Estudios sonoros desde la Región Andina UIO-BOG = Sonic Studies from the Andean Region

El presente trabajo se basa en el análisis de las prácticas sonoras y, a partir de ahí, de una apuesta por un nuevo campo de estudios, el de los Estudios Sonoros; cuyo fin último es establecer una perspectiva epistemológica y política de las prácticas experimentales con sonido, en diálogo con proyectos provenientes de los Estudios Culturales, como son el proyecto modernidad/ colonialidad, las teorías poscoloniales y los estudios subalternos. Desde estas posiciones teóricas y políticas, estoy conciente de que el sonido, y sus posibilidades experimentales, articulan un régimen influyente en el mundo contemporáneo. Razón por la cual, sobre todo, esta es una reflexión desde las prácticas sonoras que surgen en dos ciudades andinas: Quito y Bogotá, como una expresión emergente para establecer encuentros Sur-Sur, que puedan generar diálogos epistemológicos sobre el sonido. En otras palabras, en este libro estoy proponiéndo a mis lectoras y lectores, una especie de “juego epistémico”: comprender el sonido como un lugar de conocimiento.Y el sonido es conocimiento precisamente porque el sonido nos permite vernos (y permite verme) como un sujeto históricamente ubicado. En el capítulo primero abordaré la pregunta de cómo se fue articulando el régimen discursivo del sonido como arte, dentro de diálogos y conflictos que se generaron en el contexto de la Guerra Fría que, para el caso de Latinoamérica, constituyó la transferencia de conocimientos articulados desde promesas como el desarrollismo y la modernización. También analizaré el cómo se configuraron, tanto en Quito como en Bogotá, las nuevas subjetividades “artísticas” frente al discurso de las vanguardias europeas del siglo XX y el experimentalismo estadounidense. Como verán mis lectoras y lectores, estos modelos, aparentemente originales e innovadores, fueron influidos por formas de saber y poder moduladas alrededor de la idea de la renovación de las artes a través del sonido, formulación que instaló el sonido como dispositivo/materia desde el cual, en detrimento de lo local, se articuló la fantasía de un universal deseado: las máquinas de sonido y de reproducibilidad técnica. En el segundo capítulo me centraré en algunas prácticas de experimentación sonora para indagar cuestiones como el estilo, procedimiento posmodernista ampliamente diseminado dentro de las instituciones artísticas y de éstas hacia la vida cotidiana. A partir de lo cual intentamos esclarecer el porqué de la confiscación y sometimiento de lo sonoro bajo el cuidadoso encierro del régimen discursivo del arte, que de manera eficiente lo absorbe como un “nuevo” medio para disciplinarlo y nombrarlo como proyecto sonoro, pieza sonora, instalación sonora, performance sonoro, acción sonora, objeto sonoro, paisaje sonoro, composición, loop. En otras palabras, cómo todo lo que genera el posmodernismo es apropiado por las universidades para crear la noción de “pastiche”, en donde todo cabe, bajo la indulgencia del “estilo”, procedimiento desde el cual se va instalando el régimen de verdad de un nuevo universal deseado: El Arte Sonoro. En este mismo capítulo, indagamos sobre las lógicas de producción de estas prácticas, para avanzar hacia las lógicas culturales donde lo sonoro se define y redefine por el posicionamiento y el lugar desde el que actúan los sujetos. Bajo estas consideraciones, queda planteada la propuesta, acuñada por esta investigación, la de un nuevo campo de estudio: Los Estudios Sonoros, propuesta que debe ser entendida como lo que algunos intelectuales latinoamericanos llaman epistemes emergentes11, precisamente porque esta investigación hace un esfuerzo por esclarecer las interdependencias existentes entre prácticas artísticas con sonido, el campo discursivo del arte y otras construcciones discursivas de la modernidad-colonialidad que establecen y regulan la formación del régimen sonoro. En el capítulo tercero analizaré cómo un “medio de creación” se vuelve hegemónico y cómo ciertos artistas que usan el sonido, bajo la pretensión de representar la marginalidad, marginalizan aún más a las personas que han sido históricamente subalternizadas. Seguido de este análisis, en el capítulo cuarto, indagamos sobre las tácticas que marcan nuevas formas de adhesión, de representación y de resistencia cultural, las mismas que son estrategias suplementarias frente, y en contra, de los discursos dominantes de las prácticas artísticas con sonido y las geopolíticas de conocimiento.

