bluuebunny/crossref_metadata_2025 huggingface dataset:
The Potential of E-Participation in Sustainable Development Evaluation
Authors: Lombardi Patrizia , Huovila Pekka , Sunikka-Blank Minna
Published: May 2010

If sustainable development is really to be based on substantive community participation, a change in attitudes, beliefs and values is required. Even these changes will not be sufficient to reach the ambitious goals set across Europe through the Local Agenda 21 and other policy documents. The rigorous adaptation of decision-making processes to include community participation is necessary. Development and specification of indicators play an important role in bridging this gap. The indicators should not only form a technical input in the latter type of assessment tools but act as media to communicate the progress towards sustainable development to the local communities and other stakeholders. This chapter deals with the issue of e-participation in decision making and sustainable development evaluation. It presents first a critical overview of sustainable development and knowledge society indicators, metrics and assessment tools currently in use. Then, it introduces the role of Civil Society Organizations (CSOs) in urban regeneration processes by using a number of European case studies. Finally, it states the need for a more systematic approach to integrate CSOs earlier in the decision-making process and to ensure a more effective use of sustainable development indicators – with the help of the Information and Communication Technologies (ICTs).
E-Government and Citizen Participation in Chile
Authors: Moreno Eduardo Araya , Traverso Diego Barría
Published: May 2010

Various international assessments have drawn attention to the level of development e-government has reached in Chile during the early 2000s. Despite this, even official reports recognize that there is an e-government deficit in opening spaces for citizen participation. These results coincide with several works which have shown the limits the State of Chile put to citizen participation. This chapter analyzes the participation supply that the websites of Chilean ministries offer the citizenry. We describe the existing interactive applications offered by the websites, and the possibilities they make available for citizens to participate in public policy discussions. Our conclusion is that there is a wide range of available information regarding ministerial management but, on the other; the lack of participatory mechanisms is confirmed. These results can be understood if considering that within the Chilean public administration a managerial predisposition exists, which makes open participation spaces subordinated to prevailing managerial logics.
Perception Differences of Online Voting Between Young and Senior Voters
Authors: Powell Anne , Bock Douglas B. , Doellman Thomas , Allen Jason W.
Published: May 2010

This chapter presents a research study that examines the antecedents to voting intention with regard to the use of computer-based, online voting systems. The research is based on the Unified Theory of Acceptance and Use of Technology (UTAUT) model. Subjects from two different age groups (18-to-25 and 60+ years) in the United States are surveyed to determine the factors affecting their intent to use online voting systems. The results indicate that performance expectancy, social influence, and computer anxiety are factors affecting the intent to use online voting. Significant differences were found between the young adults (18-to-25) and seniors (60+ years) study groups on all four independent variables as well as on intent to use online voting. For young adults performance expectancy, social influence, and computer anxiety are significant factors affecting the intent to use online voting, while for senior citizens, performance expectancy and computer anxiety are significant factors. Ease of use was not a significant indicator of intent to use online voting for either group.
E-Government and the EU
Authors: Lake Brian
Published: May 2010

This chapter looks at the efficacy of The European Union’s e-government initiatives in addressing a key problem of European integration – a lack of democratic legitimacy. Citizens of the European Union witnessed endemic corruption in the EU’s governing institutions in the late 1990s. As part of a long-term project to ensure greater transparency and accessibility, the EU launched an e-government initiative, the “Information Society.” This chapter addresses the unique challenges for e-government and citizen participation at the supranational level. In a polity such as the EU, concepts of citizenship and democracy take on new dimensions. Technology as a social process is examined, and its relationship with public policy explored. It is in this context that the effectiveness of the EU’s e-government initiative is considered. As this chapter argues, the ability of e-government initiatives to increase citizen awareness does not necessarily correspond to an increase in democratic legitimacy.
Evaluating Social Networking in Public Diplomacy
Authors: Seo Hyunjin , Thorson Stuart
Published: May 2010

While many e-government applications have focused on governments connecting with their citizens, recently social networking tools have begun to transform the practice of public diplomacy by permitting governments to build and maintain direct relationships with citizens of other countries. In this chapter, we describe several such initiatives undertaken by the U.S. Department of State (DOS). Our particular focus is on efforts aimed at South Korea. We present results from interviews with DOS officials responsible for technology-based relationship-focused public diplomacy as well as with U.S. Embassy officials tasked with managing one of these initiatives–Café USA–and South Korean participants in Café USA. The chapter concludes with a discussion of the implications of e-government applications that cross national boundaries for our understanding of citizenship and suggestions for further research aimed at evaluating the effects of e-government applications within public diplomacy.
Explaining the Global Digital Divide
Authors: Gulati Girish J. , Yates David J. , Tawileh Anas
Published: May 2010

