Changes in diatom patch-size distribution and degradation in a spatially self-organized intertidal mudflat ecosystem

Self-organized spatial patterns have been proposed as possible indicators for regime shifts in ecosystems. Until now, this hypothesis has only been tested in drylands. Here, we focus on intertidal mudflats where regular spatial patterns develop in early spring from the interaction between diatom growth and sedimentation but disappear when benthic herbivore abundance increases in early summer, accompanied by a dramatic shift to a bare mudflat. We followed the patch-size distributions of diatom biofilms during this degradation process. As time progressed, we found a temporal change in the spatial configuration occurring simultaneously with the loss of the diatom-sediment feedback. This indicates a gradual failure in time of the self-organization process that underlies regular patterning in this ecosystem. The path to degradation co-occurred with the loss of the larger patches in the ecosystem, which resulted in a decrease of the truncation in the patch-size distribution. Hence, our study in mudflat ecosystems confirms the general hypothesis that spatial patterns can provide important clues about the level of degradation. Nevertheless, our study highlights the need for thorough study about the type of spatial patterns and the nature of the underlying feedbacks before a reliable assessment of ecosystem status can be made, as changes in patch-size distribution differed markedly with those observed in other ecosystems.     

Large-scale diversity and biogeography of benthic copepods in European waters

A large-scale database concerning benthic copepods from the Arctic, Baltic Sea, North Sea, British Isles, Adriatic Sea and Crete was compiled to assess species richness, biodiversity, communities, ecological range size and biogeographical patterns. The Adriatic showed the highest evenness and the most species-rich communities. Assemblages from the North Sea, British Isles, Baltic and Crete had a lower evenness. The British Isles were characterised by impoverished communities. The ecological specificity of copepod species showed two diverging trends: higher specificity of species in more diverse assemblages was observed in the Adriatic, North Sea and Baltic. A uniformly high species specificity disregarding sample diversity was found on Crete and in the British Isles. Benthic copepod communities showed distinct patterns that clearly fit the predefined geographical regions. Communities were distinguishable and β-diversity was found to be high around Europe, indicating a high species turnover on the scale of this investigation. The British Isles and the North Sea were found to be faunistic links to the Baltic and the Arctic.     

Cognitive‐affective stress propensity: a field study

A cognitive‐affective stress propensity model was examined using field study data. Structural equation models analyses tested hypothesized and alternate models to determine their goodness‐of‐fit with the data. The results supported a direct relationship between stress propensity and strain, and an indirect, mediated relationship between stress propensity and strain through a subjective stress construct. In addition, stress propensity was found to moderate the relationships of experienced negative affect with somatic and with psychological strain, and with one of three measures of subjective stress. Implications of the results for research and practice are discussed. Copyright © 1999 John Wiley & Sons, Ltd.     

Examining the interpersonal process and consequence of leader–member exchange comparison: The role of procedural justice climate

Individuals are always sensitive to their relative standing in interpersonal comparison processes of leader–member exchanges (LMXs) in teams. Little research, however, has investigated whether coworkers with a higher LMX influence the emotional and behavioral reactions of individuals with a lower LMX in different dyads. Drawing on social comparison theory and the symbolic model of procedural justice (PJ) climate, we conducted 2 independent studies—an experimental study focusing on the self‐perceived upward LMX comparison (i.e., an individual perceives that a coworker's LMX is higher than the LMX that he or she has with the supervisor; N = 203; Study 1: American working adults) and a field survey study focusing on the other‐perceived downward LMX comparison (i.e., a coworker perceives that his or her own LMX is higher than the LMX that the individual has with the supervisor; N = 177; Study 2: Chinese software engineers). Results from these studies consistently revealed that a coworker's higher LMX elicits an individual's hostile emotions when the PJ climate is low but that this relationship is buffered when the PJ climate is high. Results of both studies also showed that the coworker's higher LMX arouses the individual to direct harmful behavior toward that coworker (via the individual's feelings of hostility) when the PJ climate is low but not when it is high.     

Climate Services and Communication for Development: The Role of Early Career Researchers in Advancing the Debate

Climate services entail providing timely and tailored climate information to end-users in order to facilitate and improve decision-making processes. Climate services are instrumental in socio-economic development and benefit substantially from interdisciplinary collaborations, particularly when including Early Career Researchers (ECRs). This commentary critically discusses deliberations from an interdisciplinary workshop involving ECRs from the United Kingdom and South Africa in 2017, to discuss issues in climate adaptation and climate services development in water resources, food security and agriculture. Outcomes from the discussions revolved around key issues somewhat marginalized within the broader climate service discourse. This commentary discusses what constitutes “effective” communication, framings (user framings, mental models, narratives, co-production) and ethical dimensions in developing climate services that can best serve end-users. It also reflects on how ECRs can help tackle these important thematic areas and advance the discourse on climate services.     

