Cradle-to-Gate and Use-Phase Carbon Footprint of a Commercial Plug-in Hybrid Electric Vehicle Lithium-Ion Battery.

Increased use of vehicle electrification to reduce greenhouse gas (GHG) emissions has led to the need for an accurate and comprehensive assessment of the carbon footprint of traction batteries. Unfortunately, there are few lifecycle assessments (LCAs) of commercial lithium-ion batteries available in the literature, and those that are available focus on the cradle-to-gate stage, often with little or no consideration of the use phase. To address this shortfall, we report both cradle-to-gate and use-phase GHG emissions for the 2020 Model Year Ford Explorer plug-in hybrid electric vehicle (PHEV) NMC622 battery. Using primary industry data for battery design and manufacturing, cradle-to-gate emissions are estimated to be 1.38 t CO2e (101 kg CO2e/kWh), with 78% from materials and parts production and 22% from cell, module, and pack manufacturing. Using mass-induced energy consumptions of 0.6 and 1.6 kWh/(100 km 100 kg) for charge-depleting and -sustaining modes, respectively, the mass-induced use-phase emission of the battery is estimated to be 1.04 t CO2e. We show that battery emissions during the cradle-to-gate and use phases are comparable and that both phases need to be considered. A holistic and harmonized LCA approach that includes battery use is required to reduce carbon footprint uncertainties and guide future battery designs.

Propensity score matching analysis of perioperative outcomes including quality of life after multi-port vs. single port laparoscopic cholecystectomy: a nationwide prospective multicenter study in Korea.

INTRODUCTION: The usefulness of single-port laparoscopic cholecystectomy (SPLC) as compared to multi-port laparoscopic cholecystectomy (MPLC) remains controversial. Between SPLC and MPLC, we compared outcomes, especially subjective aspects, such as quality of life (QoL). MATERIAL AND METHODS: This multi-center study, involving 20 institutions from 2016 to 2017, enrolled 2507 patients who underwent laparoscopic cholecystectomy. Various perioperative outcomes, pain assessed by the numeric rating scale (NRS) score, and QoL evaluated by the gastrointestinal QoL index (GIQLI) questionnaire, were compared between the two procedures. We generated balanced groups after propensity score matching (PSM) using preoperative factors that influence the decision to perform MPLC or SPLC. RESULTS: MPLC and SPLC were performed in 2176 and 331 patients, respectively. Nine hundred and twelve and 329 patients, respectively, were selected from the two groups by PSM. Operation time was longer and surgical difficulty was lower in SPLC. There were no significant differences in most outcomes, including biliary complications. Significant superiority of SPLC over MPLC was shorter hospitalization, lower NRS score, and favorable GIQLI. CONCLUSIONS: From nationwide prospective data, SPLC showed outcomes comparable to MPLC. In SPLC, morbidity was not high and postoperative QoL was favorable. In the future, more implementations and studies are needed to ensure the safety and feasibility of SPLC.

Cell-Type-Specific Expression of Hyaluronan Synthases HAS2 and HAS3 Promotes Goblet Cell Hyperplasia in Allergic Airway Inflammation.

Allergic rhinitis (AR) is a multifactorial airway disease characterized by basal and goblet cell hyperplasia. Hyaluronic acid (HA) is a major component of extracellular matrix and a critical contributor to tissue repair and remodeling after injury. We previously demonstrated that the intermediate progenitor cell (IPC) surface marker CD44v3 is upregulated in the basal and suprabasal layers of well-differentiated primary human nasal epithelial (HNE) cells after stimulation with the Th2 (T-helper cell type 2) cytokine IL-4, and an antibody blocking the CD44v3-HA interaction suppressed IL-4-induced goblet cell hyperplasia. We now show that the expression of HA and two HA synthases, HAS2 and HAS3, was upregulated in both the nasal surface epithelium of subjects with AR and IL-4-stimulated HNE cells. Inhibition of HA synthesis by 4-methylumbelliferone suppressed IL-4-induced goblet cell hyperplasia. Moreover, HAS2 and HAS3 were expressed in IPCs depending on the differentiation events, as follows: the rapid, transient upregulation of HAS2 induced basal IPC proliferation and basal-to-suprabasal transition, whereas the delayed upregulation of HAS3 promoted the transition of suprabasal IPCs to a goblet cell fate. 4-methylumbelliferone treatment in a house dust mite-induced murine AR model attenuated goblet cell metaplasia. Last, HA concentrations in nasal epithelial lining fluids from patients with AR positively correlated with the concentrations of mediators causing allergic inflammation. These data suggest that HA produced after the sequential upregulation of HAS2 and HAS3 contributes to goblet cell hyperplasia in allergic airway inflammation and modulates disease progression.

