Dans un contexte général de dégradation de nombreux écosystèmes aquatiques, les travaux de ma thèse se sont intéressés à la problématique des proliférations de cyanobactéries benthiques potentiellement toxiques qui peuvent former des biofilms épais sur le fond de certaines rivières. Alors que les proliférations de cyanobactéries planctoniques ont fait l’objet de nombreuses études, notamment en raison de leurs effets néfastes sur les écosystèmes et des limitations de leurs usages qu’elles provoquent, seul un nombre très restreint de travaux s’est intéressé aux proliférations de cyanobactéries benthiques. Partant de ce constat, les données acquises au cours de cette thèse se sont inscrits à la fois dans une démarche fondamentale d’acquisition de connaissances sur la composition microbienne et l’écologie des biofilms périphytiques, avec un regard particulier sur les proliférations de cyanobactéries benthiques en rivières, et dans une démarche plus appliquée sur les stratégies et outils pour la surveillance des biofilms à cyanobactéries dans les rivières afin de répondre à une demande des Agences de l’Eau et des gestionnaires de milieux aquatiques. Ces travaux ont reposé sur des prélèvements de biofilms dans deux rivières françaises, le Tarn et la Loue, et dans neuf rivières néo-zélandaises. Les communautés microbiennes au sein des biofilms ont été caractérisées par des approches de séquençage à haut débit ciblant un fragment du gène de la petite sous-unité de l’ARN ribosomal 16S et 18S. Des données environnementales permettant de décrire le contexte dans lequel les biofilms se sont développés ont été également acquises. Les résultats principaux permettant une amélioration des connaissances sur les communautés microbiennes et l’écologie des biofilms de rivières se rapportent à la mise en évidence (i) de l’importance fondamentale de certains facteurs comme la température de l’eau sur les variations temporelles de l’ensemble des communautés périphytiques et de la nécessité de prendre en compte les contextes hydrologique et géologique des stations de prélèvements pour comprendre ces variations, (ii) par l’analyse des corrélations entre les OTU dominantes des communautés phototrophes et hétérotrophes, d’interactions positives entre certaines de ces OTU, par exemple dans le cadre du recyclage de la matière organique ou d’interactions négatives, par exemple dans le cas des compétitions pour l’accès à la lumière entre bactéries et micro-algues phototrophes et (iii) d’une structuration géographique des communautés bactériennes associées aux biofilms à cyanobactéries qui semble plus s’expliquer par le contexte environnemental local des biofilms que par leur éloignement par la distance. Concernant les données acquises lors de cette thèse pour améliorer la surveillance et la gestion des risques liés aux proliférations de cyanobactéries benthiques, nos travaux ont permis de montrer les limites d’un nouvel outil (sonde spectrofluorimétrique) pour la détection et la quantification des cyanobactéries benthiques et de proposer des stratégies d’échantillonnage pour évaluer l’importance des biofilms à cyanobactéries en rivières. Finalement, nos résultats suggèrent que la prévention des risques liés aux cyanobactéries benthiques potentiellement toxiques devrait essentiellement reposer sur l’information des usagers. / In a general context of aquatic ecosystems degradation, my thesis focuses on the issue of potentially toxic benthic cyanobacterial proliferations that can form thick biofilms fixed on the riverbed of certain rivers. While planktonic cyanobacterial blooms have been the subject of numerous studies, mainly due to their detrimental effects on the ecosystems, only a limited number of works have focused on benthic cyanobacteria. Therefore, the thesis involves a fundamental approach for knowledge acquisition on biofilms biodiversity and ecology, with an interest on benthic cyanobacterial proliferations, and an applied approach concerning strategies and tools for their monitoring on rivers in order to meet a request from water agencies and aquatic environmental managers.The main results of the thesis highlight (i) the importance of the hydrogeological context of sampling stations and water temperature on the temporal variations of periphytic communities, (ii) by OTU correlation analysis, positive interactions on the framework of organic matter recycling, and negative interactions in the case of light access competition, and (iii) a geographical structure of cyanobacterial-associated bacterial communities that seems to be mostly explained by local environmental context rather than distance. Concerning surveillance, we showed the limitations of a new spectrofluorometric tool for the quantification of benthic cyanobacteria and we propose sampling strategies to evaluate the importance of cyanobacterial biofilms in rivers.

