bluuebunny/crossref_metadata_2025 huggingface dataset:
Distributed Libraries Management for Remote Compilation and Execution on Grid Platforms with JaDiMa
Authors: De Oliveira Jesús , Cardinale Yudith , Blanco Eduardo , Figueira Carlos
Published: May 2010

In distributed environments (e.g. grid platform) it is common to find pieces of reusable code distributed among multiple sites. The possibilities of compilation and execution with remote libraries have a great potential to facilitate the integration of pieces of software developed among different organizations. This chapter describes JaDiMa (Java Distributed Machine), a collaborative framework to construct Java applications on grid platforms. JaDiMa automatically manages library repositories to allow users to compile and execute applications which use distributed libraries, without keeping these libraries locally. JaDiMa services are implemented as Web Services following the SOA approach; library repositories are modeled as a JXTA P2P network; and semantic annotations of libraries assist developers on the tasks of discovering libraries. We describe an implementation of JaDiMa as part of SUMA/G, a Globus-based grid environment. We show experiences and an empirical evaluation of JaDiMa execution and compilation processes for an application which uses remote libraries for managing graph and network data.
A Self-Organized Structured Overlay Network for Video Streaming
Authors: Ragab Khaled
Published: May 2010

Peer-to-Peer (P2P) file downloading and streaming applications have recently attracted a large number of users on the Internet. Currently, several P2P video streaming systems have been deployed to reduce the cost at server. They are classified into two categories live and on-demand streaming systems. The live streaming systems disseminate live video contents to all peers in real time. On the other hand, the on-demand video (VoD) streaming system enables peers to enjoy the flexibility of watching video. It realizes the goal of watch whatever you want, whenever you want. The current P2P-VoD systems cannot realize such goals efficiently. This chapter proposes a self-organized structured overlay network of peers to realize that goal and improve performance. Each peer is able to cache some video minutes associated with the current media being played. The proposed overlay network is organized into clusters. Each cluster contains peers with overlapped buffer windows where their playing points are located between lower and upper play point limits. When a peer in the cluster moves its play point within the limits, for example by performing a seek operation, it then can rapidly discover and fetch the required blocks for the playback buffer from peers in the same cluster. Clusters improve both discovery and fetch overheads. However, it needs cluster management overhead.
Clinical Decision Support System To Prevent Toxicity In Patients Treated With Digoxin
Authors: Albert Asunción , Serrano Antonio J. , Soria Emilio , Jiménez Nicolás Victor
Published: May 2010

In this chapter, authors develop a system for prevention and detection of congestive heart failure and fibrillation. Due to its narrow therapeutic range more than 10% of the patients treated with DGX can suffer toxic effects, but it is estimated that half of the cases of digitalis toxicity could be prevented. Two multivariate models were developed to prevent digitalis toxicity.
Breast Cancer
Authors: Janghel R. R. , Shukla Anupam , Tiwari Ritu
Published: May 2010

In this chapter authors did one technological survey for breast cancer and found very large scale of people working on this field.  So many techniques are used in that field and they found that Breast cancer is the second leading cause of cancer deaths in women and occurring one out of eight women in worldwide. They found that three techniques like Mammography, FNA and Open surgery are mostly seen in the literature of breast cancer.
A Step Towards Characterization of Surgical Actions Involved in Mastoidectomy
Authors: Lahiri Uttama , Labadie Robert F. , Liu Changchun , Majdani Omid , Sarkar Nilanjan
Published: May 2010

In this chapter authors give an idea for automation of open surgery.  Mastoidectomy is a core surgical procedure in otologic surgery.  Here they present a novel approach to developing methods for parsing raw data (position and orientation of the surgical tool and end-effector force) into a sequence of surgical actions (APs) that can be used by a robot in the future.
Communication, Structural Links, and Conflict in Three Inter-Organizational Virtual Collaborations
Authors: Harrison Tyler R. , Williams Elizabeth A.
Published: May 2010

Conflict is just as common in virtual teams as it is in collocated teams. However little is known about the process of conflict in these teams. The study presented in this chapter analyzed conflict in three inter-organizational teams. The purpose of this research is to identify primary types of conflict in virtual teams, examine the role that the structure of communication plays in the conflict, and examine the influence of the social context. Specifically, this chapter (1) reviews the extant literature on conflict in virtual teams and organizational conflict in general; (2) presents results from a study of three inter-organizational virtual team collaborations; and (3) offers an outline of potential future research in this area and provides best practices and potential pitfalls for practitioners to consider when structuring inter-organizational virtual teams.
Sense of Community in Professional Virtual Communities
Authors: Blanchard Anita , Askay David A. , Frear Katherine A.
Published: May 2010