Carbon Footprint of Alternative Grocery Shopping and Transportation Options from Retail Distribution Centers to Customer.

The COVID-19 pandemic has accelerated the growth of e-commerce and automated warehouses, vehicles, and robots and has created new options for grocery supply chains. We report and compare the greenhouse gas (GHG) emissions for a 36-item grocery basket transported along 72 unique paths from a centralized warehouse to the customer, including impacts of micro-fulfillment centers, refrigeration, vehicle automation, and last-mile transportation. Our base case is in-store shopping with last-mile transportation using an internal combustion engine (ICE) SUV (6.0 kg CO2e). The results indicate that emissions reductions could be achieved by e-commerce with micro-fulfillment centers (16-54%), customer vehicle electrification (18-42%), or grocery delivery (22-65%) compared to the base case. In-store shopping with an ICE pick-up truck has the highest emissions of all paths investigated (6.9 kg CO2e) while delivery using a sidewalk automated robot has the least (1.0 kg CO2e). Shopping frequency is an important factor for households to consider, e.g. halving shopping frequency can reduce GHG emissions by 44%. Trip chaining also offers an opportunity to reduce emissions with approximately 50% savings compared to the base case. Opportunities for grocers and households to reduce grocery supply chain carbon footprints are identified and discussed.

CD44v3-Positive Intermediate Progenitor Cells Contribute to Airway Goblet Cell Hyperplasia.

In allergic airway diseases, intermediate progenitor cells (IPCs) increase in number in the surface epithelium. IPCs arise from basal cells, the origin of hallmark pathological changes, including goblet cell hyperplasia and mucus hypersecretion. Thus, targeting IPCs will benefit future treatment of allergic airway diseases. However, the lack of adequate cell surface markers for IPCs limits their identification and characterization. We now show that CD44 containing exon v3 (CD44v3) is a surface marker for IPCs that are capable of both proliferating and generating differentiated goblet cells in allergic human nasal epithelium. In primary human nasal epithelial cells that had differentiated at an air-liquid interface, IL-4 upregulated mRNA expression of three CD44v variants that include exon v3 (CD44v3-v6, CD44v3,v8-v10, and CD44v3-v10), and it induced expression of CD44v3 protein in the basal and suprabasal layers of the culture. FACS analysis revealed two subpopulations differing in CD44v3 concentrations, as follows: CD44v3low cells expressed high amounts of proliferative and basal cell markers (Ki-67 and TP63), whereas CD44v3high cells strongly expressed progenitor and immature and mature goblet cell markers (SOX2, CA2, and SPDEF). Importantly, a blocking anti-CD44 antibody suppressed IL-4-induced mucin production by human nasal epithelial cells. Furthermore, CD44v3 was coexpressed with TP63, KRT5, or SOX2 and was upregulated in the basal and suprabasal layers of the nasal surface epithelium of subjects with allergic rhinitis. Taken together, these data demonstrate that high CD44v3 expression contributes to goblet cell hyperplasia in inflammation of the allergic airway.

Characterizing the Changes in Material Use due to Vehicle Electrification.

Modern automobiles are composed of more than 2000 different compounds comprising 76 different elements. Identifying supply risks across this palette of materials is important to ensure a smooth transition to more sustainable transportation technologies. This paper provides insight into how electrification is changing vehicle composition and how that change drives supply risk vulnerability by providing the first comprehensive, high-resolution (elemental and compound level) snapshot of material use in both conventional and hybrid electric vehicles (HEVs) using a consistent methodology. To make these contributions, we analyze part-level data of material use for seven current year models, ranging from internal combustion engine vehicles (ICEV) to plug-in hybrid vehicles (PHEVs). With this data set, we apply a novel machine learning algorithm to estimate missing or unreported composition data. We propose and apply a metric of vulnerability, referred to as exposure, which captures economic importance and susceptibility to price changes. We find that exposure increases from $874 per vehicle for ICEV passenger vehicles to $2344 per vehicle for SUV PHEVs. The shift to a PHEV fleet would double automaker exposure adding approximately $1 billion per year of supply risk to a hypothetical fleet of a million vehicles. The increase in exposure is largely not only due to the increased use of battery elements like cobalt, graphite, and nickel but also some more commonly used materials, most notably copper.