The Neogene history of Caribbean deep-sea benthic foraminifera was investigated by calculating changes in paleoproductivity, diversity and paleobiogeography ~26 to 2 Ma, which includes the progressive closure of the Central American Seaway. Three hypotheses were tested: (1) Paleoproductivity values prior to closure of the Central American Seaway are similar in both the Caribbean and equatorial Pacific and then diverge by the time of early shoaling events; (2) Diversity values of benthic foraminifera prior to the closure of the Central American Seaway were similar in the Caribbean and EEP, and had changed by the time of early shoaling; and (3) during the Miocene and into the Pleistocene, the progressive constriction of the CAS affected deep-sea benthic foraminiferal assemblages by increasing their dissimilarity between the Caribbean and equatorial Eastern Pacific. These hypotheses were tested with 104 samples from five Caribbean and EEP deep-sea cores by calculating paleoproductivity with multiple proxies, determining diversity indices and calculating biogeographic similarity coefficients. The data supported the first two hypotheses: The greatest change in paleoproductivity occurred at ~8 Ma during seaway constriction, when values diverged between the Caribbean and EEP. After complete seaway closure at ~4 Ma, the Caribbean became oligotrophic, noted by a decrease in high-organic flux species, and an increase in Nuttalides umbonifera, an indicator species. The largest changes in species-level diversity occurred with the barrier to deep-water flow at ~12 Ma, and Caribbean diversity increased at ~8 Ma with seaway constriction. However, the third hypothesis was rejected: Increases in assemblage similarity actually occurred during most major paleoceanographic events, with the only decrease in Caribbean-EEP similarity occurring at ~12 Ma, coincident with a drop in diversity and emplacement of the Panama isthmian sill. Thus, the barrier to deep-water flow at ~12 Ma affected the composition of tropical American benthic foraminifera more than the largest change in paleoproductivity at ~8 Ma, or closure of the Central American Seaway at ~4 Ma.

Efforts that are underway to rehabilitate the Florida Bay ecosystem to a more natural state are best guided by a comprehensive understanding of the natural versus human-induced variability that has existed within the ecosystem. Benthic foraminifera, which are well-known paleoenvironmental indicators, were identified in 203 sediment samples from six sediment cores taken from Florida Bay, and analyzed to understand the environmental variability through anthropogenically unaltered and altered periods. In this research, taxa serving as indicators of (1) seagrass abundance (which is correlated with water quality), (2) salinity, and (3) general habitat change, were studied in detail over the past 120 years, and more generally over the past ~4000 years. Historical seagrass abundance was reconstructed with the proportions of species that prefer living attached to seagrass blades over other substrates. Historical salinity trends were determined by analyzing brackish versus marine faunas, which were defined based on species’ salinity preferences. Statistical methods including cluster analysis, discriminant analysis, analysis of variance and Fisher’s α were used to analyze trends in the data. The changes in seagrass abundance and salinity over the last ~120 years are attributed to anthropogenic activities such as construction of the Flagler Railroad from the mainland to the Florida Keys, the Tamiami Trail that stretches from the east to west coast, and canals and levees in south Florida, as well as natural events such as droughts and increased rainfall from hurricanes. Longer term changes (over ~4000 years) in seagrass abundance and salinity are mostly related to sea level changes. Since seawater entered the Florida Bay area around ~4000 years ago, only one probable sea level drop occurring around ~3000 years was identified.

Permafrost thaw slumping along lakeshores in lakes of the Mackenzie Delta Uplands, NT is known to alter water chemistry significantly. Its impact on benthic communities and persistent organic pollutant (POP) behaviour in lakes is not known. Benthic invertebrate communities responded to slumps through changes to community composition and size spectra. Larger taxa tended to dominate in lakes with slumps. Variability in biomass size spectra was related to total dissolved nitrogen concentration and slump size. Concentrations of POPs in Gammarus were negatively correlated with total phosphorus and positively correlated with the percentage of the catchment slumped. Lakes with slumps generally had higher mean concentrations of POPs in Gammarus (ex. ΣPCBsDisturbed = 27.54 ng/g lipid, ΣPCBsUndisturbed = 16.97 ng/g lipid; ΣDDT Disturbed =18.47 ng/g lipid and ΣDDTUndisturbed =10.86 ng/g lipid). Benthic invertebrate biomass was also negatively correlated with concentrations of contaminants in Gammarus, supporting the biomass dilution hypothesis. Thaw slumps have large enough impacts on the physico-chemical characteristics of lakes that they alter benthic invertebrate community composition and size-structure, and contaminant concentrations in Gammarus.

