Download or read book Relations entre les oiseaux marins pelagiques tropicaux et l environnement oceanique written by Matthieu Le Corre and published by . This book was released on 1998 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The links between the tropical pelagic marine birds and the ocean environment are being investigated in Europa (channel of Mozambique), has two levels of additional perception, populations and individuals. The geographical variation in the morphology of three species, the Audubon's shearwater (Puffinus lherminieri), the red footed booby (Sula sula) and the white-tailed tropicbird (Phaethon lepturus) shows that the populations of Europa are distinct from most of the populations of the Indian Ocean. The causes of this insulation are discussed in relation with the oceanographic characteristics of Mozambique Channel. The geographical variation of the timing of the reproduction shows the capacity of adaptation of certain species, such as the sooty terns (Sterna fuscata) and the red footed booby. The joint analysis of environmental variations and the breeding seasons of stresses the importance, for the populations of Europa, the reloading winter at the subtropical waters, and seasonal variations in the abundance of tuna in the south of the channel of Mozambique. Has the opposed of these species, the red tailed tropic bird (P. rubricauda), has a summer breeding in the entire Indian Ocean Western. Has the individual scale, the joint study of the Ecology of Food, of the body condition of adults and that of chicks was conducted among the red tailed tropic bird, in order to identify the strategies acquired by individuals to carry out the reproduction. This species has a system specialist food during the breeding, or 2 species of fish INFEODES to warm waters (the CORYPHENES Coryphaena equiselis and C. hippurus) constitute 40% of the biomass made to the chick. The large variability of journeys in SEA during the incubation and during the breeding, and the fact that some adults are unable to restore their condition or has to bring large meals are interpreted as the consequence of the IMPREVISIBILITE in the day on the day of the availability or the distribution of prey, at sea. Facing this IMPREVISIBILITE, adults have the capacity of young Important, allowing them to alternate sittings of incubation and research in food of several days. However, the success of the incubation depends on the capacity of individuals to maintain a body condition stable, in order to avoid reaching the critical mass (720 G.) which causes the abandonment. We suggest that the PRENUPTIALE phase must be a decisive factor to accumulate the necessary reserves to the phases of the young of the incubation. During the breeding, adults regulate the allocation of food resources between the chick and themselves, and this Regulation seems self-levelling by their body condition. The quantity of food furnished by the parents is decisive for the body condition of the chicks at the time of the flight, and therefore probably for their survival. They are faced with large variations in the quantity of food received by day. For chicks, the accumulation of reserves and a capacity of ingestion ELEVEE could be adaptations has the IMPREVISIBILITE on the frequency of the NOURRISSAGES. Integrating the body condition to the study of the reproduction of the tropical seabirds, the results have helped to identify certain environmental constraints suffered by individuals (IMPREVISIBILITE the day-to-day food resources), as well as adaptations for COPE has these constraints (Faculty of young adults and chicks, large capacity of ingestion of chicks). We propose to extend this approach to other tropical species different by the length of the cycles of reproduction, and has other communities varying by their environmental constraints.

