Grunda, näringsrika sjöar förekommer i två stadier: antingen ett med grumligt vatten och hög biomassa av växtplankton, eller ett med klart vatten och riklig undervattensvegetation. Det klara stadiet är eftersträvansvärt eftersom det skapar goda förutsättningar för en rad ekosystemtjänster, inklusive vattenkvalitet, rekreation och förutsättningar för biodiversitet. Vid eutrofiering, d v s ökat tillskott av näringsämnen, kvarstår det klara stadiet tills näringsbelastningen blir så hög att sjön övergår till ett grumligt stadium. Sjön Tåkern, i Östergötland, har under de senaste åren blivit alltmer eutrofierad och kalkning av vattnet har diskuterats som en möjlig åtgärd för att bevara det klara stadiet som sjön numera befinner sig i. Undersökningar om kalkning av eutrofierade sjöar har gjorts tidigare, men det har varit få studier av effekterna av kalkning på undervattensvegetation, substratlevande djur och påväxtalger. För att undersöka detta, gjordes ett fält- och ett laboratorieexperiment inriktade på effekter på överlevnad av vattengråsugga, Asellus aquaticus, fysiologisk status (halten klorofyll a) i kransalgen Chara globularis och tillväxt av nyetablerade påväxtalger i sjön Tåkern. Resultaten visar att A. aquaticus hade lägre överlevnad efter kalkning till pH 10 i laboratorieexperiment, men i fältförsöket hade kalkning till detta pH inte någon inverkan. C. globularis hade en högre halt klorofyll a efter kalkning till pH 10 i laboratorieexperimentet, men i fältexperimentet hade kalkning ingen effekt på halten klorofyll a. Påväxtalger hade en lägre tillväxthastighet efter kalkning i fältexperimentet. Slutsatsen är att kalkning kan vara en metod för att motverka eutrofiering av sjön Tåkern. Några inkonsekvenser mellan mesokosm- och laborationsresultaten tyder på att fler studier behövs göras för att undersöka hur kalkning till pH 10 påverkar bentiska organismer. / Shallow, nutrient-rich lakes can occur in two alternative states: either a turbid water state with high biomass of phytoplankton, or a clear water state with abundant submerged vegetation. The clear water state is worth striving for because it creates good conditions for a range of ecosystem services and biodiversity. Lake Tåkern, Östergötland, has in recent years become increasingly eutrophic and liming has been discussed as a method to reduce the phosphorus level and maintain, or trigger a shift to, the clear water state. Investigations regarding the effects of liming of eutrophic lakes on phosphorus level and plankton have been performed in the past, but few studies have examined the effects on submerged vegetation, benthic invertebrates and periphyton. To study this, a field and a laboratory experiment were performed to examine how liming to pH 10 affects survival of the benthic invertebrate Asellus aquaticus, the chlorophyll a content in the stonewort Chara globularis and growth of periphyton. Survival of A. aquaticus was not affected in a field mesocosm experiment in Lake Tåkern, but decreased after liming in a laboratory experiment. The chlorophyll a content of C. globularis was not affected in the field experiment but higher than in the controls in the laboratory experiment. Growth of periphyton was reduced in the field experiment. Based on the field experiment, effects on A. aquaticus and C. globularis were negligible, but the laboratory experiment indicate that liming to pH 10 may under certain conditions affect benthic organisms. The conclusion is, however, that liming can be a suitable method to counteract the eutrophication of Lake Tåkern. Some inconsistencies between the field and laboratory results suggest that more studies needs to be made to see how liming to pH 10 affect benthic organisms.

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

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.

