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Evening at Egan
Annual UAS Fall Semester Lecture Series -
One Campus, One Book
One Campus, One Book is the common reading program at UAS-Juneau. -
Writing Center
The Writing Center advises students from all disciplines on writing projects.
Recent Submissions
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Compartmental modeling for the neophyte: An application of Berkeley-MadonnaCompartmental modeling serves as a necessary framework in many fields, especially biomathematics and ecology. This article introduces readers to a user-friendly approach to constructing compartmental models and solving the resulting systems of differential equations to simulate real-world applications. The platform used is Berkeley Madonna, a software package that has an intuitive graphical interface which empowers users—even those with limited mathematical and programming backgrounds—to focus on modeling concepts rather than mathematical or programming intricacies. This makes Berkeley Madonna an ideal platform for students, educators, and researchers.
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The decolonization of Arctic library and archives metadata (DALAM) thematic network at the University of the ArcticIn 2022, the Polar Libraries Colloquy created a thematic network within the University of the Arctic thematic network’s structure to address the decolonization of metadata. Metadata, including archival description, subject headings, and other descriptive terminology, sometimes includes terms that are offensive to Indigenous peoples, incorrect, or too general to be useful. The purpose of the Decolonization of Arctic Library and Archives Metadata (DALAM) thematic network is to create an alliance of librarians, archivists, and other information professionals working in metadata decolonization. The network, provisionally approved in 2022, focuses on member education and information as well as resource sharing with the goal of improving efficiencies in circumpolar metadata decolonization efforts. This chapter details the creation of DALAM, its purpose, and its future activities.
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Eroding permafrost coastlines release biodegradable dissolved organic carbon to the Arctic OceanCoastal erosion mobilizes large quantities of organic matter (OM) to the Arctic Ocean where it may fuel greenhouse gas emissions and marine production. While the biodegradability of permafrost‐derived dissolved organic carbon (DOC) has been extensively studied in inland soils and freshwaters, few studies have examined dissolved OM (DOM) leached from eroding coastal permafrost in seawater. To address this knowledge gap, we sampled three horizons from bluff exposures near Drew Point, Alaska: seasonally thawed active layer soils, permafrost containing Holocene terrestrial and/or lacustrine OM, and permafrost containing late‐Pleistocene marine‐derived OM. Samples were leached in seawater to compare DOC yields, DOM composition (chromophoric DOM, Fourier transform ion cyclotron resonance mass spectrometry), and biodegradable DOC (BDOC). Holocene terrestrial permafrost leached the most DOC compared to active layer soils and Pleistocene marine permafrost. However, DOC from Pleistocene marine permafrost was the most biodegradable (33 ± 6% over 90 days), followed by DOC from active layer soils (23 ± 5%) and Holocene terrestrial permafrost (14 ± 3%). Permafrost leachates contained relatively more aliphatic and peptide‐like formulae, whereas active layer leachates contained relatively more aromatic formulae. BDOC was positively correlated with nitrogen‐containing and aliphatic formulae, and negatively correlated with polyphenolic and condensed aromatic formulae. Using estimates of eroding OM, we scale our results to estimate DOC and BDOC inputs to the Alaska Beaufort Sea. While DOC inputs from coastal erosion are relatively small compared to rivers, our results suggest that erosion may be an important source of BDOC to the Beaufort Sea when river inputs are low.
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Tidal Echoes 2004Tidal Echoes 2004 features the work of the students, faculty, and staff of the University of Alaska Southeast.
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ONeSAMP 3.0: Estimation of effective population size via SNP data from one populationThe genetic effective size (Ne) is arguably one of the most important characteristics of a population as it impacts the rate of loss of genetic diversity. Methods that estimate Ne are important in population and conservation genetic studies as they quantify the risk of a population being inbred or lacking genetic diversity. Yet there are very few methods that can estimate the Ne from data from a single population and without extensive information about the genetics of the population, such as a linkage map, or a reference genome of the species of interest. We present ONeSAMP 3.0, an algorithm for estimating Ne from single nucleotide polymorphism (SNP) data collected from a single population sample using Approximate Bayesian Computation and local linear regression. We demonstrate the utility of this approach using simulated Wright-Fisher populations, and empirical data from five endangered Channel Island fox (Urocyon littoralis) populations to evaluate the performance of ONeSAMP 3.0 compared to a commonly used Ne estimator. Our results show that ONeSAMP 3.0 is is broadly applicable to natural populations and is flexible enough that future versions could easily include summary statistics appropriate for a suite of biological and sampling conditions. ONeSAMP 3.0 is publicly available under the GNU license at https://github.com/AaronHong1024/ONeSAMP_3.
