MODELED REGIONAL CLIMATE CHANGE IN THE HYDROLOGIC REGIONS OF CALIFORNIA: A CO2 SENSITIVITY STUDY1

ABSTRACT: Using a regional climate model (RegCM2.5), the potential impacts on the climate of California of increasing atmospheric CO₂ concentrations were explored from the perspective of the state's 10 hydrologic regions. Relative to preindustrial CO₂ conditions (280 ppm), doubled preindustrial CO₂ conditions (560 ppm) produced increased temperatures of up to 4°C on an annual average basis and of up to 5°C on a monthly basis. Temperature increases were greatest in the central and northern regions. On a monthly basis, the temperature response was greatest in February, March, and May for nearly all regions. Snow accumulation was significantly decreased in all months and regions, with the greatest reduction occurring in the Sacramento River region. Precipitation results indicate drier winters for all regions, with a large reduction in precipitation from December to April and a smaller decrease from May to November. The result is a wet season that is slightly reduced in length. Findings suggest that the total amount of water in the state will decrease, water needs will increase, and the timing of water availability will be greatly perturbed.     

Evaluating the suitability of policy instruments for urban flood risk reduction

ABSTRACT

City governments have access to a range of policy instruments to reduce flood risk, but choosing among these tools is challenging. This article identifies fourteen different policy instruments that could contribute to urban flood risk reduction and draws on interviews with expert stakeholders to score these instruments across eight evaluation criteria. The results indicate which policy tools the interviewees consider to be most and least suitable and illuminate the trade-offs inherent in instrument selection. Complementary relationships between the various instruments are also considered in the context of instrument mixes – combinations of multiple policy tools designed to maximise urban flood risk reduction.     

VIRGINIA USA WATER QUALITY, 1978 TO 1995: REGIONAL INTERPRETATION1

ABSTRACT: Nine surface water‐quality variables were analyzed for trend at 180 Virginia locations over the 1978 to 1995 period. Median values and seasonal Kendall's tau, a trend indicator statistic, were generated for dissolved oxygen saturation (DO), biochemical oxygen demand (BOD), pH (PH), total residue (TR), nonfilterable residue (NFR), nitrate‐nitrite nitrogen (NN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and fecal coliform (FC) at each location. Each location was assigned to one of four physiographic regions, and mean state and regional medians and taus were calculated. Widespread BOD and NFR improvements were detected and FC improvements occurred in the state's western regions. TR and TKN exhibited predominantly increasing trends at locations throughout the state. BOD, TKN, NFR, and TR medians were higher at coastal locations than in other regions. NN, TKN, and TR exhibited predominantly increasing trends in regions with high median concentrations, while declining trends predominated in regions with relatively high BOD, FC, and NFR medians. Appalachian locations exhibited the greatest regional water‐quality improvements for BOD, FC, NFR, and TKN. Factors responsible for regional differences appear to include geology, land use, and landscape features; these factors vary regionally.     

Underappreciated species in ecology: "ugly fish" in the northwest Atlantic Ocean.

Species shifts and replacements are common in ecological studies. Observations thereof serve as the impetus for many ecological endeavors. Many of the species now known to dominate ecosystem functioning were largely ignored until studies of those underappreciated species elucidated their critical roles. Recognizing the potential importance of underappreciated species has implications for functional redundancies in ecosystems and should alter our approach to long-term monitoring. One example of an applied ecological system containing species shifts, underappreciated species, and potential changes in functional redundancies is the topic of fisheries. The demersal component of many fish communities usually consists of high-profile and commercially valuable species that are targets of fisheries, plus a diverse group of lesser known species that have minimal commercial value and focus. Yet ecologically these traditionally nontargeted species are often a major biomass sink in marine ecosystems and can also be critical in the functioning of bentho-demersal food webs. I examined the biomass trajectories of several species of skates, cottids, lophiids, anarhichadids, zooarcids, and similar species in the northeast U.S. Atlantic ecosystem to determine whether their relative abundance has changed across the past four decades. Distribution and stomach contents of these species were also evaluated over time to further elucidate the relative importance of these species. Landings of these underappreciated bentho-demersal fish were also examined in comparison to those species that historically have been commercially targeted. Of particular emphasis was the evaluation of evidence for sequential stock depletion and the ramifications for functional redundancy for this ecosystem. Results indicate that some of these fish species are now the dominant piscivores, benthivores, and scavengers in this ecosystem. These formerly under-studied species generally have either maintained a consistent population size or have increased in abundance (and expanded in distribution) over the past several decades. Nontraditionally targeted fish species are an often overlooked but important component of bentho-demersal fish communities. Implications for the energy flow and resilience specifically for future fisheries and generally for harvesting biological resources are significant, remaining critical issues for the world's ecosystems.     

