La modélisation en écologie est aujourd'hui une pratique scientifique de premier plan. Portée par l'avancement technologique, les modèles utilisés en sciences de l'environnement présentent une complexité grandissante. La complexification des modèles est une nécessité pour une variété d'études, mais elle peut être une source d'incompréhension, voire d'erreurs. Savoir gérer son implémentation apparaît donc nécessaire. Fort de ce constat, deux approches complémentaires se sont distinguées et furent étudiées dans ce travail de thèse. D'une part, il est possible de gérer la complexité a priori, en contraignant directement les hypothèses de construction et le formalisme du modèle par l'utilisation d'un cadre théorique. Une illustration de l'utilisation d'un schéma théorique, la théorie des Budgets Dynamiques d'Énergie, présente comment une description précise de l'effet des ultraviolets fut adjointe à un modèle de l'endosymbiose corallienne. Cette étude met en lumière leur possible rôle dans le blanchiment des coraux scléractiniaires. La gestion de la complexité pouvant aussi s'opérer a posteriori, c'est à dire une fois l'étape de construction passée. Ainsi, une méthodologie d'analyse statistique des sorties de modèles ayant pour but de permettre leur simplification fut établie. À titre d'exemple, cette méthode a été appliquée sur un modèle à micro-échelle de l'écosystème mésopélagique. Ne plus avoir la possibilité d'entreprendre une approche analytique de son modèle n'est donc pas une fatalité pour qui veut maitriser son outil, car une multitude d'approches permettent d'obtenir des informations toutes aussi intéressantes. / Ecological modelling is nowadays a leading topic. the models used in environmental science turn to be more and more complex. Driven by technological advancement, the models used in environmental sciences are increasingly complex. The complexity of models is a need for a variety of studies, but it can also be a source of misunderstanding, or even errors. How to manage its implementation is therefore necessary. With this in mind, two complementary approaches have been studied in this thesis. On the one hand, it is possible to manage the complexity textit a priori, by directly constraining the construction assumptions and formalism of the model using a theo- retical framework. An illustration of the use of a theoretical framework, the theory of Dynamic Energy Budgets, shows how an accurate description of the effect of ultraviolet was added to a model of scleractinian corals. This study enlightened their possible role in coral bleaching events. Managing complexity can also be carried out textit a posteriori, ie once the construc- tion phase is done. Thus, a simplification methodology using a statistical analysis of the model outputs was established . As an example, this method was applied on a micro- scale model of the mesopelagic ecosystem. Eventually, not being able of pursuing an analytical approach of the model is not inevitable for those who want to still mastering their model, it exists a multitude of tool who brings equally interesting informations.

Le bassin versant de la Mé, situé au Nord-Est d'Abidjan, comporte une couverture végétale abondante du fait de l'importance des précipitations, en baisse régulière du reste et de l'existence d'une très épaisse frange d'altération du substratum. Ce substratum est constitué, pour l'essentiel, des formations schisteuses, quartzitiques ou arkosiques du Birrimien et intrudé de granitoïdes. La partie aval du bassin est occupée par les formations sédimentaires côtières. Métasédiments et Granitoïdes ont un chimisme bien distinct. Les données de terrains et images de satellites mettent en évidence plusieurs directions de fracturation qui jouent un rôle hydraulique majeur en créant des conditions d'infiltration et d'emmagasinement des eaux. Ces eaux souterraines correspondent soit à des nappes superficielles d'altérites soit à des nappes profondes localisées dans les fractures et fissures du substratum. Elles peuvent communiquer entre elles du fait des différences de charge hydraulique. La localisation des points d'eau se fait par géomorphologie et photographies aériennes. L'étude des propriétés physico-chimiques des eaux permet de mettre en évidence d'une part l'influence des conditions d'alimentation des nappes sur la composition de leurs eaux et d'autre part l'étroite relation entre cette composition et celle des roches dans lesquelles elles circulent. Les teneurs isotopiques traduisent des difficultés de recharge des nappes et posent ainsi le problème de l'alimentation des populations locales.