Implications of Different Nitrogen Input Sources for Primary Production and Carbon Flux Estimates in Coastal Waters

The coastal Gulf of Mexico (GOM) and Coastal Sea off Korea (CSK) both suffer from eutrophication and/or hypoxia, both of which are driven mainly by humans. We compared two different regions with different nitrogen input sources to estimate organic carbon fluxes and predict future carbon fluxes based on our model scenarios. This research focuses on how we take advantage of carbon-nitrogen cycling and ecological consequences to estimate the effects of future nutrient inputs. We tested the Rowe and Chapman (RC02) three-zone hypothesis of hypoxia using two different methods. We found that RC02 applied only in certain seasons and that a major nutrient input source is necessary. We used both nutrient/salinity relationships and a N-mass balance model to identify three different zones, each with different productivity and carbon fluxes. We define the brown zone as having a linear nutrient/salinity relationship, where physical forcing (river flow) dominates over local production, and defined the blue zone as having nutrient (N or Si) concentrations < 1 μM. The green zone, with variable nutrient concentrations, occurs between them. Based on our N-mass balance model results, we could set the potential primary production rate in the brown zone of the GOM and CSK, respectively, as over 2 (GOM) and over 1.5 gC m^-2 day^-1 (CSK). In the green zone, production was between 0.1 to 2 (GOM) and 0.3 to 1.5 gC m^-2 day^-1 (CSK) and in the blue zone less than 0.1and 0.3 gC m^-2 day^-1, respectively. From our results, we have estimated the fluxes of nitrogen via the atmosphere, groundwater, and river to the ocean, based on observational and literature data. The coastal Gulf of Mexico receives nitrogen predominantly from the Mississippi and Atchafalaya Rivers and AN-D is only a minor component in this region. However, in the coastal sea off Korea, either groundwater or atmospheric nitrogen deposition is more important controlling factors of our model results. In the future, we need to consider collecting data on both groundwater and AN-D inputs in investigations of chemical cycling in the coastal ocea

Area-Optimized Fully-Flexible BCH Decoder for Multiple GF Dimensions

Recently, there are increasing demands for fully flexible Bose Chaudhuri Hocquenghem (BCH) decoders, which can support different dimensions of Galois fields (GF) operations. As the previous BCH decoders are mainly targeting the fixed GF operations, the conventional techniques are no longer suitable for multiple GF dimensions. For the area-optimized flexible BCH decoders, in this paper, we present several optimization schemes for reducing hardware costs of multi-dimensional GF operations. In the proposed optimizations, we first reformulate the matrix operations in syndrome calculation and Chien search for sharing more common sub-expressions between GF operations having different dimensions. The cell based multi-m GF multiplier is newly introduced for the area-efficient flexible key-equation solver. As case studies, we design several prototype flexible BCH decoders for digital video broadcasting systems and NAND flash memory controllers managing different page sizes. The implementation results show that the proposed fully-flexible BCH decoder architecture remarkably enhances the area-efficiency compared with the conventional solutions.112Ysciescopu

Saturating relationship between phytoplankton growth rate and nutrient concentration explained by macromolecular allocation

Phytoplankton account for about a half of photosynthesis in the world, making them a key player in the ecological and biogeochemical systems. One of the key traits of phytoplankton is their growth rate because it indicates their productivity and affects their competitive capability. The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed yet the mechanisms behind the relationship remain elusive. Here we use a mechanistic model and metadata of phytoplankton to show that the saturating relationship between growth rate and nitrate concentration can be interpreted by intracellular macromolecular allocation. At low nitrate levels, the diffusive nitrate transport linearly increases with the nitrate concentration, while the internal nitrogen requirement increases with the growth rate, leading to a non-linear increase in the growth rate with nitrate. This increased nitrogen requirement is due to the increased allocation to biosynthetic and photosynthetic molecules. The allocation to these molecules reaches a maximum at high nitrate concentration and the growth rate ceases to increase despite high nitrate availability due to carbon limitation. The produced growth rate and nitrate relationships are consistent with the data of phytoplankton across taxa. Our study provides a macromolecular interpretation of the widely observed growth-nutrient relationship and highlights that the key control of the phytoplankton growth exists within the cell

Saturating growth rate against phosphorus concentration explained by macromolecular allocation

The saturating relationship between phytoplankton growth rate and environmental nutrient concentration has been widely observed, yet the mechanisms behind the relationship remain elusive. Here, we use a mechanistic model of phytoplankton and show that the saturating relationship between growth rate and phosphorous concentration can be interpreted by intracellular macromolecular allocation. At low nutrient levels, the diffusive nutrient transport linearly increases with the phosphorous concentration, while the internal phosphorous requirement increases with the growth rate, leading to a non-linear increase in the growth rate with phosphorous. This increased phosphorous requirement is due to the increased allocation to biosynthetic and photosynthetic molecules. The allocation to these molecules reaches a maximum at high-phosphorous concentration, and the growth rate no longer increases despite the rise in phosphorous concentration. The produced growth rate and phosphorous relationships are consistent with the data of phytoplankton across taxa. Our study suggests that the key control of phytoplankton growth is internal, and nutrient uptake is only a single step in the overall process