Download or read book RELATIONS ENTRE LES OISEAUX MARINS PELAGIQUES TROPICAUX ET L ENVIRONNMENT OCEANIQUE written by MATTHIEU.. LE CORRE and published by . This book was released on 1998 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: LES LIENS ENTRE LES OISEAUX MARINS PELAGIQUES TROPICAUX ET L'ENVIRONNEMENT OCEANIQUE SONT ETUDIES A EUROPA (CANAL DU MOZAMBIQUE), A DEUX NIVEAUX DE PERCEPTION COMPLEMENTAIRES, LES POPULATIONS ET LES INDIVIDUS. LA VARIATION GEOGRAPHIQUE DE LA MORPHOLOGIE DE TROIS ESPECES PHYLOGENETIQUEMENT INDEPENDANTES, LE PUFFIN D'AUDUBON (PUFFINUS LHERMINIERI), LE FOU A PIEDS ROUGES (SULA SULA) ET LE PAILLE EN QUEUE A BRINS BLANCS (PHAETHON LEPTURUS) MONTRE QUE LES POPULATIONS D'EUROPA SONT DISTINCTES DE LA PLUPART DES POPULATIONS DE L'OCEAN INDIEN. LES CAUSES DE CETTE ISOLATION SONT DISCUTEES EN RELATION AVEC LES CARACTERISTIQUES OCEANOLOGIQUES DU CANAL DU MOZAMBIQUE. LA VARIATION GEOGRAPHIQUE DE LA PHENOLOGIE DE LA REPRODUCTION MONTRE LES CAPACITES D'ADAPTATION DE CERTAINES ESPECES, COMME LES STERNES FULIGINEUSES (STERNA FUSCATA) ET LES FOUS A PIEDS ROUGES. L'ANALYSE CONJOINTE DES VARIATIONS ENVIRONNEMENTALES ET DES SAISONS DE REPRODUCTION SOULIGNE L'IMPORTANCE, POUR LES POPULATIONS D'EUROPA, DE LA REMONTEE HIVERNALE DES EAUX SUBTROPICALES, ET DES VARIATIONS SAISONNIERES DE L'ABONDANCE DES THONS DANS LE SUD DU CANAL DU MOZAMBIQUE. A L'OPPOSEE DE CES ESPECES, LE PAILLE EN QUEUE A BRINS ROUGES (P. RUBRICANDA), A UNE REPRODUCTION ESTIVALE DANS TOUT L'OCEAN INDIEN OCCIDENTAL. A L'ECHELLE INDIVIDUELLE, L'ETUDE CONJOINTE DE L'ECOLOGIE ALIMENTAIRE, DE LA CONDITION CORPORELLE DES ADULTES ET DE CELLE DES POUSSINS A ETE MENEE CHEZ LE PAILLE EN QUEUE A BRINS ROUGES, AFIN D'IDENTIFIER LES STRATEGIES ACQUISES PAR LES INDIVIDUS POUR MENER A BIEN LA REPRODUCTION. CETTE ESPECE A UN REGIME ALIMENTAIRE SPECIALISE PENDANT L'ELEVAGE, OU 2 ESPECES DE POISSONS INFEODES AUX EAUX CHAUDES (LES CORYPHENES CORYPHAENA EQUISELIS ET C. HIPPURUS) CONSTITUENT 40% DE LA BIOMASSE APPORTEE AU POUSSIN. LA GRANDE VARIABILITE DES TRAJETS EN MER PENDANT L'INCUBATION ET PENDANT L'ELEVAGE, ET LE FAIT QUE CERTAINS ADULTES NE PARVIENNENT PAS A RESTAURER LEUR CONDITION OU A APPORTER DES REPAS IMPORTANTS SONT INTERPRETES COMME LA CONSEQUENCE DE L'IMPREVISIBILITE AU JOUR LE JOUR DE LA DISPONIBILITE OU DE LA REPARTITION DES PROIES, EN MER. FACE A CETTE IMPREVISIBILITE, LES ADULTES ONT DES CAPACITES DE JEUNE IMPORTANTES, LEUR PERMETTANT D'ALTERNER DES SEANCES D'INCUBATION ET DE RECHERCHE ALIMENTAIRE DE PLUSIEURS JOURS. CEPENDANT, LE SUCCES DE L'INCUBATION DEPEND DE LA CAPACITE DES INDIVIDUS A MAINTENIR UNE CONDITION CORPORELLE STABLE, AFIN D'EVITER D'ATTEINDRE LA MASSE CRITIQUE (720 G.) QUI PROVOQUE L'ABANDON. NOUS SUGGERONS QUE LA PHASE PRENUPTIALE DOIT ETRE DETERMINANTE POUR ACCUMULER LES RESERVES NECESSAIRES AUX PHASES DE JEUNE DE L'INCUBATION. PENDANT L'ELEVAGE, LES ADULTES REGULENT L'ALLOCATION DES RESSOURCES ALIMENTAIRES ENTRE LE POUSSIN ET EUX-MEMES, ET CETTE REGULATION SEMBLE PILOTEE PAR LEUR CONDITION CORPORELLE. LA QUANTITE DE NOURRITURE APPORTEE PAR LES PARENTS EST DETERMINANTE POUR LA CONDITION CORPORELLE DES POUSSINS AU MOMENT DE L'ENVOL, ET DONC PROBABLEMENT POUR LEUR SURVIE. CEUX-CI SONT CONFRONTE A DE GRANDES VARIATIONS DE LA QUANTITE DE NOURRITURE RECUE PAR JOUR. POUR LES POUSSINS, L'ACCUMULATION DE RESERVES ET UNE CAPACITE D'INGESTION ELEVEE POURRAIENT ETRE DES ADAPTATIONS A L'IMPREVISIBILITE DE LA FREQUENCE DES NOURRISSAGES. EN INTEGRANT LA CONDITION CORPORELLE A L'ETUDE DE LA REPRODUCTION DES OISEAUX MARINS TROPICAUX, LES RESULTATS ONT PERMIS D'IDENTIFIER CERTAINES CONTRAINTES ENVIRONNEMENTALES SUBIES PAR LES INDIVIDUS (IMPREVISIBILITE AU JOUR LE JOUR DES RESSOURCES ALIMENTAIRES), AINSI QUE LES ADAPTATIONS POUR FAIRE FACE A CES CONTRAINTES (FACULTE DE JEUNE DES ADULTES ET DES POUSSINS, GRANDE CAPACITE D'INGESTION DES POUSSINS). NOUS PROPOSONS D'ETENDRE CETTE DEMARCHE A D'AUTRES ESPECES TROPICALES DIFFERANT PAR LA LONGUEUR DES CYCLES DE REPRODUCTION, ET A D'AUTRES LOCALITES VARIANT PAR LEURS CONTRAINTES ENVIRONNEMENTALES.