Life Cycle Greenhouse Gas Emissions for Last-Mile Parcel Delivery by Automated Vehicles and Robots.

Increased E-commerce and demand for contactless delivery during the COVID-19 pandemic have fueled interest in robotic package delivery. We evaluate life cycle greenhouse gas (GHG) emissions for automated suburban ground delivery systems consisting of a vehicle (last-mile) and a robot (final-50-feet). Small and large cargo vans (125 and 350 cubic feet; V125 and V350) with an internal combustion engine (ICEV) and battery electric (BEV) powertrains were assessed for three delivery scenarios: (i) conventional, human-driven vehicle with human delivery; (ii) partially automated, human-driven vehicle with robot delivery; and (iii) fully automated, connected automated vehicle (CAV) with robot delivery. The robot's contribution to life cycle GHG emissions is small (2-6%). Compared to the conventional scenario, full automation results in similar GHG emissions for the V350-ICEV but 10% higher for the V125-BEV. Conventional delivery with a V125-BEV provides the lowest GHG emissions, 167 g CO2e/package, while partially automated delivery with a V350-ICEV generates the most at 486 g CO2e/package. Fuel economy and delivery density are key parameters, and electrification of the vehicle and carbon intensity of the electricity have a large impact. CAV power requirements and efficiency benefits largely offset each other, and automation has a moderate impact on life cycle GHG emissions.

LncRNAs in molluscan and mammalian stages of parasitic schistosomes are developmentally-regulated and coordinately expressed with protein-coding genes.

Despite the low level expression of some long noncoding RNAs (lncRNAs), the differential expression of specific lncRNAs plays important roles during the development of many organisms. Schistosomes, parasitic flatworms that are responsible for schistosomiasis, infects over 200 million people resulting in chronic disease and hundreds of thousands of deaths. Schistosomes have a complex life cycle that transitions between molluscan and mammalian hosts. In a molluscan snail host, the sporocyst stage develops over 5 weeks undergoing asexual reproduction to give rise to free-swimming and infectious cercariae that penetrate human skin and eventually mature into egg producing worms in mammals. The tight integration of the sporocyst to the snail host hepatopancreas hinders the -omics study in the molluscan stage, so the sporocyst transcriptome has only been examined for lncRNAs in immature in vitro samples. Here we analyzed the in vivo mature sporocyst transcriptome to identify 4,930 total lncRNAs between the molluscan and mammalian stages of the parasite. We further demonstrate that the lncRNAs are differentially expressed in a development-dependent manner. In addition, we constructed a co-expression correlation network between lncRNAs and protein-coding (PC) genes that was used to identify clusters of lncRNA transcripts with potential functional relevance. We also describe lncRNA-lncRNA and lncRNA-kinome correlations that identify lncRNAs with prospective roles in gene regulation. Finally, our results show clear differential expression patterns of lncRNAs in host-dependent development stages of S. mansoni and ascribe potential functional roles in development based on predicted intracellular interaction.

Economic and Environmental Feasibility of Second-Life Lithium-Ion Batteries as Fast-Charging Energy Storage.

Energy storage can reduce peak power consumption from the electricity grid and therefore the cost for fast-charging electric vehicles (EVs). It can also enable EV charging in areas where grid limitations would otherwise preclude it. To address both the need for a fast-charging infrastructure as well as management of end-of-life EV batteries, second-life battery (SLB)-based energy storage is proposed for EV fast-charging systems. The electricity grid-based fast-charging configuration was compared to lithium-ion SLB-based configurations in terms of economic cost and life cycle environmental impact in five U.S. cities. Compared to using new batteries, SLB reduced the levelized cost of electricity (LCOE) by 12-41% and the global warming potential (GWP) by 7-77%. Photovoltaics along with SLB reduced the use of grid electricity and provided higher GWP and cumulative energy demand (CED) reduction compared to only using SLB. The LCOE of the SLB-based configurations was sensitive to SLB cost, lifetime, efficiency, and discount rate, whereas the GWP and CED were affected by SLB lifetime, efficiency, and the required enclosure materials. Solar insolation and electricity pricing structures were key in determining the configuration, which was economically and environmentally suitable for a location.

Regional Heterogeneity in the Emissions Benefits of Electrified and Lightweighted Light-Duty Vehicles.

