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Full-Text Articles in Physical Sciences and Mathematics

Supply And Consumption Of Dissolved Organic Phosphorus Across The Subtropical Indian Ocean, Corinne Richard Jan 2024

Supply And Consumption Of Dissolved Organic Phosphorus Across The Subtropical Indian Ocean, Corinne Richard

Honors Theses and Capstones

The Indian Ocean is an understudied region for marine phosphorus (P) biogeochemistry. Emerging evidence indicates marine phytoplankton can adapt to decreasing supplies of inorganic P, a required nutrient for growth, by alternatively utilizing organic forms of P. Here we investigate the dissolved organic phosphorus concentration ([DOP]) distribution across the southern Indian Ocean using observations collected on the I05 US GO-SHIP Cruise (2023) across ~33ºS latitude. We quantify the longitudinal variability of [DOP] in the upper 350 m of the Indian Ocean and infer its rate of biological consumption from surface waters, contributing as an organic nutrient to sustain marine autotrophs …


Plastic Storage In River Sediments Across An Urbanization Gradient In The Ipswich Watershed In Massachusetts, Jackie L. Harris Jan 2023

Plastic Storage In River Sediments Across An Urbanization Gradient In The Ipswich Watershed In Massachusetts, Jackie L. Harris

Honors Theses and Capstones

The importance of plastic pollution research has become apparent as plastic pollution has increased exponentially since its introduction in the 1950s. Plastics mechanically break down into minuscule particles called microplastics, which are plastic particles with a size range of 0.1 micrometers (μm) to 5 millimeters (mm). Most of the research on microplastic pollution has centered around marine ecosystems rather than freshwater ecosystems. More freshwater microplastic research to date is emerging but is still nascent and sparse. Furthermore, the idea that rivers are merely conduits of microplastics to the ocean is even more limited and ignores microplastic loading and retention in …


Controls On Carbon Gas Fluxes From A Temperate Forest Soil, Natalie A. White, Ruth K. Varner, Clarice R. Perryman Jan 2022

Controls On Carbon Gas Fluxes From A Temperate Forest Soil, Natalie A. White, Ruth K. Varner, Clarice R. Perryman

Honors Theses and Capstones

Forest soils consume atmospheric methane (CH4), serving as a major global CH4 sink that uptake an estimated 22 ± 12 Tg of CH4 per year. Temperature and soil moisture have been identified as key controls of the microbial consumption of CH4 in forest soils. Climate-driven warming and changing moisture regimes may impact forest soils’ role in the carbon cycle, and recent works suggests that forests could become weaker CH₄ sinks. Long-term monitoring sites can capture these changes, leading to better predictions of CH4 exchange between the atmosphere and soils under climate change. This study …


Environmental And Societal Impacts In New England Following A Potential Yellowstone Eruption, Serena L. Butler Jan 2022

Environmental And Societal Impacts In New England Following A Potential Yellowstone Eruption, Serena L. Butler

Honors Theses and Capstones

Yellowstone National Park is famously known for its history of “super-volcano” eruptions. From the evidence of volcanic deposits, scientists know that the ash cloud that erupted from Yellowstone covered most of the western U.S. states, but until recently, models have not shown the ash could also have reached eastern states. The scope of this investigation is to determine what would happen to New England if Yellowstone were to erupt today in terms of health, agriculture, transportation, relocation, economy, and climate. In order to do so, three significant eruptions during human history are considered as case studies in order to compare …


An Analysis Of River Channel Change Over Time In The Lamprey River, Trevor R. Fenoff Jan 2021

An Analysis Of River Channel Change Over Time In The Lamprey River, Trevor R. Fenoff

Honors Theses and Capstones

Flooding causes river channel change that threatens people and property. Due to climate change and urbanization, flooding events are projected to happen more frequently in the future, which will make the associated hazards worse. This project estimated the historical river channel change in the Lamprey River in southern New Hampshire. River channel change was estimated by delineating riverbank location on historical aerial photographs. The river channel change was compared to river width, curvature, and the number of 1.5-year flood events to explore the drivers of river channel change in the Lamprey River.


The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification, Margaret Phillips, Wil Wollheim Jan 2019

The Role Of Small Reservoirs In Reducing Reactive N Export Via Denitrification, Margaret Phillips, Wil Wollheim

Honors Theses and Capstones

Reactive nitrogen (N), which harms ecosystem health, has been increasing in the biosphere, leading to higher N export to coastal ecosystems. Although man-made reservoirs can be significant sources of greenhouse gases, they can also retain N, thus reducing N export. Because many dams are relics from industrial hydropower, their removal is becoming increasingly common. It is therefore crucial to understand the ecological tradeoffs of man-made reservoirs. While previous studies have examined nutrient budgets and denitrification at inputs and outputs of large reservoirs, small reservoir dynamics remain understudied. In this study, we measured inputs and outputs of NO3 and N …


Effects Of Silvopasture Establishment On Aqueous And Gaseous Soil N Losses At The University Of New Hampshire Organic Dairy Research Farm, Kathryn Ann Slebodnik Jan 2017

Effects Of Silvopasture Establishment On Aqueous And Gaseous Soil N Losses At The University Of New Hampshire Organic Dairy Research Farm, Kathryn Ann Slebodnik

Honors Theses and Capstones

The expansion of local agriculture in the New England region is putting increased pressure on farmers to expand their arable land base. While clear-cutting is a traditional method of converting forested land to agriculture, it is known for having adverse ecological impacts. To minimize these impacts, farmers can create a silvopasture which incorporates a portion of the original forest canopy into pastures or crop fields. This study evaluates the impact of land-use changes for agriculture on soil nitrogen (N) retention. In particular, this study investigates the differences in soil N turnover, gaseous loss, and aqueous loss among an established forest, …


Fine-Scale Plant Species Identification In A Poor Fen And Integration Of Techniques And Instrumentation In A Classroom Setting, Dylan Schiff Jan 2015

Fine-Scale Plant Species Identification In A Poor Fen And Integration Of Techniques And Instrumentation In A Classroom Setting, Dylan Schiff

Honors Theses and Capstones

Refining carbon flux measurements in the carbon cycle is an ongoing challenge. This study attempted to identify plant species in Sallie’s Fen, a nutrient-poor fen in Barrington, New Hampshire, at a fine scale in order to better model and understand carbon exchange between plants and the atmosphere in this type of ecosystem. A protocol for estimating percent cover of species in plots via ground measurements was developed. The next stage of this project was to compare these measurements with measurements derived from spectral images using ImageJ computer software. Statistical tests of the ground measurement data revealed that patterns of seasonal …


Cycling Of Molecular Hydrogen In Subarctic Sweden, Victoria Ward Apr 2013

Cycling Of Molecular Hydrogen In Subarctic Sweden, Victoria Ward

Honors Theses and Capstones

No abstract provided.


Phosphate Availability During Sediment Resuspension Events In The Great Bay Estuary, Taylor Langkau Apr 2012

Phosphate Availability During Sediment Resuspension Events In The Great Bay Estuary, Taylor Langkau

Honors Theses and Capstones

Phosphate is an important nutrient to marine ecosystems such as the Great Bay Estuary. However, its bioavailability is limited due to its tendency to adsorb to marine sediments, especially iron oxides. This paper investigates phosphate dynamics during a simulated storm compared to calm conditions and aims to quantify the mechanisms of phosphate adsorption.