The rapid development of information and communication technologies (ICTs) has created an environment for citizens to have greater access to their government and to make citizen-to-government contact more inclusive. Previous research does not provide a comprehensive explanation for variation in recent e-government initiatives and, in particular, the impact of national public policy initiatives that seek to expand access to ICTs. This chapter examines the global digital divide by analyzing the impact of national policies on the ITU’s Digital Opportunity Index and the UN’s Web Measure Index in 171 countries. A multivariate regression analysis shows that when controlling for economic, social and political development, there is greater capacity for e-governance in countries that have a regulatory authority for telecommunications, competition in telecommunication industries, and higher financial investment in technological development. The analysis also shows that none of the examined policy initiatives appear to affect the reach of ICTs within countries.
E-Government in Brazil
Authors: Rodrigues Filho José
Published: May 2010

Despite the popularity of, and blossoming research on the use of, information and communication technologies (ICTs) in the information society, especially in terms of e-government and e-democracy, little research has been conducted to answer questions related to the effects of ICTs on citizenship, which is said to be at risk. It is claimed that the political science research in modern democracy has narrowed citizenship down to voting, turning democracy into something to be experienced at election time only and not between elections. We need a very clear understanding of the opportunities brought by new technologies and the dangers and risks regarding the realization of citizenship and civil rights. If it is true that ICT has done little to change our democracy, and if it in itself does not guarantee the realization of the rights of the citizens, research work must be developed in order to better analyze the relationship between ICT and citizenship. Because this kind of research is almost non-existent, even in the developed world, this paper attempts to see whether e-government projects in Brazil are designed in ways which reflect our best understanding of freedom, social justice, addressing the sources of inequalities, alienation, and injustice.
Web Services Integration in Multi-Agent Systems
Authors: Guidi Davide , Gaspari Mauro , Profiti Giuseppe
Published: May 2010

The development of distributed systems is influenced by several paradigms. For example, in the last few years, great emphasis has been placed on Service Orientation. In addition, technologies such as Web services are now considered standard, deployed in common development tools and widely used. However, despite this recent trend, the constantly growing number of powerful personal devices will inevitably revitalize the interest in another paradigm known as Autonomous Agents. Agents are in fact considered one of the main building blocks of the emerging next generation Web infrastructure. Web services are very important resources for agents. Agents should be able to retrieve, execute and compose Web services, providing an intelligent and personalized support to users. On the other hand, agents should also be able to export their functionalities as Web services in order to be fully integrated in the Service Oriented paradigm. In this chapter we present a survey of the current state of the art about Web services integration in open Multi-Agent Systems (MAS). Considering these approaches, we identify a set of requirements needed to achieve full integration and we present a communication infrastructure, which satisfies these requirements.
Context Dissemination in Peer-to-Peer Networks
Authors: Barth Antje , Kleis Michael , Klenk Andreas , Radier Benoit , Elmoumouhi Sanaa , Carle Georg , Salaun Mikael
Published: May 2010

In recent years, peer-to-peer overlay networks have become a popular communication paradigm with the potential to further change communication fundamentally in the future. Overlays allow communication abstraction but suffer from one inherent problem: The overlay is unaware of the context of a service or the context of a service consumer. The concept of context-awareness emerged out of the research done within the area of ubiquitous computing. Context-aware computing is one key technology to enable services and applications in the communication environment to adapt their behaviour based on the knowledge of environmental (contextual) information, thereby enhancing the system’s ability to become ever more responsive to the needs of the end-user or application domain. In this chapter we first introduce context and context architectures in general. In the remainder of the chapter we focus on the question: How can highly distributed context information be located and retrieved regarding small-scale as well as large-scale networks, addressing the topics of inter-domain management and scalability of context architectures?
Request-Driven Cross-Media Content Adaptation Technique
Authors: Fudzee Mohd Farhan Md , Abawajy Jemal
Published: May 2010

Devices, standards and software develop rapidly, but still often independently of each other. This creates problems in terms of content suitability on various devices. Also, in mobile environment, user and system-level applications must execute subject to a variety of resource constraints. In order to deal with these constraints, content adaptation is required. In this chapter, we justify the need of distributed cross media content adaptation and the potential of utilizing Web Services as the adaptation providers. We introduce request-driven context to complement constraint-driven and utility-driven approaches. We describe the request context mapping and propose a novel path’s determination scheme for determining the optimal service proxies to facilitate the adaptation tasks. To better illustrate the disjoint portions in content passing between service proxies, two communication models were associated. Then, within Web Services, we explain the related protocols and socket connection between adaptation’s services. We conclude with discussion regarding the strengths of the proposed architecture.
Web Services for Quality of Service Based Charging
Authors: Pencheva Evelina , Atanasov Ivaylo
Published: May 2010

