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The responses of division rate, cell volume, cellular carbon (C) and nitrogen (N), cellular pigments and optical characteristics to changes in salinity were examined in the dinoflagellate Heterocapsa circularisquama. The physiological and optical characteristics of H. circularisquama were significantly affected by changes in salinity. When cells were exposed to different salinities, they exhibited physiological acclimation by adjusting their cellular properties associated with growth. This could be a beneficial tactic for ensuring proliferation and limiting damages induced by adverse environmental factors. The results of this study could be essential for assisting in the development of growth models for H. circularisquama.

(2006). N:P supply ratio-dependent growth, cellular chemical composition and toxicity in Alexandrium tamarense. SIL Proceedings, 1922-2010: Vol. 29, No. 3, pp. 1306-1310.

To evaluate the prognostic significance of the pretreatment neutrophil-to-lymphocyte ratio in patients with metastatic urothelial carcinoma who underwent salvage chemotherapy.We reviewed 200 metastatic urothelial carcinoma patients who received salvage chemotherapy at our five affiliate institutions between 2003 and 2011. The associations of pretreatment clinicopathological factors, including neutrophil-to-lymphocyte ratio, with cancer-specific survival and overall survival from the start of chemotherapy were assessed. Cox proportional hazards model was used for multivariate analysis.A total of 15 cases with missing data were excluded. Among the remaining 185 patients, 157 died during follow up, with a median survival of 13.0 months. Multivariate analysis showed that the pretreatment neutrophil-to-lymphocyte ratio ≥3, Eastern Cooperative Oncology Group performance status ≥2 and liver metastasis were independent poor prognostic factors, both for cancer-specific survival and overall survival. A prognostic model predicting overall survival was constructed based on the number of these three variables (0, 1 and ≥ 2). The classified patients showed significantly different overall survival (each P 0.0001, log-rank test), with Harrell's concordance index as high as 0.81.Pretreatment neutrophil-to-lymphocyte ratio elevation was an independent poor prognostic factor for metastatic urothelial carcinoma undergoing salvage chemotherapy. Our newly constructed prognostic model including the pretreatment neutrophil-to-lymphocyte ratio proved to be an excellent discriminator of overall survival.

The chlorophyll a specific absorption coefficient a ph ∗ and absorption ratio ( a ph ratio) of Alexandrium tamarense at five concentrations of nitrate, ammonium and urea over a range from 6 to 100 μM were examined. The experimental results were compared to two coastal diatom species and a prymnesiophyte to identify differences in absorption ratios. Cells exposed to increasing nitrate concentrations were characterized by an increase in a ph ∗ at 443, 490, 510, 555 and 675 nm. However, ammonium and urea induced low a ph ∗ values at their lowest and highest concentrations. The a ph relative to 510 or 555 nm was constant regardless of the concentration of the N source, but dependent on the N source. Oxidized N induced a lower a ph ratio than the reduced form. Comparisons of the a ph ratio among taxonomic groups revealed significant differences. The a ph ratio of A . tamarense was 20–30 and >50% lower than those of two diatoms and a prymnesiophyte, respectively. The a ph ratio of the present study could assist in increasing the capability for detecting harmful species such as A . tamarense .

Silicate urinary calculi are rare in humans, with an incidence of 0.2% of all urinary calculi. Most cases were related to excess ingestion of silicate, typically by taking magnesium trisilicate as an antacid for peptic ulcers over a long period of time; however, there also existed unrelated cases, whose mechanism of development remains unclear. On the other hand, zonisamide, a newer antiepileptic drug, is one of the important causing agents of iatrogenic urinary stones in patients with epilepsy. The supposed mechanism is that zonisamide induces urine alkalinization and then promotes crystallization of urine components such as calcium phosphate by inhibition of carbonate dehydratase in renal tubular epithelial cells. Here, we report a case of silicate urolithiasis during long-term treatment with zonisamide without magnesium trisilicate intake and discuss the etiology of the disease by examining the silicate concentration in his urine.

The responses of cellular C and N, pigments and growth rates of Alexandrium tamarense to different sources of N at high concentrations (6, 12, 25, 50 and 100 μM-N) were examined. Nitrate induced the highest concentration of cellular C (an indicator of biovolume) and cellular N, followed by ammonium and then urea. Cellular C to N ratio (an indicator of physiological status) also varied between N sources. Nitrate grown cells had lower range of C:N ratios and ammonium grown cells had highly variable range. Urea cultures had the highest range of cellular C:N ratio. Pigment composition remained unchanged with all N substrates. The pigments decreased with increasing nitrate concentrations, but with ammonium pigments increased. On the other hand, urea concentrations had no clear relationship with cellular pigments. Variability in the growth of cells was due to both the physiological condition and pigments. When the cells are exposed to different N environments and concentration, they exhibit a physiological acclimation by regulating their cellular materials which is associated with growth.