Download or read book Impact des changements climatiques sur la biodiversit marine tropicale written by Brice Legrand and published by . This book was released on 2016 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Les changements climatiques affecteront les écosystèmes terrestres et marins mais les conséquences en termes de répartition globale de la biodiversité sont encore mal connues. Les études portant sur la sélection des habitats des prédateurs marins pour leurs recherches alimentaire et leurs évolutions provoquées par le réchauffement climatique sont en plein développement actuellement. Les suivis télémétriques apportent des informations précieuses sur la variabilité spatio-temporelle de la distribution en mer des prédateurs marins. L'ensemble des problématiques étant très importantes, nous avons décidé de nous focaliser sur les oiseaux marins. Le premier objectif de ce projet de thèse est d'étudier, la distribution et la sélection des habitats d'alimentation des oiseaux marins tropicaux pendant leurs phases de reproduction et pendant leurs migrations. Afin de caractériser les habitats d'un point de vue abiotique. Le deuxième objectif de ce projet de thèse est d'utiliser les scénarios d'évolution des habitats océaniques produits par GIEC pour simuler, à l'aide des modèles d'habitats, l'évolution temporelle de la distribution des habitats favorables. Le troisième objectif de ce projet de thèse est d'utiliser les données de suivi disponibles d'identifier les « points chauds » de la biodiversité.Nous nous sommes intéressés, dans un premier temps, aux puffins du Pacifique. Plus particulièrement, nous avons étudié les variations entre les différentes colonies d'une même espèce, du point de vue de la distribution, de l'activité et de la sélection des habitats. Ensuite, nous avons étudié l'impact de l'évolution du changement climatique sur les habitats d'hivernage des Pétrels (Pterodroma baraui) de Barau, une espèce endémique de l'île de la Réunion. Nous avons construit des modèles de sélection des habitats. Ces modèles ont ensuite été utilisés pour prédire l'évolution des habitats d'hivernage à l'horizon 2100, en fonction de différents scénarios du GIEC. Enfin, Nous avons compilé les données de suivi disponibles sur les oiseaux marins, les tortues de mer et les mammifères marins pour étudier la répartition de la mégafaune marine dans l'océan Indien, et d'identifier les points chauds de haute densité et de haute diversité. Afin de mettre en place, à terme, des zones marines protégées. »