L'accumulation de composés persistants dans le biote constitue des préoccupations écologiques, sanitaires et réglementaires. Parmi ces substances, les composés per- et polyfluorés (PFASs) représentent un cas d'intérêt, en raison de leurs propriétés physico-chimiques particulières. Ces dernières rendent le comportement des PFASs dans l'environnement difficilement prévisibles, les outils actuels n'étant pas adaptés. Bien qu'il soit reconnu que ces composés sont persistants et s'accumulent dans le biote, de nombreuses inconnues subsistent, notamment sur les mécanismes de transferts sédiment–biote et des facteurs qui les contrôlent. Ce travail de thèse aborde le rôle du sédiment dans les processus d'accumulation, et plus particulièrement (a) les voies d'exposition du biote, (b) le rôle de la diversité biologique dans l'accumulation, par l'exposition de deux invertébrés benthiques (Chironomus riparius et gammarus sp.) à du sédiment naturel. La description des cinétiques d'accumulation et d'élimination des PFASs ont mis en évidence la biodisponibilité des composés pour les organismes. Ainsi, un modèle de bioaccumulation en accord avec la croissance des organismes et des particularités des composés a permis d'estimer des constantes d'accumulation et de dépuration (ku et ke). Une représentation conceptuelle du transfert des composés, a permis de comprendre les principales voies de contamination des organismes. D'autre part, la variabilité interspécifique a été évaluée par la comparaison de la bioaccumulation et des voies de transfert des PFASs chez ces deux invertébrés. Ce travail de thèse aura alors permis d'ouvrir de nombreuses questions, notamment celles du rôle du biofilm et de la bioturbation des organismes dans la bioaccumulation et ouvre les perspectives quant à l'étude de la bioamplification / The accumulation of persistent compounds in biota creates environmental, health and regulatory concerns. Among these substances, the poly-fluorinated compounds (PFASs) represents a case of interest due to their specific physicochemical properties. So the PFAs behavior in the environment is difficult to predict as the existing tools are not suitable. Athough it is recognized that these compounds are persistent and accumulate in biota, many knowledge gaps remain, including the mechanisms of sediment-biota transfer and the factors that control them. This thesis examines the role of sediment in the accumulation process, especially (a) exposure routes of biota, (b) role of biodiversity in the accumulation, by exposing two benthic invertebrates (Chironomus riparius and Gammarus sp.) to natural sediment. The description of PFASs kinetics of accumulation and elimination have showed the biodisponibility of the compounds to organisms. Thus, a bioaccumulation model including the organisms growth and the specificity of the compounds was used to estimate the accumulation and depuration rate constants (ku and ke). A conceptual representation of compounds transfer allowed us to understand the major routes for organisms contamination. Moreover, the interspecific variability has been assessed by comparing the PFASs bioaccumulation and transfer pathways for both invertebrates. This thesis have helped to open up many issues, and especially the influence of both biofilm and organism bioturbation onPFASs bioaccumulation. Moreover some new perspectives on the study of biomagnification were opened

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-04-13T12:48:36Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Daniele Maciel, 2015.pdf: 8269323 bytes, checksum: 502a5b895730f3f0f1d5a51d67510dac (MD5) / Made available in DSpace on 2016-04-13T12:48:36Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Daniele Maciel, 2015.pdf: 8269323 bytes, checksum: 502a5b895730f3f0f1d5a51d67510dac (MD5) Previous issue date: 30-09-30 / CAPEs / O sistema Estuarino do Rio Capibaribe (SERC) está localizado na região metropolitana do Recife e trata-se de uma área muito importante do ponto de vista socioeconômico. Apesar disto, recebe intensa carga de efluentes domésticos e industriais, na sua maioria sem tratamento. Vários processos físicos e químicos regem o destino destes contaminantes, incluindo a tendência dos mesmos serem adsorvidos ao material particulado. O regime de circulação do SERC favorece a retenção deste material e, por consequência, os contaminantes acabam se depositando nos sedimentos. O objetivo deste trabalho foi investigar, pela primeira vez, a saúde ambiental do SERC, considerando aspectos químicos e biológicos. Primeiramente, investigou-se a contaminação de sedimentos por Hidrocarbonetos (HCs) e Organoestânicos (OTs), em 9 estações distribuídas dentro do estuário. Também foram analisados HCs em mais 5 pontos da plataforma adjacente ao SERC, com o intuito de se investigar o potencial de transferência de contaminantes do estuário para a área costeira. Os compostos foram determinados através de cromatografia em fase gasosa associada a um detector de ionização de chama (para hidrocarbonetos alifáticos - HAs) e a um detector de espectrometria de massas (para hidrocarbonetos policíclicos aromáticos (HPAs) e OTs). As concentrações dos alifáticos totais no estuário variaram entre 7,5 μg g-1 e 190,3 μg g-1. A Mistura Complexa Não Resolvida esteve presente em