Life Sciences Commons^™

Macroinvertebrate Community Composition, Food Web Structure, And Emergence Rate In Neotropical Cloud-Forest Streams In Mindo, Ecuador, Anna M. Harris

Masters Theses

Tropical cloud forest streams are one of the most threatened and understudied ecosystems in the world. Understanding how these ecosystems function is essential for effective conservation. In this study, macroinvertebrate community composition, functional feeding group analysis, ecosystem attributes, and physicochemical parameters were used to evaluate biophysical stream conditions of 3 low-order Neotropical cloud forest streams at Reserva Las Gralarias in Mindo, Ecuador. Additionally, food web structure was analyzed via stable isotope analysis and aquatic insect emergence rate was also examined. As stream size increased from 1st to 3rd order, the macroinvertebrate communities shifted from being collector-gatherer dominated (65.2 to 29.8%, …

Inquiry-Based Biotechnology Education For Kent Intermediate School District Early College Program, Meāgan N. Treadway

Masters Theses

Growth in the field of biotechnology, combined with the ability to access information instantaneously, requires a new model of science education that will nurture deeper understanding and higher order thinking to develop a scientifically literate population. Inquirybased learning is a student-centered model built on the theoretical framework of constructivism, which allows students to learn in a way that reflects how scientists come to understand the natural world. This project aimed to address the need for an inquiry-based biotechnology curriculum in a local Early College program by developing, piloting, revising, and implementing an inquiry-based biotechnology unit while simultaneously evaluating the impact …

Green And Choking: Exploring The Dynamics Of Seasonal Productivity And Hypoxia In A Great Lakes Area Of Concern And Habitat Blueprint Estuary Using Time-Series Measurements, Anthony D. Weinke

Masters Theses

Although hypoxia (dissolved oxygen <4 mg L-1) in the bottom waters of lakes, reservoirs, and estuaries may be a natural product of stratification in eutrophic or mesotrophic systems, there is increasing concern because the occurrence of hypoxia is spreading in many areas where hypoxia did not previously exist. Part of this new knowledge can be attributed to time-series data from buoy observatories that monitor systems in good weather and in bad, and allowing insight into the inner workings of a lake where sampling only a few times per year would not. This study made use of a five-year time-series of meteorological and water quality data in order to examine the effect of episodic wind-events on stratification and hypoxia within Muskegon Lake, Michigan, as well as performing bi-weekly lake-wide monitoring to evaluate the effects of stratification, hypoxia, and wind-events on the lake. In the wind-event portion of the study, we found that events where wind speeds were above average for an extended period of time occurred fairly frequently on the lake, but that thermal stratification allowed only the strongest events to significantly mix the water column at the buoy location a few times per year. This provided infrequent relief of hypoxia in the bottom waters. The second portion of the study found extensive effects on the water quality and biology in the bottom of the lake due to hypoxia such as increased phosphorus concentrations, enhanced phycocyanin following a strong windevent, and decreased fish abundance, richness, and size. We also found that hypoxia occurred lake-wide at all four sample locations, but was most stable at the deepest point in the lake that was least influenced by wind-events. It is possible that the combination of hypoxia and strong episodic wind-events leads to entrainment of phosphorus-rich waters to the surface initiating or continuing an algal bloom. Hypoxia and wind-event mediated internal loading of phosphorus could be a positive feedback loop for cyanobacterial blooms and hypoxia in Muskegon Lake.

Examining The Effect Of Climate Change On The Upper Mesophotic Coral Montastrea Cavernosa (Linnaeus 1767), John Skutnik

Masters Theses

Coral reefs are under increasing pressure from global climate change. In particular, ocean warming is having a deleterious effect on many of the world’s shallow reefs. Some authors suggest that acute exposure is more detrimental than chronic, versus others who indicate the opposite. However, little knowledge exists regarding heat induced stress on deeper mesophotic reefs. Here, I examined the effect of acute (72 hrs.) and chronic (480 hrs.) heat stress using laboratory experiments on coral Montastraea cavernosa (Linnaeus 1767) collected from an upper mesophotic (~30 m) reef off Islamorada Florida. I examined a variety of putative immune and stress genes …

Evaluating Foraging Habits, And Estimating Prey Consumption, And Growth Of Brook Trout In A Coolwater Michigan Stream, Graeme R. Zaparzynski

Masters Theses

Brook trout (Salvelinus fontinalis) are a cold water ectotherm whose native distribution includes most of eastern Canada, the upper Midwestern United States, and the eastern and mid- Atlantic United States as far south as Georgia. The native range of brook trout in the United States has been reduced as a result of interspecific interactions with introduced species, and anthropogenic land use changes that drive water temperature changes in many of their native watersheds. Anthropogenic land-use changes tend to increase thermal regimes of aquatic systems, affecting brook trout physiology and limiting them to colder, headwater reaches. The threat of …

Trophic Transfer Of A Naturally Occurring Algal Toxin From A Freshwater Lake To Little Brown Bats, Devin Jones

Masters Theses

Microcystis aeruginosa is a species of cyanobacteria capable of producing a hepatotoxin called microcystin. As toxic M. aeruginosa overwinters in the sediments of lakes, it is ingested by some mayfly larvae, such as those of Hexagenia spp., and thus

microcystin bioaccumulates in these insects. When Hexagenia emerge from lakes to

reproduce, they provide an abundant, albeit temporary, food source for many terrestrial

organisms such as bats. Little brown bats, Myotis lucifugus, likely feed opportunistically

on aquatic insects. To test if microcystin moves from aquatic to terrestrial ecosystems via trophic transfer, we 1) tested bat feces for the presence of …