Download or read book Facteurs influen ant les strat gies de recherche alimentaire des oiseaux marins written by Julien Collet and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Comprendre les décisions prises par les organismes pour s'approvisionner en nourriture est essentiel pour anticiper leurs réactions aux changements de l'environnement. Les oiseaux marins en reproduction partent s'alimenter en mer depuis leur colonie. L'utilisation de GPS miniatures révèle qu'ils effectuent des trajets de dizaines jusqu'à des milliers de kilomètres en quête de proies pour lesquelles nous disposons de très peu d'informations. Les stratégies comportementales qu'ils utilisent pour augmenter leurs chances de rencontrer des proies dans l'environnement marin, et les implications que cela peut avoir vis-à-vis des activités humaines de pêche qui semblent attirer de nombreux oiseaux sont encore très partiellement comprises. Cette thèse propose de réexaminer ces questions en trois chapitres, à travers des simulations théoriques, l'analyse empirique de trajets enregistrés par GPS sur diverses espèces et populations d'oiseaux marins, et le croisement des trajets simultanés d'oiseaux et de bateaux de pêche. Premièrement, les simulations théoriques de marches aléatoires montrent qu'on ne peut pas se servir des phases de ligne droite dans un trajet pour conclure si les oiseaux anticipent où sont leurs proies, ce qui vient nuancer les conclusions de nombreuses études précédentes. L'analyse des biais dans les directions suivies par les oiseaux permet en revanche de comprendre les informations qu'ils utilisent pour décider où s'approvisionner. Deuxièmement, les stratégies de fidélité spatiale individuelle sont comparées entre espèces, populations et contextes écologiques à l'aide de modèles statistiques multivariés (GLMM). De nombreux oiseaux marins font en effet preuve de fidélité individuelle dans la direction qu'ils prennent pour s'approvisionner depuis la colonie, suggérant l'utilisation de mémoire. Nous montrons que c'est également le cas de nombreuses populations et espèces d'oiseaux marins tropicaux, qui restent fidèles à une direction pendant plusieurs jours successifs. Ces résultats sont surprenants et difficiles à expliquer car la plupart des espèces étudiées ciblent des proies très dynamiques et disponibles à un endroit de façon très éphémère. Cela suggère que la mémoire pourrait être plus fréquemment utilisée par les oiseaux marins que ce que l'on supposait, au moins à large échelle spatiale. Finalement, nos analyses sur les réponses des albatros aux bateaux de pêche suggèrent que les albatros modulent leurs réponses en fonction de l'espèce et des contraintes énergétiques, et que les rencontres de bateaux ont peu d'influence sur les stratégies suivies par les individus lors de leur trajet suivant. Ainsi le comportement d'attraction aux bateaux de pêche pourrait être un phénomène local (à l'échelle du rayon de perception) et largement opportuniste. Globalement, nos résultats empiriques ancrés dans un socle théorique solide suggèrent que l'approvisionnement des oiseaux marins ne peut pas se résumer à rencontrer des ressources rares et imprévisibles, et semble pouvoir impliquer des processus de sélection des ressources rencontrées et/ou de choix entre utilisation de mémoire individuelle ou d'information publique. Les ressources anthropiques à ce titre pourraient ne constituer que des ressources parmi d'autres. De nombreux outils d'analyses utilisés ici sont facilement transférables à d'autres oiseaux marins ou d'autres prédateurs à place centrale. Élargir les comparaisons à d'autres organismes est en effet nécessaire pour mieux comprendre les variations complexes mises en évidence ici dans la plasticité comportementale et leurs conséquences vis-à-vis des changements environnementaux.