The leakages of metals from acid sulfate soils and their potential toxicity to benthic invertebrates were studied in the sediment profiles of Lillkvasjön and Lövselefjärden - a lake and an estuary known to be affected by acid sulfate soils - in Västerbotten, northern Sweden. The concentrations of 25 different elements were analyzed throughout both sediment profiles through X-Ray Fluorescence (XRF) Spectrometer analysis. Organic matter was measured through loss-on-ignition (LOI). By performing correlation analysis and normalizations to LOI on all sediment variables, Cu, Fe, Ni, Pb, S and Zn were found to be leached from acid sulfate soils to both sites, while Mg and Mn were related to leakages from acid sulfate soils in Lövselefjärden. The concentrations of Cu (195 mg kg-1), Ni (55 mg kg-1), Pb (90 mg kg-1) and Zn (398 mg kg-1) in the surface sediment of Lövselefjärden were classified as potentially toxic to benthic invertebrates. In Lillkvasjön, Cu (210 mg kg-1) and Ni (87 mg kg-1) were classified to have an increased risk of negative impacts on benthic invertebrates, while the concentrations of Pb (121 mg kg-1) and Zn (329 mg kg-1) were likely to low to have any negative effects. These results strengthen previous finds of impacts from acid sulfate soils in the two catchment areas and elucidate the importance of further studies on the impact of acid sulfate soils on benthic invertebrates.

A principal ecological role proposed for the hyporheic zone is as a refugium that promotes benthic invertebrate survival during adverse conditions in the surface stream. Whilst a growing body of work has examined use of this hyporheic refugium during hydrological extremes (spates, streambed drying), little research has considered variation in refugium use over prolonged periods including contrasting conditions of surface flow. In this thesis, benthic invertebrate use of the hyporheic refugium is considered at monthly intervals over a five-month period of variable surface flow, at nine sites in two groundwater-dominated streams, the River Lathkill (Derbyshire) and the River Glen (Lincolnshire). Conditions identified as potential triggers of refugium use included a flow recession and a high-magnitude spate on the Lathkill, and small spates and a decline in flow preceding localised streambed drying on the Glen. During flow recession, reductions in submerged habitat availability and concurrent increases in benthic population densities were dependent on channel morphology. An unusual paired benthic-hyporheic sampling strategy allowed the type of refugium use (active migration, passive inhabitation) to be inferred from changes in hyporheic abundance and the hyporheic proportion of the total population. Using this approach, evidence of active migrations into the hyporheic zone use was restricted to two instances: firstly, Gammarus pulex (Amphipoda: Crustacea) migrated in response to habitat contraction and increased benthic population densities; secondly, migrations of Simuliidae (Diptera) were associated with low-magnitude spates. Refugium use was site-specific, with refugial potential being highest at sites with downwelling water and coarse sediments. A conceptual model describing this spatial variability in the refugial capacity of the hyporheic zone is developed for low flow conditions. In some cases, hyporheic refugium use was apparently prevented by disturbance-related factors (rapid onset, high magnitude) regardless of the refugial potential of the sediments. The extension of the hyporheic zone's refugial role to include low flows highlights the need to explicitly protect the integrity of hydrologic exchange in river rehabilitation schemes. However, the limited capacity of the hyporheic refugium emphasizes the additional importance of maintaining habitat heterogeneity including multiple instream refugia.

