Effects of warming and eutrophication on coastal phytoplankton production

Phytoplankton production in coastal waters influences seafood production and human health and can lead to harmful algal blooms. Water temperature and eutrophication are critical factors affecting phytoplankton production, although the combined effects of warming and nutrient changes on phytoplankton production in coastal waters are not well understood. To address this, phytoplankton production changes in natural waters were investigated using samples collected over eight months, and under 64 different initial conditions, established by combining four different water temperatures (i.e., ambient T, + 2, + 4, and + 6 degrees C), and two different nutrient conditions (i.e., non-enriched and enriched). Under the non-enriched conditions, the effect of warming on phytoplankton production was significantly positive in some months, significantly negative in others, or had no effect. However, under enriched conditions, warming affected phytoplankton production positively in all months except one, when the salinity was as low as 6.5. These results suggest that nutrient conditions can alter the effects of warming on phytoplankton production. Of several parameters, the ratio of initial nitrate concentration to chlorophyll a concentration [NCCA, mu M (pg L-1)(-1))] was one of the most critical factors determining the directionality of the warming effects. In laboratory experiments, when NCCA in the ambient or nutrient-enriched waters was >= 1.2, warming increased or did not change phytoplankton production with one exception; however, when NCCA was < 1.2, warming did not change or decreased production. In the time series data obtained from the coastal waters of four target countries, when NCCA was 1.5 or more, warming increased phytoplankton production, whereas when NCCA was lower than 1.5, warming lowered phytoplankton production, Thus, it is suggested that NCCA could be used as an index for predicting future phytoplankton production changes in coastal waters.11Ysciescopu

X-linked Severe Combined Immunodeficiency Syndrome: The First Korean Case with γc Chain Gene Mutation and Subsequent Genetic Counseling

X-linked severe combined immunodeficiency (X-SCID) is a rare, life-threatening immune disorder, caused by mutations in the γc chain gene, which encodes an essential component of the cytokine receptors for interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21. A 13-month-old boy with recurrent infections who had reduced serum immunoglobulin levels and decreased numbers of CD3, CD16/56 cells was evaluated for γc chain gene mutation and protein expression. The patient had a C-to-T point mutation at nucleotide position 690, one of the hot spots, resulting in a single amino acid substitution of cysteine for arginine (R226C), as determined by direct sequencing and PCR-RFLP. The patient's mother was a heterozygous carrier. Percutaneous umbilical cord blood sampling was performed at the 6-month of gestation in a subsequent pregnancy. As the immunophenotype of the fetus showed an identical pattern, the pregnancy was terminated and genetic analysis of the abortus confirmed recurrence. This is the first report of the molecular diagnosis of X-SCID in Korea. Genetic analysis of the γc chain gene is useful for definite diagnosis and genetic counseling for X-SCID

Red tides in Shiwha Bay, western Korea: A huge dike and tidal power plant established in a semi-enclosed embayment system

To investigate red tides in Shiwha Bay, Korea, where a 12.7-km dike with two outlets (at the water gate and tidal power plant) was constructed, we measured physical, chemical, and biological properties at 3 fixed stations inside the dike on a monthly basis from May 2008 to July 2012. During the study period, red tides were present in Shiwha Bay during 33 of 46 (i.e., 72%) sampling events. Clearly, red tides are common in the bay. Red tides occurred 33, 12, and 10 times at Stations 1, 2, and 3, respectively. Restriction of water circulation at Station 1 (in the innermost part of the bay) may cause more frequent red tides due to phototrophic dinoflagellates than at Station 3, where water exchange between the inside and outside of the dike occurs through a water gate. After the world&apos;s largest tidal power plant was established in 2011, red-tide causative species switched from phototrophic dinoflagellates such as Gymnodinium aureolum, Heterocapsa rotundata, Heterocapsa triquetra, Kariodinium veneficum, Paragymnodinium shiwhaense, and Pro rocentrum minimum to diatoms such as Chaetoceros spp., Skeletonema costatum, and Thalassiosira spp. Exchange of seawater between the inside and outside of the dike through the tidal power plant may have resulted in this change in the causative species. Inorganic nitrogen concentrations for the growth of phototrophic dinoflagellates and small flagellates during red tides were likely unlimited, but inorganic phosphorus concentrations may be limited. Thus, some phototrophic dinoflagellates and flagellates may acquire phosphorus from prey. The maximum grazing coefficients of the heterotrophic dinoflagellates Pfiesteria piscicida, Gyrodiniellum shiwhaense, Gyrodinium dominansl Gyrodinium moestrupii, and Protoperidinium bipes feeding on red-tide causative taxa including cryptophytes, Eutreptiella gymnastica, P. minimum, and S. costatum, were found to be 0.14-0.77 h(-1). Therefore, heterotrophic protistan grazers in Shiwha Bay may, at times, have considerable grazing impact on populations of co-occurring red-tide organisms. (C) 2013 Elsevier B.V. All rights reserved.N

Epidemiology of Type 1 Diabetes Mellitus in Korea through an Investigation of the National Registration Project of Type 1 Diabetes for the Reimbursement of Glucometer Strips with Additional Analyses Using Claims Data

