Global Environmental Science Theses

Permanent URI for this collectionhttps://hdl.handle.net/10125/60447

The Bachelor of Science Degree Program in Global Environmental Science (GES) is administered by the department of Oceanography in the School of Ocean and Earth Science and Technology of the University of Hawai‘i.

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Changes in the Ejected Products of the Eruptions of Halema'uma'u Crater, Kilauea, in 2009-2010: Implication for Eruption Processes
(University of Hawaiʻi at Mānoa, 2010) Poulain, Adrienne; Houghton, Bruce; Oceanography; Global Environmental Science
The Halema’uma’u eruptive activity from 2009 — 2010 is characterized by near continuous degassing and pulsating eruption of tephra, significantly different than the larger fountain eruptions typical of 200 century Kilauea eruptions. This study focuses on the varying volcanic processes influencing the eruptive activity, including rockfalls, spatter, filling and draining cycles, high standing lava surfaces, and deflation / inflation events. The morphology and size of the ejecta reflect these processes within the vent, and samples are collected almost daily with nine strategically placed buckets. The ejecta have been categorized into five main groups: juvenile vesicular, dense non-vesicular juvenile, recycled juvenile material, fresh / slightly altered wall rock, and heavily altered wall rock. The juvenile vesicular and dense non-vesicular juvenile fluxes reflect the activity beneath the free surface. The fluxes of recycled juvenile, fresh / slightly altered wall rock, and heavily altered wall rock reflect the stability of the vent walls. The varying componentry fluxes can be attributed to three major influences, the stability of the vent walls, the fluctuating supply of deeper magma, and influences of near surface activity.
Movements of the Male and Female Blue Shark in Response to Environmental Conditions
(University of Hawaiʻi at Mānoa, 2010) Gray, Michael; Weng, Kevin; Oceanography; Global Environmental Science
Quite little is known about the life of the Blue shark, Prionace glauca, and its role as a apex pelagic predator. Understanding the environment that the blue shark swims through allows the scientist to make conjectures about why the blue shark migrates in a particular manner. However, constant visual monitoring is too expensive to pursue, therefore, surgically attached Argos tags serve as a cheaper alternative to monitoring aquatic animals. In this study a combination of pop-up archival tags (PAT) and smart-position or temperature tags (SPOT) were used to track the movements of 87 blue sharks from June 24 2002-June 30 2006. Variables such as temperature, latitude, longitude, and light were monitored, while environmental conditions were queried from NOAA’s Ocean Watch Server. Using Matlab to combine location and environmental data allows for the development of a physiological ecology for the Pacific North East blue shark. Understanding where the blue shark migrates to and why provides a foundation for further queries such as how can fishing gear be altered to avoid excessive bycatch of the blue shark.
Characterization of the Physical Environment in He'eia Fishpond, O'ahu, Hawai'i
(University of Hawaiʻi at Mānoa, 2010) Benjamin, Lindsey; McManus, Margaret; Oceanography; Global Environmental Science
The physical characteristics of He’eia Fishpond are important in studying the fishpond system as a whole. Information about the flow rates and water exchange, the forces influencing water movement, and the physical gradients in the pond is essential to understanding the environment. Acoustic current meters were placed at the pond makahas, or openings, to collect data to make rating curves. Pressure sensors were used to collect pressure data for both flow rate calculations and frequency spectra. A YSI probe was used at the makaha and internal sites to monitor surface and bottom temperature and salinity. The majority (63%) of the water exchange with the environment occurs through the northeast corner, through sites TM and OM1. Most of the variability in the water flux is due to the tides, though a shift in the winds from Trade to Kona does have some effect. Surface and bottom gradients in temperature and salinity are due to colder, low salinity river inputs in the northwest and warmer, high salinity inputs along the eastern side of the pond. This thesis forms a physical framework for the continuing biological and chemical studies in He’eia Fishpond.
