Considerando a reconhecida importância dos Crustáceos para os peixes da família Sciaenidae, decidiu-se estudar a alimentação das espécies: Cynoscion jamaiacensis Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Paralonchurus brasiliensis e Umbrina canosai, em relação aos itens-Crustacea e em especial aos Amphipoda. O material em estudo foi obtido de três cruzeiros do Convênio GEDIP e IOUSP, coletados na Plataforma Continental, entre as latitudes 29º 21\'S (Torres) e 33º 41\'s (Chuí) entre outubro de 1968 e março de 1969. Embora em C.jamaicensis, P.brasiliensis o número de exemp1ares examinados fosse pequeno, foram calculados para a aná1ise do conteúdo estomacal (itens-Crustacea): a freqüência de ocorrência, porcentagem numérica, volume percentual e IRI (índice de re1ativa importância). O número de itens-Crustacea encontrado para as espécies de Sciaenidae foi muito variado. Assim, em M.ancylodon e P.brasiliensis foram encontrados 4 itens, em C.jamaicensis 5, em C.striatus 9, em M.furnieri 13 e em U.canosai 15. O IRI forneceu os itens mais importantes para cada espécie como segue: Amphipoda para C.jamaicensia, P.braisiliensis e U.canosai; Natantia para C.striatus e M.ancylodon e Brachyura para M.furnieri. A análise sobre a variação do regime alimentar com o aumento do tamanho do peixe, revelou que em M.ancylodon, M.furnier, P.brasiliensis e U.canosai, os peixes maiores vão adicionando outros itens, ampliando o seu espectro alimentar. À medida que o peixe cresce, diminui a freqüência de ingestão de presas maiores e aumenta a de presas maiores. O número de espécies de Amphipoda predadores por esses peixes também foi variável. Algumas espécies de Amphipoda foram encontradas em uma só espécie de peixe, outras ao contrário são presas comuns a vários peixes; outras ainda foram encontradas eu alta porcentagem numérica nos estômagos. C.jamaicensis, C. striatus e U.canosai consumiram mais espécies de Amphipoda da infauna, P. brasiliensis ingeriu mais espécies da epifauna, enquanto M. furnieri parece não ter preferência por nenhum desses dois grupos de Amphipoda. Espécies de Amphipoda registradas no levantamento bentônico feito na mesma região de captura dos peixes, revelou uma coincidência de várias espécies encontradas no conteúdo estomacal, indicando que os peixes devem capturar pelo menos parte de sua dieta sobre os organismos disponíveis no seu habitat. Muitas das espécies de Amphipoda predadas pelos Sciaenidae podem também ser as presas de peixes Pleuronectiformes da mesma região. Seis espécies de Amphipoda não haviam sido assinaladas em conteúdo estomacal de peixes, enquanto duas espécies já haviam sido encontradas em estômagos de outras espécies de Sciaenidae. A sobreposição alimentar verificada para pares de espécies de peixes a níve1de ordem dos itens alimentares foi confirmada quando da identificação específica do item Amphipoda. / Considerando a reconhecida importância dos Crustáceos para os peixes da família Sciaenidae, decidiu-se estudar a alimentação das espécies: Cynoscion jamaiacensis Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Paralonchurus brasiliensis e Umbrina canosai, em relação aos itens-Crustacea e em especial aos Amphipoda. O material em estudo foi obtido de três cruzeiros do Convênio GEDIP e IOUSP, coletados na Plataforma Continental, entre as latitudes 29º 21\'S (Torres) e 33º 41\'s (Chuí) entre outubro de 1968 e março de 1969. Embora em C.jamaicensis, P.brasiliensis o número de exemp1ares examinados fosse pequeno, foram calculados para a aná1ise do conteúdo estomacal (itens-Crustacea): a freqüência de ocorrência, porcentagem numérica, volume percentual e IRI (índice de re1ativa importância). O número de itens-Crustacea encontrado para as espécies de Sciaenidae foi muito variado. Assim, em M.ancylodon e P.brasiliensis foram encontrados 4 itens, em C.jamaicensis 