Electrification and lightweighting technologies are important components of greenhouse gas (GHG) emission reduction strategies for light-duty vehicles. Assessments of GHG emissions from light-duty vehicles should take a cradle-to-grave life cycle perspective and capture important regional effects. We report the first regionally explicit (county-level) life cycle assessment of the use of lightweighting and electrification for light-duty vehicles in the U.S. Regional differences in climate, electric grid burdens, and driving patterns compound to produce significant regional heterogeneity in the GHG benefits of electrification. We show that lightweighting further accentuates these regional differences. In fact, for the midsized cars considered in our analysis, model results suggest that aluminum lightweight vehicles with a combustion engine would have similar emissions to hybrid electric vehicles (HEVs) in about 25% of the counties in the US and lower than battery electric vehicles (BEVs) in 20% of counties. The results highlight the need for a portfolio of fuel efficient offerings to recognize the heterogeneity of regional climate, electric grid burdens, and driving patterns.

A Dynamic Fleet Model of U.S Light-Duty Vehicle Lightweighting and Associated Greenhouse Gas Emissions from 2016 to 2050.

Substituting conventional materials with lightweight materials is an effective way to reduce the life cycle greenhouse gas (GHG) emissions from light-duty vehicles. However, estimated GHG emission reductions of lightweighting depend on multiple factors including the vehicle powertrain technology and efficiency, lightweight material employed, and end-of-life material recovery. We developed a fleet-based life cycle model to estimate the GHG emission changes due to lightweighting the U.S. light-duty fleet from 2016 to 2050, using either high strength steel or aluminum as the lightweight material. Our model estimates that implementation of an aggressive lightweighting scenario using aluminum reduces 2016 through 2050 cumulative life cycle GHG emissions from the fleet by 2.9 Gt CO2 eq (5.6%), and annual emissions in 2050 by 11%. Lightweighting has the greatest GHG emission reduction potential when implemented in the near-term, with two times more reduction per kilometer traveled if implemented in 2016 rather than in 2030. Delaying implementation by 15 years sacrifices 72% (2.1 Gt CO2 eq) of the cumulative GHG emission mitigation potential through 2050. Lightweighting is an effective solution that could provide important near-term GHG emission reductions especially during the next 10-20 years when the fleet is dominated by conventional powertrain vehicles.

Life Cycle Assessment of Connected and Automated Vehicles: Sensing and Computing Subsystem and Vehicle Level Effects.

Although recent studies of connected and automated vehicles (CAVs) have begun to explore the potential energy and greenhouse gas (GHG) emission impacts from an operational perspective, little is known about how the full life cycle of the vehicle will be impacted. We report the results of a life cycle assessment (LCA) of Level 4 CAV sensing and computing subsystems integrated into internal combustion engine vehicle (ICEV) and battery electric vehicle (BEV) platforms. The results indicate that CAV subsystems could increase vehicle primary energy use and GHG emissions by 3-20% due to increases in power consumption, weight, drag, and data transmission. However, when potential operational effects of CAVs are included (e.g., eco-driving, platooning, and intersection connectivity), the net result is up to a 9% reduction in energy and GHG emissions in the base case. Overall, this study highlights opportunities where CAVs can improve net energy and environmental performance.

Barriers to reporting of patient safety incidents in tertiary hospitals: A qualitative study of nurses and resident physicians in South Korea.

We explored the barriers to reporting patient safety incidents experienced by nurses and resident physicians while working in tertiary hospitals in South Korea. Sixteen in-depth interviews with 10 nurses and 6 resident physicians, all of whom had experienced patient safety incidents, were conducted. The interviews were analyzed using directed content analysis in accordance with a coding scheme developed in this study, which contains 4 categories (incidents and reporters, reporting procedures and systems, feedbacks, and reporting culture) and 9 subcategories. The barriers to reporting near-misses included the following: characteristics of the incident (eg, nonhazardous and high frequency), reporters' lack of knowledge, uncertainty, fear of blame, lack of role model, and inappropriate responses. Reporting adverse/sentinel events was also prevented by feelings of pressure or guilt, the fact that reporting was nonmandatory, and a belief that reporting was not part of the job. Some other barriers included lack of education, review process after reporting, lack of confidentiality when reporting, absence of feedback for reporting, unfair reporting based on work experience, perception of potential blame, and stigmatization resulting from it. In South Korea, a national system for reporting and learning of patient safety accidents has been operating since July 2016. To fully implement this system, it is necessary to encourage reporting at the institutional level. Our results might help reduce the barriers to patient safety incident reporting among nurses and resident physicians in tertiary hospitals in Korea through informing the development of improvement plans.