Several hypotheses from community ecology were tested using habitat and diet patterns for six catostomid fishes of the Assiniboine River, Manitoba. Specifically, I examined expected assemblage patterns based on the equilibrium-nonequilibrium continuum that are based on competition as a structuring mechanism. The catostomid assemblage showed characteristics of both equilibrium and nonequilibrium assemblages. Habitat utilization was not proportional to habitat availability for depth, velocity, and substrate indicating habitat selection occurs. These patterns are influenced by the distributions of soft Lake Agassiz deposits and harder glacial till-plain habitats and therefore localized. Species co-occurred in relation to abundance indicating negative associations assumed in competition-based theory were not apparent. In addition, species from the same subfamily co-occurred more often than expected by chance, indicating positive within-group comparisons, except for silver redhorse, which did not co-occur differently than random. Species from the same feeding group co-occur most frequently with conspecifics, indicating species have specific habitat patterns. Benthic invertebrate distributions and fish distributions were positively correlated with fish diet. Within-feeding-group comparisons indicated species that co-occurred frequently consumed the same food items, but showed subtle differences in abundance of diet items. The most common diet items varied among white sucker, silver redhorse, golden redhorse, and shorthead redhorse, indicating that, although these species co-occur, subtle differences in feeding behavior may account for differences in relative abundance and frequency of diet items. Quillback and bigmouth buffalo shared a few core food items, but co-occurred infrequently. Inter-specific interactions showed silver redhorse diets were a subset of white sucker diets, white sucker diets were a subset of golden redhorse diets, shorthead redhorse diets were a subset of silver redhorse and golden redhorse diets, while bigmouth buffalo diets were a subset of quillback diets. Lower richness and prevalence of organisms in quillback and bigmouth buffalo diets were due to highly aggregated prey items. Benthic invertebrate distributions were aggregated and dependent on the predictable patterns of substrates, based on hydraulic sorting in the meandering along the river. Large-scale redundancy of species-habitat associations was correlated with historical (phylogenetic) or adaptive (morphological) constraints on habitat selection. Stream habitats are constrained by regional factors of slope and sediments, but also determined by stable, repetitive and predictable local processes of erosion, transport, and deposition (meandering). The fish-habitat associations of catostomids in the Assiniboine River provide an example of interaction between the abundance of the component species, the phylogenetic constraints on the niche, and the deterministic nature of the spatial distribution of habitats. Within-feeding-group pairs showed that local habitat overlap is positively correlated with geographic overlap, while local diet overlap is negatively correlated with geographic overlap. Two species pairs (silver redhorse and golden redhorse and bigmouth buffalo and quillback) were concluded to have symmetric overlaps at the geographic scale and stable interactions. Using the functional niche concept ecological theory provides a link between ecology and biogeography of sympatric species. The multi-analytical approaches in this study provide insights into the structuring of north temperate prairie river fish communities, through hypothesis testing and correlation that have application beyond Prairie Rivers. / October 2005

Created lakes are an end product of phosphate mining in Florida. Beginning in 1975, Florida reclamation rules set criteria for phosphate created lakes aiming to approximate the structure of natural lakes, and emphasizing extensive littoral zones with both emergent and submersed vegetation. Lake development relative to lake age and design were examined for 22 phosphate lakes representing a 40-year age trajectory, utilizing water quality and benthic invertebrate communities from littoral and deep-water locations (Chapter 1). The relative importance of morphometry and lake age in the development of littoral plant communities was examined using multiple vegetation surveys throughout the year, in a separate investigation of 39 littoral locations from 13 lakes reflecting age and morphometry gradients (Chapter 2). The same littoral locations were used to investigate benthic community composition in relation to emergent and submersed plant habitats (depth of 0.5 m and 1.5 m respectively), water quality, sediment characteristics, morphometry and lake age (Chapter 3). Phosphate lakes >5.5m deep are warm monomictic water bodies, stratifying from April to October/November, and developing thermoclines at approximately 4 m. Shallow lakes (<5.5 m deep) are polymictic. Phosphate lakes become eutrophic or hypertrophic immediately after creation and remain so through time. Unlike reservoirs, they do not go through a trophic surge, which is an initial period of great productivity that declines as sediment nutrient storage is exhausted. Among the 22 sampled lakes, epilimnetic physical and chemical water quality variables (Secchi depth, chlorophyll a, turbidity, pH) did not differ along the age trajectory. Only specific conductance declined significantly, 10-20 years after lake creation, most probably due to bank stabilization. All water quality variables were within the range of natural lakes in the region, and were most similar to urban rather than suburban or rural natural lakes. Benthic invertebrate abundance (total, Chironomidae, Oligochaeta, invertebrates other than Chironomidae and Oligochaeta) and taxa richness displayed great variability with lake age and did not differ among decadal lake groups at any depths examined (1 m, deepest point). Invertebrate abundance did not differ between littoral and deep habitats, except for lakes >10 years old, where littoral abundance was greater than deep-water