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The proposal expressed by this work is the defense of the thesis that metaphysics is originally the result of a resentment of the will with the finite and unpredictable mode of Being of life, making it impossible to control and rule the existence and whose summit takes place with the advent of modern philosophy of Descartes and of the cogito as absolute foundation of the reality of the real. Nietzsche identifies this scenario as originating from a change in the essence of the Greco-Roman man who, in modern times, shall be characterized by the rejection of any kind of transcendence to establish himself as the principle and cause of the real. Nietzsche, the Greek world enthusiast, sees this supposed ontological change as establishment of hubris, the Hellenic notion of h bris whose primary sense points to break the man's limit m tron, man's Being - and that is an attempt to equalize or exceed divinity transcendence. In modernity, the h bris settles ontologically in man when the opening of the cogito as an operation of will promotes the death of God. In fact, kill the transcendence and take his place is wanting to be ground when, in fact, is only a means to the ground Being, the truth appear, founding, through man, all that is. Heidegger, another Greek world enthusiast, agrees with Nietzsche, but sees the h bris of the phenomenon more broadly, watching his character history and its connection to what he called a history of Being and its manifestation as metaphysics. The author of Being and Time notes that the will which entails the modern h bris has a Greek origin, more precisely at the time of transition from the pre- Socratic philosophy and metaphysics of Plato and Aristotle. That\'s where Heidegger says the change of attitude in the Being of man identified by Nietzsche in modernity takes shape. The birth of metaphysics is the end of ontological agreement between man and ph sis Being for the establishment of Eros for knowledge, or philosophy. This desire is the will that will establish the will which will promote the death of God and the establishment of man as the real measure, ie, the h bris of modern man. Heidegger finds the origin of this event and its entire historical development the nihilism that Nietzsche saw only in modernity. As a result of crystallization of contemporary rampant posture of man, Heidegger points out the appearance of technique and its ambiguous nature, which can be both a threat to the Being of man to equalize the way in which being is shown from it as a possibility of "new beginning" for humanity. The itinerary, mediated by Heidegger and Nietzsche, of the establishment of the ancient metaphysics as principle of h bris to its heyday in modernity as the death of God, and its unfolding as a technique, it is the task of the following work. / A proposta expressa por este trabalho consiste na defesa da tese de que a metafí sica originalmente resultado de um ressentimento da vontade com o modo de ser finito e imprevis ível da vida, impossibilitando o controle e o dom ínio racional da existê ncia e cujo ápice se dá no mundo moderno com o advento da filosofia de Descartes e o estabelecimento do cogito como fundamento absoluto de realidade do real. Nietzsche identifica este cenário como proveniente de uma mudança na essê ncia do homem greco-romano, que, na modernidade, passa a se caracterizar pela rejeição de todo e qualquer tipo de transcendê ncia para se estabelecer como princí pio e causa do real. Nietzsche, entusiasta do mundo grego, encara esta suposta mudança ontológica como instauração da hýbris, a noção helê nica de desmedida cujo sentido primordial aponta para a ruptura do limite do homem o metrón, seu ser , e que se constitui como tentativa de equalização ou superação da divindade a transcend ência. Na modernidade, a hýbris se instala ontologicamente no homem quando a instauração do cogito como operação da vontade promove a morte de Deus. De fato, matar a transcendê ncia e tomar-lhe o lugar é querer ser fundamento quando, na verdade, não passa, de fato, de meio para o fundamento o ser, a verdade aparecer, fundando, por meio do homem, tudo o que é. Heidegger, outro entusiasta dos gregos, concorda com Nietzsche, mas vê o fenômeno da hýbris de forma mais ampla, observando seu caráter historial e sua vinculação ao que chamou de história do ser e de sua manifestação como metaf ísica. O autor de Ser e Tempo observa que a vontade que enseja a hýbris moderna tem uma proveniê ncia grega, mais precisamente no momento de transição entre a filosofia pré -socrática e a metafí sica de Platão e Aristóteles. É de lá que Heidegger afirma originar-se a mudança de postura no ser do homem identificado por Nietzsche apenas na modernidade. O nascimento da metafí sica o fim do acordo ontológico entre homem e phýsis o ser para o estabelecimento do Eros pelo saber, ou seja, a filosofia. Este desejo o querer que vai fundar a vontade promovedora da morte de Deus e o estabelecimento do homem como medida do real, ou seja, da hýbris instauradora do homem moderno. Heidegger encontra na proveniê ncia deste evento e de todo o seu desenvolvimento historial o niilismo que Nietzsche s via na modernidade. Como resultado contemporâneo da cristalização da postura desmedida do homem, Heidegger aponta o aparecimento da t écnica e sua ambí gua essê ncia, que pode ser tanto uma ameaça ao ser do homem ao equalizar o modo pela qual o ser se mostra a partir dele quanto uma possibilidade de novo in cio para a humanidade. O itinerário, mediado por Heidegger e Nietzsche, do estabelecimento da metafísica antiga enquanto princí pio da hýbris até o seu apogeu na modernidade enquanto morte de Deus, alé m de seu desdobramento enquanto t écnica, a tarefa do trabalho a seguir. / Mestre em Filosofia