Metabolic and biogeochemical processes in hyporheic zones may depend on inputs of coarse particulate organic matter. Our research focused on how differing quantity and quality of organic matter affects metabolism and nutrient retention in the hyporheic zone of a low-order Appalachian stream. We hypothesized that hyporheic metabolic rates should increase with organic matter additions because the biotic activity is limited by organic matter availability. Four sets (n=4 amendments/set) of plots were established on a tributary of Hugh White Creek, NC. Sediment was extracted and was either supplemented with leaves, wood, or plastic strips, or sediments remained unamended sediments. Following augmentation sediments were reimbedded and approximately three months later sediment was removed from each plot. Aerobic and anaerobic metabolism were measured as the change in O2, and CO2 in recirculating microcosms. At the same time, we monitored other possible terminal electron accepting processes and changes in nutrients. Aerobic metabolism was low in all treatments and respiratory quotients calculated for all treatments indicated that metabolism was dominated by anaerobic processes. Anaerobic and total (combined aerobic and anaerobic) respiration rates were significantly greater (P < 0.05) in plots treated with leaf organic matter compared to controls. Nutrient retention (NO3-N, NH4-N, and DOC) was enhanced in augmented treatments. Measured losses of dissolved organic carbon accounted for 50% total carbon liberated by respiration in amended sediments, whereas in unamended sediments loss of DOC represented only 7% of measured respiration. Augmentation with greater quality organic matter stimulated respiration in hyporheic sediments. Anaerobic processes dominated metabolic rates in both control and amended sediments. Enhanced metabolic rates increased retention of many solutes indicating that energy flow and nutrient dynamics in the subsurface of streams may depend upon the quantity and quality of imported carbon. / Master of Science

No description available.

Im Abstrom von Uranbergbauobjekten (Sachsen, Deutschland) wurden Uran, Radium-226 und Arsen in unterschiedlichen Feuchtgebieten untersucht. Dabei wurden Wasser (vor¬wiegend neutrale bis leicht basische pH-Werte), Sedimente und im Wasser befindlicher Bestandesabfall (CPOM) beprobt. Zur Klärung der Genese der Urangehalte im Sediment erfolgten Untersuchungen an Pb-Isotopen. Sie zeigen u. a., dass das Uran in den obersten Zentimetern des Sediments (organische Auflage) aus der wässrigen Phase und nicht von ca. 300 Millionen Jahre alten Erzteilchen stammt. Für die Verlagerung von Radionukliden und Arsen aus dem Wasserkörper in das Sediment wird ein neuer Weg aufgezeigt. Eine Fixierung dieser Stoffe an Bestandesabfällen (plant litter) ist möglich. Allochthoner Bestandesabfall (Blätter, Früchte, Zweige von Alnus spec. und Quercus spec.) weist nach Kontakt mit kontaminiertem Wasser (ca. 100 - 300 µgU L-1) Urangehalte von 50 - 2.000 µgU g-1 auf. Im Vergleich zu Uran sind Ra-226 und Arsen labiler am Bestandesabfall gebunden. Für die Genese der Gehalte in den subhydrischen Auflagen sind die Herkunft des (autochthonen bzw. allochthonen) Bestandesabfalls und der Abbau eine entscheidende Rolle. Sedimente aus leicht abbaubaren Bestandesabfällen (z.B. Lemna spec., Algen) weisen im Vergleich mit allochthonen Bestandesabfällen (von Bäumen) deutlich geringere Urangehalte auf. Exemplarisch wurde für einen aus allochthonen Bestandesabfällen bestehenden Sedimentkern mittels Cs-137-Bestimmung eine maximale Uranfestlegung von 1 – 2 g m-² a-1 ermittelt. Neben allochthonem Bestandesabfall führen Eisen- und Manganhydroxide, die unmittelbar an den Sickerwasseraustrittstellen ausfallen, bei relativ geringen Arsen- und Radiumkon¬zentrationen im Wasser zu hohen Arsen- bzw. Radiumgehalten im Sediment (As ≤ 5 mg g-1; Ra-226 ≤ 25 Bq g-1). Unter reduktiven Bedingungen werden Ra-226 und Arsen jedoch leicht freigesetzt. Ausgehend von den Untersuchungsergebnissen wird eine mögliche Anordnung für eine naturnahe passive Sickerwasserbehandlung vorgeschlagen.