Analysis of Concentrations of Black Carbon in the Arctic
(University of Hawaiʻi at Mānoa, 2009) Sawano, Hirotaka; Clarke, Antony; Oceanography; Global Environmental Science
Black carbon (BC) is produced when fossil fuels and/or biomass is burned. Its dark color absorbs sunlight and releases heat. This feature is problematic when BC is deposited on snow because it can melt ambient snow by releasing heat. Despite the significance of black carbon, properties of BC have not been completely understood. This research focuses on concentrations of BC in northern Canada and in Greenland. By using a single-particle soot photometer (SP2), we analyzed concentrations of BC in snow from northern Canada. We also analyzed snow samples from Greenland to compare, and we found that concentrations of BC from Greenland are lower than those from Canada. Presumably this is because Greenland is an isolated place compared to Canada, and thus less BC is trapped in snowpack. Since we had a problem in calibration, we were not able to get real BC concentrations from snow samples. Hence, we decided to use arbitrary BC concentrations. We found spatial trends of concentrations of BC in Canada. Amongst samples from Canada, the closer to continental Canada samples are collected from, the more BC concentrations were found. Presumably the reason BC concentration in continental Canada is higher is that continental Canada is closer to urbanized areas and boreal forests that can have forest fires. This experiment reveals that our method (using a SP2 system to analyze BC concentration of snow samples) can be used for analyzing real soot concentration. The resolution of this calibration problem is expected.
Variation in Dinoflagellate Abundance Between Two Reef Sites with Varying Degrees of Anthropogenic Impact in Relation to Ciguatera Fish Poisoning
(University of Hawaiʻi at Mānoa, 2009) Mabardy, Rebecca; Bienfang, Paul; Oceanography; Global Environmental Science
Ciguatera literature contains anecdotal suggestions for a linkage between disturbances to reef environments and the incidence of ciguatera fish poisoning. Ciguatera is caused by dinoflagellates (Gambierdiscus spp.) that are consumed by herbivorous reef fish and subsequently by carnivores, including humans. It has been speculated that differences in dinoflagellate composition and/or abundance may result in disturbed reef environments and in turn subsequently influence the ciguatoxic status of fish. My investigation involves the comparison of dinoflagellate composition and abundance between two reef sites with varying degrees of anthropogenic impact. During May 2009 and August 2009, fifty-eight macroalgae samples were collected from two reefs on Maui, a location considered to be non-distressed (Olowalu) and a location considered distressed (Ka’anapali). Data on the frequency of ciguateric fish exists for these locations. The macroalgae samples were preserved using glutaraldehyde solution to quantify epiphytic dinoflagellate composition in the two locations. Compositional analysis quantified three groups of dinoflagellates, i.e. (1) Gambierdiscus spp. and Ostreopsis spp., 2) Prorocentrum spp., and 3) other dinoflagellates). Aliquots of some samples were also taken for isolation and culture and are to be used by others to identify dinoflagellate characteristics to better understand ciguatera poisoning. The epiphytic dinoflagellate of the genera Gambierdiscus spp. and Ostreopsis spp. dominated the numerical abundance, ranging between 73%-85% of the total dinoflagellates, in all samples. Significant differences in dinoflagellate variability or abundance were not apparent between the non-distressed Olowalu reef site and the distressed Ka’ anapali reef site (p<0.05). Comparing dinoflagellate abundances in May 2009 and August 2009 did not show significant temporal differences in dinoflagellate variability or abundance (p<0.05). Melanamansia sp. was the genus of macroalgae that was most frequently represented in the collections (37.9% of samples), and it supported a mean abundance of 29.9 Gambierdiscus spp. and Ostreopsis spp. cells per g wet wt macroalgae. Tubinaria ornata (representing 5.2% of the samples) was the macroalgae species that supported highest mean abundance of 90.9 Gambierdiscus spp. And Ostreopsis spp. cells per g wet wt macroalgae. The presence of toxic dinoflagellates genera in Hawai’i deserves future study on possible impacts of dinoflagellates on the coastal ecosystem and human health.