Parlay X is a set of Web Service interfaces. These interfaces are designed to provide open access to telecommunication network functions in order to hide underlying network technology, and its control protocol complexity, from application developers. The Parlay X “intelligence” is concentrated in a node called Parlay X Gateway which converts interfaces methods in protocol messages and vice versa. An inherent constraint on any implementation requires the Parlay X Gateway to govern the interface to the underlying network i.e., to provide a single point of contact at which vertical signaling is received from the network. This chapter presents a study on alternatives for Parlay X Web Service deployment in Internet Protocol based multimedia networks (IMS). The focus is set on Parlay X Web Services for application-driven quality of service (QoS) management and charging control. It is presented as an analysis of the interfaces. Particularly the discussion is about their applicability to Policy and Charging Control architecture in IMS. Going further, the Web Service interfaces are mapped onto network protocols that they affect, namely Session Initiation Protocol (SIP) and Diameter. On that base an improvement is suggested concerning Parlay X interfaces for QoS management without violating the specified interface functionality. The usage of Web Services is exemplified with an application for charging control based on the provided QoS.
Hemoglobin Level Analysis in Hemodialysis Patients Treated With Erythropoiesis Stimulating Agents
Authors: Martín J. D. , Soria Emilio , Soldevila A. , Climente M. , Pallardó L. M. , Jiménez Nicolás Victor
Published: May 2010

In this chapter authors try to develop an expert system with the help of neural network method like Organizing Maps (SOMs) for hemodialysis patient.  Neural network models play a very important role for data analysis of hemodialysis patients with end-stage renal disease.  There are two main goals: firstly, the knowledge extraction from a database using Self-Organizing Maps (SOMs); and secondly, to provide an accurate prediction of Hb levels next month.
Hybrid Intelligent Systems for Medical Diagnosis
Authors: Kala Rahul , Shukla Anupam , Tiwari Ritu
Published: May 2010

In this chapter authors describe the application of various soft computing techniques in the field of medical diagnosis. They also explained new approaches being applied to the field of Bio-Medical Engineering as well as many new models being proposed, like Hybrid Systems and standard Back Propagation Algorithm for this purpose. These are Adaptive Neuro Fuzzy Inference Systems, Ensembles and Evolutionary Artificial Neural Networks.
Virtual Team Identity Construction and Boundary Maintenance
Authors: Zhang Huiyan , Poole Marshall Scott
Published: May 2010

This chapter reports the results of a multiple case study which investigated how virtual teams appropriated multiple media to facilitate the construction of group identity and manage group boundaries. It focuses on relationships within and between virtual teams. The study found five processes that shaped group identity, including clarification of goals and mission, developing regularized pattern of interaction, group norms for media use, and negotiation of task jurisdiction with interlocking groups. The study discovered that groups managed boundaries in terms of clarity distinctness, and permeability. It indicated that group boundaries were blurred and maintained simultaneously through purposeful use of communication technologies.
The Amplification of Power Dynamics in Virtual Work
Authors: Yungbluth Stephen C. , Hart Zachary P.
Published: May 2010

This chapter examines how power dynamics are manifested in virtual work. It starts with a look at how power is demonstrated in traditional decision making, and progresses to an exploration of how some organizations are experimenting with different forms of e-participation. Two cases are presented to illustrate some of the decisions associated with the implementation of information and communication technology (ICT), and the consequences of those choices. The first case looks at President Obama’s platform on technology and how his administration has embraced it to expand his vision of democracy in the information age. The second case portrays a utility company seeking to increase the involvement of its stakeholders through the creation of a blog site for the exclusive use of its community council. Both cases reveal a complex view of how organizations attempting to increase participation can paradoxically find themselves stifling it.
Paving the Way towards Virtual Biorefineries
Authors: Rapp Barbara , Bremer Jörg
Published: May 2010

Biomass nowadays gets an ever increasing importance as a substitute for fossil fuels and as a source of energy as well as of materials for chemical products. In comparison with other raw materials, biomass has distinguishing and additional production or rather clearing characteristics that have to be taken into account for sustainable and successful biomass supply chains. This chapter explores the drawbacks and opportunities of existing approaches to biomass logistics and continues with a detailed description of an advanced procurement system, which has been developed as a proof-of-concept by the authors. Procurement driven by meta-data based data acquisition will be discussed as a starting point for a variety of missing features in today’s environmental information system’s support for forming inter-business linkages in regional biomass networks. These ideas are further developed into a concept for a virtual biorefinery as an advanced system for an appropriate treatment of biomass concerning economical, ecological and sociological sustainability issues at the same time.
Cooperative Inter-Municipal Waste Collection
Authors: Bevilacqua Vitoantonio , Intini Francesca , Kühtz Silvana , Renna Paolo
Published: May 2010