grande parte das amostras indicando a contaminação dos sedimentos do estuário por óleo. A concentração de HPAs variou desde abaixo do limite de detecção a 497,6 ng g-1, com predominância de fontes pirolíticas, mas, em alguns pontos do estuário, há indicações de contribuição petrogênica, sugerindo uma mistura de fontes. Observou-se uma diminuição na concentração dos HCs em direção a foz do estuário. As concentrações de OTs variaram entre 13,97 e 541,69 ng Sn g-1, e os resultados indicam aporte recente destes contaminantes no ambiente, mesmo após obanimento de seu uso como agente anti-incrustante. A partir da constatação da contaminação dos sedimentos, cinco dos locais mais contaminados e próximos a potenciais fontes de contaminação foram novamente amostrados. O objetivo foi avaliar a qualidade dos sedimentos do estuário através da abordagem clássica ―Tríade da Qualidade de Sedimento‖ (TQS) e o uso de análises multivariadas. Foram investigadas a contaminação por HAs e HPAs, compostos organoclorados (OCs) e metais pesados. Testes ecotoxicológicos e análise da estrutura da comunidade bentônica também foram realizados. Para determinação dos compostos orgânicos foi usada a mesma metodologia descrita anteriormente e, para determinação dos metais, a técnica de ICP-MS. Todas as estações apresentaram contaminação por HCs, OCs e metais pesados, sendo as maiores concentrações na porção superior do estuário e na área portuária. Em alguns casos, alguns compostos excederam os limites de segurança estabelecidos por agências reguladoras internacionais, podendo causar efeitos nocivos à biota. As estações localizadas em frente ao Porto do Recife e na parte mais interna do estuário apresentaram toxicidade para o copépodo Tisbe biminiensis e, ainda, na porção mais interna do estuário foram registrados os menores valores de abundância e diversidade de organismos. Os resultados das análises integradas indicaram a presença de um gradiente de diminuição da degradação, do interior do estuário à sua desembocadura. A TQS mostrou-se eficaz para avaliar a qualidade e saúde ambiental da região e pode ser usada em programas de monitoramento de outras regiões estuarinas. / The Capibaribe Estuarine System (CES) is located in the metropolitan region of Recife and, besides its important socio-economic role, it receives high load of domestic and industrial effluents, mostly untreated. Several physical and chemical processes govern the fate of these contaminants, but the hydrophobics tend to be adsorbed to the particulate material. The CES hydrodynamics favors the retention and deposition of this material and, consequently, the contaminants as well. The objective of this study was to investigate, for the first time, the environmental health of CES, considering chemical and biological aspects. Firstly, the sediment contamination by Hydrocarbons (HCs) and Organotins (OTs) was investigated in 9 stations distributed along the estuary. HCs were also analyzed in five stations on the adjacent shelf, in order to investigate the potential transfer of contaminants from estuary to the coastal area. The compounds were analyzed by gas chromatography coupled to a flame ionization detector (aliphatic hydrocarbons - HAs) and a mass spectrometric detector (polycyclic aromatic hydrocarbons - PAHs, and OTs). Concentrations of total aliphatic in the estuary ranged from 7.5 μg g-1 to 190.3 μg g-1. The Unresolved Complex Mixture was registered in most samples indicating the contamination of sediments by oil. PAHs concentrations ranged from <limit of detection to 497.6 ng g-1. Pyrolytic compounds predominated in most sites but, in some portions of the estuary, the dominance of petrogenic suggests a mixture of sources. There was a decrease in the HCs concentration from upper to lower estuary. OTs concentrations ranged between 13.97 and 541.69 ng Sn g-1, and the results indicated recent input of this contaminant in the environment, even after its banishment as antifouling agent. Based on the sediments contamination and proximity of potential sources, five stations were again sampled. The objective was to evaluate the quality of the sediments through the classical approach "Sediment Quality Triad" (SQT) and multivariate analyzes. The contamination by PAHs, HAs, organochlorine (OC) and heavy metals were investigated. The OCs were analyzed using the same methodology described above, and for metals, the ICP-MS technique was used. Ecotoxicological bioassays and analysis of benthic community structure were also performed. All stations are contaminated by HCs, OC and heavy metals, and the highest concentrations were recorded in the upper portion of the estuary and in the port area. Some compounds exceeded the safe limits established by international regulatory agencies in a few samples, and they may be harmful to biota. The stations located in front of the Port of Recife and in the inner part of the estuary showed toxicity to the copepod Tisbe biminiensis. In addition, the inner portion had the lowest abundance and diversity of organisms. Integrated analyses indicated a decreasing gradient of degradation, from most inner part of the estuary to river mouth. The SQT was effective to assess the quality and environmental health and should be used in monitoring programs of other estuarine areas.

