Thesis (M.S.)--Miami University, Dept. of Zoology, 2009. / Title from first page of PDF document. Includes bibliographical references (p. 17-21).

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Bio-optical variability of surface waters in Northeastern Gulf of Mexico (NEGOM) was examined using satellite and in situ data. Relatively high chlorophyll-a concentration (chl>=1 mg m-3) and high colored dissolved organic mater (ag443>=0.1 m-1) were generally observed inshore, near major river mouths, and in plumes of Mississippi River water that extended offshore during the three consecutive summer seasons (1998, 1999, and 2000). River discharge dominated chlorophyll-a concentration variability inshore, particularly near major river mouths. Strong interannual variability in chlorophyll-a concentration was observed inshore from Escambia to Tampa Bay region during the winter to spring transition, which was different in 1998 compared to the winter to spring transition in 1999 and 2000. This was related to higher fresh water discharge during the 1997-1998 El Niño-Southern Oscillation event as well as strong upwelling in spring 1998. The Mississippi plume extended >500 km southeast of the Mississippi delta and up to the Florida Keys was observed for the periods extending over 14 weeks between May and September every year of the study. In general, ag443 covaried linearly and inversely with salinity inshore during spring and fall, indicating conservative mixing. The NEGOM salinity-ag443 relationship of fall 1998, i.e., Salinity=36.59-29.86*ag443 (n=8771, r2=0.86; 0.01<=ag443<=0.52, 16 <=S<=36), served as the best predictor of NEGOM salinity based on in situ ag443 observations for spring and fall seasons from all years (<3% mean percentage errors; corresponding to <1.03 psu). This may help estimate salinity from satellite ocean color data, but further testing using data from multiple years is needed to improve such relationship. While river discharge was an important source of colored dissolved organic matter (CDOM), phytoplankton blooms also contributed to CDOM formation in the NEGOM. Using a pigment index of phytoplankton taxonomic groups, the variability in biomass proportion of microphytoplankton explained up to 76% of the variability of the average of normalized phytoplankton absorption coefficients (545, 625, and 673 nm). The clorophyll-specific absorption coefficient, a*ph(440), varies by a factor of 7 (0.02-0.15 m2mg-1). Particle size and pigment composition played important roles in determining a*ph(440) variability. This must be accounted for in chlorophyll-a concentration algorithms based on aph.

<p>This study seeks to investigate the dynamics of dead plant carbon over fifty years of old-field forest development at the Calhoun Long Term Soil-Ecosystem Experiment (LTSE) in South Carolina, USA. Emphasis is on the transition phase of the forest, which is less well studied than the establishment and early thinning phase or the steady state phase. At the Calhoun LTSE, the biogeochemical and ecosystem changes associated with old field forest development have been documented through repeated tree measurements and deep soil sampling, and archiving of those soils, which now allow us to examine changes that have occurred over the course of forest development to date.</p><p> In this dissertation, I first quantify the accumulation of woody detritus on the surface of the soil as well as in the soil profile over fifty years, and estimate the mean residence times of that detrital carbon storage. Knowing that large accumulations of C-rich organic matter have piled onto the soil surface, the latter chapters of my dissertation investigate how that forest-derived organic carbon has been incorporated into mineral soils. I do this first by examining concentrations of dissolved organic carbon and other constituents in soil solutions throughout the ecosystem profile and then by quantifying changes in solid state soil carbon quantity and quality, both in bulk soils and in soil fractions that are thought to have different C sources, stabilities, and residence times. To conclude this dissertation, I present the 50-year C budget of the Calhoun LTSE, including live and dead plant carbon pools, to quantify the increasing importance of detrital C to the ecosystem over time.</p><p>This exceptional long term soil ecosystem study shows that 50 years of pine forest development on a former cotton field have not increased mineral soil carbon storage. Tree biomass accumulated rapidly from the time seedlings were planted through the establishment phase, followed by accumulations of leaf litter and woody detritus. Large quantities of dissolved organic carbon leached from the O-horizons into mineral soils. The response of mineral soil C stocks to this flood of C inputs varied by depth. The most surficial soil (0-7.5cm), saw a large, but lagged, increase in soil organic carbon (SOC) concentration over time, an accumulation almost entirely due to an increase of light fraction, particulate organic matter. Yet in the deepest soils sampled, soil carbon content declined over time, and in fact the loss of SOC in deep soils was sufficient to negate all of the C gains in shallower soils. This deep soil organic matter was apparently lost from a poorly understood, exchangeable pool of SOM. This loss of deep SOC, and lack of change in total SOC, flies in the face of the general understanding of field to forest conversions resulting in net increases in soil carbon. These long term observations provide evidence that the loss of soil carbon was due to priming of SOM decomposition by enhanced transpiration, C inputs, and N demand by the growing trees. These results suggest that large accumulations of carbon aboveground do not guarantee similar changes below.</p> / Dissertation

