessment (LCA) community has persisted for more than a decade. While no clear consensus across stakeholder groups has emerged, the metals industry has endorsed a set of recycling “facts” that support a single approach, end‐of‐life recycling, for evaluating the environmental benefits of metals recycling. In this article we draw from research conducted in several disciplines and find that three key tenets of the metals industry capture the theoretical potential of metals recycling from a metallurgical standpoint rather than reflecting observed behavior. We then discuss the implications of these conclusions on environmental emissions from metals production and recycling. Evidence is provided that, contrary to the position of the metals industry, metals are not necessarily recycled at high rates, are recycled only a small number of times before final disposal, and are sometimes limited in recycling potential by the economics of contaminant removal. The analysis concludes that metal recycled from old scrap largely serves as an imperfect substitute for primary metal. As a result, large‐scale displacement of primary production and its associated environmental emissions is currently limited to a few specific instances.     

Environmental and Genetic Control of Dormancy in Picea abies

The effects of temperature, photoperiod and chilling on the leafing-out of Norway spruce, Picea abies (L.) Karst. were studied. High temperature promotes breakage of post-dormancy, long photoperiods having no such effect. Photoperiod and chilling cause the breakage of true dormancy. However, under field conditions, photoperiod will have no effect on leafing-out date in the spring. By use of clonal material it was possible to show substantial genetic differences between individuals in response to temperature and photoperiod. When the effect of clones was accounted for, treatments could be compared more precisely. Differences between clones were apparent in heat-sum required for leafing-out, in rapidity of response to favorable post chilling conditions, and in chilling requirement This latter quantity was given a new definition, applicable when both chilling and post chilling temperatures are controlled and specified. This is that period beyond which a further 10 days of chilling accelerates leafing-out by less than one day, i.e. the point at which the slope of the line relating days till leafing-out to chilling period, is equal to minus 0.10. Differences in leafing-out date were shown between provenances taken from throughout the range of Picea abies. These differences were related to latitude with provenances of high latitude leafing-out first.     

Environmental Control of Carbohydrate and Lipid Synthesis in Euglena

Dark-grown and light-grown nitrogen deficient Euglena accumulatedcarbohydrates and lipids under heterotrophic and phototrophicconditions. Although cellular lipid content increased, lipidas a percentage of dry weight was unaltered. Nitrogen deficientand sufficient heterotrophic cultures synthesized equal amountsof lipid per mole of exogenous carbon. Nitrogen deficiency doesnot alter the partitioning of available carbon between the synthesisof lipid and other cellular constituents but simply inhibitscell division so that the carbohydrate and lipid produced aredivided among fewer cells increasing the quantity of storageproducts per cell. Cellular chlorophyll content decreased onlywhen nitrogen deficient cells were maintained at high lightintensities suggesting that chlorophyll loss is due to a reductionin the rate of resynthesis of chlorophyll destroyed throughphotooxidative damage. Anaerobiosis triggered lipid synthesisand promoted carbohydrate breakdown in the dark and light. Evenafter six days of nitrogen deficiency, anaerobiosis triggeredadditional lipid accumulation and carbohydrate breakdown. Incontrast to nitrogen deficiency, anaerobiosis produced a preferentialincrease in the percentage of dry weight as lipid. This increasewas due as much to a decrease in cellular dry weight as it wasto the preferential utilization of available carbon for lipidsynthesis. ¹Present Address: The Mycology Center, Washington UniversitySchool of Medicine, St. Louis, MO 63178, U.S.A. ²Present Address: Department of Biology, University of Tampa,Tampa, Florida 33060, U.S.A. (Received September 16, 1987; Accepted January 18, 1988)     

Fast Detection of Nutrient Limitation in Macroalgae and Seagrass with Nutrient-Induced Fluorescence

Background

Rapid determination of which nutrients limit the primary production of macroalgae and seagrasses is vital for understanding the impacts of eutrophication on marine and freshwater ecosystems. However, current methods to assess nutrient limitation are often cumbersome and time consuming. For phytoplankton, a rapid method has been described based on short-term changes in chlorophyll fluorescence upon nutrient addition, also known as Nutrient-Induced Fluorescence Transients (NIFTs). Thus far, though, the NIFT technique was not well suited for macroalgae and seagrasses.

Methodology & Principal Findings

We developed a new experimental setup so that the NIFT technique can be used to assess nutrient limitation of benthic macroalgae and seagrasses. We first tested the applicability of the technique on sea lettuce (Ulva lactuca) cultured in the laboratory on nutrient-enriched medium without either nitrogen or phosphorus. Addition of the limiting nutrient resulted in a characteristic change in the fluorescence signal, whereas addition of non-limiting nutrients did not yield a response. Next, we applied the NIFT technique to field samples of the encrusting fan-leaf alga Lobophora variegata, one of the key algal species often involved in the degradation of coral reef ecosystems. The results pointed at co-limitation of L. variegata by phosphorus and nitrogen, although it responded more strongly to phosphate than to nitrate and ammonium addition. For turtle grass (Thalassia testudinum) we found the opposite result, with a stronger NIFT response to nitrate and ammonium than to phosphate.