The cooperative inter-municipal waste collection can be a real added value in terms of costs reduction and high performance services. The chapter proposes a Multi Agent Approach to support the inter-municipal infrastructure. The Multi Agent Systems (MAS) is an approach suitable to implement a distributed physically problem as the inter-municipal waste collection. The architecture of the approach is formalized by work-flow analysis: a static view by IDEF0 diagram and a dynamic view by UML activity diagram. This analysis promotes the cooperation among municipalities to manage the waste collection service in an optimal way. According to Italian laws, the municipalities are responsible for organizing the management of municipal waste in agreement with the principles of transparency, efficiency, effectiveness and inexpensiveness. The coordination protocol among the agents allows to divide the costs among the municipalities in an efficient way. Finally, a discrete event simulation environment is developed to test the proposed MAS architecture.
Factory Planning Based on Environmental Information
Authors: Grünwald Christian
Published: May 2010

The high complexity and a multitude of constraints in today’s industrial manufacturing require a detailed planning of techniques as well as processes even before the building of production plants. Apart from technique- or process-related planning parameters, environmental aspects are separately considered in the task of planning. The approach of an integration of environmental information into a tool for planning production processes pursues the combination of both points of view. As a result, the expected generation of substances causing environmental hazards during production can hereby be uncovered even before an industrial plant is built. In this way actions for protecting employees and environment will early be considered and later high-cost conversions of plants are avoidable. The described concept is related to business practise by the development of a prototype in connection with a case study and shows the potential of the integration of both planning views.
The German Environmental Information Portal PortalU
Authors: Konstantinidis Stefanie , Kruse Fred , Klenke Martin
Published: May 2010

In Germany, public environmental data are in the responsibility of several different public organisations and institutions. The German Environmental Information Portal PortalU® (www.portalu.de) is a web service operated by the environmental administrations to make digital environmental information easier accessible, usable and exploitable for both citizens and environmental experts. The fruitful long-time co-operation between the environmental administrations is an example for a well working organisational structure within a federal state. In this chapter the PortalU technology and the content of the portal are presented. Due to the current discussion referring to INSPIRE, a special focus is set on publishing INSPIRE conform metadata.
E-Learning and Teaching
Authors: Hamdan Amani
Published: May 2010

The last three decades have witnessed the phenomenal growth of the Internet as a medium for teaching and learning in higher education. Yet educational systems have done little to gain a better understanding of how these methods affect the nature and level of student engagement. Although there is a rapidly growing literature on the use of the Internet for teaching and learning purposes, there is relatively little literature and associated research on effective Pedagogical approaches to web-based instruction. This chapter starts by outlining the advantages and disadvantages of using the web for teaching in the context of higher education. One aspect of the disadvantages that is addressed in this chapter is the dilemma that Online learning and teaching pose for decision-makers, educators and students with regard to the implementation of Pedagogical approaches aimed at enhancing critical thinking and metacognitive skills.
Visual Literacy and Its Impact on Teaching and Learning
Authors: Song Kim H. , Turner Gwendolyn Y.
Published: May 2010

The chapter explores the importance of visual literacy in teaching and learning using multiple literacies as a main framework. Its goals are: (1) to explore visual literacy as a critical literacy in teaching and learning and (2) to share the perceptions of teacher education candidates’ understandings and uses of visual literacy. From the research, nine visual literacy competences were developed and used to analyze these perceptions in a pilot study. Findings indicate that most participants operate in lower levels of the visual literacy competences, e.g., ‘identify, translate, and access’. Most participants realized the significant role of visual images in their own learning and teaching and the need for higher levels of visual competencies. Based upon the findings of the study and review of the research literature, it appears logical that visual literacy should be taught to develop the ability to incorporate, analyze and integrate to enhance verbal literacies.
Contemplative Interaction
Authors: Sable David
Published: May 2010

This chapter deals with an online course using innovative pedagogy and innovative technology to enable transformative learning. It concerns the application of reflective practices including mindfulness, guided contemplation, and journal writing as the groundwork for active listening, inquiry, and dialogue that builds new meaning for individuals and groups. Positive student feedback and preliminary research indicate individual and interactive contemplation exercises strengthen characteristics of transformative learning.
Identity Awareness
Authors: Adebowale O.F.
Published: May 2010

To ensure an effective transformative learning, the concept of self and personal identity is a germane concept that needs the attention of researchers and other stakeholders. This chapter gives a clear expose of the concept of self or personal identity, it representation in an online interaction (online identity), how people manage their online identities as well as challenges to online identity management. The chapter concludes by discussing the implication of identity awareness to transformative learning.
Cytometric diversity in marine ultraphytoplankton
Authors: Li W. K. W.
Published: May 2010

The concept and methods of ecological diversity in communities were applied to phytoplankton categorized by flow cytometric measurements related to size and chlorophyll content. Each cytometric signature was condensed to single numerical values indicative of diversity and evenness. Measurements pooled from studies disparate in temporal and spatial scales indicated greater chlorophyll biomass and primary production with greater cytometric diversity and evenness. Future development of these ideas may help link biological oceanographic processes with patterns established through ecological processes at the community level.
Grazer and nutrient impacts on epilimnetic ciliate communities
Authors: Marchessault Philippe , Mazumder A.
Published: May 2010