A recente explosão de visitação em áreas naturais está causando o desgaste justamente dos valores que tornaram tais áreas atrativas. As mudanças na estrutura da comunidade são problemas graves, principalmente onde há falta de conhecimento prévio, como os costões rochosos. O levantamento fisionômico visa possibilitar o aumento da velocidade e abrangência na aquisição de dados, importante em estudos de avaliação de impacto. O objetivo deste trabalho foi realizar uma avaliação das alterações na estrutura da comunidade bentônica relacionadas à visitação pública. O estudo foi realizado na Piscina Natural do Parque Estadual da Ilha Anchieta, um importante destino turístico do litoral norte paulista que apresenta grande visitação durante o mês de janeiro. Amostragens foram realizadas na Piscina Natural e em duas áreas de referência, em dezembro de 2008 e no final de janeiro de 2009, seguindo o modelo BACI (befor-after-control-impact). Os dados foram analisados através de Índices de Similaridade e dendogramas. Foram encontrados 24 povoamentos. No médio-litoral o maior recobrimento foi de Banco de Chtamallus (>35%) e no infra-litoral foi de Tapete de Jania e Amphiroa (>45%). Para os dados qualitativos, a similaridade entre as áreas foi alta (>0,79), assim como entre as duas amostragens em cada área (>0,75). Para os dados quantitativos a similaridade também foi alta (>0,82). Os únicos povoamentos que apresentaram diferença significativa entre as amostragens foram Banco de Ectocarpaceae, Banco de Brachidontes e Banco de Sargassum na Área de Referência 1 e Crosta de Corallinaceae na Área de Referência 2. Os resultados indicam que a comunidade bentônica de substrato consolidado da Piscina Natural não apresentou alterações significativamente maiores que as áreas de referência nesse intervalo de tempo. Entretanto, não é possível concluir que não está ocorrendo impacto, já que o método pode não ter detectado alterações. Este foi o primeiro trabalho que se propôs a fazer uma avaliação de impacto utilizando esse método. Portanto, são necessários mais estudos para adequar o método a este objetivo. / The recent boom in visiting natural areas is destroying the very features that make those areas so attractive. Changes in the structure of natural community are serious problems, especially at poor known areas, such as rocky shores. A physiognomic assessment aims to produce an increase in data acquisition amplitude and speediness, relevant features in impact evaluation studies. Our goal was to evaluate structure changes in a benthic community related to public visitation. The study was realized at Piscina Natural in the State Park Anchieta Island, a important touristic point at northern coast of São Paulo state, which receive many tourists during January. Samplings were done at Piscina Natural and at tow reference areas, in 2008 December and at the end of 2009 January, following BACI model (before-after-control-impact). Data were analyzed using similarity index and dendrogram. Twenty four settlements were found. At midlittoral Chtamallus Bed had the highest percent cover (>35%), and at infrallittoral Jania and Amphiroa Turf had the highest percent cover (>45%). With qualitative data, similarity among areas was high (>0,79), as well as among sampling periods in the same area (>0,75). With quantitative data similarity was also high (>0,82). Only a few settlements showed significant differences between sampling periods, Ectocarpaceae Bed, Brachiontes Bed and Sargassum Bed at Reference Area 1 and Corallinaceae Crusts at Reference Are 2. This results indicate that benthic community on consolidated substrate at Piscina Natural did not undergo alteration significantly higher than those from reference areas in this time interval. However, we cannot conclude that there is no impact, the methodology could had not be able to detect the impact. This was the first study that aimed to evaluate environmental impact, using this methodology. Therefore more studies are needed to fit this methodology to this objective.