5, em C.striatus 9, em M.furnieri 13 e em U.canosai 15. O IRI forneceu os itens mais importantes para cada espécie como segue: Amphipoda para C.jamaicensia, P.braisiliensis e U.canosai; Natantia para C.striatus e M.ancylodon e Brachyura para M.furnieri. A análise sobre a variação do regime alimentar com o aumento do tamanho do peixe, revelou que em M.ancylodon, M.furnier, P.brasiliensis e U.canosai, os peixes maiores vão adicionando outros itens, ampliando o seu espectro alimentar. À medida que o peixe cresce, diminui a freqüência de ingestão de presas maiores e aumenta a de presas maiores. O número de espécies de Amphipoda predadores por esses peixes também foi variável. Algumas espécies de Amphipoda foram encontradas em uma só espécie de peixe, outras ao contrário são presas comuns a vários peixes; outras ainda foram encontradas eu alta porcentagem numérica nos estômagos. C.jamaicensis, C. striatus e U.canosai consumiram mais espécies de Amphipoda da infauna, P. brasiliensis ingeriu mais espécies da epifauna, enquanto M. furnieri parece não ter preferência por nenhum desses dois grupos de Amphipoda. Espécies de Amphipoda registradas no levantamento bentônico feito na mesma região de captura dos peixes, revelou uma coincidência de várias espécies encontradas no conteúdo estomacal, indicando que os peixes devem capturar pelo menos parte de sua dieta sobre os organismos disponíveis no seu habitat. Muitas das espécies de Amphipoda predadas pelos Sciaenidae podem também ser as presas de peixes Pleuronectiformes da mesma região. Seis espécies de Amphipoda não haviam sido assinaladas em conteúdo estomacal de peixes, enquanto duas espécies já haviam sido encontradas em estômagos de outras espécies de Sciaenidae. A sobreposição alimentar verificada para pares de espécies de peixes a níve1de ordem dos itens alimentares foi confirmada quando da identificação específica do item Amphipoda. ABSTRACT Crustacea are considered one of the most important items of the Benithos feeding fish Sciaenidae. The present study analyses the Crustacea and more particular1y the Amphipoda found in the stomach of the Sciaenidae: Cynoscion jamaicensis, Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Parolonchurus brasiliensis and Umbrina canosai. The material was collected on the continental shelf in Southern Brazil (Lat. 29º 21\'S and 33º 41\'S) from October 1968 through March 1969. Although samples with only few specimens of C.jamaicensis and P.brasiliensis were obtained, the results gave important information about the feeding habits of the fish. The number of Crustacea itens varied from one fish species to another. The indice IRI (Pinkas et al., 1971) calculated for the different crustacean itens indicated Amphipoda for C.jamaicensis, P.brasiliensis and U.carosai ; Natantia for C.striatus and M.ancylodon and finally Brachyura for M.furnieri as the most important item. For M.ancylodon, M.furnieri, P.brasilinsis and U.canosai, it was observed that their food spectrun enlarges as their length increases. Each fish species consumed a diverse number of Amphipoda species, same of them being exclusive for only one fish, while others are common prey of several species. Few planktonic Amphipoda especies were found in the contents examined. Bentonic, epifaunal and infauna1 Amphipoda were comsumed in different percentages. Many Amphipoda found in the benthoc sampling of the fishing area were reacorded in the stomach contents. Same of the species preyed by Sciaenidae are the same as those recorded by a previous study (wakabara et al., 1982) on the feeding habits of P1euronectiformes from the same region. The food over1apping among pairs of fishes previous1y observed by Vazzo1er (1975) was confirmed by the specific identification of the preys although this preying is done in different percentages, in terms of composition.