abundace, suggesting faster colonization of the littoral zone. Littoral taxa richness was greater than richness in deep-water, which was attributed to taxa other than Chironomidae and Oligochaeta. Deep-water and most littoral habitats were dominated by Chironomidae, whereas Oligochaeta were occasionally dominant in the littoral zone. Dissolved oxygen was the variable explaining most variance of both littoral abundance and richness. Littoral macrophyte communities in phosphate lakes differed from natural Florida lakes. Although most phosphate lakes developed emergent littoral zones, submersed vegetation was absent, with few exceptions of the non-indigenous Hydrilla verticillata. Plants clustered in groups reflecting their hydrological designations. Frequently encountered plants classified either in the obligate wetland plant group, characterized by Typha, and inhabiting mostly intermediate-age lakes or the facultative wetland plant group, characterized by Panicum repens. Most plants in the latter group were bimodally distributed in youngest and oldest lakes, whereas few plants were ubiquitous. Littoral plant community composition was determined by both lake morphology and age, but the relative influence of these two components was not clear. Littoral plant composition was a good predictor of lake development. Morphometric (slope) and sediment characteristics (organic content, particle size) did not differ between the two littoral depths examined (0.5 m and 1.5 m). Slope correlated moderately but significantly with lake age, and organic content was low in all samples. Total littoral benthic invertebrate abundance and its major component Chironomidae, started from low values at newly created lakes and remained low or increased unpredictably with time. Total, Chironomidae, Oligochaeta and Gastropoda abundances did not differ between the depths of 0.5 m and 1.5 m, whereas taxa richness and the abundance of invertebrates other than Chironomidae, Oligochaeta, and Gastropoda was greater at the shallower depth (0.5 m).The relative effect of lake morphology versus age on benthic invertebrate composition was not clear. Total and Chironomidae abundance increased with lake age at 0.5 m, and bank slope at 1.5 m. Both littoral invertebrate abundance and richness in phosphate lakes were lower than in a natural, mesotrophic, macrophyte-dominated lake in the region, characterized by great Oligochaeta densities.

Several hypotheses from community ecology were tested using habitat and diet patterns for six catostomid fishes of the Assiniboine River, Manitoba. Specifically, I examined expected assemblage patterns based on the equilibrium-nonequilibrium continuum that are based on competition as a structuring mechanism. The catostomid assemblage showed characteristics of both equilibrium and nonequilibrium assemblages. Habitat utilization was not proportional to habitat availability for depth, velocity, and substrate indicating habitat selection occurs. These patterns are influenced by the distributions of soft Lake Agassiz deposits and harder glacial till-plain habitats and therefore localized. Species co-occurred in relation to abundance indicating negative associations assumed in competition-based theory were not apparent. In addition, species from the same subfamily co-occurred more often than expected by chance, indicating positive within-group comparisons, except for silver redhorse, which did not co-occur differently than random. Species from the same feeding group co-occur most frequently with conspecifics, indicating species have specific habitat patterns. Benthic invertebrate distributions and fish distributions were positively correlated with fish diet. Within-feeding-group comparisons indicated species that co-occurred frequently consumed the same food items, but showed subtle differences in abundance of diet items. The most common diet items varied among white sucker, silver redhorse, golden redhorse, and shorthead redhorse, indicating that, although these species co-occur, subtle differences in feeding behavior may account for differences in relative abundance and frequency of diet items. Quillback and bigmouth buffalo shared a few core food items, but co-occurred infrequently. Inter-specific interactions showed silver redhorse diets were a subset of white sucker diets, white sucker diets were a subset of golden redhorse diets, shorthead redhorse diets were a subset of silver redhorse and golden redhorse diets, while bigmouth buffalo diets were a subset of quillback diets. Lower richness and prevalence of organisms in quillback and bigmouth buffalo diets were due to highly aggregated prey items. Benthic invertebrate distributions were aggregated and dependent on the predictable patterns of substrates, based on hydraulic sorting in the meandering along the river. Large-scale redundancy of species-habitat associations was correlated with historical (phylogenetic) or adaptive (morphological) constraints on habitat selection. Stream habitats are constrained by regional factors of slope and sediments, but also determined by stable, repetitive and predictable local processes of erosion, transport, and deposition (meandering). The fish-habitat associations of catostomids in the Assiniboine River provide an example of interaction between the abundance of the component species, the phylogenetic constraints on the niche, and the deterministic nature of the spatial distribution of habitats. Within-feeding-group pairs showed that local habitat overlap is positively correlated with geographic overlap, while local diet overlap is negatively correlated with geographic overlap. Two species pairs (silver redhorse and golden redhorse and bigmouth buffalo and quillback) were concluded to have symmetric overlaps at the geographic scale and stable interactions. Using the functional niche concept ecological theory provides a link between ecology and biogeography of sympatric species. The multi-analytical approaches in this study provide insights into the structuring of north temperate prairie river fish communities, through hypothesis testing and correlation that have application beyond Prairie Rivers.