Nitrogen (N) supply in pulses was simulated by exposing Alexandrium tamarense which was acclimatized at low N concentration (6 microM-N) to sudden increase in concentrations of nitrate, ammonium and urea, and the variability in toxicity due to nutrient status of A. tamarense was examined. The toxin composition did not vary dramatically among the three N sources, however, ammonium induced the highest concentration of intracellular toxin, followed by urea and then nitrate. Therefore, populations utilizing high ammonium concentration could be more toxic than those growing on nitrate or urea. The toxin content was dependent on the cellular N status of nitrate grown cells only, suggesting that the competition for N in toxin production with other metabolic pathways such as growth may be different among N sources. The relationship between toxin and nutrient status is a complex interaction and it involves the redistribution of cellular N within the cells. Understanding the toxin dynamics of natural populations in relation to nutrient is essential for the mitigation of harmful dinoflagellates in a given coastal ecosystem.

In coastal regions of Sagami Bay, Japan, we examined the nutrient limitations of primary productivity of phytoplankton blooms during spring to summer 2000, using 2 approaches; (1) dissolved nutrient concentrations and ratios, and (2) bioassay experiments. During the study period, maximum concentration of nitrate + nitrite (19.2 pM) and silicate (31.2 pM) were measured on July 10 after heavy rainfalls, where the supplies of nitrate, nitrite and silicate to the coastal regions primarily related to the increase in freshwater discharge by precipitation. However, such relationships were not found regarding the phosphate concentration. Chlorophyll (Chl) a concentration increased after the increase in freshwater discharge and Chl a peaks over 10 mg m -3 were observed 5 times. Phosphate concentration observed at the depth of the 5 Chl a peaks was low enough to indicate probable P limitation based on criteria of nutrient concentrations and ratios. Bioassay experiments were carried out 12 times, every 8 d from May 1 to July 28. Primary productivities following nitrate and silicate additions showed no response compared to the controls. However, phosphate additions in the post-bloom period caused a significant increase in the primary productivity. On May 25, the primary productivity increased 51 % relative to the control. These results suggest that phytoplankton productivity was limited by phosphate during the spring-summer blooms, and that phosphate availability in the Sagami Bay is an important factor in the termination of the blooms.

To the Editor:We read this article with great interest. To our knowledge, this study is the first to demonstrate the prognostic significance of sarcopenia in patients with metastatic renal cell carcinoma, while previous research in this setting has only shown an association with drug toxicity. Sarcopenia has recently been investigated for its significance in predicting prognosis and treatment related complications in patients with cancer. However, methods to evaluate sarcopenia have not been entirely standardized. The European consensus definition of sarcopenia describes computerized tomography (CT) based methods as the gold standard for estimating muscle mass rather than nonCT based approaches, including bioelectrical impedance and dual energy x-ray absorptiometry. The most common CT based metric would be skeletal muscle index (SMI), defined as the cross-sectional area of all skeletal muscles at the L3 level and normalized by height squared (cm/m). For this metric the current international consensus definitions of sarcopenia are SMI less than 55 cm/m in males and less than 39 cm/m in females. These cutoffs are based on absolute muscularity below the 5th percentile for young, healthy individuals. It is noteworthy that Psutka et al have recently advocated use of these definitions in The Journal of Urology . Accordingly we demonstrated SMI as an independent poor prognostic factor in Japanese patients with metastatic urothelial carcinoma using these definitions. For reference total psoas area, defined as the cross-sectional area of bilateral psoas muscles at the L3 level and normalized by height squared (mm/m), is another well investigated CT based metric of sarcopenia with a cutoff at the lowest gender specific quartile. In this regard the definitions used by Fukushima et al would be peculiar, ie SMI less than 43 cm/m for males with a body mass index (BMI) below 25 kg/m, less than 53 cm/m for males with a BMI of 25 kg/m or greater and less than 41 cm/m for females. Given that SMI has already been normalized by height squared, is it reasonable to further make an adjustment according to BMI? These definitions were actually derived from a study that especially focused on obesity along with sarcopenia in patients with cancer, and thus might not be applicable to general studies. Adopting these specific definitions may invalidate interpretation of the results or cause confusion among following researchers. The authors are to be commended for addressing sarcopenia as a survival predictor in patients with urological cancers. However, standardization of the evaluation method along with appropriate cutoffs is urgently needed.