The coastal (terrestrial) and benthic environments along the southeast Florida continental shelf show a unique biophysical succession of marine features from a highly urbanized, developed coastal region in the north (i.e. northern Miami-Dade County) to a protective marine sanctuary in the southeast (i.e. Florida Keys National Marine Sanctuary). However, the establishment of a standard bio-geomorphological classification scheme for this area of coastal and benthic environments is lacking. The purpose of this study was to test the hypothesis and answer the research question of whether new parameters of integrating geomorphological components with dominant biological covers could be developed and applied across multiple remote sensing platforms for an innovative way to identify, interpret, and classify diverse coastal and benthic environments along the southeast Florida continental shelf. An ordered, manageable hierarchical classification scheme was developed to incorporate the categories of Physiographic Realm, Morphodynamic Zone, Geoform, Landform, Dominant Surface Sediment, and Dominant Biological Cover. Six different remote sensing platforms (i.e. five multi-spectral satellite image sensors and one high-resolution aerial orthoimagery) were acquired, delineated according to the new classification scheme, and compared to determine optimal formats for classifying the study area. Cognitive digital classification at a nominal scale of 1:6000 proved to be more accurate than autoclassification programs and therefore used to differentiate coastal marine environments based on spectral reflectance characteristics, such as color, tone, saturation, pattern, and texture of the seafloor topology. In addition, attribute tables were created in conjugation with interpretations to quantify and compare the spatial relationships between classificatory units. IKONOS-2 satellite imagery was determined to be the optimal platform for applying the hierarchical classification scheme. However, each remote sensing platform had beneficial properties depending on research goals, logistical restrictions, and financial support. This study concluded that a new hierarchical comprehensive classification scheme for identifying coastal marine environments along the southeast Florida continental shelf could be achieved by integrating geomorphological features with biological coverages. This newly developed scheme, which can be applied across multiple remote sensing platforms with GIS software, establishes an innovative classification protocol to be used in future research studies. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Considerando a reconhecida importância dos Crustáceos para os peixes da família Sciaenidae, decidiu-se estudar a alimentação das espécies: Cynoscion jamaiacensis Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Paralonchurus brasiliensis e Umbrina canosai, em relação aos itens-Crustacea e em especial aos Amphipoda. O material em estudo foi obtido de três cruzeiros do Convênio GEDIP e IOUSP, coletados na Plataforma Continental, entre as latitudes 29º 21\'S (Torres) e 33º 41\'s (Chuí) entre outubro de 1968 e março de 1969. Embora em C.jamaicensis, P.brasiliensis o número de exemp1ares examinados fosse pequeno, foram calculados para a aná1ise do conteúdo estomacal (itens-Crustacea): a freqüência de ocorrência, porcentagem numérica, volume percentual e IRI (índice de re1ativa importância). O número de itens-Crustacea encontrado para as espécies de Sciaenidae foi muito variado. Assim, em M.ancylodon e P.brasiliensis foram encontrados 4 itens, em C.jamaicensis 5, em C.striatus 9, em M.furnieri 13 e em U.canosai 15. O IRI forneceu os itens mais importantes para cada espécie como segue: Amphipoda para C.jamaicensia, P.braisiliensis e U.canosai; Natantia para C.striatus e M.ancylodon e Brachyura para M.furnieri. A análise sobre a variação do regime alimentar com o aumento do tamanho do peixe, revelou que em M.ancylodon, M.furnier, P.brasiliensis e U.canosai, os peixes maiores vão adicionando outros itens, ampliando o seu espectro alimentar. À medida que o peixe cresce, diminui a freqüência de ingestão de presas maiores e aumenta a de presas maiores. O número de espécies de Amphipoda predadores por esses peixes também foi variável. Algumas espécies de Amphipoda foram encontradas em uma só espécie de peixe, outras ao contrário são presas comuns a vários peixes; outras ainda foram encontradas eu alta porcentagem numérica nos estômagos. C.jamaicensis, C. striatus e U.canosai consumiram mais espécies de Amphipoda da infauna, P. brasiliensis ingeriu mais espécies da epifauna, enquanto M. furnieri parece não ter preferência por nenhum desses dois grupos de Amphipoda. Espécies de Amphipoda registradas no levantamento bentônico feito na mesma região de captura dos peixes, revelou uma coincidência de várias espécies encontradas no conteúdo estomacal, indicando que os peixes devem capturar pelo menos parte de sua dieta sobre os organismos disponíveis no seu habitat. Muitas das espécies de Amphipoda predadas pelos Sciaenidae podem também ser as presas de peixes Pleuronectiformes da mesma região. Seis espécies de