Made available in DSpace on 2014-06-11T19:22:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-03-28Bitstream added on 2014-06-13T20:10:13Z : No. of bitstreams: 1 rocha_fc_me_sjrp.pdf: 876174 bytes, checksum: 186df0b1db60e6a2c675e44fa547a313 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As plantas aquáticas são importantes componentes dos ecossistemas lóticos e lênticos. Como conseqüências de transformações ambientais, algumas podem se tornar dominantes, sendo que as plantas aquáticas do gênero Typha são bem sucedidas em brejos e alagados, podendo também ser encontradas em córregos e ribeirões. O presente estudo foi realizado com o objetivo de avaliar a influência de T. angustifolia para a ictiofauna em riachos. Foram estudados seis riachos na bacia do Alto Rio Turvo, Estado de São Paulo, desprovidos de vegetação ripária nativa, mas com abundância de T. angustifolia no hábitat interno e ripário. Por meio da análise de mapas de cobertura do solo, observou-se que T. angustifolia está amplamente distribuída nas zonas ripárias ao longo das drenagens estudadas. Os riachos com as maiores proporções de T. angustifolia nas zonas ripárias também apresentaram a menor riqueza de espécies e abundância de peixes. A baixa semelhança na composição e estrutura da ictiofauna entre os períodos sazonais, a grande quantidade de espécies tolerantes e o fato de que a maioria das espécies foi ou acessória ou acidental, sugerem uma dinâmica populacional do tipo “fonte e dreno” nos riachos estudados. Desta forma, os trechos livres de Typha atuam como “fontes”, provendo indivíduos que, por migração, podem ocasionalmente explorar os trechos com elevada abundância de T. angustifolia. Nestes trechos, que teriam o papel funcional de “drenos”, as condições ambientais são pouco apropriadas para a manutenção de uma comunidade diversa e residente de peixes. Os indivíduos dos trechos “fonte” à montante e à jusante que para ali migram se beneficiam de uma oferta relativamente constante de alimento, embora pouco variada (principalmente larvas aquáticas de Chironomidae e detritos), e abrigos (raízes de Typha). / Aquatic plants are a major component of lenthic and lotic ecosystems. As consequences of environmental changes, some species may became dominant, being that aquatic plants of the genus Typha are a well successful group of weeds in swamps and flooded areas, but also found in headwaters and large streams. This study was made with the aim to investigate the influences of T. angustifolia on the fish assemblages in streams. A total of six streams in the Upper Rio Turvo basin, São Paulo state, without riparian vegetation but with abundance of T. angustifolia in the instream and riparian habitat, were studied. By analyzing soil coverage maps, it was registered that T. angustifolia was widespread in the riparian zones along studied drainages. Streams with the largest proportions of T. angustifolia along riparian zones were also those with lowest fish species richness and abundance. Low similarity in the composition and structure of fish fauna between seasonal periods, together with a large number of tolerant species, and the fact that most species are accessory or accidental, suggest a “source and sink” population dynamic in the studied streams. Thus, free Typha stretches play as a “source” habitat, providing individuals that, by migration, may occasionally explore stretches with large abundance of T. angustifolia. In these stretches, which play a “sink” functional role, environmental conditions are often little appropriated to the maintenance of a diverse and resident fish assemblage. The migrating individuals from up and down “source” stretches are benefited by relatively constant food offer, but few diverse (mostly aquatic larvae of Chironomidae and detritus), and shelters (Typha roots).