<p>The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden.</p><p>Wood variables were important predictors of the frequency of debris dams, pool area, the proportion of pools formed by wood, and variation in the bankfull channel width. Pools formed by woody debris were mainly created by damming and had larger surface areas and residual depths than pools formed by other agents. Stream reaches intersecting old-growth forest (with minor influence of forest management) had coarser and longer woody debris pieces, greater amounts of wood, more debris dams, and wood-formed pools compared to streams surrounded by forests influenced by selective logging.</p><p>The influence of past forest management on the quality and quantity of woody debris in streams were analyzed by using dendrochrnological methods. Selective loggings and absence of forest fires after 1831 resulted in lower input rates and a gradual replacement of pine by sruce over time. Residence times in stream channels of woody debris (>10 cm in basal diameter) were long and the oldest dated pieces of pine and spruce were over 300 and 100 years, respectively.</p><p>Dynamics of woody debris were explored by comparing wood volumes and characteristics between stream channels and their riparianforests and between old growth and managed sites. Wood volumes recorded in the stream channels exceeded, but were related to, the volumes found in the riparian forests. Limited input of woody debris by bank cutting and absence of slope processes suggest that recruitment processes of woody debri to stream channels are similar as in riparian forests and slow decay in channels results in greater volumes.</p><p>The retentiveness of organic material in stream channels was examined by using release and capture experiments in multiple reaces during varying discharges using different sizes of leaf mimics. Sixty eight percent of the variation in retention was explained by a multiple regression model including discharge and leaf mimic siz. Between 44 and 80% of the variation in retention among reaches was explained by channel constraint, gravel coverage, and woody debris variables as the most important. Estimates from a partial least squares (PLS) model suggest an increase in mean transport distances by 22 to 53% in managed forest streams compared to old growth conditions and in a low wood scenario, mean transport distances increased by 38 to 99% with larger increases for higher discharges and larger particle sizes.</p><p>To regain more pristine conditions of stream channels, management and restoration are needed to increase the amount of woody debris that recreates lost channel structures and increaes the retention of organic material.</p>

The conversion of native forest to agricultural land has been an on-going issue threatening the health of New Zealand’s freshwater systems. However, despite the fact that this has been occurring since early European settlement, our understanding of the mechanistic relationships between riparian vegetation and stream condition are poorly developed. This research investigated: (i) how forests affect downstream benthic macroinvertebrate communities in pasture and the environmental factors driving community change; (ii) how upstream forest size impacted the rate of change in downstream environmental drivers and associated macroinvertebrate community structure; and (iii) whether the addition of coarse particulate organic matter (a single potential driver of forest community structure) can reset community structure to that of a forested state. Physico-chemical conditions, basal energy resources, and macroinvertebrates were surveyed in several New Zealand headwater streams. At Mount Egmont National Park, 10-12 sites were surveyed across a longitudinal forest-pasture gradient in each of five streams flowing from continuous forest to dairy farmland. My results showed that forests can have marked effects downstream. From the forest edge, water temperatures increased consistently, with a rise of approximately 0.2ºC per 100 m of downstream distance. By contrast, coarse particulate organic matter (CPOM) decreased rapidly downstream of the forest, however, low levels of “forest-derived” CPOM were still present 300m downstream from the forest edge. These environmental changes drove significant shifts in macroinvertebrate community structure. Moreover, pasture communities were markedly different from those in forest, despite being only 100 m from the forest edge. In particular, total macroinvertebrate and EPT richness and densities decreased, and communities shifted from evenly distributed allochthonous-based communities to autochthonous-based communities, highly dominated by molluscs (e.g., Potamopyrgus spp.) Subsequent surveys of 6-8 sites across a longitudinal forest-pasture gradient in each of eleven streams flowing from forest fragments of different sizes into grazed pastures throughout the Canterbury region, indicated that stream temperature increased more rapidly downstream of small- and medium-sized fragments, than larger fragments. A Berger-Parker dominance index also indicated that macroinvertebrates responded principally to water temperature, with communities being more highly dominated by temperature-tolerant molluscs in streams flowing from small-sized forest fragments. Several headwater streams in Canterbury were also highly retentive, with marked CPOM rarely exported beyond 50 m downstream of the forest. Experimental additions of leaf litter to the pasture reaches of the same streams dramatically increased amounts of stored benthic CPOM. Although non-significant, trends indicated that EPT and shredder densities increased at litter addition sites, providing promise that CPOM can function as a mechanism directly enhancing healthy stream communities. My findings support the contention that when the replanting of entire stream reaches is infeasible, the use of riparian management strategies which focus on the planting of intermittent patches along stream banks can potentially improve stream habitat and community health downstream.