INTERACTIVE CONTROLS OF WATER TABLE POSITION AND PLANT FUNCTIONAL TYPES ON PEAT POREWATER CHARACTER IN NORTHERN BOG ECOSYSTEMS: IMPLICATIONS FOR CARBON CYCLING DYNAMICS

Northern wetlands, and particularly peatlands, have been shown to store around 30% of the world's soil carbon and thus play a significant role in the carbon cycle of our planet. Changes in climate are altering peatland hydrology and vegetation communities. These changes are possibly resulting in declines in the ability of peatlands to sequester carbon because losses through carbon oxidation and mineralization are likely to increase relative to C inputs from net primary production in a warmer, drier climate. However, the consequences of interactive effects of altered hydrology and vegetation on carbon storage are not well understood. This research evaluated the importance of plant species, water table, and their interactive effects on porewater quality in a northern peatland with an average pH of 4.54, ranging from 4.15 to 4.8. We assessed the effects of plant functional group (ericaceous shrubs, sedges, and bryophytes) and water table position on biogeochemical processes. Specifically, we measured dissolved organic carbon (DOC), total dissolved nitrogen (TDN), potential enzyme activity, organic acids, anions and cations, spectral indexes of aromaticity, and phenolic content. Our results indicate that acetate and propionate concentrations in the sedge-dominated communities declined with depth and water table drawdown, relative to the control and ericaceous treatments. DOC increased in the lowered water table treatments in all vegetation community types, and the peat porewater C:N ratio declined in the sedge-dominated treatments when the water table was lowered. The relationship between DOC and ferrous iron showed significant responses to vegetation type; the exclusion of Ericaceae resulted in less ferrous iron per unit DOC compared to mixed species treatments and Ericaceae alone. This observation was corroborated with higher mean oxidation redox potential profiles (integrating 20, 40, and 70 cm) measured in the sedge treatments, compared with the mixed and Ericaceae species treatments over a growing season. Enzymatic activities did not show as strong of a response to treatments as expected; the oxidative enzyme peroxidase and the hydrolytic enzyme phosphatase were the only enzymes to respond to water table, where the potential activity of both enzymes increased with water table drawdown. Overall, there were significant interactive effects between changes in vegetation and water table position on peat porewater composition. These data suggest that vegetation effects on oxidation reduction potentials and peat porewater character can be as important as water table position in northern bog ecosystems.

Palaeohydrology, fires and vegetation succession in the southern Baltic during the last 7500 years reconstructed from a raised bog based on multi-proxy data

We present the first 7500 yr long multi-proxy record from a raised bog located at the southern Baltic coast, Poland. Testate amoebae, plant macrofossils, pollen and microscopic charcoal were used to reconstruct environmental changes in Pomerania (northern Poland, Kaszuby Lakeland) from a 7-m thick peat archive of Stążki bog dated 5500 BC–AD 1250. We obtained a record of proxies representing different spatial scales: regional vegetation changed simultaneously with local vegetation, and testate amoebae showed a pattern of change similar to that of pollen and plant macrofossils. On the basis of the combined proxies, we distinguished three hydroclimatic stages: moist conditions 5500–3450 BC, drier conditions with regionally increased fires up to 600 BC, and again moist conditions from 600 BC onward. During the drier interval, a first climatic shift to wetter conditions at 1700 BC is indicated by regional pollen as the replacement of Corylus by Carpinus, and locally by, e.g., the increase of Hyalosphenia elegans and mire plants such as Sphagnum sec. Cuspidata. Furthermore, we observed a correlation since 600 BC among the re-expansion of Carpinus (after a sudden decline ca. 950 BC), increased peat accumulation, increase of Hyalosphenia species, and fewer fires, suggesting lower evapotranspiration and a stable high water table in the bog. Fagus started to expand after AD 810 gradually replacing Carpinus, which was possibly due to a gradually more oceanic climate, though we cannot exclude human impact on the forests. Peat accumulation, determined by radiocarbon dating, varied with bog surface wetness. The hydroclimatic phases found in Stążki peatland are similar to moisture changes recorded in other sites from Poland and Europe. This is the first detailed record of hydroclimatic change during the Holocene in the southern Baltic region, so it forms a reference site for further studies on other southern Baltic bogs that are in progress.