Sense of virtual community (feelings of identity, belonging, and attachment) is an essential component of virtual communities. In this chapter, we develop a model of how sense of virtual community develops in professional virtual communities. Based on sense of virtual community models in social virtual communities, we expect that the exchange of support, development of a group identity, and group norms will lead to a stronger professional sense of virtual community. Unlike social virtual communities, we also predict that employee/members occupational identification will increase professional sense of virtual community, particularly when the virtual community can provide support and information not available in the employee/member’s face-to-face life. Finally, we propose that increased occupational commitment, professional networks, and employee performance are outcomes of sense of virtual community in professional virtual communities.
Politics in Virtual Work
Authors: Long Shawn D. , Boughton Marla D. , Widener Rachel
Published: May 2010

Due to their hierarchical structure and limited resources, organizations are inherently political. Employees need to know how to “play the game” in order to get ahead. In this chapter, we provide a background on politics, examining how the study of politics has evolved over time. We also examine the relationship between politics and similar constructs, such as authority, power, and influence. We then apply politics to an increasingly common organizational structure—virtual teams. Based upon research on trust, resource allocation, and influence in virtual teams, we suggest that, rather than being attenuated in the virtual environment, politics may in fact become exacerbated by the use of computer-mediated communication. We end the chapter with suggestions for future research on politics in virtual teams.
Engineers' Perceptions of Relational Limitations Intrinsic to Virtual Work
Authors: Gilchrist Eletra S.
Published: May 2010

Virtual work is increasingly prevalent in organizational settings. Many corporations communicate virtually to reduce travel and facility costs and expedite production. Benefits of employees communicating virtually are recognizable and advantageous, but the benefits can come at a price—decreased human interactions. This study explored engineers’ perceptions of relational limitations inherent to virtual work. Engineers enrolled in a communication course who use virtual work methods on the job comprised the sample. Qualitative content analysis revealed engineers perceive virtual work as a convenient and easy-to-use medium that bridges geography, curtails expenses, expedites meetings, and allows flex time. Conversely, engineers reported several relational limitations associated with virtual work, including reduced personal interactions, diminished nonverbal cues, increased miscommunications, added interference, and weakened interpersonal skills. Engineers exercise supplemental face-to-face communication, occasional on-site meetings, and social activities to counter virtual relational limitations. A social exchange theoretical perspective explains engineers’ continued use of virtual work.
Aided System of Competence Management for Virtual Team Building Adapted to Specific Needs of Design Projects
Authors: Schumacher Marinita , Le Cardinal Julie Stal , Bocquet Jean-Claude
Published: May 2010

Virtual instruments and tools are future trends in Engineering which are due to the growing complexity of engineering tasks. Individuals who are working in Virtual Teams must be equipped with spanning competencies that provide a basis for Virtual Team building. In the first step this chapter gives a broad insight to the field of Competence Management and Virtual Teams. The second step responds to the need of a method of Competence Management to build Virtual Teams that are active in virtual design projects in the area of New Product Development (NPD). Due to the systemic approach of the functional analysis, we present an Aided Competence Management for Virtual Team Building System (Aided CMVTB System) that permits to be adapted not only to organizations but also to design projects without a real organizational structure. The focus of this work is set on the generic aspect to highlight the adaptability and flexibility of the system.
From Traditional Non-Sustainable Production to Closed Loop Manufacturing
Authors: Golinska Paulina
Published: May 2010

The scope of this chapter addresses the issues related to materials management for closed loop manufacturing based on the integration of material flows management systems with production planning and control systems (PPC) or business systems (like ERP) applicable to remanufacturing environments. It aims to identify and discuss the main issues and further research steps needed in order to improve materials management, as well as assessment of the environmental impact of remanufactured products. The main problems that appear in the area of materials management by shifting from non-sustainable production to closed loop manufacturing have been identified and discussed. The integrated materials management approach has been presented.
Environmental Monitoring, Data Mining, and Dynamic Analysis
Authors: Minke Anneke , Lessing Helmut
Published: May 2010

Online-monitoring systems as well as systems regarding environmental observation have evolved from classic analytic methods on the laboratory scale. Still, they are structured mainly medially and sectorally. At this point, the multi-sensorial array-technology opens up new possibilities. Today, the integration of these multi-sensorial chips into mobile units of the automotive domain or into cell phones and the transmission of empirical data to an integrated network are possible; there are no fundamental technological barriers. Nevertheless, the examination of this data collected by mobile sensors which are often in motion and the extraction of reliable, supra-regional information yield a new class of problems. In this chapter, an implementation concept will be described which will be evaluated within a pilot scheme.
Structuring Information for Industrial Environmental Management
Authors: Carlson Raul
Published: May 2010

Environmental management of an organization is to a large extent about management, interpretation and development of environmental information. Therefore, for any organization to have a functioning environmental management system a matching well-functioning environmental information system is needed. To develop such a well-functioning information system it is necessary to structure all the relevant dimensions, ranging from indicators, reporting paths, material management and process management. This chapter provides an introduction to the structuring of the environmental information system.
Progression in Corporate Sustainability Reporting
Authors: Isenmann Ralf
Published: May 2010