The work in this thesis deals with (1) the effects of woody debris on stream channel morphology and retention of organic material, and (2) the dynamics of woody debris and its relation to riparian forest history and composition. The studied stream reaches are situated in mature, productive forests in the boreal zone of Sweden. Wood variables were important predictors of the frequency of debris dams, pool area, the proportion of pools formed by wood, and variation in the bankfull channel width. Pools formed by woody debris were mainly created by damming and had larger surface areas and residual depths than pools formed by other agents. Stream reaches intersecting old-growth forest (with minor influence of forest management) had coarser and longer woody debris pieces, greater amounts of wood, more debris dams, and wood-formed pools compared to streams surrounded by forests influenced by selective logging. The influence of past forest management on the quality and quantity of woody debris in streams were analyzed by using dendrochrnological methods. Selective loggings and absence of forest fires after 1831 resulted in lower input rates and a gradual replacement of pine by sruce over time. Residence times in stream channels of woody debris (&gt;10 cm in basal diameter) were long and the oldest dated pieces of pine and spruce were over 300 and 100 years, respectively. Dynamics of woody debris were explored by comparing wood volumes and characteristics between stream channels and their riparianforests and between old growth and managed sites. Wood volumes recorded in the stream channels exceeded, but were related to, the volumes found in the riparian forests. Limited input of woody debris by bank cutting and absence of slope processes suggest that recruitment processes of woody debri to stream channels are similar as in riparian forests and slow decay in channels results in greater volumes. The retentiveness of organic material in stream channels was examined by using release and capture experiments in multiple reaces during varying discharges using different sizes of leaf mimics. Sixty eight percent of the variation in retention was explained by a multiple regression model including discharge and leaf mimic siz. Between 44 and 80% of the variation in retention among reaches was explained by channel constraint, gravel coverage, and woody debris variables as the most important. Estimates from a partial least squares (PLS) model suggest an increase in mean transport distances by 22 to 53% in managed forest streams compared to old growth conditions and in a low wood scenario, mean transport distances increased by 38 to 99% with larger increases for higher discharges and larger particle sizes. To regain more pristine conditions of stream channels, management and restoration are needed to increase the amount of woody debris that recreates lost channel structures and increaes the retention of organic material.

Im Abstrom von Uranbergbauobjekten (Sachsen, Deutschland) wurden Uran, Radium-226 und Arsen in unterschiedlichen Feuchtgebieten untersucht. Dabei wurden Wasser (vor¬wiegend neutrale bis leicht basische pH-Werte), Sedimente und im Wasser befindlicher Bestandesabfall (CPOM) beprobt. Zur Klärung der Genese der Urangehalte im Sediment erfolgten Untersuchungen an Pb-Isotopen. Sie zeigen u. a., dass das Uran in den obersten Zentimetern des Sediments (organische Auflage) aus der wässrigen Phase und nicht von ca. 300 Millionen Jahre alten Erzteilchen stammt. Für die Verlagerung von Radionukliden und Arsen aus dem Wasserkörper in das Sediment wird ein neuer Weg aufgezeigt. Eine Fixierung dieser Stoffe an Bestandesabfällen (plant litter) ist möglich. Allochthoner Bestandesabfall (Blätter, Früchte, Zweige von Alnus spec. und Quercus spec.) weist nach Kontakt mit kontaminiertem Wasser (ca. 100 - 300 µgU L-1) Urangehalte von 50 - 2.000 µgU g-1 auf. Im Vergleich zu Uran sind Ra-226 und Arsen labiler am Bestandesabfall gebunden. Für die Genese der Gehalte in den subhydrischen Auflagen sind die Herkunft des (autochthonen bzw. allochthonen) Bestandesabfalls und der Abbau eine entscheidende Rolle. Sedimente aus leicht abbaubaren Bestandesabfällen (z.B. Lemna spec., Algen) weisen im Vergleich mit allochthonen Bestandesabfällen (von Bäumen) deutlich geringere Urangehalte auf. Exemplarisch wurde für einen aus allochthonen Bestandesabfällen bestehenden Sedimentkern mittels Cs-137-Bestimmung eine maximale Uranfestlegung von 1 – 2 g m-² a-1 ermittelt. Neben allochthonem Bestandesabfall führen Eisen- und Manganhydroxide, die unmittelbar an den Sickerwasseraustrittstellen ausfallen, bei relativ geringen Arsen- und Radiumkon¬zentrationen im Wasser zu hohen Arsen- bzw. Radiumgehalten im Sediment (As ≤ 5 mg g-1; Ra-226 ≤ 25 Bq g-1). Unter reduktiven Bedingungen werden Ra-226 und Arsen jedoch leicht freigesetzt. Ausgehend von den Untersuchungsergebnissen wird eine mögliche Anordnung für eine naturnahe passive Sickerwasserbehandlung vorgeschlagen.