Modeling the Impacts of an Ocean Thermal Energy Conversion Plant on Plankton Populations in Kaneohe Bay
(University of Hawaiʻi at Mānoa, 2020) Wagenvoord, Jakkob; Powell, Brian; Oceanography; Global Environmental Science
Adoption of alternative energy is a key component in reducing adverse anthropogenic impacts on the environment. Ocean thermal energy conversion, or ORES has been considered as an alternative to conventional energy production due to its capability to provide consistent power with less environmental impacts than conventional powerplants. However, OTEC has been previously predicted and modeled to pose impacts towards the surrounding environment. These impacts include elevated nutrient concentrations near the effluent discharge point due to the addition of nutrient-rich waters sourced from depth to shallower waters. Previous studies and modeling efforts have assessed the impacts of an OTEC plant on the leeward coast of Oahu, however there is little knowledge on the impacts of an OTEC plant situated on the windward coast. Therefore, the effects of a 1OOMW OTEC plant in Kaneohe Bay on the biogeochemistry of the waters were modeled. This model was conducted using the Regional Ocean Modeling System (ROMS) to simulate ocean physics coupled to the Carbon, Ocean Biogeochemistry and Lower Trophics (COBALT) model to simulate biochemistry. In this model, a 100MW OTEC plant was simulated through the release of 420 cubic meters per second of surface water and 320 cubic meters per second of water drawn from 1000m depth in a combined discharge at a depth of 40 meters. The discharge point was located offshore of Mokapu Point, Oahu. Results showed changes well within natural variability on average for nutrients and plankton within Kaneohe Bay.
An Investigation of CO2 Signals Caused by Weather Disturbances in Mamala Bay
(University of Hawaiʻi at Mānoa, 2020) Barro, Anthony; Bushinsky, Seth; Sabine, Christopher; Oceanography; Global Environmental Science
With continued increase of atmospheric carbon dioxide concentrations due to human activity, it is important to maintain an understanding of the carbon dioxide (CO2) concentrations and cycles in coastal waters. Coastal CO2 fluctuations are highly variable in comparison to open ocean systems, they also differ in roles as sources and sinks for atmospheric CO2. This study was an investigation on the effects of weather events, such as Kona-storms, on CO2 concentrations and fluctuations in the coastal waters of Oahu's South-Shore. CO2 data has been collected in the coastal waters of O’ahu with the use of Moored Autonomous Partial-pressure CO2 (MAPCO2) sensors since 2008. These data were combined with hydrology data from the United States Geological Survey in order to detail weather disturbance effects on pCO2 cycles in the near shore system of Mamala Bay, Hawaii. Biological processes dominate the short-term CO2 fluctuations in the near-shore system, but these cycles can be disrupted by weather events and the effects that those weather events have on the biological activity in the system. We found that the disturbances were identifiable in the data record by CO2 signals. High CO2 signals and low signals were identified, the highest and lowest both correlated with weather disturbances prior to the signals.
Nā Wai Momona o Meheanu: Correlating He'eia Fishpond Plankton Community Abundance and Distribution with Environmental Conditions
(University of Hawaiʻi at Mānoa, 2019) Machado, No'eau; Alegado, Rosanna; Oceanography; Global Environmental Science
The state of Hawai‘i is overwhelmingly reliant on imported food. Improving Hawai‘i’s food security and sustainability, require advancements in local food production systems. Native Hawaiian fishponds (loko i‘a) are historically important systems of aquaculture. Fish production in these systems rely on nutrient availability and physical factors (dissolved oxygen, water temperature, salinity, conductivity, pH), that influence plankton community composition at the base of the loko i‘a food web. Runoff carries allochthonous nutrients from land to the nearshore. We hypothesize that the majority of loko i‘a were built at the base of watersheds to take advantage of nutrient fluxes that would stimulate primary production. This project examines the relationship between physical and geochemical parameters and plankton communities within He‘eia Fishpond on O’ahu. Between October 2017-February 2019, discrete nutrient sampling of dissolved inorganic nutrients and direct cell counts of autotrophic and heterotrophic plankton were undertaken to characterize the physical and biogeochemical conditions from from 14 sites within He‘eia Fishpond and 2 control sites in He‘eia Stream and nearby reef. As coastal loko i’a were brackish water ecosystems, we predict that fishpond sampling sites with salinity ranging from 15-25 PSU will have the highest autotroph abundance. While understanding autotroph abundance is of importance to loko i‘a stewards, diatoms - the primary food source for juvenile fish are of greatest concern. We found that heterotrophs dominated sites nearest He‘eia Stream whereas autotrophs dominated sites nearest to Kane‘ohe Bay. The relative abundance of diatoms was only 3-8% with highest values at sites with salinity ~ 5-15 PSU, adjacent to He‘eia Stream. As restoration has lead to increased mixing of the loko i‘a and decreased salinity, we predict that the relative abundance of diatoms will increase, increasing the carrying capacity for fish production. This research improves our understanding of the complex relationship between plankton biogeography and physicochemical parameters so that fishpond stewards can identify conditions that promote maximal fish productivity.