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Tidal Echoes 2005Tidal Echoes 2005 features the work of the students, faculty, and staff of the University of Alaska Southeast.
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Tidal Echoes 2006Tidal Echoes 2006 features the work of the students, faculty, and staff of the University of Alaska Southeast.
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If you choose not to decide... Alaska’s budgeting process in 2023Alaska in 2023 is experiencing the first results of the new election system—the top-four all-party primary and Ranked Choice Voting. So far, that system seems to be generating results consistent with what advocates expected; a more moderate and collegial policy-making environment, and possibly even more sensible budgetary policy. This, coupled with relatively strong (though declining) oil prices, and abundant sovereign wealth led to a relatively low-drama, low-conflict budgeting process in spring 2023, as well as relatively moderate budgeting outcomes.
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Increasing multi-hazard climate risk and financial and health impacts on northern homeownersCurrently, more than half of the world’s human population lives in urban areas, which are increasingly affected by climate hazards. Little is known about how multi-hazard environments affect people, especially those living in urban areas in northern latitudes. This study surveyed homeowners in Anchorage and Fairbanks, USA, Alaska’s largest urban centers, to measure individual risk perceptions, mitigation response, and damages related to wildfire, surface ice hazards, and permafrost thaw. Up to one third of residents reported being affected by all three hazards, with surface ice hazards being the most widely distributed, related to an estimated $25 million in annual damages. Behavioral risk response, policy recommendations for rapidly changing urban environments, and the challenges to local governments in mitigation efforts are discussed.
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Responses of chlorophyll a content for conchocelis phase of alaskan porphyra (bangiales, rhodophyta) species to environmental factorsInvestigations were performed on variations of photosynthetic pigment in conchocelis of Alaskan Porphyra species, P. abbottae (Pa), P. pseudolanceolata (Pe), P. pseudolinearis (Pi) and P. torta (Pt), in response to environmental variables. Conchocelis were cultured under varying conditions of irradiance (0, 10, 40 and 160 µmol photons m-2s-1), nutrient concentration (0, f/4, f/2 and f) for up to 60 days (with temperature 11°C and salinity 30ppt). Chlorophyll a (Chl a ) content was measured by spectrophotometry. Results indicated that Chl content varied with different culture conditions and species. Photosynthetic pigment was significantly affected by irradiance, nutrient concentration and culture duration, including some interactions of major factors for different species. Light had the most obvious influence on pigment content. For all four species and culture conditions tested, the higher Chl a content (3.6-8.6 mg/g.dw) generally occurred at 0-10 µmol photons m 2 s 1than at higher irradiances (≥40 µmol photons m-2s-1 ) culture. For all culture conditions, Chl a content in conchocelis culture with no nutrients added was the lowest. Although there was some difference in Chl a content for cultures with f/2-f nutrient concentration, it was not statistically significant. ANOVA results showed that culture duration had influence on Chl a content of Pa, Pe and Pi species. However, pooled data analysis indicated there was no obvious difference in Chl content for four species of 10-60day culture. There were significant differences in photosynthetic pigment content for different species. Pa and Pi produced much higher pigment content than the other two species responding to different environmental conditions. Maximal Chl. a content (8.6 mg/g.dw) for Pa occurred at 0 µmol photons m-2s-1, f/2 nutrient concentration and 10 day culture duration. Pt contained the lowest pigment content for all culture conditions. Photosynthetic pigment remained relatively higher content under the complete darkness or the low irradiance continuously as long as 60 days for all tested species, which demonstrated the unique survival feature of Porphyra conchocelis. Variation patterns of pigment content, ecological significance and adaptation strategy to low or dark light conditions for microscopic conchocelis stage of Porphyra were discussed.
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Coexistence despite recruitment inhibition of kelps by subtidal algal crustsIn temperate subtidal reefs, kelp species often dominate light, while encrusting algae often dominate the substrate and are well adapted to low light conditions. Yet whether changes in algal crust cover impact recruitment dynamics of kelp species remains largely unexplored. To address this gap, we combined field surveys with laboratory and field experiments to investigate (1) the impact of algal crusts on kelp settlement and recruitment and (2) the potential effect such inhibition may have on density of subtidal kelps in a southeast Alaskan fjord. Experimental removal of algal crusts in the field resulted in dense kelp recruitment, whereas in plots where algal crusts dominated space, kelp recruitment was sparse. Kelp zoospores settled in the laboratory with no apparent selectivity for bare rock over crust surfaces, yet kelp sporophyte densities were reduced by 97 to 99% on non-coralline algal crust patches compared to bare rock, suggesting post-settlement recruitment inhibition. Despite such strong inhibition, we show that very low kelp recruit density, such as that observed in the algal crust dominated patches of our experiment, can yield high adult densities. Such observations are supported by positive correlations between kelp density and crust percent cover in field surveys of 1 m2 plots across 6 reefs, suggesting broad-scale coexistence. Thus, the strong ability of kelps to colonize bare substrata in this region appears to facilitate persistence of kelps despite strong dominance of space by certain algal crusts.