Vehicle emissions of short-lived and long-lived climate forcers: trends and tradeoffs.

Evaluating technology options to mitigate the climate impacts of road transportation can be challenging, particularly when they involve a tradeoff between long-lived emissions (e.g., carbon dioxide) and short-lived emissions (e.g., methane or black carbon). Here we present trends in short- and long-lived emissions for light- and heavy-duty transport globally and in the U.S., EU, and China over the period 2000-2030, and we discuss past and future changes to vehicle technologies to reduce these emissions. We model the tradeoffs between short- and long-lived emission reductions across a range of technology options, life cycle emission intensities, and equivalency metrics. While short-lived vehicle emissions have decreased globally over the past two decades, significant reductions in CO2 will be required by mid-century to meet climate change mitigation targets. This is true regardless of the time horizon used to compare long- and short-lived emissions. The short-lived emission intensities of some low-CO2 technologies are higher than others, and thus their suitability for meeting climate targets depends sensitively on the evaluation time horizon. Other technologies offer low intensities of both short-lived emissions and CO2.

Review of the Fuel Saving, Life Cycle GHG Emission, and Ownership Cost Impacts of Lightweighting Vehicles with Different Powertrains.

The literature analyzing the fuel saving, life cycle greenhouse gas (GHG) emission, and ownership cost impacts of lightweighting vehicles with different powertrains is reviewed. Vehicles with lower powertrain efficiencies have higher fuel consumption. Thus, fuel savings from lightweighting internal combustion engine vehicles can be higher than those of hybrid electric and battery electric vehicles. However, the impact of fuel savings on life cycle costs and GHG emissions depends on fuel prices, fuel carbon intensities and fuel storage requirements. Battery electric vehicle fuel savings enable reduction of battery size without sacrificing driving range. This reduces the battery production cost and mass, the latter results in further fuel savings. The carbon intensity of electricity varies widely and is a major source of uncertainty when evaluating the benefits of fuel savings. Hybrid electric vehicles use gasoline more efficiently than internal combustion engine vehicles and do not require large plug-in batteries. Therefore, the benefits of lightweighting depend on the vehicle powertrain. We discuss the value proposition of the use of lightweight materials and alternative powertrains. Future assessments of the benefits of vehicle lightweighting should capture the unique characteristics of emerging vehicle powertrains.

Life Cycle Assessment of Vehicle Lightweighting: A Physics-Based Model To Estimate Use-Phase Fuel Consumption of Electrified Vehicles.

Assessing the life-cycle benefits of vehicle lightweighting requires a quantitative description of mass-induced fuel consumption (MIF) and fuel reduction values (FRVs). We have extended our physics-based model of MIF and FRVs for internal combustion engine vehicles (ICEVs) to electrified vehicles (EVs) including hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs). We illustrate the utility of the model by calculating MIFs and FRVs for 37 EVs and 13 ICEVs. BEVs have much smaller MIF and FRVs, both in the range 0.04-0.07 Le/(100 km 100 kg), than those for ICEVs which are in the ranges 0.19-0.32 and 0.16-0.22 L/(100 km 100 kg), respectively. The MIF and FRVs for HEVs and PHEVs mostly lie between those for ICEVs and BEVs. Powertrain resizing increases the FRVs for ICEVs, HEVs and PHEVs. Lightweighting EVs is less effective in reducing greenhouse gas emissions than lightweighting ICEVs, however the benefits differ substantially for different vehicle models. The physics-based approach outlined here enables model specific assessments for ICEVs, HEVs, PHEVs, and BEVs required to determine the optimal strategy for maximizing the life-cycle benefits of lightweighting the light-duty vehicle fleet.

Cradle-to-Gate Emissions from a Commercial Electric Vehicle Li-Ion Battery: A Comparative Analysis.