Standoff Categorization of Organics for Planetary Exploration
(University of Hawaiʻi at Mānoa, 2017) Muchow, Dalton; Misra, Anupam; Oceanography; Global Environmental Science
Using passive reflectance spectroscopy, organic material has been detected on near-Earth asteroids, furthering the search for life elsewhere in the universe. This discovery is a significant step, but quickly categorizing found organics as biogenic “life” or non-biogenic organic molecules allows scientists and the media to appropriately respond to findings. Our near-UV biofinder has proven its ability to rapidly and remotely distinguish organic fluorescence from mineral fluorescence, and shows potential to further separate biogenic from non-biogenic organics. Using Time Resolved Laser Induced Native Fluorescence (TRLINF) and Fluorescence Spectroscopy, the spectra and response times of biogenic (leaves, shells, etc.) and non-biogenic (polypropylene, polyethylene, benzene, etc.) materials can be compared. The ability to conclusively categorize organic material with spectra collected from long distances alone would be a significant improvement in the automation, efficiency, and contamination mitigation of life-finding projects. These preliminary results show potential for zones of limited response, where subcategories of organics can be partially classified by their spectral response. Notably, a zone of interest between 380nm - 400nm while using 355nm laser excitation shows responses of all tested material groups, except biogenic substances. Accurately categorizing newly discovered organic materials based on spectral data alone will allow scientists to accurately report on the composition and significance of their findings to the scientific community for further research and general population interests.
Analyzing Groundwater and Algal Distribution in Maunalua Bay Using GIS Software
(University of Hawaiʻi at Mānoa, 2015) Williams, Faline; Thomas, Florence; Oceanography; Global Environmental Science
Algal distribution and population growth can be controlled by the nutrient loading within the ecosystem. One source of these nutrients can be groundwater. The distribution of algae was mapped for Maunalua Bay, O‘ahu, Hawai‘i for comparison to the distribution of nutrient delivery to the system. In this study, data collected on algal distribution at two sites within the bay, Black Point and Wailupe, were mapped using QGIS. These maps were used to visually compare the distribution of algae to the distribution of groundwater. Distribution of groundwater was estimated from the distribution of passive tracers fro groundwater, salinity, silicate and radon distribution obtained from Nelson et al (submitted). The majority of the algal population occurs in areas of low groundwater influence except for the Brvopsis pennta and Acanthopohora spicifera species. More invasive species were observed at the Wailupe site, the site of less nutrient loading as opposed to Black Point.
Desalination and Bio-Purification Using Hydrates
(University of Hawaiʻi at Mānoa, 2013) Chinaka, Bryan; Masutani, Stephen; Oceanography; Global Environmental Science
Scarcity of potable water is one of the main problems that must be faced by many societies and the world in the 21st century. Currently, water is purified using a variety of methods to remove unwanted chemical and biological contaminants. These processes, however, tend to require significant energy and the capital and operating costs can be large. My research focused on investigating the viability of using hydrates to purify water. Solid hydrates form from water (like ice) and this crystallization process generally excludes contaminants. Experiments were conducted in which hydrates were formed using saline solutions of known concentrations or water containing proxies for biological contaminants. The levels of salt or biological contaminants were measured before and after hydrate formation to determine whether the hydrates decontaminated the water. Results from multiple tests suggest that hydrates can be used as a first step in a water purification process.
Laboratory Experiments of Tidal Dispersion Around Irregular Boundaries
(University of Hawaiʻi at Mānoa, 2008) Kusumoto, Yoshimu; Pawlak, Geno; Canals,Miguel; Oceanography; Global Environmental Science
Coastal eddy formation and dissipation are important for the dispersal of biogenic material and pollutants. Eddies are commonly generated by tidal currents that flow near rough boundaries. Previous field experiments with drifters have been used to investigate the tidal currents in Puget Sound, Washington, and have shown that eddies are generated due to tidal flow past headlands. These drifter deployments have revealed irregular patterns of tidal dispersion. In this study, laboratory experiments are used to examine particle trajectories by tracking beads in a water tank to better understand particle dispersion in oscillatory flow. In the laboratory experiments, turbulent dispersion is investigated around a rough boundary in both regular and irregular oscillatory flows. Each irregular oscillatory flow is composed of different sine waves. The average dispersion over a tidal cycle is estimated for each flow configuration as a function of space and is mapped out. The results indicate that the dispersion field depends on the patter of oscillation.