Geophysical and Hydrological Evaluation of Two Bog Complexes in a Northern Peatland: Implications for the Distribution of Biogenic Gases at the Basin Scale

Ground penetrating radar (GPR) was used to determine peat basin geometry and the spatial distribution of free-phase biogenic gasses in two separate units of a northern peatland (Central and Southern Unit of Caribou Bog, Maine). The Central Unit is characterized by a deep basin structure (15 m maximum depth) and a raised (eccentric) bog topographic profile (up to 2 m topographic variation). Here numerous regions of electromagnetic (EM) wave scattering are considered diagnostic of the presence of extensive free-phase biogenic gas. In contrast, the Southern Unit is shallower (8 m maximum depth) and has a slightly convex upwards bog profile (less than 1 m topographic variation), and areas of EM wave scattering are notably absent. The biogenic gas zones interpreted from GPR in the Central Unit are associated with: (1) wooded heath vegetation at the surface, (2) open pools at the surface, (3) high water table elevations near the center of the basin, and (4) a region of overpressure (at approximately 5 m depth) immediately below the zone of free-phase gas accumulation. The latter suggests (1) a transient pressure head associated with low hydraulic conductivity resulting from the biogenic gasses themselves or confining layers in the peat that restrict both gas release and groundwater flow and/or (2) overpressure in the peat column as a result of the gas buildup itself. In contrast, the Southern Unit, where zones of EM scattering are absent, is characterized by: (1) predominantly shrub vegetation, (2) a lack of open pools, (3) only minor variations (less than 1 m) in water table elevation throughout the entire unit; and (4) generally upward groundwater flow throughout the basin. The results illustrate the nonuniformity of free-phase biogenic gas distribution at the peat basin scale and provide insights into the processes and controls associated with CH4 and CO2 accumulation in peatlands.

Biogeochemical indicators of peatland degradation – a case study of a temperate bog in Northern Germany

Organic soils in peatlands store a great proportion of the global soil carbon pool and can lose carbon via the atmosphere due to degradation. In Germany, most of the greenhouse gas (GHG) emissions from organic soils are attributed to sites managed as grassland. Here, we investigated a land use gradient from near-natural wetland (NW) to an extensively managed (GE) to an intensively managed grassland site (GI), all formed in the same bog complex in northern Germany. Vertical depth profiles of δ13C, δ15N, ash content, C / N ratio and bulk density as well as radiocarbon ages were studied to identify peat degradation and to calculate carbon loss. At all sites, including the near-natural site, δ13C depth profiles indicate aerobic decomposition in the upper horizons. Depth profiles of δ15N differed significantly between sites with increasing δ15N values in the top soil layers paralleling an increase in land use intensity owing to differences in peat decomposition and fertilizer application. At both grassland sites, the ash content peaked within the first centimetres. In the near-natural site, ash contents were highest in 10–60 cm depth. The ash profiles, not only at the managed grassland sites, but also at the near-natural site indicate that all sites were influenced by anthropogenic activities either currently or in the past, most likely due to drainage. Based on the enrichment of ash content and changes in bulk density, we calculated the total carbon loss from the sites since the peatland was influenced by anthropogenic activities. Carbon loss at the sites increased in the following order: NW < GE < GI. Radiocarbon ages of peat in the topsoil of GE and GI were hundreds of years, indicating the loss of younger peat material. In contrast, peat in the first centimetres of the NW was only a few decades old, indicating recent peat growth. It is likely that the NW site accumulates carbon today but was perturbed by anthropogenic activities in the past. Together, all biogeochemical parameters indicate a degradation of peat due to (i) conversion to grassland with historical drainage and (ii) land use intensification.