Submitted by Marcus Rogério Oliveira dos Santos (marksan@uol.com.br) on 2016-10-03T17:43:30Z No. of bitstreams: 1 DISSERTAÇÃO MESTRADO 02OUT16.pdf: 994430 bytes, checksum: 299ad53656c7387d4e3531f117fcf32d (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2016-10-03T17:45:01Z (GMT) No. of bitstreams: 1 DISSERTAÇÃO MESTRADO 02OUT16.pdf: 994430 bytes, checksum: 299ad53656c7387d4e3531f117fcf32d (MD5) / Made available in DSpace on 2016-10-03T17:47:05Z (GMT). No. of bitstreams: 1 DISSERTAÇÃO MESTRADO 02OUT16.pdf: 994430 bytes, checksum: 299ad53656c7387d4e3531f117fcf32d (MD5) Previous issue date: 2016-09 / The simulation of establishment is a phenomenon that usually occurs in a context where there is fiscal war between municipalities, but not necessarily. In this practice is common for service providers to use an establishment used as front organization in the municipality of lower taxation, at the same time that they are established in another property, in another municipality, with higher tax incidence, with all the elements for the service provision, however, declare that the services are provided by the first establishment. To prevent and combat this practice, in the year 2005, the Municipality of São Paulo established the Registration of services providers domiciled in other municipalities (CPOM) for intercity service benefits, when the taker is in São Paulo territory. However, simulations of establishment cases continue being judged by the Municipal Council of Taxes, which is an indication that the Registration may require adjustments to better fulfill its function. This paper aims to examine whether CPOM properly combat the simulation of establishment and, if the answer is negative, adjustments will be presented so that it fulfills the function for which it was implemented. These adjustments are intended to increase efficiency and provide an evidential context to detect and point simulations, improving its performance. / A simulação de estabelecimento é um fenômeno que normalmente ocorre num contexto em que há guerra fiscal entre os Municípios, mas não necessariamente. Nessa prática é comum os prestadores de serviço se utilizarem de um estabelecimento de fachada no Município de menor tributação, ao mesmo tempo em que estão estabelecidos em outro estabelecimento, em outro Município, de maior incidência tributária, com todos os elementos para a prestação do serviço, porém, declaram que os serviços são prestados pelo primeiro estabelecimento. Para prevenir e combater essa prática, no ano de 2005, o Município de São Paulo instituiu o Cadastro de Prestadores de Outros Municípios (CEPOM) para as prestações intermunicipais de serviço, quando o tomador estiver em território paulistano. Porém, casos de simulação de estabelecimento continuam sendo julgados pelo Conselho Municipal de Tributos, o que constitui um indício de que o Cadastro pode necessitar de ajustes para que melhor cumpra a sua função. O presente trabalho pretende analisar se o CPOM combate adequadamente a simulação de estabelecimento e, caso a resposta seja negativa, serão apresentados ajustes para que ele cumpra a função para a qual ele foi implementado. Tais ajustes têm como objetivo aumentar sua eficiência e fornecer um contexto probatório para detectar e apontar simulações, melhorando o seu desempenho.