Several hypotheses from community ecology were tested using habitat and diet patterns for six catostomid fishes of the Assiniboine River, Manitoba. Specifically, I examined expected assemblage patterns based on the equilibrium-nonequilibrium continuum that are based on competition as a structuring mechanism. The catostomid assemblage showed characteristics of both equilibrium and nonequilibrium assemblages. Habitat utilization was not proportional to habitat availability for depth, velocity, and substrate indicating habitat selection occurs. These patterns are influenced by the distributions of soft Lake Agassiz deposits and harder glacial till-plain habitats and therefore localized. Species co-occurred in relation to abundance indicating negative associations assumed in competition-based theory were not apparent. In addition, species from the same subfamily co-occurred more often than expected by chance, indicating positive within-group comparisons, except for silver redhorse, which did not co-occur differently than random. Species from the same feeding group co-occur most frequently with conspecifics, indicating species have specific habitat patterns. Benthic invertebrate distributions and fish distributions were positively correlated with fish diet. Within-feeding-group comparisons indicated species that co-occurred frequently consumed the same food items, but showed subtle differences in abundance of diet items. The most common diet items varied among white sucker, silver redhorse, golden redhorse, and shorthead redhorse, indicating that, although these species co-occur, subtle differences in feeding behavior may account for differences in relative abundance and frequency of diet items. Quillback and bigmouth buffalo shared a few core food items, but co-occurred infrequently. Inter-specific interactions showed silver redhorse diets were a subset of white sucker diets, white sucker diets were a subset of golden redhorse diets, shorthead redhorse diets were a subset of silver redhorse and golden redhorse diets, while bigmouth buffalo diets were a subset of quillback diets. Lower richness and prevalence of organisms in quillback and bigmouth buffalo diets were due to highly aggregated prey items. Benthic invertebrate distributions were aggregated and dependent on the predictable patterns of substrates, based on hydraulic sorting in the meandering along the river. Large-scale redundancy of species-habitat associations was correlated with historical (phylogenetic) or adaptive (morphological) constraints on habitat selection. Stream habitats are constrained by regional factors of slope and sediments, but also determined by stable, repetitive and predictable local processes of erosion, transport, and deposition (meandering). The fish-habitat associations of catostomids in the Assiniboine River provide an example of interaction between the abundance of the component species, the phylogenetic constraints on the niche, and the deterministic nature of the spatial distribution of habitats. Within-feeding-group pairs showed that local habitat overlap is positively correlated with geographic overlap, while local diet overlap is negatively correlated with geographic overlap. Two species pairs (silver redhorse and golden redhorse and bigmouth buffalo and quillback) were concluded to have symmetric overlaps at the geographic scale and stable interactions. Using the functional niche concept ecological theory provides a link between ecology and biogeography of sympatric species. The multi-analytical approaches in this study provide insights into the structuring of north temperate prairie river fish communities, through hypothesis testing and correlation that have application beyond Prairie Rivers.