Cross-Reef Transport of Invasive Macroalge on the Northern Reef Flat of Coconut Island in Kane'ohe Bay, Hawai'i
(University of Hawaiʻi at Mānoa, 2007) Weston Jr., Joseph; Stimson, John; Oceanography; Global Environmental Science
Cross-reef transport of invasive macroscopic algae may be significant to algal accumulation at downstream sites. On the northern reef flat of Coconut Island in Kane’ohe Bay, Hawai’i there is a substantial population of Gracilaria salicornia and Acanthophora spicifera, with algal accumulation on the leeward reef slope. The goal of this project was to study possible modes of algal transport across the reef flat. Algae were measured at several sites along the leeward edge of the reef flat and compared to weather data from Coconut Island. There is no linear correlation between algal biomass and wind speed, and seasonality appears to be the best predictor for algal transport. However, multiple regression analysis shows that maximum wind speed and water temperature are significant (P < 0.05). This suggests that algal accumulation is dependent on productivity and wind events.
A Study of Submarine Groundwater Discharge on Two Shorelines of Oahu
(University of Hawaiʻi at Mānoa, 2006) Bukunt, Justin; Glenn, Craig; Oceanography; Global Environmental Science
Both terrestrial and marine forces drive the flow of fluids into nearby coastal waters. Comparing submarine groundwater discharge (SGD) along coastlines of Oahu, differences in the characteristics of groundwater flow are examined, particularly with respect to salinity and nutrient variations. A salinity/temperature probe tested water sources allowing for immediate data collection. Water samples were taken along a transect line via hand-dug pits from the shoreline up the beach face. There is a direct relationship between water samples having low salinity value and high nutrient (N,P) content. This correlation can be shown by examining beach face to shoreline data. These results may be significant in that marine ecosystems can be strongly influenced by minute changes in dissolved nutrient concentrations to coastal marine waters. Water samples were collected from two separate coastlines: Aina Haina, southeast Oahu (November 2005 & May 2006), and Sunset Point, northeast Oahu (November 2005). Salinity was used as a natural conservative tracer because its chemical behavior is controlled by physical processes and its physical transport is faster than any chemical processes that it alters. Concentrations of nitrate, nitrite, phosphate, ammonium and silica were used as geochemical indicators that may be of biogeochemical interest at these coastal sites. The water sampling techniques used were hand-dug pits and offshore water sample collection. A noticeable submarine spring and beach face seepage was discovered at Kawaiku’i Beach Park area, in Aina Haina. The spring exists the beach at the base of a resident’s beach access exhibiting pronounced elevations in dissolved nutrients relative to normal seawater (i.e. at a maxima of 1.71µM PO4, 213.8µM Si(OH)4, 137.2 µM NO3, 0.30 µM NH4, 2.33 µM TP, and 69.6 µM TN at 0.88 psu salinity). Dissolved nutrient concentrations measured for samples from hand dug pits in the nearby beachface showed very similar nutrient/salinity values to that of the spring. Transect data of water samples measured seaward from the spring at low tide showed strong linear correlation between decreasing salinity and increasing concentrations of individual nutrient species. These results show that groundwater locally contributes a significant quantity of these species to the ocean in the vicinity of Maunaulua Bay, and also that these groundwaters are rapidly mixed with normal, nutrient-depleted seawater within about 100-200 meters of the identified source input. At Sunset Point, springs are absent. There, use of hand-dig pits are required to reach water levels below the beach face. Within the pits, concentrations of nitrate, phosphate, silica and ammonium showed weak linear correlation with salinity. Nonetheless, the nutrient concentrations at Sunset Point were significantly greater (with maxima of 1.76 µM PO4, 23.35 µM Si(OH)4, 137.20 µM NO3, and 4.61 µM NH4, at a salinity of 12.77 psu) than those obtained from Aina Haina, possibly due to anthropogenic influences. The results from these two locations may help to elucidate the importance that SGD in Hawaii plays in the delivery of terrestrial water and dissolved nutrients to coastal marine waters. Further field work examining SGD needs to be done to determine its extent islandwide.