The relationship between the xanthophyll pool [diadinoxanthin plus diatoxanthin normalized to chlorophyll (Chl) a] and irradiance was examined during phytoplankton blooms in Sagami Bay from the end of April to July 2000. In the case of Chl a concentrations >2 mg m -3 , a linear correlation was found between the xanthophyll pool and irradiance of the previous day. On the other hand, for Chl a concentrations

Influence of UVB radiation (UVBR) on hatching success of the marine copepod Paracalanus parvus s. l. was determined in the laboratory using UVB lamps and the same effect was confirmed in the field under natural solar radiation condition. Hatching success antisigmoidally decreased with UVB dose. The dose-specific mortality of eggs was higher when the UVBR exposure included shorter wavelength than 290 nm. The UVB dose which decreased the hatching success by 50% (LD50) showed that P. parvus egg was more sensitive to UVB than other previously reported marine copepods. UVB-induced influence was not a simple function of UVB dose but also of UVB exposure time. Relatively long exposure of low UVBR was more detrimental than a short exposure of high UVBR for equal cumulative doses. Sensitivity to UVB decreased with time after spawning. After exposure to solar UVBR, the hatching success decreased in a similar manner to the experiment using UVB lamps. The depths where 10% and 20% egg mortalities are expected were estimated as 1.4 and 3.0 m, respectively, assuming the median attenuation coefficient of UVBR at 305 nm in the water off Hokkaido (0.44 m−1) and the same solar UVBR during the experiment. Solar UVBR at mid-latitude area is estimated as a factor affecting the recruitment of P. parvus even under the present level of ozone concentration.

Variability in the effect of solar ultraviolet radiation (UV-B) on primary productivity of natural phytoplankton assemblages was examined in coastal water off Manazuru Harbor, Sagami Bay, central Japan for two full years during the period from September 1996 to September 1998. Solar UV-B, UV-A, and PAR were determined in air and water. Surface water was exposed to UV-B+UV-A+PAR and UV-A+PAR with Mylar film and primary productivity under those two light regimes was determined with 13C method. Size distribution of chlorophyll a concentration was also examined. When the occurrence of >10 μm size fraction was lower than 80% in a warm season, the UV-B effect was significant. Whenever red tide species occurred, they did not respond to UV-B radiation. Although winter population was also dominated by >10 μm size fraction, a ratio of UV-B to UV-A+PAR was already so low that the UV-B effect was insignificant. The occurrence of >10 μm size fraction, which might be enhanced by a supply of nitrate and consequently could be related to high supply of dissolved organic matter, seemed to play a significant role in controlling the effect of UV-B on primary productivity in the coastal water. Reduction rate of primary productivity ranged from

Size-dependence of chlorophyll a (Chl a) specific absorption coefficient a*(λ) for six irradiances ranging from 25 to 750 μmol m -2 s -1 was quantified for six species of phytoplankton of varying size. These included Bacillariophyceae Thalassiosira weissflogii, Chaetoceros gracilis and Coscinodiscus sp., Chlorophyceae Dunaliella tertiolecta, and Prymnesiophyceae Isochrysis galbana and Pleurochrysis carterae. For the six irradiances, statistically significant relationships were obtained between cell volume and a*(675), which decreased significantly with increasing cell volume at all irradiances. However, a*(440) showed a statistically significant relationship between cell volume and a* at only 25, 40 and 90 μmol m -2 s -1 . The relative contributions of several pigments were estimated using the pigment-based reconstruction technique. At high irradiance, absorption by photoprotective pigments increased in relative importance. Under high light conditions, size-dependence of absorption at 440 nm weakens due to the effects of absorption by photoprotective pigments in the blue region of the spectrum. Thus observed variability in a* is dependent on the physiological characteristics of marine phytoplankton, the result of this study indicates that size-dependence of absorption is a robust characteristic of phytoplankton under low light conditions.

The chl a specific absorption coefficients [a* (λ), m 2 .mg chl a - 1 ] were examined in chemostat culture of the Prymnesiophyceae Isochrysis galbana (Parke) under a 12:12-h light:dark cycle at low light (75 μmol photons.m - 2 .s - 1 ) and high light (500 μmol photons m - 2 .s - 1 ) conditions. Other associated measurements such as pigment composition, cell density, and diameter as the measure of cell size were also made at the two light regimes every 2 h for 2 days to confirm the periodicity. A distinct diel variability was observed for the a* (λ) with maxima near dawn and minima near dusk. The magnitude of diel variation in a* (440) was 15% at low light and 22% at high light. Pronounced diel patterns were observed for cell size with minima near dawn and maxima near dusk. The magnitude of diel variation in cell size was 9.3% at low light and 21% at high light. The absorption efficiency factors [Q a (440)] were determined by reconstruction using intracellular concentrations of pigments and cell size. The Q a (440) also showed a distinct diel variability, with minima near dawn and maxima near dusk. The diel variation in a* (λ) and Q a (λ) was primarily caused by changes in cell size due to growth, although there was some influence from diel variations in the intracellular pigment concentrations. The results presented here indicated that diel variation in a* (λ) was an important component of the optical characterization of phytoplankton.