Download or read book Overview of mitigation measures to reduce the incidental catch of vulnerable species in fisheries written by Sacchi, J. and published by Food & Agriculture Org.. This book was released on 2021-06-23 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Potentially harmful contact between fisheries and marine vulnerable species represents a global conservation issue and efforts to mitigate the negative repercussions of these interactions belong in strategies for ensuring the sustainability of fisheries. This literature review offers a survey of mitigation measures and techniques that have been developed and tested around the world, aiming to address both the incidental catch of highly mobile species – specifically, cetaceans, seabirds, sharks and rays, and sea turtles – and depredation caused by dolphins. Based on research detailed in over 300 documents, including peer-reviewed publications, reports from international organizations and papers available on the internet, most of the mitigation techniques illustrated are still under development, with only a few already adopted through legislation. The selected mitigation measures are grouped by main types of fishing gear – gillnets and trammel nets, longlines and lines, trawls, purse seines, traps and pots – and further subdivided according to which of the four main groups of vulnerable species – cetaceans, seabirds, sharks and rays, or sea turtles – they are designed to protect. Preventive and curative approaches covering both technical measures (gear modifications, strategies, as well as acoustic, visual, magnetic and chemosensory deterrents) and management measures are described.

Download or read book The Tree of Life written by Guillaume Lecointre and published by Harvard University Press. This book was released on 2006 with total page 568 pages. Available in PDF, EPUB and Kindle. Book excerpt: Did you know that you are more closely related to a mushroom than to a daisy? That dinosaurs are still among us? That the terms "fish" and "invertebrates" do not indicate scientific groupings? All this is the result of major changes in classification. This book diagrams the tree of life according to the most recent methods of this system.

Download or read book Le Pacifique Sud written by Frédéric Angleviel and published by Presses Univ de Bordeaux. This book was released on 1991 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Marine Protected Areas written by Jessica S. Sanders and published by Food & Agriculture Organization of the UN (FAO). This book was released on 2013 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The five case studies from Belize, Mauritania, Samoa, Philippines and Japan were prepared as part of a set of 16 studies gathering national experiences from around the world. The studies are intended to ground the FAO Technical Guidelines on Marine Protected Areas (MPAs) and Fisheries1 in practical experience and to inform the use of MPAs globally

Download or read book The Mediterranean region under climate change written by Collectif and published by IRD Éditions. This book was released on 2018-11-19 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines.

Download or read book Marine Protected Areas written by Joachim Claudet and published by . This book was released on 2011-09-29 with total page 400 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides regional and global perspectives on the role of Marine Protected Areas in the restoration and conservation of biodiversity.

Download or read book Ecosystem Function in Heterogeneous Landscapes written by Gary M. Lovett and published by Springer Science & Business Media. This book was released on 2005-12-15 with total page 528 pages. Available in PDF, EPUB and Kindle. Book excerpt: This groundbreaking work connects the knowledge of system function developed in ecosystem ecology with landscape ecology's knowledge of spatial structure. The book elucidates the challenges faced by ecosystem scientists working in spatially heterogeneous systems, relevant conceptual approaches used in other disciplines and in different ecosystem types, and the importance of spatial heterogeneity in conservation resource management.

Download or read book Global Atlas of Marine Fisheries written by Daniel Pauly and published by Island Press. This book was released on 2016-10-06 with total page 519 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Global Atlas of Marine Fisheries is the first and only book to provide accurate, country-by-country fishery catch data. This groundbreaking information has been gathered from independent sources by the world's foremost fisheries experts. Edited by Daniel Pauly and Dirk Zeller of the Sea Around Us Project, the Atlas includes one-page reports on 273 countries and their territories, plus fourteen topical global chapters. Each national report describes the current state of the country's fishery; the policies, politics, and social factors affecting it; and potential solutions. The global chapters address cross-cutting issues, from the economics of fisheries to the impacts of mariculture. Extensive maps and graphics offer attractive and accessible visual representations.