Amphipoda não haviam sido assinaladas em conteúdo estomacal de peixes, enquanto duas espécies já haviam sido encontradas em estômagos de outras espécies de Sciaenidae. A sobreposição alimentar verificada para pares de espécies de peixes a níve1de ordem dos itens alimentares foi confirmada quando da identificação específica do item Amphipoda. / Considerando a reconhecida importância dos Crustáceos para os peixes da família Sciaenidae, decidiu-se estudar a alimentação das espécies: Cynoscion jamaiacensis Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Paralonchurus brasiliensis e Umbrina canosai, em relação aos itens-Crustacea e em especial aos Amphipoda. O material em estudo foi obtido de três cruzeiros do Convênio GEDIP e IOUSP, coletados na Plataforma Continental, entre as latitudes 29º 21\'S (Torres) e 33º 41\'s (Chuí) entre outubro de 1968 e março de 1969. Embora em C.jamaicensis, P.brasiliensis o número de exemp1ares examinados fosse pequeno, foram calculados para a aná1ise do conteúdo estomacal (itens-Crustacea): a freqüência de ocorrência, porcentagem numérica, volume percentual e IRI (índice de re1ativa importância). O número de itens-Crustacea encontrado para as espécies de Sciaenidae foi muito variado. Assim, em M.ancylodon e P.brasiliensis foram encontrados 4 itens, em C.jamaicensis 5, em C.striatus 9, em M.furnieri 13 e em U.canosai 15. O IRI forneceu os itens mais importantes para cada espécie como segue: Amphipoda para C.jamaicensia, P.braisiliensis e U.canosai; Natantia para C.striatus e M.ancylodon e Brachyura para M.furnieri. A análise sobre a variação do regime alimentar com o aumento do tamanho do peixe, revelou que em M.ancylodon, M.furnier, P.brasiliensis e U.canosai, os peixes maiores vão adicionando outros itens, ampliando o seu espectro alimentar. À medida que o peixe cresce, diminui a freqüência de ingestão de presas maiores e aumenta a de presas maiores. O número de espécies de Amphipoda predadores por esses peixes também foi variável. Algumas espécies de Amphipoda foram encontradas em uma só espécie de peixe, outras ao contrário são presas comuns a vários peixes; outras ainda foram encontradas eu alta porcentagem numérica nos estômagos. C.jamaicensis, C. striatus e U.canosai consumiram mais espécies de Amphipoda da infauna, P. brasiliensis ingeriu mais espécies da epifauna, enquanto M. furnieri parece não ter preferência por nenhum desses dois grupos de Amphipoda. Espécies de Amphipoda registradas no levantamento bentônico feito na mesma região de captura dos peixes, revelou uma coincidência de várias espécies encontradas no conteúdo estomacal, indicando que os peixes devem capturar pelo menos parte de sua dieta sobre os organismos disponíveis no seu habitat. Muitas das espécies de Amphipoda predadas pelos Sciaenidae podem também ser as presas de peixes Pleuronectiformes da mesma região. Seis espécies de Amphipoda não haviam sido assinaladas em conteúdo estomacal de peixes, enquanto duas espécies já haviam sido encontradas em estômagos de outras espécies de Sciaenidae. A sobreposição alimentar verificada para pares de espécies de peixes a níve1de ordem dos itens alimentares foi confirmada quando da identificação específica do item Amphipoda. ABSTRACT Crustacea are considered one of the most important items of the Benithos feeding fish Sciaenidae. The present study analyses the Crustacea and more particular1y the Amphipoda found in the stomach of the Sciaenidae: Cynoscion jamaicensis, Cynoscion striatus, Macrodon ancylodon, Micropogonias furnieri, Parolonchurus brasiliensis and Umbrina canosai. The material was collected on the continental shelf in Southern Brazil (Lat. 29º 21\'S and 33º 41\'S) from October 1968 through March 1969. Although samples with only few specimens of C.jamaicensis and P.brasiliensis were obtained, the results gave important information about the feeding habits of the fish. The number of Crustacea itens varied from one fish species to another. The indice IRI (Pinkas et al., 1971) calculated for the different crustacean itens indicated Amphipoda for C.jamaicensis, P.brasiliensis and U.carosai ; Natantia for C.striatus and M.ancylodon and finally Brachyura for M.furnieri as the most important item. For M.ancylodon, M.furnieri, P.brasilinsis and U.canosai, it was observed that their food spectrun enlarges as their length increases. Each fish species consumed a diverse number of Amphipoda species, same of them being exclusive for only one fish, while others are common prey of several species. Few planktonic Amphipoda especies were found in the contents examined. Bentonic, epifaunal and infauna1 Amphipoda were comsumed in different percentages. Many Amphipoda found in the benthoc sampling of the fishing area were reacorded in the stomach contents. Same of the species preyed by Sciaenidae are the same as those recorded by a previous study (wakabara et al., 1982) on the feeding habits of P1euronectiformes from the same region. The food over1apping among pairs of fishes previous1y observed by Vazzo1er (1975) was confirmed by the specific identification of the preys although this preying is done in different percentages, in terms of composition.

