“Biogeochemical and Molecular Analysis of pCO2-enriched Marine Diazotroph Assemblages in the Oligotrophic North Pacific Ocean”
Mentor: Matthew Church and Daniela Böttjer
With atmospheric CO2 levels projected to nearly triple by the year 2150, surface-layer ocean acidification could drastically alter the microbial communities responsible for “fixing” atmospheric nitrogen into biologically available forms in the oligotrophic (nutrient-poor) ocean. Through perturbation experiments, we will analyze the response of naturally occurring diazotrophic communities to increased pCO2 in the oligotrophic North Pacific Ocean. In particular, I will perform DNA extractions, as well as qPCR analysis of experimentally perturbed diazotrophs, quantify autotrophic biomass through chlorophyll-a fluorometry, and determine silicic acid concentrations by spectrophotometry. My goal is to gain exposure to, and become proficient with, analytical methods used to shed light on the microbial underpinnings of the ocean’s biogeochemical cycles.
“The diversity of diazotrophs in coral tissue and the water column at two sites on Hawai‘i”
Mentor: Misaki Takabayashi
Groundwater seepage is a major source of nutrients in tropical waters, which are usually nutrient-poor. Nitrogen is thought to be a limiting nutrient in tropical coastal waters and is important in biological processes. Despite being found in nutrient-poor waters, coral reefs are highly productive ecosystems that support high biodiversity. The high productivity of corals is largely attributed to symbiotic single-celled algae found within coral tissue. Diazotrophs, or nitrogen-fixing bacteria, are also found within coral tissue and are important for converting inorganic nitrogen into useable forms for photosynthesis. To examine the effect of nutrient concentration on diazotroph diversity, molecular techniques will be used to determine the diversity of bacteria in the water column and coral tissue from nutrient-poor and nutrient-rich environments (Pohue, Hawai‘i and Leleiwi, Hawai‘i, respectively).
“Pathogenicity of Vibrio parahaemolyticus in the Ala Wai Canal, HI”
Mentor: Grieg Steward
Vibrio parahaemolyticus is an abundant bacteria found in most coastal waters of the world. This bacterium is naturally found inhabiting brackish waters. Some strains of V. parahaemolyticus have been found to be pathogenic to humans. Introduction of the species into humans may be through ingestion of under cooked or raw shellfish as well as through open cuts and wounds. Investigation of the temporal, spatial, and seasonal changes in abundance of this species is essential in efforts to predict severity of human infection and risks that are posed by the species in coastal waters. The goal of the project this semester is to be isolate strains that have been screened for molecular markers for pathogenicity. These will then be sequenced compared to other isolates that have been screened for molecular markers of pathogenicity.
“Reproducing oceanographic and atmospheric processes in a rotating tank to demonstrate conceptual principals in undergraduate classes for non-majors”
Mentor: Chris Measures, Niklas Schneider, Eric De Carlo
Physical oceanography and meteorology classes are primarily taught by explaining theories using mathematics and computer generated models, but rarely through demonstrations. This is because the processes occur on a global scale which is often difficult to duplicate on a small scale, there is little or no written material to guide laboratory demonstrations and there is no equipment capable of reproducing these phenomenas. The goal of my project is to produce a lab to be used in the OCN 201 Lab section of a course taught by the Oceanography Department at University of Hawai‘i. A recent acquisition of a rotating table, driven by a variable speed motor, equipped with a rotating frame video camera and fluid tanks, makes this feasible. Adapting materials from a recently produced booklet, Weather in a Tank, I intend to develop an experiment, or series of experiments, that will demonstrate the principles of Ekman pumping, Coriolis effect, density currents.
“Mapping Shoreline Change, using digital imaging and Orthophotography on Maui, Hawai‘i”
Mentor: Charles Fletcher
Coastal systems are dynamic environments of change governed by the inland environment, weather, currents, and tides. Here in Hawai‘i the coastal zone is effected by both natural and anthropogenic factors. Extreme tides and storm events cause coastal change and beach loss through migration of sediments. Coastal and beach development change the way these factors affect the coastal zone. Rising ocean waters due to global climate change may also began to affect coastal zones here in Hawai‘i. The objective of my project will be to document shoreline change on Maui coastlines using digital orthophotography and NOAA topographic maps. This will allow for determining the annual erosion rate to be used by shoreline managers and planners in Maui county.
“Evaluation of Clostridium perfringens and water quality along the Eastern Coast of Hawai‘i Island”
Mentor: Tracy Wiegner, Misaki Takabayashi, and Jason Turner
Clostridium perfringens is a gram-positive anaerobic bacterium, which can be used as an effective indicator of water pollution. It is found in soils and sewages where it accumulates and eventually seeps into the watershed and the coastal marine ecosystem. This study aims to identify C. perfringens presence at various sites along the Eastern Coast of Hawai‘i Island. PCR will be incorporated to identify the presence or absence of C. perfringens, and will be analyzed to find correlations with water quality parameters and coral health.
“Assessing Soil Carbon (C) with Diffuse Reflectance Spectroscopy”
Mentor: Greg Bruland
Soil carbon (C) is an important pool in the global C cycle, has been shown to increase soil fertility and water holding capacity, and provides an energy source for microbes. Traditional methods to measure soil C are very time consuming and generate toxic byproducts. Diffuse Reflectance Spectroscopy (DRS) offers a rapid, non-toxic, and non-destructive method to measure soil C based on the reflectance spectra of illuminated soils. However this method is relatively new and requires more testing on various soil types and parent materials. The goal of my project this semester is to use DRS to assess soil C in Hawaiian soils..
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