Walden Pond: Ecological and Anthropological History Reflected in the Sedimentary Record
Tue, 05/03/2016 - 23:13
Abstract: This study examined environmental changes reflected in the microfossil record of a sediment core taken in August 2015 from Walden Pond, Massachusetts spanning the last 600 years. In particular changes in the eutrophication status, inorganic sediment deposition due to land use, lake water depth and temperature were examined using phytoplankton indicator species—diatoms and chrysophytes— to reconstruct environmental conditions. The study site was a basin shallower and closer to the source of anthropogenic N and P inputs than the site of previous studies at Walden’s deepest basin, allowing for finer detection of changes in water level and organic content of sediment. A gravity corer was used to collect the sediment core to preserve topmost sediment layers for analysis, as more than a decade has passed since the last published study of this kind at Walden Pond by Köster et. al. (2005). Results show a significant increase in indicators of eutrophic lake conditions since European settlement ca. 1630, and especially since the 20th century. However, relative Asterionella formosa and Synedra nana abundances had not changed significantly in the last decade since Köster et. al.’s 2005 study, and have in fact decreased somewhat, suggesting water treatment efforts by the Massachusetts Dept. of Environmental Protection (DEP) have had some success. Loss on ignition (LOI) of organic content shows a precipitous decline from the mid 19th century from 37% to 22%, representing intensive land clearance and development until the 1970’s when DEP management began. After that point, LOI rose, perhaps due to increased lake productivity, and has fluctuated around 25%. Relative Discostella stelligera abundance, while used in the WAl-3 piston core as a proxy for water depth, could not be used in the WAL-1 gravity core from this study as eutrophication has significantly impacted their abundance. Chrysophyte scale:diatom ratios corroborate an observed trend of increasing abundance in lakes globally since the 20th century, perhaps in response to rising global temperatures over the same period.
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File Attachments: Capstone Paper.docx
Analysis of Forage Quality in Adirondack Macrophytes: Implications for Waterfowl Nutrition
Fri, 04/29/2016 - 14:48
Abstract: To understand the relative nutritional value of macrophyte food sources for Adirondack waterfowl, the forage quality of four common Adirondack macrophytes were assessed. An analysis of two native pondweeds (Potamogeton) and two invasive watermilfoil (Myriophyllum) was conducted to deduce how invasive and native macrophytes compare in their relative concentrations of nitrogen and mineral content; important indicators of forage quality for waterfowl. Nitrogen content is used as a metric for relative concentration of protein. Macrophyte species were sampled from four Adirondack lakes of the same trophic status to account for effects of lake nutrient characteristics on plant nutrient uptake and synthesis. Total nitrogen was determined with the Kjeldahl procedure using flow injection analysis. Ash (mineral) content was acquired through high-heat burning in a muffle furnace. The invasive watermilfoil species had a higher percentage of nitrogen than the native species. There was no significant difference in the ash content between the species. It is critical to understand the ecological function of these species in relation to wildlife populations. The nutritional value of these aquatic macrophytes may have implications for the fitness and distribution of breeding herbivorous waterfowl in Adirondack lakes. These results may indicate that invasive plants will serve as a viable food source for herbivorous waterfowl as watermilfoil continues to spread across Adirondack aquatic systems.
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File Attachments: Bianca Fournier Capstone Draft 4th Edit.docx
Rooted Education: learning from aquaponics
Sat, 04/30/2016 - 15:02
Abstract: Aquaponics is the integration of soil-less agriculture (hydroponics) within closed-loop aquaculture systems to reduce the toxic accumulation of nutrient waste from aquatic animals. Bacteria naturally establish to purify water by oxidizing the ammonia secreted by fish, which reduces the toxicity of effluent while creating a usable nitrogen source for plants. The conversion of ammonia and nitrite into nitrate by living bacteria communities is called a biological filter, or biofiltration (FAO 2014). Aquaponics would not be possible without biofiltration; the slightest amount of ammonia would be fatally toxic to fish, and plants wouldn't receive the nitrates they need to grow. There are unique opportunities offered by an aquaponics system to learn about ecological and human communities. 1.1. Aquaponics enables users to grow fish and agricultural plants with limited space and resource use (water, soil, and time). This enables an aquaponics user to invest less physical energy and time into expanding sustainable food resources for their household use. 1.2. A small aquaponics system could promote cultural values of self-sufficiency, energy consciousness, and connection to food systems. It could inspire individual efforts to produce food for one’s household, to build healthier and more resilient systems, and a greater appreciation for farming. Therefore, this project aims to actualize a mobile and functional aquaponics system for the educational benefit of the Paul Smith's College community. I will provide the background knowledge needed to maintain an aquaponics system, as well as describe the general concept of aquaponics design.
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Major: Environmental Sciences, Natural Resources Sustainability Studies
File Attachments: The Author has selected not to publish this complete work.
An Assessment of Heavy Metal Concentrations in Adirondack Waterfowl
Thu, 04/28/2016 - 22:53
Abstract: We analyzed heavy metal concentrations in waterfowl liver and breast tissue from ducks harvested within the Adirondack Park from October 3 to November 13, 2015. Interspecific, intersex, and feeding behavior variation in heavy metal concentrations were assessed. Waterfowl from two feeding behavior groups (diving and dabbling) were harvested from the watershed within a 50 mile radius of Paul Smith’s, New York. Harvested waterfowl species included mallard (Anas platyrhynchos), American black duck (Anas rubripes), common merganser (Mergus merganser), ring-necked duck (Aythya collaris), bufflehead (Bucephala albeola), and hooded merganser (Lophodytes cucullatus). Legal harvest of these species during regulated New York State duck hunting season allows for permissible use of internal organs for heavy metal determination. Dry weight (mg/kg) of digested liver and breast tissue samples were analyzed using atomic absorption spectroscopy. Due to unknown laboratory error, absolute concentration values were inaccurate, thus, rendering accurate analyses unfeasible. However, relative observable trends were able to be assessed given our data’s high precision. Analyte concentrations were significantly greater in liver tissues and there were significant differences between species. Variation in mercury, lead, bismuth, cadmium, chromium, and zinc concentrations in waterfowl serve as an indicator of the presence, cycling, bioaccumulation, and temporal trends of these metals in northeastern aquatic habitats.
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Major: Environmental Sciences, Fisheries and Wildlife Science
File Attachments: Final2.docx