Does More Storage Give California More Water?

Increasing reservoir storage is commonly proposed to mitigate increasing water demand and provide drought reserves, especially in semiarid regions such as California. This paper examines the value of expanding surface reservoir capacity in California using hydroeconomic modeling for historical conditions, a future warm‐dry climate, and California's recently adopted policy to end groundwater overdraft. Results show expanding surface storage capacity rarely provides sizable economic value in most of California. On average, expanding facilities north of California's Delta provides some benefit in 92% of 82 years modeled under historical conditions and in 61% of years modeled in a warm‐dry climate. South of California's Delta, expanding storage capacity provides no benefits in 14% of years modeled under historical conditions and 99% of years modeled with a warm‐dry climate. Results vary across facilities between and within regions. The limited benefit of surface storage capacity expansion to statewide water supply should be considered in planning California's water infrastructure.     

Governance innovations for climate change adaptation in urban Denmark

Urban areas worldwide are challenged by climate change and urban flooding. Within the academic literature, adaptive measures that can be integrated into other issues such as recreation, nature reserves, and social issues are considered the way forward. Adaptation has recently become a mandatory planning theme for Danish municipalities, which in the absence of established practices are struggling to find the best institutional set-up to address adaptation as an integrated issue. Based on a case study of an integrated project organised as a partnership, this article identifies and discusses governance challenges that must be addressed if municipalities are to benefit from synergies through integrated projects. The municipality in question has established a partnership with housing organisations, foundations, and a utility company as well as facilitated a dialogue with citizens and institutions to address flooding threats and social issues at the neighbourhood scale. Because of strong political and leadership support, funding from partners, and good project facilitation both partners and politicians are enthusiastic about the project and its potential. Several challenges, however, needed to be addressed, particularly in relation to clashing norms from different governance paradigms. This is an issue requiring more attention both in research and practice.     

Mechanism(s) of long chain n-3 essential fatty acid production in two species of heterotrophic protists: <Emphasis Type="Italic">Oxyrrhis marina</Emphasis> and <Emphasis Type="Italic">Gyrodinium dominans</Emphasis>

As intermediaries, some heterotrophic protists can enhance the content of the long chain n-3 essential fatty acids (LCn-3EFAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), of low food quality algae for subsequent use at higher trophic levels. However, the mechanisms that produce LCn-3EFAs are presently unknown, although LCn-3EFA production by heterotrophic protists at the phytoplankton–zooplankton interface may potentially affect the nutritional status of the pelagic system. We investigated whether the heterotrophic protists, Oxyrrhis marina and Gyrodinium dominans, produce LCn-3EFAs via elongation and desaturation of dietary LCn-3EFA precursors and/or synthesize LCn-3EFAs de novo by: (1) feeding the two heterotrophic protists with a prey deficient in n-3 fatty acids, (2) incubating them in medium containing ¹³C-labeled sodium acetate, and (3) feeding the two protists gelatin acacia microspheres (GAMs) containing a deuterium-labeled LCn-3EFA precursor, linolenic acid [18:3(n-3)-d4]. Both O. marina and G. dominans synthesized EPA and DHA when fed the n-3 fatty acid-deficient prey, Perkinsus marinus, a parasitic protozoan. O. marina, but not G. dominans utilized ¹³C-labeled acetate from the medium to produce uniformly labeled fatty acids, including DHA. Both heterotroph species consumed GAMs containing 18:3(n-3)-d4 and catabolized 18:3(n-3)-d4 to 16:3(n-3)-d4 and 14:3(n-3)-d4, while no 20 or 22 carbon metabolites of 18:3(n-3)-d4 were detected. These results suggest that O. marina and G. dominans do not elongate and desaturate dietary LCn-3EFA precursors to produce LCn-3EFAs, but rather they produce LCn-3EFAs de novo, possibly via a polyketide synthesis pathway.     