Analyzing the Variability of Remote Sensing and Hydrologic Model Evapotranspiration Products in a Watershed in Michigan

The goal of this paper was to statistically explore the spatiotemporal performance of remotely sensed actual evapotranspiration (ETa) datasets and a remotely sensed ensemble in a region that lacks observed data. The remotely sensed datasets were further compared with ETa results from a physically based hydrologic model (Soil and Water Assessment Tool) to examine the differences and determine the level of agreement between the ETa datasets and the model outputs. ETa datasets were compared on temporal (i.e., monthly and seasonal basis) and spatial (i.e., landuse) scales at both watershed and subbasin levels. The results showed a lack of consistent similarities and differences among the datasets when evaluating the monthly ETa variations; however, the seasonal aggregated data presented more consistent similarities and differences during the spring and summer compared to the fall and winter. Meanwhile, spatial analysis of the datasets showed the MOD16A2 500 m ETa product was the most versatile of the tested datasets, being able to differentiate between landuses during all seasons. Furthermore, the use of an averaging ensemble was able to improve overall ETa performance in the study area. This study showed that the remotely sensed ETa products are not similar throughout the year, but the appropriate application periods for different ETa products were identified. Finally, spatial variabilities of the ETa products are more in tune with landuse and climate characteristics.     

From Global to Local: Providing Actionable Flood Forecast Information in a Cloud‐Based Computing Environment

Global and continental scale flood forecast provide coarse resolution flood forecast, but from the perspective of emergency management, flood warnings should be detailed and specific to local conditions. The desired refinement can be provided by the use of downscaling global scale models and through the use of distributed hydrologic models to produce a high‐resolution flood forecast. Three major challenges associated with transforming global flood forecasting to a local scale are addressed in this work. The first is using open‐source software tools to provide access to multiple data sources and lowering the barriers for users in management agencies at local level. This can be done through the Tethys Platform that enables web water resources modeling applications. The second is finding a practical solution for the computational requirements associated with running complex models and performing multiple simulations. This is done using Tethys Cluster that manages distributed and cloud computing resources as a companion to the Tethys Platform for web app development. The third challenge is discovering ways to downscale the forecasts from the global extent to the local context. Three modeling strategies have been tested to address this, including downscaling of coarse resolution global runoff models to high‐resolution stream networks and routing with Routing Application for Parallel computatIon of Discharge (RAPID), the use of hierarchical Gridded Surface and Subsurface Hydrologic Analysis (GSSHA) distributed models, and pre‐computed distributed GSSHA models.     

AERCOARE: An overwater meteorological preprocessor for AERMOD

AERCOARE is a meteorological data preprocessor for the American Meteorological Society and U.S Environmental Protection Agency (EPA) Regulatory Model (AERMOD). AERCOARE includes algorithms developed during the Coupled-Ocean Atmosphere Response Experiment (COARE) to predict surface energy fluxes and stability from routine overwater measurements. The COARE algorithm is described and the implementation in AERCOARE is presented. Model performance for the combined AERCOARE-AERMOD modeling approach was evaluated against tracer measurements from four overwater field studies. Relatively better model performance was found when lateral turbulence measurements were available and when several key input variables to AERMOD were constrained. Namely, requiring the mixed layer height to be greater than 25 m and not allowing the Monin Obukhov length to be less than 5 m improved model performance in low wind speed stable conditions. Several options for low wind speed dispersion in AERMOD also affected the model performance results. Model performance for the combined AERCOARE-AERMOD modeling approach was found to be comparable to the current EPA regulatory Offshore Coastal Model (OCD) for the same tracer studies. AERCOARE-AERMOD predictions were also compared to simulations using the California Puff-Advection Model (CALPUFF) that also includes the COARE algorithm. Many model performance measures were found to be similar, but CALPUFF had significantly less scatter and better performance for one of the four field studies. For many offshore regulatory applications, the combined AERCOARE-AERMOD modeling approach was found to be a viable alternative to OCD the currently recommended model.

Implications: A new meteorological preprocessor called AERCOARE was developed for offshore source dispersion modeling using the U.S. Environmental Protection Agency (EPA) regulatory model AERMOD. The combined AERCOARE-AERMOD modeling approach allows stakeholders to use the same dispersion model for both offshore and onshore applications. This approach could replace current regulatory practices involving two completely different modeling systems. As improvements and features are added to the dispersion model component, AERMOD, such techniques can now also be applied to offshore air quality permitting.     

Influence of pH on the sonolysis of ciprofloxacin: Biodegradability, ecotoxicity and antibiotic activity of its degradation products

The presence of antibiotics in the aquatic environment has raised concerns due to the potential risk for the emergence or persistence of antibiotic resistance. Antibiotics are often poorly degraded in conventional wastewater treatment plants. In this study, sonolysis at 520 kHz and 92 W L⁻¹ was used for the degradation of the fluoroquinolone antibiotic ciprofloxacin. In a first experiment at pH 7, 57% of the ciprofloxacin (15 mg L⁻¹) was degraded after 120 min of ultrasonic irradiation at 25 °C. pH proved to be an important parameter determining the degradation rate, since the pseudo first order degradation constant increased almost fourfold when comparing treatment at pH 7 (0.0058 min⁻¹) and pH 10 (0.0069 min⁻¹) with that at pH 3 (0.021 min⁻¹). This effect can be attributed to the degree of protonation of the ciprofloxacin molecule. The BOD/COD ratio of the solutions, which is a measure for their biodegradability, increased from 0.06 to 0.60, 0.17, and 0.18 after 120 min of irradiation depending on the pH (3, 7, and 10, respectively). The solution treated at pH 3 can even be considered readily biodegradable (BOD/COD > 0.4). The antibiotic activity against Escherichia coli (G−) and Bacillus coagulans (G+) of the treated solutions also reduced after sonolysis. The highest decrease was again found when irradiated at pH 3. In contrast, ecotoxicity of the solutions to the alga Pseudokirchneriella subcapitata increased 3- to 10-fold after 20 min of treatment, suggesting the formation of toxic degradation products. The toxicity slowly diminished during further treatment.