BackgroundThe aim of this study was to estimate the prevalence and incidence of type 1 diabetes mellitus (T1DM) in Korea. In addition, we planned to do a performance analysis of the Registration Project of Type 1 diabetes for the reimbursement of consumable materials.MethodsTo obtain nationwide data on the incidence and prevalence of T1DM, we extracted claims data from July 2011 to August 2013 from the Registration Project of Type 1 diabetes on the reimbursement of consumable materials in the National Health Insurance (NHI) Database. For a more detailed analysis of the T1DM population in Korea, stratification by gender, age, and area was performed, and prevalence and incidence were calculated.ResultsOf the 8,256 subjects enrolled over the 26 months, the male to female ratio was 1 to 1.12, the median age was 37.1 years, and an average of 136 new T1DM patients were registered to the T1DM registry each month, resulting in 1,632 newly diagnosed T1DM patients each year. We found that the incidence rate of new T1DM cases was 3.28 per 100,000 people. The average proportion of T1DM patients compared with each region's population was 0.0125%. The total number of insurance subscribers under the universal compulsory NHI in Korea was 49,662,097, and the total number of diabetes patients, excluding duplication, was 3,762,332.ConclusionThe prevalence of T1DM over the course of the study was approximately 0.017% to 0.021% of the entire population of Korea, and the annual incidence of T1DM was 3.28:100,000 overall and 3.25:100,000 for Koreans under 20 years old

Grazing impact of heterotrophic dinoflagellates and ciliates on common red-tide euglenophyte Eutreptiella gymnastica in Masan Bay, Korea

The euglenophyte Eutreptiella gymnastica is a common red tide causative species. However, there have been no studies on the grazing impact of heterotrophic protists on this species. To investigate the grazing impact of heterotrophic protists on E. gymnastica, we measured daily the abundances of E. gymnastica and co-occurring potential heterotrophic protistan grazers in Masan Bay, Korea, in August 2004 when an E. gymnastica red tide occurred. In addition, we tested whether the common heterotrophic dinoflagellates Gyrodinium dominans, Oxyrrhis marina, Pfiesteria piscicida, Polykrikos kofoidii, Protoperidinium bipes, and Stoeckeria algicida and the naked ciliates Strobilidium sp. (30-40 mu m in cell length) and Strombidinopsis sp. (70-100 mu m in cell length) were able to feed on E. gymnastica. We also measured their growth and ingestion rates on E. gymnastica as a function of prey concentration. Finally, we calculated the grazing coefficients by combining field data on the abundance of the heterotrophic dinoflagellate and ciliate grazers and co-occurring E. gymnastica with laboratory data on ingestion rates obtained in this study. The maximum abundance of E. gymnastica in Masan Bay in August, 2004 was 7575 cells ml(-1), while those of Gyrodinium spp., P. kofoidii, P. bipes, the naked ciliates (&lt;= 50 mu m in cell length), and naked ciliates (&gt;50 mu m in cell length) were 50, 9, 58, 32, and 3 cells ml(-1), respectively. The maximum growth rate of G. dominans on E. gymnastica (1.13 d(-1)) was higher than that of O. marina (0.81 d(-1)) or P. bipes (0.77 d(-1)). However, E. gymnastica did not support positive growth of P. kofoidii, Strobilidium sp., and Strombidinopsis sp. (-0.04 similar to -2.8 d(-1)). The maximum ingestion rates of G. dominans, P. kofoidii, P. Pipes, O. marina, and Strobilidium sp. on E. gymnastica (2.1-2.7 ng C predator(-1) d(-1)) were similar, but they were much lower than that of Strombidinopsis sp. (156 ng C predator(-1) d(-1)). The calculated grazing coefficients for P. bipes, small heterotrophic Gyrodinium spp. (25-35 mu m in cell length), naked ciliates (&lt;= 50 mu m in cell length). P. kofoidii, and naked ciliates (&gt;50 mu m in cell length) on E. gymnastica were up to 0.77, 0.61, 0.22, 0.07 and 0.03 d(-1), respectively (i.e., up to 54%, 46%, 20%, 7%, and 3% of E. gymnastica populations were removed by the population of each of these heterotrophic protistan grazers in 1 d, respectively). The results of the present study suggest that P. bipes, small heterotrophic Gyrodinium spp., and naked ciliates (&lt;= 50 mu m in cell length) sometimes have considerable potential grazing impact on the populations of E. gymnastica. (C) 2011 Elsevier B.V. All rights reserved.N

The newly described heterotrophic dinoflagellate gyrodinium moestrupii, an effective protistan grazer of toxic dinoflagellates

Few protistan grazers feed on toxic dinoflagellates, and low grazing pressure on toxic dinoflagellates allows these dinoflagellates to form red-tide patches. We explored the feeding ecology of the newly described heterotrophic dinoflagellate Gyrodinium moestrupii when it fed on toxic strains of Alexandrium minutum, Alexandrium tamarense, and Karenia brevis and on nontoxic strains of A. tamarense, Prorocentrum minimum, and Scrippsiella trochoidea. Specific growth rates of G. moestrupii feeding on each of these dinoflagellates either increased continuously or became saturated with increasing mean prey concentration. The maximum specific growth rate of G. moestrupii feeding on toxic A. minutum (1.60/d) was higher than that when feeding on nontoxic S. trochoidea (1.50/d) or P. minimum (1.07/d). In addition, the maximum growth rate of G. moestrupii feeding on the toxic strain of A. tamarense (0.68/d) was similar to that when feeding on the nontoxic strain of A. tamarense (0.71/d). Furthermore, the maximum ingestion rate of G. moestrupii on A. minutum (2.6 ng C/grazer/d) was comparable to that of S. trochoidea (3.0 ng C/grazer/d). Additionally, the maximum ingestion rate of G. moestrupii on the toxic strain of A. tamarense (2.1 ng C/grazer/d) was higher than that when feeding on the nontoxic strain of A. tamarense (1.3 ng C/grazer/d). Thus, feeding by G. moestrupii is not suppressed by toxic dinoflagellate prey, suggesting that it is an effective protistan grazer of toxic dinoflagellates.N