Virtually all marine conservation planning and management models in place or proposed have in common the need for improved scientific rigour in identifying and characterising the marine habitats encompassed. An emerging central theme in the last few years has been the concept of representativeness, or representative systems of Marine Protected Areas (MPAs). The habitat classification and mapping needed to incorporate considerations of representativeness into MPA planning must logically be carried out at the same scale at which management occurs. Management of highly protected areas occurs almost exclusively at local scales or finer, independent of the reservation model or philosophy employed. Moreton Bay, on Australia’s east coast, was selected for studies at the local scale to map and classify macrobenthic habitats. In a site scale (1 km) trial for the major habitat classification study, remote underwater videography was used to map and characterise an unusual assemblage of epibenthic invertebrates on soft sediments. The assemblage included congregations of the comatulid crinoid Zygometra cf. Z. microdiscus (Bell) at densities up to 0.88 individuals.m-2, comparable to those found in coral reef habitats. There was no correlation between the distribution of this species and commonly used abiotic surrogates depth (6 – 18 m), sediment composition and residual current. This site scale trial is the first quantitative assessment of crinoid density and distribution in shallow water soft-sediment environments. The high densities found are significant in terms of the generally accepted picture of shallow-water crinoids as essentially reefal fauna. The findings highlight the conservation benefits of an inclusive approach to marine habitat survey and mapping. Assemblages such as the one described, although they may be of scientific and ecological significance, would have been overlooked by common approaches to marine conservation planning which emphasise highly productive or aesthetically appealing habitats. Most habitat mapping studies rely solely or in part on abiotic surrogates for patterns of biodiversity. The utility of abiotic variables in predicting biological distributions at the local scale (10 km) was tested. Habitat classifications of the same set of 41 sites based on 6 abiotic variables and abundances of 89 taxa and bioturbation indicators were compared using correlation, regression and ordination analyses. The concepts of false homogeneity and false heterogeneity were defined to describe types of errors associated with using abiotic surrogates to construct habitat maps. The best prediction by abiotic surrogates explained less than 30% of the pattern of biological similarity. Errors of false homogeneity were between 20 and 62%, depending on the methods of estimation. Predictive capability of abiotic surrogates at the taxon level was poor, with only 6% of taxon / surrogate correlations significant. These results have implications for the widespread use of abiotic surrogates in marine habitat mapping to plan for, or assess, representation in Marine Protected Areas. Abiotic factors did not discriminate sufficiently between different soft bottom communities to be a reliable basis for mapping. Habitat mapping for the design of Marine Protected Areas is critically affected by the scale of the source information. The relationship between biological similarity of macrobenthos and the distance between sites was investigated at both site and local scales, and for separate biotic groups. There was a significant negative correlation between similarity and distance, in that sites further apart were less similar than sites close together. The relationship, although significant, was quite weak at the site scale. Rank correlograms showed that similarity was high at scales of 10 km or less, and declined markedly with increasing distance. There was evidence of patchiness in the distributions of some biotic groups, especially seagrass and anthozoans, at scales less than 16 km. In other biotic groups there was an essentially monotonic decline in similarity with distance. The spatial agglomeration approach to habitat mapping was valid in the study area. Site spacing of less than 10 km was necessary to capture important components of biological similarity. Site spacing of less than 2.5 km did not appear to be warranted. Macrobenthic habitat types were classified and mapped at 78 sites spaced 5 km apart. The area mapped was about 2,400 km2 and extended from estuarine shallow subtidal waters to offshore areas to the 50 m isobath. Nine habitat types were recognised, with only one on hard substrate. The habitat mapping characterised several habitat types not previously described in the area and located deepwater algal and soft coral reefs not previously reported. Seagrass beds were encountered in several locations where their occurrence was either unknown or had not previously been quantified. The representation of the derived habitat types within an existing marine protected area was assessed. Only two habitat types were represented in highly protected zones, with less than 3% of each included The study represents the most spatially comprehensive survey of epibenthos undertaken in Moreton Bay, with over 40,000 m2 surveyed. Derived habitat maps provide a robust basis for inclusion of representative examples of all habitat types in marine protected area planning in and adjacent to Moreton Bay. The utility of video data to conduct a low-cost habitat survey over a comparatively large area was also demonstrated. The method used has potentially wide application for the survey and design of marine protected areas.