Download or read book Coasts Under Changing Climate Observations and Modeling written by Rafael Almar and published by Frontiers Media SA. This book was released on 2022-01-04 with total page 197 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Incidental catch of vulnerable species in Mediterranean and Black Sea fisheries A review written by Carpentieri, P., Nastasi, A., Sessa, M., Srour, A. (eds.) and published by Food & Agriculture Org.. This book was released on 2021-06-28 with total page 339 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bycatch – a term widely used to refer to part of the catch unintentionally caught during a fishing operation, in addition to target species, and consisting of the discards and incidental catch of vulnerable species – is considered one of the most important threats to the profitability and sustainability of fisheries, as well as to the conservation of the marine environment and ecosystems. Understanding the bycatch issue and adopting effective measures in order to reduce bycatch rates are essential steps towards minimizing the impacts on vulnerable species and ensuring both a sustainable fisheries sector and healthy seas. In the Mediterranean and the Black Sea, the incidental catch of vulnerable species – namely seabirds, sea turtles, elasmobranchs, marine mammals and macrobenthic invertebrates – represents one of several challenges for the industrial, semi-industrial and small-scale fisheries that coexist in the region, as well as for the diverse and sensitive ecosystems impacted. Typically, data on this issue have been collected in an opportunistic manner and in ways that make comparisons difficult. The annual absolute values of incidental catch of vulnerable species are not available: studies cover only a small portion of the total fishing activity and often present important knowledge gaps for many types of fishing gear, countries and/or subregions, as well as on temporal scales, for example, to establish reliable baselines. The result is that little is known of the scope of the problem, despite incidental catch being a significant pressure on the populations of vulnerable species, as well as a concern for fishers.This regional review is an attempt to compile, in one single document, all available data and historical records on the incidental catch of vulnerable species in the Mediterranean and Black Sea fisheries, obtained from existing literature, databases and other grey sources, and collated in a standardized and comparable way. The main objective is to provide comprehensive baseline information, earmark the main data gaps, as well as identify the most impacting types of fishing gear by taxonomic group. This work is a reminder of the importance of standardized data collection and the need to have baseline information in order to support decision-making in the identification of appropriate bycatch mitigation techniques, thus enabling analysis of their effectiveness and comparison over time and space, as well as facilitating the implementation of relevant conservation and/or management measures at the national, subregional and regional levels.

Download or read book What is the Code of Conduct for Responsible Fisheries written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2001 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: The actual Code of conduct is also available (1996) (ISBN 9251038341).

Download or read book Effects of Trawling and Dredging on Seafloor Habitat written by National Research Council and published by National Academies Press. This book was released on 2002-08-09 with total page 137 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns over the potential ecological effects of fishing have increased with the expansion of fisheries throughout the marine waters of the United States. Effects of Trawling and Dredging on Seafloor Habitat describes how assessment of fishing impacts depends on gear type, number and location of bottom tows, and the physical and biological characteristics of seafloor habitats. Many experimental studies have documented acute, gear-specific effects of trawling and dredging on various types of habitat. These studies indicate that low mobility, long-lived species are more vulnerable to towed fishing gear than short-lived species in areas where the seabed is often disturbed by natural phenomena. Trawling and dredging may also change the composition and productivity of fish communities dependent on seafloor habitats for food and refuge. The scale of these impacts depends on the level of fishing effort. This volume presents color maps of fishing effort for all regions with significant bottom trawl or dredge fisheries-the first time that such data has been assembled and analyzed for the entire nation.

Download or read book Nitrogen Cycling in Coastal Marine Environments written by T. Henry Blackburn and published by . This book was released on 1988-03-21 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nitrogen discharge to the coastal environment has been increasing, posing the threat of accelerated eutrofication. Considerable research has been conducted in recent years to examine the impact of the nitrogen loading in coastal ecosystems. Based on proceedings from a SCOPE symposium held at the University of Aarhus in July of 1985, this volume covers a variety of up-to-date developments in research on nitrogen cycling in coastal marine environments. Topics include the role of nitrogen in algal productivity, regeneration of nutrients in the water column and the sediments, and the flow of nitrogen in coastal ecosystems.