From Land To Lake: Contrasting Microbial Processes Across A Great Lakes Gradient Of Organic Carbon And Inorganic Nutrient Inventories, Deborah K. Dila

Masters Theses

Freshwater ecosystems have strong linkages to the terrestrial landscapes that surround them, and contributions of carbon and inorganic nutrients from soil, vegetation and anthropogenic sources subsidize autochthonous water body productivity to varying degrees. Abundant freshwater phytoplankton and bacterioplankton are key to linking the planet's geosphere and atmosphere to the food webs in the hydrosphere through their growth and respiration. Rich resources that move through land margin waterways make them active sites for cycling organic carbon and thus important, but understudied, contributors to global climate. During 2010-2011, we examined seasonal changes in carbon and nutrient inventories, plankton community composition and metabolism …

Detection And Attribution Of Long-Term Vegetation Changes In Northern Alaska, Robert Barrett

Masters Theses

Climate change is impacting terrestrial ecosystems world-wide and the Arctic is particularly vulnerable as it is warming faster and with greater magnitude than other regions. Understanding the responses of arctic plants species to abiotic factors is crucial to predicting the impact climate change will have on the Arctic because plants play critical roles in carbon exchange, energy balance, and trophic interactions. Using data from long-term research sites in Barrow and Atqasuk, Alaska, the purpose of this thesis was to investigate how arctic plants respond to 17-19 years of experimental warming, establish the relative strengths of various abiotic factors in predicting …

Scalable Parallelization Of A Markov Coalescent Genealogy Sampler, Philip E. Davis

Masters Theses

Coalescent genealogy samplers are effective tools for the study of population genetics. They are used to estimate the historical parameters of a population based upon the sampling of present-day genetic information. A popular approach employs Markov chain Monte Carlo (MCMC) methods. While effective, these methods are very computationally intensive, often taking weeks to run. Although attempts have been made to leverage parallelism in an effort to reduce runtimes, they have not resulted in scalable solutions. Due to the inherently sequential nature of MCMC methods, their performance has suffered diminishing returns when applied to large-scale computing clusters. In the interests of …

Investigating Ph Banding Kinetics Of Chara Corallina In Alternating Light Conditions With Rectangular Pulse Voltammetry, Matthew C. Zandee

Masters Theses

Chara corallina is an important biological model due to its large internodal cells, the simple shape, and the wide range of techniques that can be used to study it. The alternating acidic and basic banding pattern of Chara corallina upon illumination has been studied and well described over the past several decades. However, much of this complex mechanism is not fully understood. Few studies have shown how the acidic and basic regions have responded in real time as lighting conditions change. Utilizing rectangular pulse voltammetry (RPV) and pH-sensitive carbon microelectrodes along the cell wall allows for a real time profile …

The Effect Of Seasonal Fish Migration On Energy Budgets In Two Coastal Michigan Streams, Emily M. Dean

Masters Theses

Migratory fish are known to seasonally enter coastal stream systems but the magnitude of the effects these migrations have on stream energy budgets is not fully understood. The Laurentian Great Lakes have several introduced and native adfluvial fish, where only a few studies have investigated the impacts of their migration on energy budgets in Michigan coastal streams. We quantified the contribution of energy from Chinook salmon (Oncorhynchus tshawytscha) muscle and eggs, steelhead (Oncorhynchus mykiss) eggs, and larval white suckers (Catostomus commersonii) to coastal stream energy budgets. Energy densities and energy delivered to streams were estimated using bomb calorimetry and annual …

Categorization Of Food Value Via Crayfish Aggression, Justin Thanh-Tuan Tran

Masters Theses

In numerous species, social interactions play a key role in deciding the allocation of resources. Aggression is a tactic that crayfish utilize to become dominant, which allows them to acquire higher quality resources. Many studies of aggression and agonistic interactions have used crayfish because they are known to be innately aggressive and are quick to become involved in agonistic interactions that may escalate into fighting. The primary objective of this study is to elucidate the relationship between differing food resources and their effect on aggression of crayfish. It is hypothesized that increased desirability for the food resource will induce more …

Does Phosphorus From Agricultural Tile Drains Fuel Algal Blooms?, Delilah R. Clement

Masters Theses

Phosphorus (P) is often implicated as a contributing factor to algal blooms. Attention has been focused on P in surface runoff, but agricultural tile drains also can be a source. Lake Macatawa is a hypereutrophic lake located in west Michigan, and the watershed is dominated by row crop agriculture. Further research is needed to understand the influence of bioavailable P originating from tile drains on water quality in Lake Macatawa. The objectives of this study were to 1) conduct a tile drain effluent sampling survey to assess their importance as a source of P in the Macatawa Watershed; 2) investigate …

American Marten Denning Behavior In Michigan, Melissa J. Nichols

Masters Theses

Female American marten (Martes americana) produce litters of 1-5 kits between late March and early May. Kits remain with their mother for the duration of their first summer in a series of den structures. We located these den structures using radio-telemetry and placed remotetriggered cameras at the entrances to capture information on litter size, female activity patterns, and den visits by males and potential predators. From the summer of 2012 to the summer of 2014 we tracked 13 individual female marten (8 in the Lower Peninsula, 5 in the Upper Peninsula) with 17 litters to 75 unique den sites (60 …