The palaeoecological history of the Praz-Rodet bog (Swiss Jura) based on pollen, plant macrofossils and testate amoebae (Protozoa)

Stratigraphy, radiocarbon dating and analyses of pollen, plant macrofossils and testate amoebae were used to reconstruct the development and ecology of a small raised bog in a karst-dominated landscape in the Swiss Jura Mountains. Special focus was on past vegetation and on the history of Pinus rotundata in relation to anthropogenic and climatic influences. Testate amoebae were used to reconstruc-t past local soil pH and water-table depth. The inferred development of the Praz-Rodet bog typifies a classic hydroseral tefrestrialization of a small basin. Two features are specific for this site. First, the bog was much wetter than today for a long period; according to our hypothesis, this only changed as a consequence of human activities. Second, two hiatuses are present at the coring location (Younger Dryas--early Preboreal, and 4700-2800 cal. yr BP), the former probably caused by low lake productivity due to cold temperatures and the latter by the erosional activity of the adjacent small river. The date of 2800 cal. yr BP for renewed peat accumulation may be related to climatic change (Subboreal-Subatlantic transition). Pollen indicators failed to show one hiatus: an apparently complete pollen sequence is therefore no guarantee of an uninterrupted sediment accumulation. Evidence of early minor human impact on the vegetation in the Joux Valley dates back to c. 6850 calendar years, congruous with the early Neolithic in the Jura Mountains. The history of Pinuis rotindata appears to be more complex than previously believed. Human activity is clearly responsible for the present abundance of this species, but the tree was naturally present on the bog long before the first evidence of important human disturbance of the site (1500 cal. yr BP). It is suggested that, in karst-dominated landscapes, dense forests growing on mineral soils around raised bogs may significantly reduce summer evapotranspiration by acting as windbreaks. Forest clearance results in increased evapotranspiration, causing a lowering of the water table on the bog and a modification of the vegetation cover. This hypothesis has implications for the management of similar small raised bogs in karst-dominated landscape.

History of Atmospheric Lead Deposition Since 12,370 14C yr BP from a Peat Bog, Jura Mountains, Switzerland

A continuous record of atmospheric lead since 12,370 carbon-14 years before the present (14C yr BP) is preserved in a Swiss peat bog. Enhanced fluxes caused by climate changes reached their maxima 10,590 14C yr BP (Younger Dryas) and 823014C yr BP. Soil erosion caused by forest clearing and agricultural tillage increased lead deposition after 532014C yr BP. Increasing lead/scandium and decreasing lead-206/lead-207 beginning 3000 14C yr BP indicate the beginning of lead pollution from mining and smelting, and anthropogenic sources have dominated lead emissions ever since. The greatest lead flux (15.7 milligrams per square meter per year in A.D. 1979) was 1570 times the natural, background value (0.01 milligram per square meter per year from 8030 to 5320 14C yr BP).

Geochemical parameters and element contents in a peat section of the Kyzyltun (Bokarevskii) ryam bog

The paper reports geochemical parameters of units in a peat bed from a raised bog in the southern Tyumen territory. Based on radiocarbon dates and variability of geochemical data the following four evolutionary stages of the bed in Holocene are distinguished: an ancient lake (5600-5750 years B.P.), lowland-bog peat (4550-5600 years B.P.), transitional-type peat (4200-4550 years B.P.), raised-bog peat. The major-component technique was applied to analyze relations between various parameters of the bed and evaluate variations in conditions, under which the bog evolved with time, including climatic conditions (in relative units). An anthropogenic signal of accumulation of certain metals in bog systems is distinguished.

Compositions of branched glycerol dialkyl glycerol tetraethers (GDGTs) in sediment samples from Bullenmoor peat bog, Northern Germany

Two types of intact branched glycerol dialkyl glycerol tetraethers (GDGTs) were detected in peat bog samples from Bullenmoor, Northern Germany. Glucuronosyl and glucosyl branched GDGTs comprise on average ca. 4% of the microbial intact polar lipids in the anoxic, acidic peat layer ca. 20 cm below the surface of the bog, suggesting an important ecological role for the source microorganisms. No corresponding phospholipids were detected. Notably, glycosidic branched GDGTs are 5-10 times less abundant than their intact isoprenoid counterparts derived from Archaea, while branched GDGT core lipids exceed their isoprenoid analogues by about an order of magnitude. These contrasting relationships may reflect lower standing stocks of the biomass of producers of branched GDGTs, combined with higher population growth rates relative to soil Archaea. Search strategies for the microbial producers of these conspicuous orphan lipids should benefit from the discovery of their intact polar precursors.