In corporate reporting, greater internet use, reports available on the world wide web (WWW) and movements towards a more balanced reporting approach have become the most noticeable trends since the inception of sustainability reporting in the late 1980’s and early 1990’s. While early sustainability reports merely have been available on print media, today most are accessible on the WWW as HTML (Hypertext Markup Language) files. Such a layout oriented data format, however, does not seem to be sufficient any longer, especially in terms of content-syndication, harmonization, efficiencies, future ICT requirements, stakeholders’ reporting expectations, and data exchange, be it inside and outside the companies. Hence, reference architecture for sustainability reports built on XBRL (eXtensible Businesses Reporting Language) is proposed. This development is based on a research initiative embedded in the German Environmental Informatics community. The proposed document structure within the reference architecture particularly meets the requirements of the Global Reporting Initiative’s (GRI) sustainability reporting guidelines (G3). While developing the document structure, an existing XBRL FRTA (Financial Reporting Taxonomies Architecture) - common for business financial reporting- was used. Such a unifying document structure is a key for advanced reporting systems, particularly for current ICT applications like (web) content management systems. Using the reference architecture offers an impressive array of benefits, e.g. it helps: to facilitate data exchange between reporters and report users, to improve a company’s information management, to support its reporting workflow, and to refine communication with its target groups in a meaningful way.
Environment-Enterprise Integration
Authors: Michelini R. C. , Razzoli R. P.
Published: May 2010

Part of manufacturers’ responsibility when bringing out new products is to consider their environmental footprint. The legal supply chain combines hardware/software delivery, granting on-duty conformance to use preservation, and end-of-life take-back, with compulsory recovery targets. These entrepreneurial competencies appear externally, in respect to old manufacturing practices, which were internal. Networking options provide fundamental technological aids. This chapter analyses some technologically-driven solutions which stand out for the exploitation of net concerns at these three integration levels: business project co-operation, through spot-wise agreements; the factually united organisation or virtual corporation; joint and several liability, or extended corporation. The checks are centered on the bottom up series of appraisals, to evidence the return on investment from below so that the partnership permanently spurs motivation and fosters competition through properly established facilities/functions integration into unified competitive entrepreneurial organisations.
Sustainable Supply Chain Management
Authors: Dukovska-Popovska Iskra , Bertoni Malcolm , Hvolby Hans-Henrik , Turner Paul , Steger-Jensen Kenn
Published: May 2010

Integrating environmental considerations into supply-chain management has become an increasingly important issue for industry, government and academic researchers. Supply chain managers are being required to respond to the challenges of new legislation, standards and regulations; changing customer demands; drivers for efficiency, cost effectiveness and return on investment; while simultaneously being ‘green’. The fundamental tension between business and environmental drivers is difficult, but critical to understanding how to effectively re-engineer and re-design existing supply chains in a manner that is sustainable both financially and environmentally. Information systems have a significant role to play in supporting corporate responses to environmental management and the development of holistic green logistic solutions. This chapter examines contemporary discussions on the current state of sustainable supply-chain management and green logistics. It presents a case study from the Fujitsu Corporation in Japan and explores models of information systems and RFID use in green logistics. Combining insights from the case and existing models the chapter explores an example of how a combined model can be used to explore the potential of a specific emerging technology (RFIDs) in ‘greening’ supply chains.
Eco-Industrial Parks and Application of Corporate Environmental Management Information System in China
Authors: Wen Juan , Lu Xueqiang
Published: May 2010

The history, current situation, policy system and three typical cases for eco-industrial parks in China have been described and analyzed systematically. On the basis of this, application of CEMIS to EIPs has been discussed. A CEMIS framework for EIPs has been proposed according to the Chinese policy system. Furthermore, a schematic control diagram for EIPs has been suggested using box model.
Change or Transformation?
Authors: Browne Liz
Published: May 2010

This chapter draws on research carried out into a major national project funded by the government in the United Kingdom aimed a transforming teaching and learning in one sector of education known as the Learning and Skills sector. This sector, recognised as suffering from the ‘middle child syndrome’ (DfES: 2006), locates as a optional part of the learner journey between school and work or university and tends to be followed by those pursing a vocational training pathway. The sector is also renowned for providing new opportunities for adult learners wanting to re-train or gain qualifications required for new career pathways. This chapter explores the discourse of transformation in a programme of Continuous Professional Development for Teachers which adopted an e-portfolio for assessment purposes. The training programme was delivered using a blended learning approach. The research that informs this chapter was collated using electronic investigative tools. These are assessed for their usefulness whilst particular focus is given to evaluating the ambition for transformation as articulated in the programme aims.
Turbulence and Transformation
Authors: Buskey Frederick C.
Published: May 2010

