Spatial variation in dimethylsulfoniopropionate (DMSP) production in <Emphasis Type="Italic">Ulva lactuca</Emphasis> (Chlorophyta) from the Northeast Pacific

Although dimethylsulfoniopropionate (DMSP) has a variety of functions in marine macroalgae including that of a cryoprotectant, an osmolyte, a way to remove excess sulfur and energy, an antioxidant, and an allelopathic precursor, the latter two functions are believed to be the most important in Ulva lactuca L. (=U. fenestrata) in intertidal populations on the coast of Washington state, USA. The present study found significant variation in DMSP concentrations among U. lactuca collected in May 2005 from six sites ranging from 47°54.45′N (Possession Point, Whidbey Island, WA, USA) to 48°30.55′N (Shannon Point Beach, Anacortes, WA, USA), and also among individuals within sites, and among tissues (basal tissues near the holdfast, middle of the blades, and tips). Concentrations ranged from 37 to 224 μmol g⁻¹ fresh mass (FM). In several 10-day experiments between July 2001 and August 2004 with U. lactuca collected from several places on the coast of Washington, the effects of nutrient level (DIN), light intensity and wavelength, and grazing by the herbivorous gastropod Lacuna vincta, were examined. None of these manipulations resulted in DMSP concentrations that differed significantly from controls, and variance in DMSP concentrations within each experiment was very low. Although DMSP concentrations in U. lactuca may be affected by factors not tested in these experiments, it is also possible that the observed spatial differences reflect constitutive genotypic or phenotypic differences among geographically separated U. lactuca populations or among cryptic Ulva species. Electronic supplementary material Supplementary material is available in the online version of this article at and is accessible for authorized users.     

Characterization of colloidal arsenic at two abandoned gold mine sites in Nova Scotia, Canada, using asymmetric flow-field flow fractionation-inductively coupled plasma mass spectrometry

Asymmetric flow-field flow fractionation-inductively-coupled plasma-mass spectrometry was used to determine whether colloidal arsenic(As) exists in soil pore water and soil extract samples at two arsenic-contaminated abandoned gold mines(Montague and Goldenville, Nova Scotia). Colloidal arsenic was found in 12 out of the 80 collected samples(= 15%), and was primarily associated with iron(Fe) in the encountered colloids. The molar Fe/As ratios indicate that the colloids in some samples appeared to be discrete iron–arsenic minerals, whereas in other samples, they were more consistent with As-rich iron(oxy)hydroxides. Up to three discrete size fractions of colloidal As were encountered in the samples, with mean colloid diameters between 6 and 14 nm. The pore water samples only contained one size fraction of As-bearing colloids(around 6 nm diameter), while larger As-bearing colloids were only encountered in soil extracts.     

Using spatial patterns in illegal wildlife uses to reveal connections between subsistence hunting and trade

Although most often considered independently, subsistence hunting, domestic trade, and international trade as components of illegal wildlife use (IWU) may be spatially correlated. Understanding how and where subsistence and commercial uses may co‐occur has important implications for the design and implementation of effective conservation actions. We analyzed patterns in the joint geographical distribution of illegal commercial and subsistence use of multiple wildlife species in Venezuela and evaluated whether available data were sufficient to provide accurate estimates of the magnitude, scope, and detectability of IWU. We compiled records of illegal subsistence hunting and trade from several sources and fitted a random‐forest classification model to predict the spatial distribution of IWUs. From 1969 to 2014, 404 species and 8,340,921 specimens were involved in IWU, for a mean extraction rate of 185,354 individuals/year. Birds were the most speciose group involved (248 spp.), but reptiles had the highest extraction rates (126,414 individuals/year vs. 3,133 individuals/year for birds). Eighty‐eight percent of international trade records spatially overlapped with domestic trade, especially in the north and along the coast but also in western inland areas. The distribution of domestic trade was broadly distributed along roads, suggesting that domestic trade does not depend on large markets in cities. Seventeen percent of domestic trade records overlapped with subsistence hunting, but the spatial distribution of this overlap covered a much larger area than between commercial uses. Domestic trade seems to respond to demand from rural more than urban communities. Our approach will be useful for understanding how IWU works at national scales in other parts of the world.     