The respiration rate of adult female Calanus hyperboreus was determined in order to assess physiological activity and its relationship to food availability during spring in the North Water Polynya, northern Baffin Bay. The respiration rate increased hyperbolically with increasing ambient chlorophyll α (Chl. α) concentration regardless of the reproductive status. The increase of respiration with Chl. α concentration may be caused by activated feeding behavior. This suggests that all adult females during spring were physiologically active individuals. Possible advantages of the rapid response to food concentration in adult female copepods are discussed.

Background The benefit of adjuvant immunotherapy after nephrectomy in renal cell carcinoma (RCC) is controversial. The present study aimed to examine the possible benefit of adjuvant immunotherapy in various clinical settings. Methods We retrospectively reviewed 436 patients with pT1-3N0-2M0 RCC who underwent radical or partial nephrectomy with curative intent at our institution between 1981 and 2009. Of them, 98 (22.5%) patients received adjuvant interferon-α (IFN-α) after surgery (adjuvant IFN-α group), while 338 (77.5%) did not (control group). The primary endpoint was cancer-specific survival (CSS). Univariate and multivariate analyses were conducted using log-rank tests and Cox proportional hazards models, respectively. Results Fifty-two (11.9%) patients died from RCC with a median follow-up period of 96 months. Preliminary univariate analyses comparing CSS among treatment groups in each TNM setting revealed that CSS in the control group was equal or superior to that in the adjuvant IFN-α group in earlier stages, while the opposite trend was observed in more advanced stages. We evaluated the TNM cutoffs and demonstrated maximized benefit of adjuvant IFN-α in patients with pT2b-3cN0 (P = 0.0240). In multivariate analysis, ≥pT3 and pN1-2 were independent predictors for poor CSS in all patients. In the subgroups with ≥pT2 disease (n = 123), pN1-2 and no adjuvant treatment were significant poor prognostic factors. Conclusions Adjuvant immunotherapy after nephrectomy may be beneficial in pT2b-3cN0 RCC. Careful consideration is, however, required for interpretation of this observational study because of its selection bias and adverse effects of IFN-α.

The variability of cellular toxin content in the dinoflagellate Alexandrium tamarense isolated from Hiroshima Bay was analyzed under a variety of culture conditions. Growth and toxicity were represented as a function of light (80, 90, 110, 160 and 350 μmol m -2 s -1 ), temperature (12, 17 and 22°C), salinity (13, 16.5, 19.5, 25, 29, 33, 36.5 and 38 PSU) and ammonium concentration (0.11, 0.22 and 0.44 mM). Toxicity was measured by the tissue culture bioassay using mouse neuroblastoma cells, and expressed as saxitoxin concentration equivalents. Cellular toxicity increased with decreasing salimty. At temperatures of 17 and 22°C, maximum toxin content was observed at the lowest light intensity and growth rate. At the lowest temperature of 12°C, maximum toxin content was observed at intermediate light intensities and growth rates. A drastic increase in toxin content with an increase in ammonium concentration from 0.11 to 0.22 mM supported the idea that ammonium utilization for toxin production direcily brings about a high toxin content in A. tamarense. Our results ecologically imply that the cells become highly toxic in environments with low salinity and high ammonium concentration, and successive cloudy days. Such environmental conditions may lead to increasing risk of shellfish toxification.

Physiological characteristics of zooxanthellae were examined under nutrient-saturated conditions created by mixing ammonium (15NH4) with nitrate (15NO3) to give 0.88 mM total nitrogen. Growth rate varied with the form of nitrogen provided. Ammonium alone resulted in the lowest C:N and C:chl-a ratios. Although zooxanthellae took up nitrate in the absence of ammonium, ammonium assimilation was 1.3 times higher than nitrate assimilation. Ammonium strongly inhibited nitrate assimilation. While high-ammonium treatments resulted in the highest 14C incorporation into intermediate compounds, high nitrate levels resulted in the highest 14C incorporation into protein, suggesting that the intermediate compounds are produced prior to the subsequent production of protein when ammonium is the dominant N source. The enhanced production of intermediate compounds at the expense of carbon directed to protein synthesis in the presence of ammonium might be analogous to the “host factor” observed in zooxanthellae–host symbioses, since growth rate is depressed due to low production of protein.

