The objective of this research, conducted between November 1972 and March 1974, was to determine the effects of pollution on the benthic macroinvertebrates of Big Lick Creek. Big Lick Creek, a tributary of the Mississinewa River, is located in east central Indiana and has a permanent length of about 32.2 km. Sewage and industrial waste from the cities of Dunkirk and Hartford City are discharged into this stream.The composition and distribution of macroinvertebrate populations, collected with artificial substrate samplers, were used to determine the extent of stream pollution. Samplers consisted of cylindrical barbecue baskets (28 x 18 cm) filled with 12 concrete spheres 7.5 cm in diameter. Samplers anchored to the stream bed at five locations bracketed major sources of pollution. Chemical and physical determinations were performed to provide a general background for existing biological conditions.Significant chemical and bacteriological conditions encountered in the stream below the sewage effluents of Dunkirk and Hartford City, Indiana were as follow: (1) dissolved oxygen minima of 2 ppm or less; (2) free carbon dioxide maxima in excess of 60 ppm; (3) increases in nutrients such as the various forms of nitrogen and phosphate; and (4) drastic increases in fecal coliform densities.Twenty-six species of benthic macroinvertebrates were collected during the study with marked reductions in the number of species occurring below the effluents of Dunkirk and Hartford City. The average number of species occurring below these polluting effluents was 10.5 as compared to 22 farther downstream in recovery zones.Limiting and selective effects of organic pollution were indicated by the composition of the benthic community at each station. Tubificids, tolerant of excessive organic pollution and associated low dissolved oxygen levels, constituted more than 99 per cent of the benthic communities sampled below Dunkirk and Hartford City. Limnodrilus hoffmeisteri, L. udekemianus, and Tubifex tubifex were the dominant species. A maximum tubificid density of 13,050/m2 was obtained below Hartford City.Samples taken from a recovery zone 14.8 km downstream from Dunkirk and a corresponding zone 10.1 km below Hartford City showed more diverse fauna. In the recovery zone below Dunkirk, species other than tubificid represented 17 per cent of the total number of invertebrates collected. In the analogous zone below Hartford City, these species constituted 89 per cent of the total taken. Chironomid larvae comprised 13 per cent of the total obtained in the recovery zone downstream from Dunkirk, and 89 per cent in the similar zone below Hartford City. Chironomus was the dominant chironomid genus.All species collected, in numbers sufficient to be considered, were members of an indicator association (Gaufin 1958) characteristic of organically enriched environments. According to the pollution classification system of Goodnight and Whitley (1961), Stations 1 through 4 were heavily polluted and Station 5 was in good condition.

Graduation date: 1982

Thesis (M.S.)--University of Hawaii at Manoa, 2006. / Includes bibliographical references (leaves 102-127). / ix, 127 leaves, bound ill., maps 29 cm

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. 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. 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. 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. 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. 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.

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.

This study focuses on the potential of using a single beam echosounder as a tool for recognition and assessment of seafloor vegetation. Seafloor vegetation is plant benthos and occupies a large portion of the shallow coastal bottoms. It plays a key role in maintaining the ecological balance by influencing the marine and terrestrial worlds through interactions with its surrounding environment. Understanding of its existence on the seafloor is essential for environmental managers. / Due to the important role of seafloor vegetation to the environment, a detailed investigation of acoustic methods that can provide effective recognition and assessment of the seafloor vegetation by using available sonar systems is necessary. One of the frequently adopted approaches to the understanding of ocean environment is through the mapping of the seafloor. Available acoustic techniques vary in kinds and are used for different purposes. Because of the wide scope of available techniques and methods which can be employed in the field, this study has limited itself to sonar techniques of normal incidence configuration relative to seafloors in selected regions and for particular marine habitats. For this study, a single beam echosounder operating at two frequencies was employed. Integrated with the echosounder was a synchronized optical system. The synchronization mechanism between the acoustic and optical systems provided capabilities to have very accurate groundtruth recordings for the acoustic data, which were then utilized as a supervised training data set for the recognition of seafloor vegetation. / In this study, results acquired and conclusions made were all based on the comparison against the photographic recordings. The conclusion drawn from this investigation is only as accurate as within the selected habitat types and within very shallow water regions. / In order to complete this study, detailed studies of literature and deliberately designed field experiments were carried out. Acoustic data classified with the help of the synchronized optical system were investigated by several methods. Conventional methods such as statistics and multivariate analyses were examined. Conventional methods for the recognition of the collected data gave some useful results but were found to have limited capabilities. When seeking for more robust methods, an alternative approach, Genetic Programming (GP), was tested on the same data set for comparison. Ultimately, the investigation aims to understand potential methods which can be effective in differentiating the acoustic backscatter signals of the habitats observed and subsequently distinguishing between the habitats involved in this study.

Diss. (sammanfattning). Uppsala : Sveriges lantbruksuniversitet, 2004. / Härtill 5 uppsatser.

Thesis (Ph. D.)--George Mason University, 2004. / Includes bibliographical references (leaves 197-207).

Konstanz, Univ., Diss., 2006.

Thesis (M.M.S.)--Memorial University of Newfoundland, 2001. / Includes bibliographical references (leaves 75-82).