The effects of large grazers (Daphnia) and nutrients (nitrogen and phosphorus) on epilimnetic ciliate communities were investigated in eight large in situ enclosures. Contrasts in Daphnia abundance were created by stocking planktivorous fish (Phoxinus eos) in four of the eight enclosures. Contrasts in nutrients were created by adding nitrate and phosphate to two enclosures with fish and to two enclosures without fish. Both the biomass and mean length of total zooplankton were significantly greater in the fish‐free enclosures than in the enclosures with fish. Addition of nutrients and fish produced a four‐fold variation in concentration of total epilimnetic phosphorus and six‐fold variation in algal biomass (Chl a). Daphnia were virtually absent in the enclosures with fish. The abundance of ciliates was one to three orders of magnitude lower when Daphnia were abundant. Addition of nutrients did not increase ciliate abundance in enclosures with Daphnia, but ciliate mean lengths were larger in these enclosures. Ciliate abundance increased with increasing zooplankton biomass when Daphnia were lacking, but it declined rapidly when Daphnia were abundant, producing a hyperbolic pattern. When the data for all the treatments were considered together, there was no relationship between copepod biomass and ciliate abundance, but positive relationships, although not highly significant, emerged when the data for enclosures with and without fish were considered separately. Our results suggest that large grazers are the most important factor regulating ciliate communities as well as the responses of ciliates to nutrients and resources. Shifts of zooplankton from copepods to Daphnia dominance may result in large reductions in ciliate abundance, regardless of the trophic status of lake ecosystems.
Bloom dynamics of toxic Alexandrium species in the northeastern U.S
Authors: Anderson Donald M.
Published: May 2010

Coastal waters of the northeastern U.S. are subject to recurrent outbreaks of paralytic shellfish poisoning (PSP) caused by toxic dinoflagellates in the genus Alexandrium. PSP is not uniform across the large region, but instead reflects Alexandrium growth and toxin accumulation in five separate habitats or zones defined by circulation patterns and the discontinuous distribution of the dinoflagellates. Each of these habitats has a unique set of environmental and oceanographic forcings that determine the timing and extent of bloom development and transport and that regulate the extent of genetic exchange with adjacent populations. Several habitats (e.g. the southwestern Gulf of Maine, Massachusetts Bay, and Georges Bank) are linked hydrographically and may share the same Alexandrium population via large‐scale transport in a. coastal current, whereas the other two habitats (eastern Maine and southern salt ponds‐embayments) seem to be isolated and have little or no hydrographic or genetic linkage to adjacent regions during bloom seasons. My paper provides an overview of the regional ecology and oceanography of Alexandrium through a focus on these five subpopulations. Issues that relate to PSP and Alexandrium dynamics throughout the world are highlighted, including species dispersal, the role of cysts and “initiation zones” in bloom development, and the influence of large‐ and small‐scale hydrography on population development and transport. The ability of Alexandrium to colonize multiple habitats and to persist over a large region is emphasized in recognition of the adaptability and resilience of this important organism.
Coastal eutrophication and harmful algal blooms: Importance of atmospheric deposition and groundwater as “new” nitrogen and other nutrient sources
Authors: Paerl Hans W.
Published: May 2010

Nitrogen‐limited estuaries, shallow coastal waters, and continental shelf waters cover only 15% of the world’s ocean area, but account for nearly half the global oceanic primary production. This disproportionality is partly attributed to accelerating and geographically expanding anthropogenic N loading and eutrophication. Among accelerating N inputs, atmospheric deposition (AD) (as wet‐ and dryfall) and groundwater (GW) discharge are of considerable and growing importance. AD contributes from 300 to >1,000 mg N m−2 yr−1 to coastal waters as the biologically available forms NOx−, NH3/NH4+, and dissolved organic N. GW‐N inputs have not been extensively characterized and quantified but in certain regions may be comparable to AD. AD and GW can jointly account from 20 to >50% of total exogenous, or “new,” N loading and may uniquely mediate coastal eutrophication by bypassing estuarine filters of terrigenous N inputs. Direct AD and offshore GW inputs may impact harmful algal bloom dynamics of coastal and pelagic waters downwind of emissions and downstream of discharges. Example include North American Atlantic coastal waters, the Baltic and North Seas, the western Mediterranean, and the Yellow Sea. Impacts include enhanced N availability and alteration of stoichiometric ratios of nutrients (N, P, Si). Trace metal enrichment (e.g. Fe) in AD and GW may interact synergistically with N to stimulate coastal production. Growing urban, industrial, and agricultural AD and GW inputs to coastal and offshore waters may be linked to a purported expansion of harmful algal blooms.
Toxin variability during the cell cycle of the dinoflagellate Alexandrium fundyense
Authors: Taroncher‐Oldenburg Gaspar , Kulis David M. , Anderson Donald M.
Published: May 2010