Projetos de monitoramento de longo prazo estão sendo desenvolvidos internacionalmente a fim de monitorar continuamente os impactos que as mudanças climáticas globais vêm gerando nas comunidades marinhas bentônicas, entretanto, no âmbito nacional, há uma carência desse tipo de estudo e dados para a costa brasileira. O objetivo do presente estudo foi a instalação de uma estação de monitoramento de longo prazo, bem como a caracterização da comunidade bentônica presente no médiolitoral do costão rochoso à direita da Enseada de Palmas, no Parque Estadual da Ilha Anchieta (Ubatuba, SP) seguindo as diretrizes do \"Protocolo de Médiolitoral para Monitoramento de Comunidades de Costão Rochoso\" da ReBentos (Rede de Monitoramento de Habitats Bentônicos Costeiros). As amostragens dependentes semestrais (n = 3) foram realizadas no período de um ano, compreendendo o inverno de 2014 e o verão de 2015, utilizando fotoquadrados de 10x10 cm na faixa superior e 25x25 cm nas faixas intermediária e inferior. A análise variância ANOVA two way para dados repetidos revelou variação sazonal na largura das faixas das unidades operacionais (UO) Tetraclita (39,1 cm) e Macroalgas (27 cm) e no recobrimento percentual médio (RPM) das UO Cianobactéria (12,6%) na faixa superior, T. stalactifera (16,6%), Espaço vazio (38,4%) e Algas Calcárias Articuladas (55,7%) na faixa intermediária. As análises multivariadas (Cluster, nMDS e PCA) revelaram alta similaridade para as faixas superior (80%) e inferior (85%) e baixa (65%) para a faixa intermediaria, indicando que as maiores diferenças entre verão e inverno foram encontradas nesta faixa. Como o médiolitoral apresenta UO bioindicadoras de monitoramento, como T. stalactifera, A. beauvoisii e Sargassum vulgare, e de variação sazonal, então eleva-se a importância da realização, integração e continuidade de projetos de monitoramento de longo prazo em costões rochosos a fim de gerar dados históricos ao longo do litoral brasileiro / The development of long-term monitoring projects around the world aims to monitor continuously the impacts that global environmental changes (GEC) have been causing in the benthic marine communities. However, nationally, there are few monitoring studies and data for the Brazilian coast. In this study, we aimed to install a long-term monitoring station and characterize the benthic community located in the intertidal zone of the rocky shore in the right of the Cove of Palmas at the Anchieta Island State Park (Ubatuba, São Paulo state). We intended to do that by following the guidelines of the \"Intertidal Protocol for the Monitoring of Rocky Shore Communities\" (Rocky Shores Working group, ReBentos). We studied the rocky shore for a year and collected the dependent samples every semester (n = 3), encompassing the winter of 2014 and the summer of 2015. We used photoquadrats in the intertidal zone (10x10 cm in the upper band and 25x25 cm in the intermediate and lower bands). Two-way analysis of variance (ANOVA) for repeated measures reveled seasonal variation in the bandwidth of Tetraclita (39,1 cm) and Macroalgae (27 cm) operational units (OU) and in the average percentage overlap for Cyanobacteria (12,6%) at upper band, T. stalactifera (16,6%), Empty space (38,4%) and Articulated Calcareous Algae (55,7%) at intermediate band. Multivariate analysis (Cluster, nMDS and PCA) revealed high similarity for upper (80%) and lower (85%) bands and low similarity for intermediate band (65%), suggesting major differences between summer and winter in the intermediate band. As the intertidal zone has monitoring bioindicators operational units, like T. stalactifera, A. beauvoisii and Sargassum vulgare, and seasonal variation, it is of great importance to implement, integrate and continue long-term monitoring projects in rocky shores in order to generate Brazilian coast historical data

Das Verständnis über die Ausprägung der Lebensgemeinschaften von benthischen Invertebraten in aquatischen Ökosystemen in Abhängigkeit von abiotischen Faktoren ist von grundlegender wissenschaftlicher Bedeutung und eine Voraussetzung für die Bewertung, den Schutz und die Wiederherstellung der ökologischen Integrität in Fließgewässern. Für die Erarbeitung von Abhängigkeiten zwischen der benthischen Lebensgemeinschaft, der Hydromorphologie und der Saprobie standen insgesamt 409 Datensätze in Form von Taxalisten des Makrozoobenthos zur Verfügung. Diese wurden mit Strukturgütedaten verschnitten und anhand uni- und multivariater statistischer Methoden analysiert. Folgende Ergebnisse konnten dabei erzielt werden: (a) es können sieben Einzelparameter der Gewässerstruktur identifiziert werden, die einen signifikanten Einfluss auf die benthische Biozönose ausüben, (b) die Fließgewässertypen 5 und 5.1 unterscheiden sich auf Basis des vorliegenden