Orientador: Lilian Casatti / Banca: Katharina Eichbaum Esteves / Banca: Denise de Cerqueira Rossa Feres / Resumo: As plantas aquáticas são importantes componentes dos ecossistemas lóticos e lênticos. Como conseqüências de transformações ambientais, algumas podem se tornar dominantes, sendo que as plantas aquáticas do gênero Typha são bem sucedidas em brejos e alagados, podendo também ser encontradas em córregos e ribeirões. O presente estudo foi realizado com o objetivo de avaliar a influência de T. angustifolia para a ictiofauna em riachos. Foram estudados seis riachos na bacia do Alto Rio Turvo, Estado de São Paulo, desprovidos de vegetação ripária nativa, mas com abundância de T. angustifolia no hábitat interno e ripário. Por meio da análise de mapas de cobertura do solo, observou-se que T. angustifolia está amplamente distribuída nas zonas ripárias ao longo das drenagens estudadas. Os riachos com as maiores proporções de T. angustifolia nas zonas ripárias também apresentaram a menor riqueza de espécies e abundância de peixes. A baixa semelhança na composição e estrutura da ictiofauna entre os períodos sazonais, a grande quantidade de espécies tolerantes e o fato de que a maioria das espécies foi ou acessória ou acidental, sugerem uma dinâmica populacional do tipo "fonte e dreno" nos riachos estudados. Desta forma, os trechos livres de Typha atuam como "fontes", provendo indivíduos que, por migração, podem ocasionalmente explorar os trechos com elevada abundância de T. angustifolia. Nestes trechos, que teriam o papel funcional de "drenos", as condições ambientais são pouco apropriadas para a manutenção de uma comunidade diversa e residente de peixes. Os indivíduos dos trechos "fonte" à montante e à jusante que para ali migram se beneficiam de uma oferta relativamente constante de alimento, embora pouco variada (principalmente larvas aquáticas de Chironomidae e detritos), e abrigos (raízes de Typha). / Abstract: Aquatic plants are a major component of lenthic and lotic ecosystems. As consequences of environmental changes, some species may became dominant, being that aquatic plants of the genus Typha are a well successful group of weeds in swamps and flooded areas, but also found in headwaters and large streams. This study was made with the aim to investigate the influences of T. angustifolia on the fish assemblages in streams. A total of six streams in the Upper Rio Turvo basin, São Paulo state, without riparian vegetation but with abundance of T. angustifolia in the instream and riparian habitat, were studied. By analyzing soil coverage maps, it was registered that T. angustifolia was widespread in the riparian zones along studied drainages. Streams with the largest proportions of T. angustifolia along riparian zones were also those with lowest fish species richness and abundance. Low similarity in the composition and structure of fish fauna between seasonal periods, together with a large number of tolerant species, and the fact that most species are accessory or accidental, suggest a "source and sink" population dynamic in the studied streams. Thus, free Typha stretches play as a "source" habitat, providing individuals that, by migration, may occasionally explore stretches with large abundance of T. angustifolia. In these stretches, which play a "sink" functional role, environmental conditions are often little appropriated to the maintenance of a diverse and resident fish assemblage. The migrating individuals from up and down "source" stretches are benefited by relatively constant food offer, but few diverse (mostly aquatic larvae of Chironomidae and detritus), and shelters (Typha roots). / Mestre

This thesis paper explores some of the cultural phenomena that influence my conceptual framework and describes the logic behind the formal decision-making that defines my work. Beginning with a description of the nature of the materials and environments I appropriate, this thesis aims to deconstruct the layered system of binaries that build the logic behind my work. The concerns in my work circulate around domestic consumption and the objects detritus, a term coined in the paper, that are produced as a result. However, rather than allow the objects detritus to remain cast-aways of a culture of excess, my work reincorporates these objects as materials in conglomerate sculptures. This thesis depicts the complex of ideas that help delegate how these conglomerate works come into being.

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It is now accepted that the last British-Irish Ice Sheet (BIIS) was highly dynamic and drained by numerous fast flowing ice streams. This dynamic nature combined with its maritime location made the BIIS sensitive to the rapid climate change that characterised the Last Glacial Interglacial Transition. Gaining an understanding of the behaviour of the BIIS at this time is important to explore the nature of forcing between ice sheets and climate. This thesis presents new chronological data relating to the deglaciation of the northwest sector of the BIIS (NW-BIIS) from onshore dating of moraines using cosmogenic exposure dating. This improved chronological framework is supported by offshore data in the form of a newly constructed Ice Rafted Detritus (IRD) record from the offshore sediment core MD95-2007. These data suggest that deglaciation commenced sometime after 18 ka and that the NW-BIIS was located close to the present day shoreline by 16 ka. Further provenance analysis of the IRD using U-Pb dating of detrital minerals demonstrates that during the Last Glacial-Interglacial Transition MD95-2007 was being supplied distal IRD from a source(s) to the west. The absence of diagnostic Scottish material suggests that after retreat to the coastline at 16 ka calving margins were not re-established during Greenland Interstadial 1. By combining these results with existing data relating to the deglaciation of the NW-BIIS it is possible to summarise the deglaciation history of the NW-BIIS from the continental shelf to mountainous source regions and compare this to numerical models of BIIS behaviour during this time. With a better understanding of the chronology of NW-BIIS retreat it is possible to relate the timing of initial deglaciation to possible forcing factors and gain a better understanding of the response of a marine based sector of an ice sheet to rapid climate change.