Cultures of the toxic dinoflagellate Alexandrium fundyense Balech were subjected to conditions that induced two synchronized divisions over a period of 48 h. Before, during, and after this interval, toxin content, toxin composition, and several other physiological parameters were monitored every 2 h for 94 h. Toxin production was discontinuous, induced by light, and always occurred during a defined time frame within the G1 phase of the cell cycle. Specific toxin production rates were positive for a period of ∼8–10 h in early G1 and dropped to zero for the remainder of the interphase and mitosis. Analysis of toxin composition showed that cellular concentrations of all the saxitoxin derivatives followed a similar pattern of increase, stabilization, and decrease throughout one generation time. A putative sequence of interconversions between the derivatives could be established, with C2 as the first compound to appear. Division of a subset of the population during the first 24 h of the experiment and the ensuing total synchrony of the culture suggest the existence of two transition points in the cell cycle of this dinoflagellate. The first transition point, at the beginning of G1, is light‐dependent and holds the cells in a G0‐like period. The second block point at the end of G1 is size‐dependent and arrests the cells in G1. We propose a model of the cell cycle of A. fundyense in which progression through the cell cycle can be arrested at two different transition points located in G1 and toxin production is induced by light during G1. The restriction off toxin production to a relatively short segment of the cell cycle provides a tool for comparing cells that are and are not synthesizing toxin.
Toxic marine phytoplankton, zooplankton grazers, and pelagic food webs
Authors: Turner Jefferson T. , Tester Patricia A.
Published: May 2010

Interactions between toxic phytoplankton and their zooplankton grazers are complex. Some zooplankters ingest some toxic phytoplankters with no apparent harm, whereas others are deleteriously affected. Phycotoxins vary in their modes of action, levels of toxicity and solubility, and affect grazers in different ways. Beyond effects on direct grazers, toxins may accumulate in and be transferred through marine food webs, affecting consumers at higher trophic levels, including fish, seabirds, and marine mammals. Grazers of toxic phytoplankton include protists as well as metazoans, and the impact of zooplankton grazing on development or termination of toxic blooms is poorly understood. In most interactions of toxic phytoplankters with grazers and other marine food‐web components, outcomes are situation‐specific, and extrapolation of results from one set of circumstances to another may be inappropriate.
Models of harmful algal blooms
Authors: Franks Peter J. S.
Published: May 2010

Models used to study harmful algal blooms are a subset of those used to examine more general planktonic processes. Most models have been heuristic, examining the likelihood of certain processes generating a harmful algal bloom. Several models have been more closely coupled to field data and have been used to gain insights into the dynamics underlying the observations. As better physical and biological models are developed, models may play an increasingly important role in harmful algal bloom research. Techniques such as data assimilation may increase the predictive power of models, suggest strategies for improving field sampling, and better constrain poorly known parameters and processes.
Development of a scanning confocal laser microscopic technique to examine the structure and composition of marine snow
Authors: Holloway Charles F. , Cowen James P.
Published: May 2010

A technique was developed to image marine snow particles by scanning confocal laser microscopy (SCLM). This method allows structural and compositional characterization of fully hydrated marine snow particles with minimal disruption of the particle structure. High specificity fluorescent stains petmitted sequential imaging of selected polysaccharides (concanavalin A: specific for mannose and glucose polymers), proteins [5‐(4,6‐dichlorotriazin‐2‐yl) aminofluorescein], and DNA (propidium iodide). Chl a autofluorescence can also be imaged. SCLM produced optical slices of marine snow particles that were suited for a number of image‐processing applications. These applications include high‐resolution fluorescently derived optical slices and composite images produced from combined optical slices. Initial observations suggest that marine snow particles found in the oligotrophic Pacific Ocean vary in composition and structure. Variations in polysaccharide and protein composition of marine snow particles may be related to particle morphology. When combined with other conventional analysis, such as epifluorescent and electron microscopy, LSCM can provide important contributions to characterizing composition and structure of marine snow.
Predation by Hydra on larval fish: Field and laboratory experiments with bluegill (Lepomis macrochirus)
Authors: Elliott J. K. , Elliott J. M. , Leggitt W. C.
Published: May 2010