Studies were conducted to broadly describe and understand the sediment benthos of a shallow-water coastal area (Aramoana Beach - Heyward Point - Blueskin Bay) near the entrance to Otago Harbour, a system largely representative for southeastern New Zealand. Benthic assemblages were examined in relation to gradients of wave exposure and disturbance, sediment type and bathymetry, and dredge-spoil disposal. Sediment and macrofaunal surveys in autumn and spring 2003 found little change in sediment texture gradients from historical studies and a lack of vertical stratification. Macrobenthic samples from spring produced significantly higher abundances of three numerically dominant phyla (Arthropoda, Annelida, and Mollusca) and higher taxon richness compared to autumn. Within water depths of 6-30 m, abundance, richness, and diversity increased with depth. Multivariate analyses identified similar assemblages among deeper sites, despite sediment textural differences, whereas distinct assemblages were found in the shallow portions of the three areas. Meiofaunal abundance patterns did not reflect those of macrofauna, possibly indicating greater vertical penetration of sediments in these hydrodynamic environments. Several new kinorhynch taxa were found. In a field manipulation, part of the Aramoana dredge-spoil dumpground was protected from spoil disposal for an extended period followed by experimental dumping of sandy and muddy spoil. Macrofaunal samples were collected before dumping and at nine sites < 119 d after disposal. Water velocities at the sediment-water interface were compared to a local sediment disturbance model. Dumpground samples were depauperate in individuals and taxa compared to an area protected from dumping for > 180 d. A drop in abundance and a dissimilar community coincided with muddy spoil, but fine sediments were dispersed within 26 d and macrofaunal assemblages recovered to the pre-existing state. Sandy spoil, while not altering native sediment textures, had a more prolonged impact due to transplantation of macrofauna from the dredged area that persisted for < 41 d after disposal. Side-scan sonar mapping indicated that the disposal footprint model used approximated the extent of sandy spoil impacts well, while local conditions spread muddy sediments beyond the initial impact site. A novel sediment profile imaging device was constructed that has many advantages over existing devices for spoil mound studies and habitat mapping: it is smaller, can be manually deployed from small boats, is cheaper, and can be modified to work in almost any soft sediment. Studies of one dominant taxon, the gastropod Zethalia zelandica, showed it was better able to survive sand burial than mud burial, did not vary in overall activity through a range of 5-14� C, and contributed a large proportion of biomass of its community. The spoil disposal strategy used does not appear as environmentally neutral as originally thought. Only muds are effectively dispersed whereas coarser sediments accumulate, affecting physical and biological benthic processes of a wider area. Two mitigation strategies were evaluated using a heuristic model. Reducing the disposal area and spreading mud disposal events over a longer time span may be an effective interim strategy. Overall, the studies will help guide management of the area.

Thesis (Ph.D.)--McMaster University, 2006. / Supervisor: Patricia Chow-Fraser. Includes bibliographical references.