Submitted by Sandra Pereira (srpereira@ufrrj.br) on 2018-08-21T13:55:57Z No. of bitstreams: 1 2010 - Joaquim Neto de Sousa Santos.pdf: 1864983 bytes, checksum: e70ed9f5ee68c8f365819e496dbb0176 (MD5) / Made available in DSpace on 2018-08-21T13:55:57Z (GMT). No. of bitstreams: 1 2010 - Joaquim Neto de Sousa Santos.pdf: 1864983 bytes, checksum: e70ed9f5ee68c8f365819e496dbb0176 (MD5) Previous issue date: 2010-05-21 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico, CNPq, Brasil. / Morphodynamism, extratification and seasonality are among the main factor to influence the composition and abundance of the macroinfauna in sandy beaches. The macroinfauna of two sandy beaches were sampled between winter-2005 and summer-2006 during low tide; one beach was protected (Flamengo beach) located in Guanabara bay, and the other was exposed to waves in the oceanic zone (Grumari beach). The hypothesis that the physical characteristics of the beaches determine the difference in composition and relative abundance of the macroinfauna was tested. Flamengo beach was characterized as dissipative and had comparatively higher t?xon richenes and lower biomass, when compared with Grumari beach that was classsified as reflective. In Flamengo beaches, higher abundance was recordded for Enoploides sp, and Emerita brasiliensis, whereas in Grumari beach Sacocirrus sp and E. brasiliensis were the most abundant taxons. The beaches showed highe dissimilarity in composition and relative abundance of the taxons (91.75%). Sacocirrus sp, Enoploides sp, Dispio uncinata, Scolelepis goodbobyi and E. brasiliensis explained 63.70% of the dissimilarity between the two beaches. In both beaches, we observed extratification in occurence and abundance of the macroinfauna in two seasons. Emerita brasiliensis occurred mainly in Grumary beach in the extrate 1 and Sacocirrus sp in extrate 2, while in Flamengo beach E. brasiliensis and Enoploides sp had the highest abundance in extrate 1 and S. goodbody and D. uncinata in extrate 3. The hypothesis that the macrofauna differs among extrate and beaches was accepted and the differences in composition and relative abundance of the macroinfauna were attributed to morphodynamism, althought other environmental factores can be influencing such differences. / O morfodinamismo, estratifica??o e a sazonalidade s?o os fatores mais importantes na determina??o da composi??o e abund?ncia da macroinfauna em praias arenosas. A macroinfauna de duas praias foi amostrada no inverno/2005 e ver?o/2006 durante a mar? baixa, sendo uma praia protegida (Flamengo) localizada na ba?a de Guanabara, e outra praia exposta localizada na zona oce?nica (Grumari). Foi testada a hip?tese que as caracter?sticas f?sicas das praias determinam diferen?as na composi??o e abund?ncia da macroinfauna. A praia do Flamengo foi caracterizada como dissipativa e apresentou maior riqueza de t?xons, e menor biomassa, quando comparada com a praia de Grumari classificada como refletiva. Na praia do Flamengo as maiores abund?ncias foram registradas para Enoploides sp, e Emerita brasiliensis, enquanto em Grumari foram Sacocirrus sp e E. brasiliensis. As praias apresentaram elevada dissimilaridade na composi??o e abund?ncia relativa dos t?xons (91.75%), Sacocirrus sp, Enoploides sp, Dispio uncinata, Scolelepis goodbobyi e E. brasiliensis explicaram 63.70% das diferen?as entre as praias. Em ambas as praias foram observadas estratifica??es na ocorr?ncia e abund?ncia da macroinfauna nas duas esta??es analisadas. Na praia de Grumari, E. brasiliensis ocorreu principalmente no estrato 1 e Sacocirrus sp no estrato 2, enquanto na praia do Flamengo E. brasiliensis e Enoploides sp apresentaram as maiores abund?ncias no estrato 1 e S. goodbodyi e D. uncinata no estrato 3. A hip?tese da varia??o na composi??o da macroinfauna entre os extratos foi aceita, e as diferen?as observadas na composi??o e abund?ncia da macroinfauna foram atribu?das ao morfodinamismo; no entanto, outros fatores ambientais podem estar relacionados com tais diferen?as.