We report the first cradle-to-gate emissions assessment for a mass-produced battery in a commercial battery electric vehicle (BEV); the lithium-ion battery pack used in the Ford Focus BEV. The assessment was based on the bill of materials and primary data from the battery industry, that is, energy and materials input data from the battery cell and pack supplier. Cradle-to-gate greenhouse gas (GHG) emissions for the 24 kWh Ford Focus lithium-ion battery are 3.4 metric tonnes of CO2-eq (140 kg CO2-eq per kWh or 11 kg CO2-eq per kg of battery). Cell manufacturing is the key contributor accounting for 45% of the GHG emissions. We review published studies of GHG emissions associated with battery production to compare and contrast with our results. Extending the system boundary to include the entire vehicle we estimate a 39% increase in the cradle-to-gate GHG emissions of the Focus BEV compared to the Focus internal combustion engine vehicle (ICEV), which falls within the range of literature estimates of 27-63% increases for hypothetical nonproduction BEVs. Our results reduce the uncertainties associated with assessment of BEV battery production, serve to identify opportunities to reduce emissions, and confirm previous assessments that BEVs have great potential to reduce GHG emissions over the full life cycle and provide local emission free mobility.

Limited resections for duodenal gastrointestinal stromal tumors and their oncologic outcomes.

PURPOSE: Limited resection is considered a treatment option for duodenal gastrointestinal stromal tumors (GISTs) whenever technically feasible, but the optimal technique for this is still not well defined. We present the various types of limited resections for duodenal GISTs and analyze their postoperative outcomes. METHODS: The subjects of this retrospective clinicopathologic analysis were 21 patients who underwent limited resections for duodenal GIST between May, 2001 and June, 2014. The median follow-up period was 52 months (range 5-125 months). RESULTS: The patients comprised 12 men and 9 women, with a median age of 59 years (range 45-75 years), all of whom were treated by various forms of limited resection with clear margins. There were ten wedge resections with primary closure (eight open/two laparoscopic), two wedge resections with Roux-en Y duodenojejunostomy, three segmental duodenectomies with end-to-end duodenoduodenostomy, and six segmental duodenectomies with end-to-end duodenojejunostomy. Hepatic metastasis was found 27 months after surgery in one patient, who was given imatinib mesylate for 17 months to slow disease progression. The other 20 patients were alive and recurrence free at the time of writing. CONCLUSION: Excellent recurrence-free survival was achieved after limited resections, supporting the consideration of various methods of limited resection as the treatment of choice for duodenal GISTs.

Life Cycle Assessment of Vehicle Lightweighting: Novel Mathematical Methods to Estimate Use-Phase Fuel Consumption.

Lightweighting is a key strategy to improve vehicle fuel economy. Assessing the life-cycle benefits of lightweighting requires a quantitative description of the use-phase fuel consumption reduction associated with mass reduction. We present novel methods of estimating mass-induced fuel consumption (MIF) and fuel reduction values (FRVs) from fuel economy and dynamometer test data in the U.S. Environmental Protection Agency (EPA) database. In the past, FRVs have been measured using experimental testing. We demonstrate that FRVs can be mathematically derived from coast down coefficients in the EPA vehicle test database avoiding additional testing. MIF and FRVs calculated for 83 different 2013 MY vehicles are in the ranges 0.22-0.43 and 0.15-0.26 L/(100 km 100 kg), respectively, and increase to 0.27-0.53 L/(100 km 100 kg) with powertrain resizing to retain equivalent vehicle performance. We show how use-phase fuel consumption can be estimated using MIF and FRVs in life cycle assessments (LCAs) of vehicle lightweighting from total vehicle and vehicle component perspectives with, and without, powertrain resizing. The mass-induced fuel consumption model is illustrated by estimating lifecycle greenhouse gas (GHG) emission benefits from lightweighting a grille opening reinforcement component using magnesium or carbon fiber composite for 83 different vehicle models.

Evaluation of phytoplankton community composition in the eutrophic Masan Bay by HPLC pigment analysis.

To assess the spatiotemporal changes in phytoplankton community composition in relation to the environment of Masan Bay, a semi-enclosed bay on the southern coast of Korea, photosynthetic pigments and environmental variables were analyzed in seawater, every month between March and November 2010. The level of dissolved inorganic nutrients was highest between July and September when the freshwater influx was at its peak, whereas chlorophyll a level was highest in April and August. Phosphate concentration was low in April (average: 0.22 +/- 0.17 microM), indicating the role of phosphate as a growth-limiting factor for phytoplankton. The results of pigment analysis indicate that dinoflagellate blooms occurred under favorable conditions, where competition with diatoms occurred. Fucoxanthin- and chlorophyll b-containing phytoplankton dominated the surface layer of Masan Bay from July to September. The composition of phytoplankton community in Masan Bay changed dramatically each month according to variations in the amount and composition of nutrients introduced through surface runoff.