Acid–base regulation in the Dungeness crab (Metacarcinus magister)

Homeostatic regulation allows organisms to secure basic physiological processes in a varying environment. To counteract fluctuations in ambient carbonate system speciation due to elevated seawater pCO₂ (hypercapnia), many aquatic crustaceans excrete/accumulate acid–base equivalents through their gills; however, not much is known about the role of ammonia in this response. The present study investigated the effects of hypercapnia on acid–base and ammonia regulation in the Dungeness crab, Metacarcinus magister on the whole animal and isolated gill levels. Hemolymph pCO₂ and [HCO₃ ^?] increased in M. magister acclimated to elevated pCO₂ (330 Pa), while pH remained stable. Additionally, hemolymph [Na⁺], [Ca²⁺], and [SO₄ ^2?] were significantly increased. When challenged with varying pH during gill perfusion, the pH of the artificial hemolymph remained relatively unchanged. Overall, ammonia production and excretion, as well as oxygen consumption, were reduced in crabs acclimated to elevated pCO₂, demonstrating that either (amino acid) oxidation is reduced in response to this particular stress, or nitrogenous wastes are excreted in an alternative form.     

Demography and interannual variability of salp swarms (Thalia democratica)

Swarms of the pelagic tunicate, Thalia democratica, form during spring, but the causes of the large interannual variability in the magnitude of salp swarms are unclear. Changes in asexual reproduction (buds per chain) of T. democratica populations in the coastal waters of south-east Australia (32–35°S) were observed in three austral springs (October 2008–2010). T. democratica abundance was significantly higher in 2008 (1,312 individuals m^?3) than 2009 and 2010 (210 and 92 individuals m^?3, respectively). There was a significant negative relationship (linear regression, r ² = 0.61, F _1,22 = 33.83, P < 0.001) between abundance and asexual reproduction. Similarly, relative growth rates declined with decreasing abundance. Generalised additive mixed modelling showed that T. democratica abundance was significantly positively related to preferred food >2 μm in size (P < 0.05) and negatively related to the proportion of non-salp zooplankton (P < 0.001). Salp swarm magnitude, growth, and asexual reproduction may depend on the abundance of larger phytoplankton (prymnesiophytes and diatoms) and competition with other zooplankton.     

Mortality-minimizing sandpipers vary stopover behavior dependent on age and geographic proximity to migrating predators

Ecological theory for long-distance avian migration considers time-, energy-, and mortality-minimizing tactics, but predictions about the latter have proven elusive. Migrants must make behavioral decisions that can favor either migratory speed or safety from predators, but often not both. We compare the behavior of adult and juvenile western sandpipers Calidris mauri during the course of their temporally segregated passages at a major stopover site. Here, the passage and winter arrival of an important predator, the peregrine falcon Falco peregrinus begins near the end of the adult sandpiper passage (July) and increases rapidly through the juvenile passage (August). The mortality-minimizing hypothesis predicts that as the falcon front is distant but approaching, sandpipers should initially increase the fuel-loading rate (lowered vigilance and predator apprehension) to increase migration speed and so maintain their head start. As the falcon front gains proximity to and passes over the stopover site, sandpipers should become increasingly cautious. Our measurements show that adults decreased vigilance during the period prior to falcon arrival, and had lower vigilance overall than juveniles. Juveniles were more apprehensive, flying further and longer in response to disturbance by a falcon silhouette. This trend was reversed in response to a human approach. Both groups were more vigilant and more apprehensive in a study year with earlier falcon arrival. These results suggest that late (juvenile) and early (adult) migrants minimize mortality on migration in different ways, adults by increased migratory speed at the expense of caution on stopover sites, and juveniles by increased caution at the expense of speed.     

Pedestrians' estimates of their own visibility: a simple and effective computer-based technique

INTRODUCTION: Research has shown that both pedestrians and drivers drastically overestimate pedestrians' nighttime visibility (NHSTSA, 2008a, 2008b; Owens & Sivak, 1996) and fail to appreciate the safety benefits of proven conspicuity aids. One solution is educational intervention (Tyrrell, Patton, & Brooks, 2004); however, the on-road assessment of its effectiveness is expensive and time consuming. METHOD: Experiment One introduces a computer-based alternative to the field-based approach, successfully replicating the previous study's trends among 94 students who either receive or do not receive an educational lecture. Experiment Two utilizes the simulation's portability to determine if professional roadway workers have a more accurate understanding of pedestrian conspicuity than students. Results: Results among 88 workers show they do not significantly appreciate the advantages of effective retroflective material configurations or vehicle headlamp settings, for example, any better than non-lectured students in Experiment One. Impact: The study's results demonstrate the need for education among all pedestrians and the benefits of efficient testing methods.     

Dynamic real-time risk analytics of uncontrollable states in complex internet of things systems: cyber risk at the edge

The Internet of Things (IoT) triggers new types of cyber risks. Therefore, the integration of new IoT devices and services requires a self-assessment of IoT cyber security posture. By security posture this article refers to the cybersecurity strength of an organisation to predict, prevent and respond to cyberthreats. At present, there is a gap in the state of the art, because there are no self-assessment methods for quantifying IoT cyber risk posture. To address this gap, an empirical analysis is performed of 12 cyber risk assessment approaches. The results and the main findings from the analysis is presented as the current and a target risk state for IoT systems, followed by conclusions and recommendations on a transformation roadmap, describing how IoT systems can achieve the target state with a new goal-oriented dependency model. By target state, we refer to the cyber security target that matches the generic security requirements of an organisation. The research paper studies and adapts four alternatives for IoT risk assessment and identifies the goal-oriented dependency modelling as a dominant approach among the risk assessment models studied. The new goal-oriented dependency model in this article enables the assessment of uncontrollable risk states in complex IoT systems and can be used for a quantitative self-assessment of IoT cyber risk posture.