<p>The aim of this thesis was to identify general structuring mechanisms in benthic food webs within the framework of ecological stoichiometry theory. Ecological stoichiometry is defined as the balance of multiple chemical substances in ecological interactions and explicitly considers the combined dynamics of key elements such as carbon (C), nitrogen (N) and phosphorus (P). Ecological stoichiometry theory was developed for pelagic environments, thus it must be tested whether the same mechanisms are applicable to benthic environments. </p><p>In this thesis, ecological stoichiometry theory was used as a framework to investigate nutrient pathways in benthic littoral ecosystems. I conducted one invertebrate field sampling and six experiments. In the experiments, factors such as grazing, light, nutrients and fish presence were manipulated.</p><p>The results showed that stoichiometric variability in consumers could mostly be explained by taxa. However, there was some stoichiometric variability due to sampling season, site, and nutrient enrichment. </p><p>Grazing mostly increased periphyton N and P content, although nutrient recycling effects were dependent on grazer stoichiometry. Grazing changed benthic algal community composition by increasing the proportion of grazing resistant algae species. Additionally, grazing decreased algal diversity, especially under nutrient poor conditions. The manipulation of fish presence revealed that fish affected primary producer biomass and stoichiometry through nutrient recycling. </p><p>The manipulation of abiotic factors, such as light and nutrient addition could affect periphyton nutrient content, biomass and benthic algal chlorophyll a content. The separate addition of N or P led to an increase of the added nutrient in the periphyton. Increased light intensities led to a decreased cellular chlorophyll a content and increased C:nutrient ratios. </p><p>This thesis arrives at the conclusion that periphyton-grazer-predator interactions in the benthic are bound by stoichiometric constraints. Nutrient recycling by benthic invertebrates and fish are important mechanism in benthic littoral ecosystems.</p>

AbstractMacrobenthic population dynamics in the Indiana waters of Lake Michigan were examined from June to October, 1970. Species composition and density were compared within and between 5, 10, 15, and 18 m stations and transects at Michigan City, Burns Ditch, and Gary. The major groups of organisms sampled for all stations combined in Indiana waters, in order of abundance and percent composition, were: oligochaetes, the amphipod Pontoporeia affinis, sphaeriids, and chironomids. The Michigan City transect had the greatest abundance and percent composition of chironomids and sphaeriids. The Burns Ditch transect had the greatest abundance and percent composition of oligochaetes. The Gary transect had the greatest abundance and percent composition of P. affinis. A classification of the transects according to trophic values, derived from the proportion of indicator chironomids, revealed Michigan City and Burns Ditch transects as in the eutrophic range while the Gary transect was in the mesotrophic range.Ball State UniversityMuncie, IN 47306

In streams, wood provides protection, food and substrate for benthic macroinvertebrates, which leads a higher density and diversity of the benthic fauna compared to streams without wood. To examine wood and its effect on drift of macroinvertebrates an experiment was done in 18 sections of six semi-natural streams where fine woody debris (Salix sp.) was added to half of the sections (1-2 per stream). The purpose was to investigate possible differences in density and diversity of macroinvertebrates aswell as to investigate if there was any effect of location, upstream or downstream, in the streams. The results showed no significant effect of woody debris on total drift. The lack of an effect is probably related to the high abundance of predators (fish, brown trout) and the time of the day when the samples were taken. There was a significant effect of time on total drift; with more drift in September than in October. An effect of time was also found for the taxon Diptera (Chironomidae not included), with drift decreasing with temperature over the season. / Ved i ett vattendrag ger skydd, föda och substrat åt bentiska makroevertebrater, vilket leder till en högre täthet och diversitet av makroevertebrater än i vattendrag utan ved. För att undersöka vedens inverkan på makroevertebraternas drift utfördes ett experiment i sammanlagt 18 inhägnader i semi-naturliga bäckar där hälften av inhägnaderna behandlades med fin ved (Salix sp.). Syftet var att undersöka eventuella skillnader i täthet och diversitet av makroevertebrater samt om det fanns en skillnad i läge, uppströms och nedströms i bäckarna. Resultatet visade ingen signifikant effekt av ved med avseende på den totala driften. Det fanns heller ingen signifikant effekt av ved på tätheten i enskilda på ved än utan. De bakomliggande faktorerna till varför ingen signifikant effekt av ved visades är troligtvis den höga tätheten av predatorer (öring) och tidpunkten då proverna togs. Det fanns dock en signifikant effekt av tid gällande den totala driften, i september var det mer drift än i oktober. Det fanns även en signifikant effekt av tiden på Diptera (alla Diptera taxa förutom Chironomidae). Detta tros vara på grund av den sjunkande temperaturen mellan månaderna.

published_or_final_version / Zoology / Master / Master of Philosophy