Picture books about Korea and Korean Americans

Multicultural literature is beneficial to children to understand different cultures diversity in the global world. Koreans started to immigrate to the United States beginning in 1902. In spite of a lengthy Korean American immigration history, few children· s books portray Korea and Korean Americans. This study overviewed picture books about Korea and Korean Americans available in local libraries and universities and identified cultural values and themes in the Korean American picture books. This study also examined authenticity and stereotyping in the Korean American picture books. Few pictures books about Korea and Korean American have been published over the past 40 years in the United States. More books about Korea and Korean American need to be published to help children explore traditional Korean beliefs and values

Categorizing zonal productivity on the continental shelf with nutrient-salinity ratios

Highlights Identifying riverine influence on productivity in the northern Gulf of Mexico Use of nutrient/salinity plots to differentiate inputs from two rivers Verifying Rowe-Chapman (2002) hypothesis with in situ data Abstract Coastal ocean productivity is often dependent on riverine sources of nutrients, yet it can be difficult to determine how far the influence of the river extends. The northern Gulf of Mexico (GOM) receives freshwater and nutrients discharged mainly from the Mississippi and Atchafalaya Rivers. We used nutrient/salinity relationships to (i) differentiate the nutrient inputs of the two rivers and (ii) determine the potential extent of the zones where productivity is affected by each. We identified three different zones: one close to the coast having a linear nutrient/salinity relationship where physical forcing (river flow) dominates, one offshore with nutrient (N or Si) concentrations \u3c1 μM, and one between them with variable nutrient concentrations largely controlled by consumption by autotrophs. While in the GOM salinity/nutrient relationships varied systematically with distance from the two rivers in winter, this was not seen in summer. Thus, the methodology is not always applicable directly, because the boundaries of the different regions vary with river flow, overall nutrient flux, and grids of stations at the regional spatial scale (15–20 km in the GOM), rather than single sections are needed to determine boundaries

Reconstructing primary production in a changing estuary: A mass balance modeling approach

Estuarine primary production (PP) is a critical rate process for understanding ecosystem function and response to environmental change. PP is fundamentally linked to estuarine eutrophication, and as such should respond to ongoing efforts to reduce nutrient inputs to estuaries globally. However, concurrent changes including warming, altered hydrology, reduced input of sediments, and emergence of harmful algal blooms (HABs) could interact with nutrient management to produce unexpected changes in PP. Despite its fundamental importance, estuarine PP is rarely measured. We reconstructed PP in the York River Estuary with a novel mass balance model based on dissolved inorganic nitrogen (DIN) for the period 1994–2018. Modeled PP compared well to previous estimates and demonstrated a long-term increase and down-estuary shift over the study period. This increase occurred despite reductions in discharge, flushing time, DIN loading, and DIN standing stock over the same period. Increased PP corresponded to increased water temperature, decreased turbidity and light attenuation, and increased photic depth and assimilation ratio, suggesting that phytoplankton in the York River Estuary have become more efficient at converting nutrients into biomass primarily due to a release from light limitation. The increase in PP also coincided with the increasing occurrence of late summer HABs in the lower York River Estuary, including the emergence of a second bloom-forming dinoflagellate in 2007. Results demonstrate how changes concurrent with nutrient management could alter expected system responses and illustrate the utility of the mass balance approach for estimating critical rate processes like PP in the absence of observations

The Effect of Political Institutions on the Use of Citizen Participation Programs

Local governments use of citizen participation programs is influenced by external environments, especially in the form of political institutions. Local governments decide to expand or limit citizen participation in administrative decision-making processes in response to political uncertainties created by different types of political institutions. Despite the importance of institutional contexts, few studies have examined the effects of these political institutions on the use of citizen participation programs. This study empirically tested whether political institutions affect the adoption of citizen participation programs. The results suggest that the council-manager form of government increases both the adoption of citizen participation mechanisms and the use of citizen participation programs in functional areas, while nonpartisan elections are associated only with the adoption of citizen participation mechanisms. At-large elections show no statistical association with either type of citizen participation. These findings suggest that local political contexts play important roles in the adoption of bureaucratic practices such as citizen participation programs and still support the classical assertion that public dministration is closely connected to politics

The Influence of Contextual Factors on Collective Actions for Locating Facilities with Externalities: Applying the Institutional Collective Action Framework

This study applies the Institutional Collective Action Framework to two cases: proposals for the construction of Taekwondo Park and the location of a nuclear waste dump site in Booahn. While the proposed park caused excessive competition because its benefits were overestimated and its private goods were considered necessary, the proposed nuclear waste site resulted in excessive conflict because of uncertainty about its potential harms and because its public goods were considered unnecessary. The former case showed homogeneity of political power and cooperation based on trust, whereas the latter case showed heterogeneity of political power and conflict based on distrust. Both cases showed politicians active participation based on their reelection goals and a blocked network structure between central and local governments. Stakeholders in both cases showed strong internal ties with other stakeholders with similar potential political and economic benefits