We found high population densities of Hydra canadensis (up to 30,000 m−2) on macrophytes in Lake Opinicon (Ontario, Canada) and tested whether they influenced the survival of larval bluegill, Lepomis macrochirus. Hydra were observed to capture and ingest bluegill larvae in laboratory trials. Individuals that ingested fish larvae turned black; those fed a variety of crustacean species remained brown. The ingestion rate of Hydra on larvae in 8‐liter laboratory microcosms was higher during the night (0.197 larvae predator−1 h−1) than during the day (0.111 larvae predator−1 h−1). Many larvae also died after escaping from the stinging tentacles of Hydra (on average 26% of larval mortality). Population densities of Hydra were highest on the macrophyte Myriophyllum spicatum. Bluegill colonies were surrounded by dense beds of M. spicatum in some areas, and larvae in the colonies had to swim through the plants (with the attached Hydra) in order to reach open water. We sampled Hydra in the vicinity of bluegill colonies on the morning after larval swim‐up. The number of black Hydra decreased with increasing distance from a colony; 72% black within colonies, 45% at 0.5 m outside colonies, and 31% at 2 m outside of colonies. We estimate that up to 20% of the larvae produced by a colony can be killed by Hydra within this 2‐m zone. Many more larvae likely die as a result of encounters with Hydra that are abundant throughout the lake.
Photooxidation of triglycerides and fatty acids in seawater: Implication toward the formation of marine humic substances
Authors: Kieber Robert J. , Hydro Linda H. , Seaton Pamela J.
Published: May 2010

Unsaturated fatty acids rapidly photodecomposed in filtered seawater to aliphatic aldehydes and an ω‐oxocarboxylic acid (CHO‐(CH2)n‐COOH) upon a 5‐h exposure to ambient sunlight. The photoreactivity of fatty acids increased as their degree of unsaturation increased. Palmitic acid displayed no photodegradation while monounsaturated oleic acid photodecomposed to nonanal and 9‐oxononanoic, respectively. Photooxidation of the polyunsaturated linoleic acid produced significantly higher concentrations, primarily hexanal, and a wider variety of aldehydes. The rate of photodegradation was more than 10 times greater for the polyunsaturated fatty acids than for the monounsaturated fatty acids. Photolysis of the triglyceride, trilinolein, gave an aldehyde profile similar to its component fatty acid, indicating each undergoes a similar mechanism of photodegradation. Twenty percent of the initial triglyceride was photodegraded during the 6‐h irradiation. The rapid photoreactivity of unsaturated fatty acids may explain their low in situ levels relative to saturated fatty acids, the latter of which are found in the dissolved phase at relatively higher levels.

Fluorescent hydrophobic dissolved organic matter, operationally defined as humic substances, increased after irradiation of trilinolein‐treated seawater over a 14‐d period. The concentraticn of humic products was enhanced by postphotolysis addition of ammonia. Dissolved ammonia concentrations declined as the dissolved organic nitrogen of the extracted humics increased, indicating the added ammonia was becoming incorporated into the organic structure.
A mixotrophic ciliate as a major contributor to plankton photosynthesis in Australian lakes
Authors: Laybourn‐Parry Johanna , Perriss Stephen J. , Seaton George G. R. , Rohozinski Jan
Published: May 2010

A large mixotrophic ciliate (∼200 µm long) of the genus Stentor is a common constituent of the protozooplankton of Australian lakes. We investigated the photosynthetic rates of populations of this ciliate from two lakes, one in the Australian Capital Territory and the other on the New South Wales/Victorian border, in relation to photosynthesis by the whole phytoplankton community. The concentration of the ciliate varied between 192 and 4,267 cells liter−1 during the study period of May–January (the austral winter, spring, and autumn) and it contributed between 4.3 and 69.3% of total plankton photosynthesis. Individual photosynthetic rates ranged between 1.03 ± 0.8 and 3.98 ± 0.6 ng C cell−1 h−1 and individual Chl a content between 925 ± 62 to 1,461 ± 63 pg cell−1, giving assimilation numbers of 1.00–2.74. Light‐response curves indicated that the ciliate achieved its highest rates of photosynthesis at high photon fluxes, typical of the surface waters. Vertical distribution patterns of Stentor in the water column of one of the lakes supported these physiological data. Southern hemisphere lakes seem to have a protozooplankton that may contain substantial numbers of a large ciliate capable of contributing a significant portion of carbon fixation in the plankton.
A consumer's guide to phytoplankton primary productivity models
Authors: Behrenfeld Michael J. , Falkowski Paul G.
Published: May 2010