The chapter uses kayaking as a metaphor for describing the lessons learned by the author as he worked towards helping future school leaders develop ethical understandings in an online course. The chapter describes basic challenges of teaching online, guiding principles of transformational learning, and defines ethical leadership. The author describes key online learning components, including the role of the instructor as facilitator, using engaging and challenging content, establishing a strong learning community, deep reflection, and practice of learning in the real world. The author also shares specific examples of course structures and assignments and observations and reflections from participants in the course.
Aesthetic Decisions of Instructors and Instructional Designers
Authors: Parrish Patrick
Published: May 2010

The same qualities that make works of art beautiful, meaningful, or at times even transformative in our lives also underlie our best learning experiences. This study sought to better understand the relationship between art and instruction by looking at how aesthetics underlie the design decisions of teachers and instructional designers. Five instructional designers and teachers were interviewed about a course or online learning product they had recently designed. The interviews explored the design decisions they had made based on how they imagined learners would experience the instruction at its beginning, middle, and ending. Participants discussed the introduction of tension to enhance engagement, worked to achieve a coherent experience for learners through narrative qualities, and demonstrated concern for the immediacy of their learners’ experiences, discussing the expected thoughts and feelings of learners at each stage of the course or module.
Transformative Learning and Online Education
Authors: Garg Suresh , Sharma Ramesh C.
Published: May 2010

Education is an organic entity and it evolves continuously to cater to the emerging needs of a society. In India, the educational system has changed over the centuries and with it transformed the way teaching-learning is transacted. Education has changed from ‘art to craft to technology’. Now we are witnessing technology-induced knowledge revolution. National boundaries and location of learner in spatial and temporal dimensions have lost significance. A learner on an atoll in the vast expanse of the Pacific Ocean can learn a subject of her / his choice online, provided s/he has access to a computer, Internet and other wireless communication tools. A vast variety of online platforms are now available to meet the diverse needs of learners. In this chapter, the authors have discussed how open education in general and online education in particular has performed the role of transformative learning in India. They have also discussed various aesthetical and purposive issues addressed by online learning environments to create an egalitarian society.
Identity
Authors: Parikh Radha M.
Published: May 2010

The issue of identity awareness is rarely discussed in the context of its relevance to professional growth or autonomy, and as an essential requirement for independent functioning in a web-based learning environment. The need for integrity is at the core of every interaction, the stress on doing one’s best for the special satisfaction one derives from it, rather than for recognition and awards – these topics are related to awareness of the individual identity and development of a strong professional and ethical self which will help students to remain focused and skilled at self-monitoring strategies, essential in the online learning environment. There are various other issues related to web identity. This chapter will not deal with issues such as telepresence which is related to technological innovation creating a virtual presence, or social presence, which deals with interpersonal interaction; rather the discussion here is more intrapersonal in nature.
Evaluation of 32Si as a tracer for measuring silica production rates in marine waters
Authors: Brzezinski Mark A. , Phillips Dennis R.
Published: May 2010

The radioisotope 32Si was evaluated as a tracer for measuring silica production rates in marine waters. 32Si is a weak β‐emitter that decays to 32P allowing the isotope to be used to determine simultaneously the production rate of biogenic silica and organic phosphorus. High specific activity 32Si, 42,000–52,000 Bq (µg Si)−1, was produced by the proton spallation of KCl. Reasonable tracer additions result in only nanomolar increases in the ambient silicic acid and orthophosphate concentrations during production rate experiments. Protocols for quantifying the amount of 32Si and 32P in samples by liquid scintillation counting (LSC) and gas‐flow proportional counting (GFPC) are presented. Both protocols eliminate the 4‐month wait for secular equilibrium between 32Si and 32P required by earlier methods. GFPC is especially useful as the instrumentation is lightweight and portable allowing real‐time analysis of samples at sea. Real‐time analysis by GFPC at sea and postcruise analysis by LSC gave results that agreed to within 17 and 7% for 32Si and 32P, respectively. Subsequent intercalibrations of the LSC and GFPC methods indicated that agreement to within 0.1–4% for both isotopes can be achieved. Parallel incubations of samples from Monterey Bay, California, using the radioisotope 32Si and the stable isotope 30Si gave silica production rates that generally agreed to within 30%. No significant bias was observed between rates obtained with the two tracers. The greater sensitivity and ease of analysis of the radioisotope makes 32Si the tracer of choice for future studies of silica production in the ocean.
The role of organic complexation on ambient iron chemistry in the equatorial Pacific Ocean and the response of a mesoscale iron addition experiment
Authors: Rue Eden L. , Bruland Kenneth W.
Published: May 2010