Conclusions & Significance

Our extension of the NIFT technique offers an easy and fast method (30–60 min per sample) to determine nutrient limitation of macroalgae and seagrasses. We successfully applied this technique to macroalgae on coral reef ecosystems and to seagrass in a tropical inner bay, and foresee wider application to other aquatic plants, and to other marine and freshwater ecosystems.     

Estimation of Lipid Hydroperoxide Levels in Tropical Marine Macroalgae

The incipient levels of lipid hydroperoxides (LHPOs) were determined in selected green, brown, and red macroalgae by the FOX assay using hydroperoxy HPLC mix. The LHPOs contents varied between the investigated species and showed relatively low values in this study. Among the greens, it varied from 12 ± 6.2 μg · g^?1 (Codium sursum) to 31.5 ± 2.8 μg · g^?1 (Ulva lactuca), whereas in reds, from 5.7 ± 1.6 μg · g^?1 (Gracilaria corticata) to 46.2 ± 6 μg · g^?1 (Sarconema filiforme), and in browns, from 4.6 ± 4.4 μg · g^?1 (Dictyota bartayresiana) to 79 ± 5.0 μg · g^?1 (Sargassum tenerrimum), on fresh weight basis. These hydroperoxides represented a minor fraction of total lipids and ranged from 0.04% (S. swartzii) to 1.1% (S. tenerrimum) despite being a rich source of highly unsaturated fatty acids. The susceptibility of peroxidation was assessed by specific lipid peroxidazibility (SLP) values for macroalgal tissues. The LHPO values were found to be independent of both the PUFAs contents and their degree of unsaturation (DBI), as evident from the PCA analysis. SLP values were positively correlated with the LHPOs and negatively with DBI. The FOX assay gave ≥20‐fold higher values for LHPOs as compared to the TBARS method for all the samples investigated in this study. Furthermore, U. lactuca cultured in artificial seawater (ASW) enriched with nutrients (N, P, and NP) showed a sharp decline in LHPOs contents relative to those cultured in ASW alone P ≤ 0.05. It is inferred from this study that the FOX assay is an efficient, rapid, sensitive, and inexpensive technique for detecting the incipient lipid peroxidation in macroalgal tissues.     

Macroalgae and nutrients promote algal turf growth in the absence of herbivores

Coral Reefs - Closely cropped algal turfs are characteristic of healthy coral reefs, but unchecked growth can cause transitions into long sediment-laden turfs, which may be an alternative degraded...     

Ecological Characteristics of Macroalgae in Mangrove Forests in Fujian,China

The flora and distribution of macroalgae as well as the biomass of its two dominant species were studied in mangrove forests in Fujian Province, China. There were totally 42 species belonging to 24 genera of macroalgae, in which 15 species/8 genera belonged to Cyanophyta, 7/3 to Rhodophyta, and 20/13 to Chlorophyta. The biomass of the dominant species Caloglossa leprieurii and Catenella impudica were 2.22 to 8.44 g/m2 DW and 2.69 g/m2 DW in June,and 0.15 to 0.20 g/m2 DW and 2.12 g/m2 DW in December, respectively. On the tnmk surface of the mangrove plants,macroalgae appeared vertically to be distributed from lower upwards into six belts, namely Vaucheria sp. belt, Catenella impudica belt, Caloglossa ogasawaraensis-Bostrychia mixta belt, Calogiossa leprieurii belt, Chaetomorpha macrotona-Rhizoclonium riparium belt, and Chlorococcum sp. belt.     

MAA Synthesis and Accumulation in Polar Macroalgae are Controlled by Abiotic Factors

Mycosporine‐like amino acids (MAAs) are regarded as powerful sunscreens protecting the algae against harmful UV radiation. The MAA protection efficiency was tested in algal samples by measuring the optimum quantum yield of photosynthesis using photosystem II fluorescence. It could be demonstrated that the recovery of photosynthesis after exposure to enhanced UV radiation is faster in individuals with high MAA content. MAAs can be synthesized in several polar macroalgae in response to different radiation conditions. Although MAA induction patterns are very species‐specific, some similarities can be found. Field studies indicate that plants from different growth habitats providing distinct radiation climate can be grouped into three physiological categories depending on their MAA content. The first group (I) includes mainly deep‐water species, typically lacking MAAs. The second group (II), algal species found in a broad range of water depths (eu‐ and sublittoral), which are able to flexibly synthesize and accumulate MAAs. The third group (III) includes supra‐ and eulittoral taxa, which always contain high MAA concentrations. In laboratory studies, we showed that taxa of group II and III responded in three different ways based on MAA accumulation when exposed to different radiation conditions (PAR, PAR + UVA, PAR + UVA + UVB). Either they: (a) exhibit highest total MAA concentration under the full artificial spectrum; (b) increase their MAA concentration after exposure to PAR and PAR + UVA or (c) MAA concentration declines after exposure to the full spectrum. Our studies have indicated that when coupled with UVR, exposure to temperature fluctuations ranging from 0 to 10 °C also affect MAA biosynthesis.