Nutrients Input to South Kaneohe Bay During Storms
(University of Hawaiʻi at Mānoa, 2005) Ha, Honghuynh; De Carlo, Eric; Oceanography; Global Environmental Science
After diversion of sewage from the Bay in 1978, water quality in Kaneohe Bay has dramatically improved, and coral reefs have shown signs of recovery. Most recently the water quality in Kaneohe Bay has become even more “pristine”. However, “bubble algae” still exist in Kaneohe Bay and their abundance even increased significantly based on results of a 1990 survey. Therefore, it is reasonable to hypothesize that there remains an overload of nutrient inputs from streams to Kaneohe Bay during storms that affect bay ecosystems. This study collected and analyzed water samples from streams during storms in November 2003 to May 2004. Two stations were located in the South Kaneohe watershed. One station was in Hoomaluhia botanical garden at Luluku Stream. This station has minimal pollution since it is situated in the conservation zone. The second station was located down stream in an urban zone consisting mostly of residential and commercial areas. Additional water samples were collected manually in Southern Kaneohe Bay. The concentration of phosphate, nitrate and nitrite, ammonium, and silicon dioxide were determined in the water samples. Waters from Luluku and Kaneohe Streams had higher concentrations of nutrients during storms than concentrations observe in surface water during base flow. The concentrations of nitrate suggest an influence from human activities. Nutrient loads in Kaneohe Stream during storms affected the water quality of South Kaneohe Bay. High levels of dissolved nutrients in South Kaneohe Bay likely represent a cumulative effect of freshwater input from Kaneohe, Keahaala, and Kawa Stream. These streams input accounted for most of phosphate, silica dioxide, and about fifty percent of nitrate plus nitrite in Southern Kaneohe Bay.
Soil Characteristics of Champagne Vineyards
(University of Hawaiʻi at Mānoa, 2003) Murard, Xavier; De Carlo, Eric; Oceanography; Global Environmental Science
The Seedling Skirmish: The Effect of Metrosideros Polymorpha & Psidium Cattleyanum Plant Neighbors in Hawai'i
(University of Hawaiʻi at Mānoa, 2019) Wong, Amanda; Barton, Kasey; Oceanography; Global Environmental Science
Invasive species pose a major threat to native biodiversity across the planet, especially in island plant communities that appear to be particularly vulnerable to invasive species. However, the role of neighboring plants in native plant displacement remains unclear given the lack of experiments designed to test neighbor effects explicitly. I experimentally investigated whether invasive plants impose neighbor effects on native plants as a potential mechanism underlying native species declines in Hawaiian forests. Plant neighbor effects were tested in a controlled greenhouse experiment using two ecologically important species in the Myrtaceae family: the native Metrosideros polymorpha and non-native Psidium cattleyanum. Plant performance was measured as survival and growth of plants, grown in pots alone, with a conspecific, or heterospecific neighbor. Results indicate that P. cattleyanum is a stronger performer than M. polymorpha with a lower mortality rate and higher growth rate. The P. cattleyanum intraspecific neighbor treatment had the lowest mean change in leaf number and height. Surprisingly, in contrast to predicted competition effects, M. polymorpha grown with neighbors had significantly greater shoot biomass, then M. polymorpha grown alone. This could reflect a shift in biomass towards increased growth aboveground due to shading by neighbors, or could indicate a facilitative effect of neighbors during early seedling growth. Overall, these results indicate that the presence of a conspecific neighbor has a negative effect on plant growth, yet a heterospecific neighbor has a positive effect, suggesting that competition effects are stronger with conspecific neighbors.