We participated on the Iron‐Ex II study in the equatorial Pacific to investigate ambient iron chemistry and its response to a mesoscale iron addition experiment. As expected, dissolved iron values in the high‐nutrient, low‐chlorophyll surface waters of the South Equatorial Current (4–6°S, 105–109°W) were extremely low (∼20 pM). In studies of the chemical speciation of dissolved iron, we found two classes of Fe(III)‐binding organic ligands—a strong ligand class (L1) with a conditional stability constant and a mean concentration of 310 pM, and a weaker class (L2) with a conditional stability constant and a mean concentration of 190 pM. The total Fe(III)‐binding organic ligand concentrations were ∼25× higher than total dissolved iron concentrations (∼20 pM). Thermodynamic equilibrium calculations indicate that >99.9% of the ambient dissolved Fe(III) would be complexed with these organic ligands and exist as low‐molecular‐weight Fe(III) chelates, with <0.1% (15 fM or ∼10−14 M) existing as an inorganic Fe(III)′ fraction. In the primary Iron‐Ex II study, the total Fe(III)‐binding ligand concentrations increased by 400% to ∼2 nM within a day or two after the initial 2 nM mesoscale iron injection. Most of this increase was due to the stronger ligand class, L1, which increased from 0.3 nM to 1.3 nM. The weaker ligand class increased by a similar percentage, although the total magnitude was smaller. Similar increases in Fe(III)‐binding ligand concentrations were observed in a secondary Iron‐Ex II experiment within 17 h after an initial low‐iron 0.4 nM infusion. Results obtained from samples collected throughout the entire course of the iron‐enrichment experiments suggest that these Fe(III)‐binding organic ligands are produced rapidly in response to small iron additions to this low‐iron regime. The chelated iron appears to be directly or indirectly accessible for growth.
Nitrogen‐stable isotope signatures in estuarine food webs: A record of increasing urbanization in coastal watersheds
Authors: McClelland James W. , Valiela Ivan , Michener Robert H.
Published: May 2010

Nutrient enrichment as a result of anthropogenic activity concentrated along the land‐sea margin is increasing eutrophication of near‐shore waters across the globe. Management of eutrophication in the coastal zone has been hampered by the lack of a direct method to trace nitrogen sources from land into coastal food webs. Stable isotope data from a series of estuaries receiving nitrogen loads from 2 to 467 kg N ha−1 yr−1 from the Waquoit Bay watershed, Cape Cod, Massachusetts, indicate that producer and consumer 15N‐to‐14N ratios record increases in wastewater nitrogen inputs. Nitrate from groundwater‐borne wastewater introduces a 15N‐enriched tracer to estuaries. This study explicitly links anthropogenically derived nitrogen from watersheds to nitrogen in estuarine plants and animals, and suggests that wastewater nitrogen may be detectable in estuarine biota at relatively low loading rates, before eutrophication leads to major changes in species composition and abundance within estuarine food webs.
Pigment packaging and Chl a‐specific absorption in high‐light oceanic waters
Authors: Bissett W. Paul , Patch Jennifer S. , Carder Kendall L. , Lee Z. Ping
Published: May 2010

The absorption of light by particles at a single wavelength, aph(λ), is reduced with increased packaging of the light absorption material within these particles. This reduction can be described by the parameter :

urn:x-wiley:00243590:media:lno19974250961:lno19974250961-math-0002

where asol(λ) is the theoretical maximum light absorption of the cellular material, acm, in a completely dissolved state. In practice, the estimations asol(A) for living phytoplankton are hampered by the process of removing the chloroplast/thylakoid membranes from the organic matrix of the cell, the destruction of the pigment‐protein complexes when an organic solvent is used, and the interference of the excited states of the pigment chromophore by the organic solvent. What is actually being measured by many of the current methods trying to determine asol(λ) is aom(λ), i.e. the absorption of light by the pigment material in the organic medium of the experiment (methanol, acetone, Triton‐X, etc.). The solvation factor, S, in the above equation is the ratio of the true asol(λ) to the measured aom(λ).

We have developed an internally consistent measure of aph(λ), aom(λ), Chl a concentration, and pheopigment concentration to determine the value of . This relationship is used to determine a functional relationship for Chl a absorption for high‐light‐adapted, natural phytoplankton populations in optically clear waters. The nonlinear packaging effect in these waters is insignificant at the red end of the spectrum. Exclusion of the weight‐specific absorption of pheopigments and the assumption of a zero aph(λ) at a zero pigment (Chl a + pheopigment) concentration produces a misleading Chl a‐specific absorption and a false determination of pigment packaging. An algorithm is developed for predicting Chl a concentration from aph(675).
Fluxes of copper‐complexing ligands from estuarine sediments
Authors: Skrabal Stephen A. , Donat John R. , Burdige David J.
Published: May 2010

Most studies of the organic complexation of Cu in natural waters have focused on distributions and processes in the water column, where a significant fraction of Cu‐complexing ligands may be biologically produced. We present direct evidence for a flux of Cu‐complexing ligands from estuarine sediments, demonstrating that sediments are a significant, yet previously unrecognized source of the ligands. Fluxes of Cu‐complexing ligands from Chesapeake Bay sediments range from 300 to 1,200 nmol m−2 d−1, exceeding fluxes of total dissolved Cu by 3→40‐fold, suggesting that any Cu fluxing from the sediments is likely to be organically complexed. Our results indicate that benthic fluxes may supply from 10 to 50% of the standing stock of Cu‐complexing ligands in Chesapeake Bay and suggest that such fluxes may strongly influence the biogeochemistry of Cu in shallow water environments and potentially in the ocean as a whole.
Aureococcus anophagefferens: Causes and ecological consequences of brown tides in U.S. mid‐Atlantic coastal waters
Authors: Bricelj V. Monica , Lonsdale Darcy J.
Published: May 2010