Essential fatty acids influence metabolic rate and tolerance of hypoxia in Dover sole (Solea solea) larvae and juveniles

Dover sole (Solea solea, Linneaus 1758) were raised from first feeding on brine shrimp (Artemia sp.) with different contents and compositions of the essential fatty acids (EFA) arachidonic acid (ARA, 20:4n − 6); eicosapentaenoic acid (EPA, 20:5n − 3), and docosahexaenoic acid (DHA, 22:6n − 3), and their metabolic rate and tolerance to hypoxia measured prior to and following metamorphosis and settlement. Four dietary Artemia preparations were compared: (1) un-enriched; (2) enriched with a commercial EFA mixture (Easy DHA SELCO Emulsion); (3) enriched with a marine fish oil combination (VEVODAR and Incromega DHA) to provide a high ratio of ARA to DHA, and (4) enriched with these fish oils to provide a low ratio of ARA to DHA. Sole fed un-enriched Artemia were significantly less tolerant to hypoxia than the other dietary groups. Larvae from this group had significantly higher routine metabolic rate (RMR) in normoxia, and significantly higher O₂ partial pressure (PO₂) thresholds in progressive hypoxia for their regulation of RMR (P _crit) and for the onset of agitation, respiratory distress and loss of equilibrium. Metamorphosis was associated with an overall decline in RMR and increase in P _crit, but juveniles fed on un-enriched Artemia still exhibited higher P _crit and agitation thresholds than the other groups. Sole fed un-enriched Artemia had significantly lower contents of EFA in their tissues, both before and after settlement. Thus, enriching live feeds with EFA has significant effects on the respiratory physiology of sole early life stages and improves their in vivo tolerance to hypoxia. We found no evidence, however, for any effect of the ratio of ARA to DHA.     

Time constraints mediate predator-induced plasticity in immune function, condition, and life history

The simultaneous presence of predators and a limited time for development imposes a conflict: accelerating growth under time constraints comes at the cost of higher predation risk mediated by increased foraging. The few studies that have addressed this tradeoff have dealt only with life history traits such as age and size at maturity. Physiological traits have largely been ignored in studies assessing the impact of environmental stressors, and it is largely unknown whether they respond independently of life history traits. Here, we studied the simultaneous effects of time constraints, i.e., as imposed by seasonality, and predation risk on immune defense, energy storage, and life history in lestid damselflies. As predicted by theory, larvae accelerated growth and development under time constraints while the opposite occurred under predation risk. The activity of phenoloxidase, an important component of insect immunity, and investment in fat storage were reduced both under time constraints and in the presence of predators. These reductions were smaller when time constraints and predation risk were combined. This indicates that predators can induce sublethal costs linked to both life history and physiology in their prey, and that time constraints can independently reduce the impact of predator-induced changes in life history and physiology.     

The need for bioaugmentation after thermal treatment of a TCE-contaminated aquifer: Laboratory experiments

A microcosm study was conducted to evaluate the need for bioaugmentation after a thermal treatment to anaerobically dechlorinate trichloroethene (TCE) to ethene. The microcosms were either: heated to 100 degrees C and slowly cooled to simulate thermal remediation while bioaugmenting when the declining temperature reached 10 degrees C; or kept at ambient groundwater temperatures (10 degrees C) and bioaugmented for comparison. Aquifer samples from three sediment locations within a TCE-polluted source zone were investigated in duplicate microcosms. In biostimulated (5 mM lactate) and heated microcosms, no conversion of TCE was observed in 4 out of 6 microcosms, and in the remaining microcosms the dechlorination of TCE was incomplete to cDCE (cis-dichloroethene). By comparison, complete TCE dechlorination to ethene was observed in 4 out of 6 heated microcosms that were bioaugmented with a highly enriched dechlorinating mixed culture, KB-1, but no electron donor, and also in 4 of 6 microcosms that were augmented with KB-1 and an electron donor (5 mM lactate). These data suggest that electron donor released during heating, was capable of promoting complete dechlorination coincident with bioaugmentation. Heated microcosms demonstrated less methanogenesis than unheated microcosms, even with elevated H2 concentrations and addition of KB-1, which contains methanogens. This suggests that the heating process suppressed the native microbial community, which can decrease competition with the bioaugmented culture and increase the effectiveness of dechlorination following a thermal treatment. Specifically, cDCE removal rates were four to six times higher in heated than unheated bioaugmented microcosms. This study confirms the need for bioaugmentation following a laboratory thermal treatment to obtain complete dechlorination of TCE.     