Datensatzes weder in der taxonomischen noch in der funktionalen Zusammensetzung der Makrozoobenthoszönose und (c) bei einer erhöhten saprobiellen Belastung überlagert der Einfluss der organischen Belastung die strukturellen Gegebenheiten. Für die Entwicklung und Anpassung effizienter Strukturgüteverfahren und die daraus resultierenden Monitoring- und Maßnahmenprogramme für ein integriertes Fließgewässermanagement ist die Auswahl ökologisch relevanter Parameter von immenser Bedeutung. / The understanding about the development of benthic invertebrate communities as a function of abiotic influencing factors in aquatic ecosystems is of essential scientific relevance for the assessment of the ecological status of rivers and streams. For the development of interdependencies between benthic invertebrates, hydromorphology and saprobity, 409 species lists of the macroinvertebrates were provided. They were aggregated with morphological features and analysed with different uni- and multivariate statistical methods. On the basis of the used analyses, the following results were achieved: (a) seven ecological relevant morphological features with significant influence to benthic invertebrate community could be identified, (b) on the basis of the present database, the structural and functional composition of the benthic invertebrates can not be differ river type specific (type 5 and 5.1) and (c) if the saprobic pressure decrease, the organic pressure superpose the hydromorphology. The values of the biological attributes are low in spite of near natural morphological conditions. For an ecological efficiency stream habitat assessment, the identified relevant morphological parameters have to consider. The “morphological characteristic curves” are well describing the results of a local monitoring. This application-oriented instrument can be used for (a) the operationalisation of environmental objectives, (b) the development and adaption of monitoring strategies and (c) the derivation and prioritisation of ecological and economic efficiency measurements for an integrated river management.

<p>Aquatic macroinvertebrates of channelized headwater streams in agricultural landscapes are exposed to alterations in chemistry and physical characteristics of benthic sediments. These habitat alterations are known to influence communities of aquatic macroinvertebrates. Benthic sediments can have a wide range of impacts and influences on aquatic macroinvertebrates. I hypothesized that sediments would play a significant role in determining macroinvertebrate community structure within agriculturally dominated headwater streams. I evaluated the influences of sediment chemistry characteristics and physical characteristics on aquatic macroinvertebrate communities in Cedar Creek, Indiana and Michigan, and the Upper Big Walnut Creek, Ohio, during 2017 and 2018. Macroinvertebrates were collected twice per year using artificial substrate and leaf pack samplers and identified to the family level. Sediments were sampled two times per year and analyzed for seven physical characteristics and twenty sediment chemistry characteristics. Principle component analyses were used to create axes that are indicators of gradients of sediment chemistry and physical characteristics that occur among the samples. Macroinvertebrate community metrics used in the analyses included abundance, Shannon Diversity Index, Hilsenhoff Biotic Index scores, Invertebrate Community Index scores, percentage of collector-filters, percentage of scrapers, percentage of Chironomidae and a Berger-Parker Reciprocal Index of dominance. Linear Mixed Effect Model analyses revealed that both sediment chemistry and physical characteristics influence macroinvertebrate community metrics. Aquatic macroinvertebrate abundance was negatively correlated with increasing concentrations of simazine and decreasing concentrations of calcium. Percentages of Chironomidae were positively correlated with increasing percentages of sand and decreasing percentages of clay and decreasing diversity of sediment particle sizes. My data supported the hypothesis that benthic sediments play an important role in determining aquatic macroinvertebrate community structure in headwater streams of agriculturally dominated landscapes. Gradients of chemical characteristics containing simazine and calcium were observed to be negatively correlated with macroinvertebrate abundance. Gradients of physical characteristics including percentages of sand and clay along with the diversity of particle sizes were observed to be positively correlated with percentage of chironomids. My research increases the knowledge that benthic sediments, chemically and physically, can lead to alterations in aquatic macroinvertebrate communities within Midwestern headwater streams. </p>