Aureococcus anophagefferens is a picoplankionic alga that since 1985 has bloomed in coastal embayments of the western mid‐Atlantic, ranging from Narragansett Bay, Rhode Island, to Barnegat Bay, New Jersey, with greatest incidence of recurrence in Long Island bays, New York. Blooms of this small alga, referred to as “brown tide,” can persist for several months during late spring and summer at densities in excess of 1.0×106 cells ml−1. They are not associated with anomalous chlorophyll a, dissolved oxygen, or inorganic macronutrient (N, P) levels. Meterologically induced reduced flushing rates, elevated salinities, and delivery of micronutrients (e.g. iron) from the watershed have been implicated in bloom initiation. Brown tides have had severe detrimental effects on the benthos, especially eelgrass (Zostera marina) and suspension‐feeding bivalves, including bay scallops (Argopecten irradians) and blue mussels (Mytilus edulis). Adult bivalves experience sublethal effects (e.g. inhibition of clearance rates) at Aureococcus concentrations as low as ∼2×105 cells ml−1 and mortalities at ∼106 cells ml−1, attributed to toxicity of this microalga. Impacts of brown tide on zooplankton are less clear, but reduced egg production rates of copepods and reduced population growth rates of ciliates are documented at higher brown tide concentrations (≥1.0×106 cells ml−1). We summarize the state of knowledge about the physical, chemical, and biological factors that may contribute to brown tide initiation, maintenance, and decline and assess its ecological effects.
Physiology, ecology, and toxic properties of marine cyanobacteria blooms
Authors: Sellner Kevin G.
Published: May 2010

Cyanobacteria blooms in marine waters are limited to only a few taxa with Trichodesmium, Richelia, Nodularia, and Aphanizomenon being most commonly observed. Nonheterocystous, nitrogen‐fixing Trichodesmium spp. are found throughout low and mid‐latitude oceans and seas of the Atlantic, Pacific, and Indian Oceans, and this genus is thought to be a major contributor to new nitrogen influx into these nitrogen‐poor systems. Heterocystous, nitrogen‐fixing Richelia and other cyanobacteria form unique symbioses with the centric diatoms, Rhizosolenia and Hemiaulus, in the North Pacific, Caribbean, and North Atlantic. Heterocystous, diazotrophic, toxic Nodularia spumigena is restricted to brackish waters of the Baltic Sea and a coastal estuary of southern Australia and often arises from elevated phosphorus input accompanying anthropogenic activities or vertical mixing processes. The nontoxic nitrogen‐fixing Aphanizomenon flos‐aquae is also common in the Baltic, often co‐occurring with Nodularia in the Baltic and Gulf of Finland but more often found in lower salinity areas of the region. Although each taxon responds to its environment uniquely, it appears that bloom production in the three free‐living cyanobacteria largely supports an active microbial food web through dissolved organic compound flux to heterotrophic bacterial communities and their grazers.
Fluorescence excitation spectra and light utilization in two red tide dinoflagellates
Authors: Johnsen Geir , Prézelin Barbara B. , Jovine Raffael V. M.
Published: May 2010

We compared the impact of structural changes in the light‐harvesting machinery of two bloom‐forming dinoflagellates (Prorocentrum minimum and Heterocapsa pygmaea) by quantifying photophysiological changes in order to define the alternative mechanisms of photoacclimation. There are species‐specific and photoacclimative differences in the abundance and composition of functional light‐harvesting complexes (including photosystem 1‐ and 2‐enriched bands) which are reflected in spectral changes in absorption, and photosystem 2 (PS2) fluorescence excitation spectra of whole cells, thylakoid micelles, and discrete photosynthetic pigment‐protein complexes. DCMU‐induced variations in fluorescence excitation spectra are evident in whole cells but not in isolated thylakoid micelles or functional chromoproteins; such variations indicate that intracellular self‐shading which causes variable fluorescence is eliminated in subcellular preparations. We developed a scaling procedure of PS2‐related in vivo fluorescence excitation spectra relative to Chl a‐specific absorption coefficients and used the chromoprotein differences to illustrate how the chromoprotein composition alters cellular fluorescence properties. We also examined the energy transfer efficiency of photosynthetic pigments and the photoprotective role and location of diadinoxanthin.
Disruption of grazer populations as a contributing factor to the initiation of the Texas brown tide algal bloom
Authors: Buskey Edward J. , Montagna Paul A. , Amos Anthony F. , Whitledge Terry E.
Published: May 2010