Observed and predicted impacts of climate change on the estuaries of south-western Australia,a Mediterranean climate region

Regional Environmental Change - Regions with a Mediterranean climate are generally predicted to become warmer and drier with climate change. Estuaries in these regions are influenced by a broad...     

Effect of metabolic uncouplers on the performance of toluene-degrading biotrickling filter

Environmental Science and Pollution Research - The biomass control potential of three metabolic uncouplers (carbonyl cyanide-p-trifluoromethoxyphenylhydrazone (FCCP), carbonyl cyanide...     

INPUTS OF COPPER‐BASED CROP PROTECTANTS TO COASTAL CREEKS FROM PASTICULTURE RUNOFF1

ABSTRACT: Inputs of copper‐based crop protectants from tomato fields grown under plastic mulch agriculture (plasticulture) to an estuarine creek were investigated. Copper was measured in runoff from diverse land‐uses including conventional agriculture, plasticulture, residences, and natural areas. Water column and sediment copper concentrations were measured in plasticulture and control (nonagriculture) watersheds. Copper concentrations in plasticulture‐impacted creeks exceeded background levels episodically. High concentrations occurred during or immediately after runoff‐producing rains. Concentrations of 263 μg/L total copper and 126 μg/L dissolved copper were measured in a tidal creek affected by plasticulture; concentrations exceeded the shellfish LC₅₀ values and the water quality criteria of 2.9 μg/L dissolved copper. Control watersheds indicated background water column levels of ≤ 4 μg/L dissolved copper with similar copper levels during periods with and without rain. The copper concentrations in tomato plasticulture field runoff itself contained up to 238 μg/L dissolved copper. Copper concentrations in runoff from other land‐uses were less than 5 μg/L dissolved copper. Creek sediment samples adjacent to a plasticulture field contained significantly higher copper concentrations than sediments taken from nonplasticulture watersheds.     

Freeze/thaw durability of concrete with recycled demolition aggregate compared to virgin aggregate concrete

An increasing trend towards the use of sustainable processes has led to recycled materials being incorporated into concrete. It is generally recognised that crushed recycled construction aggregate material produces concrete of a lower compressive strength, when used as an aggregate replacement due to deleterious materials within the aggregate.It is generally accepted that in the UK, freeze/thaw attack is, after chloride-induced corrosion, the most common cause of concrete deterioration. This paper addresses the freeze/thaw durability of recycled aggregate concrete using a paired comparison test based upon weight loss and final compressive strength.Recycled aggregate concrete was found to be of at least equal durability to concrete manufactured with virgin aggregates. This was due to careful selection of the replacement aggregate and treatment prior to batching.Durability is an important material property and recycled aggregates need to be widely tested to gain confidence for use within the industry and this work shows future possibilities.     

Effects of Information on the Social Acceptability of Alternatives to Clearfelling in Australian Wet Eucalypt Forests

The effects of viewing different types of information were investigated in people judging the social acceptability of alternative forest harvest systems. Approximately 500 Tasmanians were shown still-simulated images of four harvest systems (a clearfell system, two aggregated retention systems, and a selective system) and were asked to judge their acceptability. Individual interviews were conducted with 12 of the participants. It was anticipated that people holding different beliefs about the consequences of harvesting would have different responses to information. Cluster analysis was used to group participants according to these beliefs. Responses to still images were compared with responses to two other types of information: information about consequences of the harvest systems in the form of indicator symbols, and information about regeneration over time, presented as visual animations. The effects of information differed across both harvest system and belief cluster groups of participants. The largest effects of information occurred in people who held a mix of beliefs about consequences. Within this group, participants who viewed the indicators rated a 30% aggregated retention system higher and selective harvesting lower, than those who did not view the indicators. Viewing animated sequences led to slightly higher ratings of the more intensive harvest systems and significantly lower ratings of the selective harvest system than those based on the still images. The interview data provided examples of interviewees viewing information critically against their own values and beliefs. Only some interviewees appeared to use it in judging social acceptability