Ka Pilina o nā Hā'uke'uke A Study of the Size and Genetic Connectivity of the Culturally Significant Sea Urchin (Colobocentrotus atratus) in Hawai'i
(University of Hawaiʻi at Mānoa, 2019) Keliipuleole, Ku'i; Toonen, Robert; Oceanography; Global Environmental Science
Overharvesting without proper regulation is a common and growing problem for many Hawaiian invertebrates. This paper reports differences in size and the population genetic structure of the intertidal marine urchin species Colobocentrotus atratus, also known as Hā‘uke‘uke, from the islands of Kaua‘i, O'ahu, Maui and the Big Island of Hawai'i. Individuals from the northern shores of each island were significantly larger (in terms of length, width and height) than congeners on the southern shores of the same island. Based on mitochondrial cytochrome oxidase subunit 1 (COI) sequences, genetic differentiation among sampling sites on each island were uniformly low (pairwise Fsr = 0.01 to 0.08), with only Maui and O‘ahu being significantly differentiated. In contrast, exact tests of population differentiation revealed that none of the populations are drawn from the same gene pool, and that although hd ‘uke ‘uke populations in Hawai‘i currently exhibit high gene flow, the populations are not freely interbreeding. Thus, any massive loss of individuals from a population (such as overharvest) would have major impacts for the remaining individuals on that island. We recommend these results on Ha ‘uke ‘uke population structure be used to inform better management practices for this important cultural resource.
Impact of Physical Reef Characteristics on Calcification Rates of the Kāne'ohe Bay Barrier Reef
(University of Hawaiʻi at Mānoa, 2019) Howins, Noah Michael; De Carlo, Eric; Sabine, Christopher; Oceanography; Global Environmental Science
This study elucidates the challenge of quantifying environmental parameters that exert control over calcification by providing an in-situ analysis of how localized variations in reef characteristics impact calcification rates, in addition to comparing calculated calcification rates with those previously published for the barrier reef of Kane‘ohe Bay and mesocosm experiments. NEC and was compared against wind speed (R2=0.08), seawater temperature (R2=0.42), seawater salinity (R2=0.44), and time of sampling within our midday sampling period (R2=0.00). Furthermore, we compared the results of this study with previously published literature on reef-wide calcification rates both for Kane‘ohe Bay and mesocosm experiments. The NEC value determined herein (56.9 ± 32.6 mmol *m-2 *hr-1 ) is comparable to a previous bay-wide estimate (48.3 ± 13.5 mmol *m-2 *hr-1), but larger than found in mesocosm work done with a purely coral community composition (11.2 ± 4.9 mmol *m-2 *hr-1). NEP values exhibited greater variability between this study, a previous bay-wide study, and previous mesocosm work at 210.1 ± 114.6 mmol *m-2 *hr-1, -48.3 ± 16.9 mmol *m-2 *hr-1, and 27.7 ± 4.4 mmol *m-2 *hr-1 respectively. The results of this study highlight the high degree of calcification and production variability seen within Kane‘ohe Bay, the impacts of sub-diel NEC and NEP on the CO2 system in seawater, and illustrate the need for further characterization of parameters affecting NEC and NEP parameters not examined in this study.
Tracking Shoreline Morphology Using Drone Based Photogrammetry on Rockpiles Beach in Hawai'i
(University of Hawaiʻi at Mānoa, 2019) Diaz, Ulises; Guiles, Martin; Oceanography; Global Environmental Science
Beaches around the world have huge economic, social, and recreational value to cities, which are based primarily on the aesthetic quality of the beach. There are multiple factors that contribute to coastal erosion such as wind, sediment, wave, and tidal forces. In addition, each coastal area has its own unique geomorphological, geological, and biological systems that makes coastal topography surveys challenging. Beach profiling estimates the total volume changes of sediment in any given coastal area and shows the health of the beach. These surveys inform and dictate possible management schemes needed to heal beaches, such as, beach recharge, barrage construction, beach nourishment, and manage retreat methods all to reduce the rate of coastal erosion. Generally, traditional ground-based surveys use 2-dimensional horizontal shoreline and vertical beach profiles, but tend to have limitation in expenses and are time consuming for larger surface areas. Unmanned Aerial Vehicle (UAV) photogrammetry (the science in using photography in surveying and mapping to measure distances between objects) is a simpler and cheaper way in approaching large-scale data collection, especially in capturing the rapid coastal changes caused by natural processes. This project intends to accurately quantify the impact of high swell activity on beach faces over the course of a season using UAV drones with cameras and photogrammetry with the software Agisoft. The project will focus on one beach, Rockpiles, over the 2017-18 academic year.

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