Disruption of grazer populations, or mismatches between phytoplankton blooms and population dynamics of their planktonic and benthic grazers, may play an important role in the initiation of some harmful algal blooms. The Laguna Madre of Texas has experienced a persistent, nearly monospecific phytoplankton bloom since January 1990 commonly referred to as the “brown tide.” Whole‐water samples collected in the area where the bloom began reveal the pattern of bloom initiation and dispersion during the first few months of the bloom. Enumeration of microzooplankton from these same samples also reveals that protozoan grazer populations were depressed and nearly eliminated before the bloom began. Benthic biomass and species diversity also declined before the onset of the bloom. The disruption of planktonic and benthic grazers may have been due to extreme hypersaline conditions caused by an extended period of drought (salinities > 60‰). A massive fish kill caused by an abnormal period of below freezing temperatures released a pulse of nutrients into an already disturbed environment allowing this nuisance bloom to become established. Planktonic and benthic grazers have been unable to contribute to the demise of this bloom, which has persisted for >7 yr without interruption.
Optical detection and assessment of algal blooms
Authors: Cullen John J. , Ciotti Áurea M. , Davis Richard F. , Lewis Marlon R.
Published: May 2010

Concerns about harmful algal blooms (HABs) have grown in recent years. There is a pressing need for robust, quantitative, and cost‐effective methods to detect and characterize algal blooms. Critical applications of these methods include long‐term monitoring of coastal waters to indicate the degree to which present trends of HABs and human activities are linked, early warning systems to protect aquaculture sites and to signal the need for further investigations, and systems to characterize synoptically the distributions and physiological state of phytoplankton in an oceanographic context. Because phytoplankton strongly influence the fate of light in the ocean, optical methods are well suited for HAB applications. Passive optical systems can measure ocean color or the penetration of solar irradiance in surface waters; both properties can be related to the constituents of natural waters, including phytoplankton. The sensors measure radiometric quantities: consequently, rigorous calibration is possible and measurements can be compared between sites and over long periods of time. One passive optical system—a radiometer buoy—is shown to be useful for characterizing biological variability in surface waters over scales from minutes to months. A red tide was easily observed in measures of ocean color from the buoy; sensors for downwelling irradiance detected a subsurface bloom. Some optical instruments use artificial illumination to determine optical properties such as the coefficients of absorption and scattering. These measures can be made continuously in situ and effectively related to phytoplankton. Several types of fluorometers can be used to characterize the abundance, pigmentation, and physiological state of phytoplankton. All of these optical technologies should be useful for the study of HABs, but biological interpretations of many optical measurements need further testing.
Marine algal toxins: Biochemistry, genetics, and molecular biology
Authors: Plumley F. Gerald
Published: May 2010

Toxic compounds are frequently, but not universally, associated with algal blooms. Several dinoflagellate and diatom species are capable of toxin synthesis. Some bacteria are also capable of synthesizing at least one family of “algal” toxins. Previous work on algal toxins can be broadly grouped in four categories: observations on the variability in toxin production by single species or among strains of a species, frequently as a function of environmental growth conditions; isotope feeding studies to reveal the identity of the substrates that are precursors to the toxin compounds; the genetics of toxin production; and the pharmacological aspects of toxins. Information gleaned from these studies provides a firm foundation for launching more contemporaneous research efforts to understand the biochemistry and molecular biology of toxins. The goals are to develop an understanding of the machinery (i.e. the enzymes and the genes that encode them) required to synthesize toxins, to understand how this machinery is regulated by environmental conditions, and gain insights as to how the toxin biosynthetic genes evolved and(or) have been spread through the marine community.
Biomass distribution in marine planktonic communities
Authors: Gasol Josep M. , del Giorgio Paul A. , Duarte Carlos M.
Published: May 2010

Patterns in primary production and carbon export from the euphotic zone suggest that the relative contribution of planktonic heterotrophs to community biomass should decline along gradients of phytoplankton biomass and primary production. Here, we use an extensive literature data survey to test the hypothesis that the ratio of total heterotrophic (bacteria + protozoa + mesozooplankton) biomass to total autotrophic biomass (H : A ratio) is not constant in marine plankton communities but rather tends to decline with increasing phytoplankton biomass and primary production. Our results show that the plankton of unproductive regions are characterized by very high relative heterotrophic biomasses resulting in inverted biomass pyramids, whereas the plankton of productive areas are characterized by a smaller contribution of heterotrophs to community biomass and a normal biomass pyramid with a broad autotrophic base. Moreover, open‐ocean communities support significantly more heterotrophic biomass in the upper layers than do coastal communities for a given autotrophic biomass. These differences in the biomass structure of the community could be explained by the changes in the biomass‐specific rates of phytoplankton production that seem to occur from ultraoligotrophic to eutrophic marine regions, but other factors could also generate them. The patterns described suggest a rather systematic shift from consumer control of primary production and phytoplankton biomass in open ocean to resource control in upwelling and coastal areas.
Gross growth efficiencies of protozoan and metazoan zooplankton and their dependence on food concentration, predator‐prey weight ratio, and taxonomic group
Authors: Straile Dietmar
Published: May 2010