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Effects of density and substrate type on recruitment and growth of Pyropia torta (Rhodophyta) gametophytesDoes density affect recruitment and growth in the annual, blade phase of Pyropia sp., does self-thinning occur, and does substrate affect recruitment? These questions were investigated in laboratory-cultured Pyropia torta, a naturally occurring species in Alaska with mariculture potential. Three density levels were produced from conchospores. Measurements were made, initially at settlement and germination and, subsequently, at approximately 3-week intervals, in 12 randomly selected cultures from each density level. Settled spores, germlings, or growing blades were counted microscopically and standardized to unit area. Blade surface area was measured microscopically using image analysis software. Three density levels were still distinct at germination, but the high and medium levels were not significantly different. The germination rate of conchospores was highest at the medium density level, suggesting facilitation at moderate densities but inhibition at higher densities. Significant self-thinning occurred at each density level but differed among levels, while overall blade growth was about 10-fold greater at low density than at the other two levels. In a separate experiment, counts of attached spores per unit area on artificial substrate materials were greatest on materials with interstitial spaces large enough to trap spores until they become firmly attached.
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Opportunities, challenges and future directions of open-water seaweed aquaculture in the United StatesSeaweed aquaculture is a relatively young industry in the United States compared to Asian countries. Early attempts at seaweed aquaculture in California, Washington State, New York and the Gulf of Maine in the 1980s and 1990s did not result in commercial production but provided important lessons. Since 2010, commercial cultivation of kelp (Saccharina latissima, Laminaria digitata, and Alaria esculenta) and other seaweeds (Palmaria palmata and Porphyra umbilicalis) began in the Gulf of Maine and Long Island Sound. Seaweed aquaculture is now a fast-growing maritime industry, especially in New England. If seaweed aquaculture is to maintain its momentum, it is important to (1) emphasise the environmental benefits; (2) domesticate a variety of local species; and (3) diversify seaweed products for food, animal feed, phycocolloids, cosmeceuticals, nutraceuticals, and ultimately biofuels if it becomes economically viable due to the cost of production. The exclusive economic zone (EEZ) of the United States offers opportunities for expansion of seaweed aquaculture in an area greater than the entire land mass of the United States and with limited user conflicts. This study reviews the past and current status of seaweed aquaculture in the United States and discusses potential opportunities and challenges of open-water seaweed aquaculture.
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Oceanographic growth of seaweed data, morphometric data, and data from a Spotter BuoyOn publication, data files will be available through ScholarWorks@UA (https://scholarworks.alaska.edu/handle/11122/15071), an open data repository. The datasets generated during the current study are also available from the corresponding author on reasonable request.
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Mariculture research of Macrocystis pyrifera and Saccharina latissima in Southeast AlaskaThere has been increasing interest in Alaska regarding the commercial mariculture of kelp. Kelp farming can be an economic engine for coastal communities of Alaska. Other benefits include ecosystem services, including carbon sequestration and mitigation of eutrophication. In support of this interest, several kelp species have been examined for commercial potential. In the 1980s–1990s, experiments were performed on the giant kelp Macrocystis pyrifera. Female gametophytes were exposed to varying levels of chelated iron. Relatively low levels of chelated iron (1–5 μM) stimulated the onset of oogenesis. In contrast, higher iron concentrations inhibited egg production. Outplant experiments with Macrocystis in Sitka, AK showed growth in the winter and spring, slowing down to zero growth by the end of summer. Fertilizing outplants in August allowed plants to survive and grow during the ensuing winter. Mariculture experiments with Saccharina latissima carried out near Juneau, Alaska showed exponential growth for seeded lines set out from September to March. Optimal growth occurred for outplants in October–November, with growth rates of up to 5% per day. The best growth occurred when lines were 2–3 m below the surface. Growth rates declined in May–June corresponding to a decrease in inorganic nitrogen in the water. Slower growth also resulted in severe fouling.