We describe a classification system for daily phytoplankton primary productivity models based on four implicit levels of mathematical integration. Depth‐integrated productivity models have appeared in the literature on average once every 2 years over the past four decades. All of these models can be related to a single formulation equating depth‐integrated primary production (∑ PP) to surface phytoplankton biomass (Csurf), a photoadaptive variable (Pbopt), euphotic depth (Zeu), an irradiance‐dependent function (F), and daylength (DL). The primary difference between models is the description of F, yet we found that irradiance has a relatively minor effect on variability in ∑ PP. We also found that only a small fraction of variability in ∑ PP can be attributed to vertical variability in phytoplankton biomass or variability in the light‐limited slope for photosynthesis. Our results indicate that (1) differences between or within any model category have the potential to improve estimates of ∑ PP by <10%, so long as equivalent parameterizations are used for Csurf and Pbopt, and (2) differences in estimates of global annual primary production are due almost entirely to differences in input biomass fields and estimates of the photoadaptive variable, Pbopt, not to fundamental differences between model constructs.
Effect of growth rate and CO2 concentration on carbon isotopic fractionation by the marine diatom Phaeodactylum tricornutum
Authors: Laws Edward A. , Bidigare Robert R. , Popp Brian N.
Published: May 2010

The carbon isotopic composition (δ13C) of the marine diatom Phaeodactylum tricornutum was measured over a series of growth rates (µ) in a chemostat system in which both the δ13C and the concentration of aqueous CO2 [CO2(aq)] were measured. CO2(aq) ranged from 0.64 to 35 µmol kg−1 and growth rates from 0.5 to 1.4 d−1. εp, the biological fractionation factor associated with carbon fixation, was found to be a nonlinear function of µ/CO2(aq), contrary to the predictions of a model that assumes that CO2 enters the cell by passive diffusion. The experimental results suggest that active uptake of bicarbonate does not account for the nonlinearity of the relationship and that inorganic carbon enters the cell as CO2. The data are very well described by theoretical model that assumes that P. tricornutum regulates the CO2 concentration in its cytoplasm so as to minimize the energy required to concentrate CO2 at the site of carboxylation. This is probably achieved by active uptake of CO2 or by conversion of bicarbonate to CO2 by an external carbonic anhydrase followed by transport of the CO2 into the cell via either active transport or passive diffusion. Based on the model and data, µ/CO2(aq) = 0.225 × [(26.8 − εp)/(εp − 5.5)] kg d−1 µmol−1. This equation accounts for 92% of the variance in the µ/CO2(aq) data. The model has potential utility for estimating phytoplankton growth rates in field studies without incubations and has important implications for the estimation of ancient CO2(aq) from the δ13C of preserved organic compounds.
Growth and reproduction of Daphnia galeata in response to changes in fatty acids, phosphorus, and nitrogen in Chlamydomonas reinhardtii
Authors: Weers Paul M. M. , Gulati Ramesh D.
Published: May 2010

The importance of changes in elemental and fatty acid composition of the algal food for Daphnia galeata was investigated. The green alga Chlamydomonas reinhardtii was grown under nitrogen or phosphorus limitation to modify its elemental and biochemical composition. Both N‐ and P‐limited algae exhibited similar fatty acid compositions but differed from algae grown under N and P saturation. Nutrient limitation of algae caused the amounts of saturated fatty acids, monounsaturated, and diunsaturated fatty acids to increase, but those of polyunsaturated fatty acids to decrease markedly. Life‐history experiments with D. galeata, carried out to examine the effects of the varying N and P regimes to the food quality of Chlamydomonas, revealed that N‐limited and N+P‐saturated algae were of a comparable quality. In contrast, P‐limited alga was a very poor food; that is, both population growth and somatic growth rate were much lower than with N‐ and N+P‐saturated algae. Differences of algal fatty acid composition did not explain the differences in algal food quality as N+P‐saturated and N‐limited Chlamydomonas were both similar in quality despite differences in fatty acid composition. P limitation of daphnid growth is more consistent with the observed differences in growth and reproduction. The low growth rates of the daphnids when fed P‐limited alga, however, may also be a result of indirect effects because P limitation may induce changes in algal morphology or biochemical compounds other than fatty acids.
A fast‐responding CO2 microelectrode for profiling sediments, microbial mats, and biofilms
Authors: de Beer Dirk , Glud Anni , Epping Eric , Kûhl Michael
Published: May 2010

A new CO2 microelectrode with a tip diameter of 10 µm and a response time (t90) of ∼10 s is presented. The sensor allows CO2 measurements with a detection limit of <3 µM. The microsensor was tested in experimental systems of increasing complexity. A diffusion‐reaction simulation model was used to calculate CO2 profiles in order to check the reliability of the measured profiles. Measured CO2 and O2 profiles showed that, in highly active layers with photosynthetic and respiratory organisms, local equilibrium of the carbonate system cannot be assumed. In such highly active systems, the CO2 profiles were determined by the slow CO2 hydration rate, the biological conversion rates, and the diffusion of all species of the carbonate system. We concluded that measured CO2 profiles cannot easily be extrapolated to describe the total carbonate concentration profile, because CO2 may not be in equilibrium with the rest of the carbonate system, and because a very accurate alignment of pH and CO2 profiles is needed to calculate CT. However, the new CO2 microelectrode is useful in research involving biological processes directly producing or consuming CO2 such as photosynthesis or respiration.