A comprehensive dataset on the gross growth efficiency (GGE) of planktonic protozoans and metazoans was gathered from the literature in order to (1) identify typical ranges of values, (2) to reexamine the taxon specificity of GGE, and (3) to evaluate the impact of food concentration, predator‐prey weight ratio, and temperature on GGE. All taxa (i.e. nano/microflagellates, dinoflagellates, ciliates, rotifers, cladocerans, and copepods) were found to have mean and median GGE of ∼20–30%. Contrary to the common practice of using different values of GGE for ciliates and crustaceans, I found that the GGE hardly differed between taxa. Variability within all taxa was high and could only partially be attributed to the independent variables mentioned above. The dependency of GGE on food concentrations was the most reliable relationship identified by multiple regression. Establishing further generalizations regarding the dependency of GGE on other factors was hampered by methodological differences among studies and taxa and the lack of information on other potentially important factors such as the elemental composition of prey items. Future studies of GGE should recognize the importance of these factors.
Impact of light regimes on productivity patterns of benthic microbial mats in an antarctic lake: A modeling study
Authors: Moorhead Daryl L. , Wolf Craig F. , Wharton Robert A.
Published: May 2010

Filamentous cyanobacteria often dominate benthic microbial communities of antarctic lakes and usually exhibit saturation of photosynthesis at light intensities ∼100 µEinst m−2 s−1. Incident light regimes are controlled by ice and snow accumulations overlaying water columns during much of the year. Thus, light availability to microbial mats is often below saturation intensity and is strongly influenced by modest changes in climatic factors. A model of net primary production for benthic mat communities of the subantarctic Sombre Lake, Signy Island, was developed (1) to evaluate depth‐specific productivities of mat communities, (2) to test the relative importances of model parameters to mat production, and (3) to explore the potential impacts of climate change on mat production as manifested through changes in light regime. Simulated rates of net primary production corresponded to observations on a daily basis (∼1–4 µg C fixed mg−1 ash‐free DW of mat d−1) but were an order of magnitude lower than estimates of net annual production based on field measurements (≤3 vs. 11–45 g C m−2 yr−1, respectively). Close examination suggested that the simulated values were more plausible. A detailed sensitivity analysis of model behavior revealed that variations in the time of ice and snow melt in spring accounted for 40–60% of the total variation in model behavior, emphasizing the importance of climatic factors to net primary production of mat communities and the sensitivity of mat production to climate change.
A simple fiberoptic sensor to detect the penetration of microsensors into sediments and other biogeochemical systems
Authors: Klimant Ingo , Holst Gerhard , Kûhl Michael
Published: May 2010

We have developed a simple and mechanically robust fiberoptic microsensor that enables optical detection of the sediment‐water interface at a spatial resolution of <50 µm. The sensor measures with a tapered optical fiber the increased backscatter of near‐infrared light near the sediment surface. To determine the sediment surface position independent of ambient light conditions, we developed a miniaturized opto‐electronic system with an intensity‐modulated laser diode (780 nm) as the light source and a photodiode as the detector. Laboratory tests of our system were done with artificial as well as with various natural sediments and biofilms. Fiberoptic microsensors for surface detection can be combined easily with both electrochemical and optical microsensors for oxygen or other reactive species.
Formation of macroscopic organic aggregates (lake snow) in a large lake: The significance of transparent exopolymer particles, plankton, and zooplankton
Authors: Grossart Hans‐Peter , Simon Meinhard , Logan Bruce E.
Published: May 2010

Macroscopic organic aggregates (lake snow) were collected and their abundance quantified by scuba divers at a distinct pelagic site in Lake Constance (Germany) at least twice a week throughout the growing season in 1993. Furthermore, concentrations of transparent exopolymer particles (TEP), chlorophyll, particulate organic carbon (POC), and the species composition of phytoplankton and zooplankton in the ambient water were determined. In addition, the formation of aggregates was studied in laboratory experiments by incubating water samples in rolling tanks. The abundance and composition of aggregates showed a pronounced seasonal and vertical pattern in close relation to phytoplankton and zooplankton dynamics and wind conditions. Numbers of aggregates ranged between <1 and 50 liter−1, with maximum concentrations at 6 m depth in summer and fall. In spring, the peak of TEP concentration occurred simultaneously with that of lake snow, whereas the peaks in summer and fall followed those of aggregate abundance. More detailed analyses indicated that the role of TEP in aggregate formation varies throughout the season. The laboratory experiments revealed an inverse correlation between time of aggregate formation and the concentration of POC. Two different correlations, one for the spring bloom and one for the rest of the year, were established. The results show that multiple mechanisms of aggregate formation occurred throughout the seasons due to variations in source particles and physical conditions.