Biochemical characterization of the rat liver receptor for 2,3,7,8-TCDD - a comparison to the rat liver glucocorticoid receptor

An assessment of the physicochemical characteristics of the rat hepatic receptors for 2,3,7,8-TCDD and for corticosteroid hormones reveals striking analogies between both receptor systems.     

Formation of volatile iodinated alkanes in soil: results from laboratory studies

Volatile iodinated organic compounds play an important role in the tropospheric photochemical system, but the current knowledge of the known sources and sinks of these alkyl iodides is still incomplete. This paper describes a new source of alkyl iodides from the pedosphere. Different organic-rich soils and humic acid were investigated for their release of volatile organoiodides. Six volatile organoiodides, iodomethane, iodoethane, 1-iodopropane, 2-iodopropane, 1-iodobutane and 2-iodobutane were identified and their release rates were determined. We assume an abiotic reaction mechanism induced by the oxidation of organic matter by iron(III). The influence of iron(III), iodide and pH on the formation of alkyl iodides was investigated. Additionally, different organic substances regarded as monomeric constituents of humus were examined for the production of alkyl iodides. Two possible reaction pathways for the chemical formation of alkyl iodides are discussed. As humic acids and iron(III) are widespread in the terrestrial environment, and the concentration of iodide in soil is strongly enriched (compared to seawater), this soil source of naturally occurring organoiodides is suggested to contribute significantly to the input of iodine into the troposphere.     

REASSEMBLING HETCH HETCHY: WATER SUPPLY WITHOUT O'SHAUGHNESSY DAM1

The Hetch Hetchy System provides San Francisco with most of its water supply. O'Shaughnessy Dam is one component of this system, providing approximately 25 percent of water storage for the Hetch Hetchy System and none of its conveyance. Removing O'Shaughnessy Dam has gained interest for restoring Hetch Hetchy Valley. The water supply feasibility of removing O'Shaughnessy Dam is analyzed by examining alternative water storage and delivery operations for San Francisco using an economic engineering optimization model. This model ignores institutional and political constraints and has perfect hydrologic foresight to explore water supply possibilities through reoperation of other existing reservoirs. The economic benefits of O'Shaughnessy Dam and its alternatives are measured in terms of the quantity of water supplied to San Francisco and agricultural water users, water treatment costs, and hydropower generation. Results suggest there could be little water scarcity if O'Shaughnessy Dam were to be removed, although removal would be costly due to additional water treatment costs and lost hydropower generation.     

Indicators of Biodiversity and Conservational Wildlife Quality on Danish Organic Farms for Use in Farm Management: A Multidisciplinary Approach to Indicator Development and Testing

Organic farming is expected to contribute to conserving national biodiversity on farms, especially remnant, old, and undisturbed small biotopes, forests, and permanent grassland. This objective cannot rely on the legislation of organic farming solely, and to succeed, farmers need to understand the goals behind it. A set of indicators with the purpose of facilitating dialogues between expert and farmer on wildlife quality has been developed and tested on eight organic farms. “Weed cover in cereal fields,” was used as an indicator of floral and faunal biodiversity in the cultivated land, and “uncultivated biotope area” on the farm was used as a general measure of wildlife habitats. Functional grouping of herbaceous plants (discriminating between “high conservation value” plant species and “competitive”/“ruderal” species) and low mobility butterflies were used as indicators of conservation value, especially focusing on the few sites left with considerable remnant conservation value. The dialog processes revealed that the organic farmers’ ideas and goals of conservation of wildlife quality were not necessarily the same as for biologists; the farmers expressed very different opinions on the biological rooted idea, that wildlife quality is related to the absence of agricultural impact. However, farmers also stated that the information given by the indicators and especially the dialogue with the biologist had influenced their perception and awareness of wildlife. We conclude that, combined with a dialogue process, using these indicators when mapping wildlife quality could be an important key component of a farm wildlife management advisory tool at farm level.