海水の光吸収係数は, 海洋の基礎生産や海色リモートセンシングの研究において重要なパラメータの1つである。今まで, その測定法について多くの提案がなされてきた。本稿は, まず吸収係数の定義を明確に定義し, その海洋学における意義を述べた。引き続き, オパールグラス法, グラスファイバー法, 光音響法, 積分球法の原理を述べると共に問題点を挙げた。また, 採水処理しなくて済む現場法についてその原理と問題点をまとめた。引き続き吸収係数の組成分離法について直接分離法と実測値から求めた半理論的分離法を紹介した。最後に人工衛星によるリモートセンシングによる推定法に言及した。

植物プランクトンの光吸収係数は, 海洋の基礎生産や海色リモートセンシングの研究において必要不可欠なパラメータの一つである。その測定法を標準化するために開いたワークショップの成果として, 植物プランクトンの光吸収係数を測定するためのプロトコルを作成した。過去3回のワークショップにおいて, 吸収係数測定法の一つであるQFT法(Quantitative Filter Technique)を中心に, 分光光度計間の比較, 補正式の検討, 植物色素の抽出法の検討を行った。また, 現場型の水中分光吸光度計の利用についても評価を行った。それらの結果をもとに, ろ過方法, 測定方法, さらにデータ管理に至るまで, 推奨するべき方法を提言した。このプロトコルに従って植物プランクトンの光吸収係数を測定することにより, 研究者間の測定値の相互比較が容易となると考えられる。

Dark CO2 incorporation into protein was determined from 24-hr incubations using size-fractionated natural phytoplankton populations from KaAne`ohe Bay, Hawai`i, enriched with either ammonium or ammonium plus phosphorus. Response to ammonium addition was maximum at an ammonium concentration of 3±4 mM. Dark CO2 assimilation was suppressed by addition of both ammonium and phosphorus, but percentage incorporation into protein was not signi®cantly different from addition of ammonium alone. About 75G 1% of the C taken up by the cells was incorporated into either protein or low-molecular-weight intermediate compounds. Cells smaller than 10 mm showed little response to nutrient additions. However, cells in the 10to 35-mm size fraction incorporated signi®cantly more C into protein when nutrients were added. C : N ratios calculated from the percentage of C incorporated into protein were most variable temporally in the 10to 35-mm size group and least variable in the picoplankton (0.2±2.0 mm). Nutrient limitation indices (NLIs) calculated from the quotient of C : N ratios in control and nutrient-enriched cultures were not signi®cantly different for the picoplankton and 2to 10-mm size fraction. The NLI for the 10to 35-mm size fraction was signi®cantly lower and implied a modest degree of nutrient limitation. The results suggest that cells smaller than 10 mm are growing at close to nutrient-saturated rates much of the time in KaAne`ohe Bay. However, larger cells appear to experience a signi®cant degree of nutrient limitation at some times, particularly when chlorophyll a concentrations are less than about 1 mg my3. Dark protein synthesis appears to be a useful modi®cation of previous methods based on the dark uptake of CO2 for studying nutrient limitation. Nitrogen-limited phytoplankton are known to take up ammonium rapidly in the dark as well as in the light (Goldman and Glibert 1983). In contrast to ammonium, nitrate uptake is light-dependent (MacIsaac and Dugdale 1972) for most phytoplankton, with the exception of some dino agellates (Dortch and Maske 1982). When ammonium is taken up in the dark, it may be incorporated into amino acids using carbon also assimilated in the dark (MortainBertrand et al. 1988). Dark ammonium uptake is accompanied by enhanced dark CO2 assimilation by nitrogen-limited phytoplankton. The degree of enhancement of dark CO2 assimilation may be a function of nitrogen limitation. This idea was suggested by Morris et al. (1971) and Yentsch et al. (1977) and later con®rmed experimentally by Goldman and Dennett (1983). Glibert et al. (1985) and Cook et al. (1992, 1994) used this approach to study nutrient limitation of natural phytoplankton populations and symbiotic zooxanthellae, respectively. Ammonium enrichment in the dark led to signi®cant CO2 uptake by the marine diatom Chaetoceros sim1 1 SOEST contribution number 5232. Manuscript accepted 24 April 2000. 2 Hawai`i Institute of Marine Biology and Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawai`i at MaAnoa, Honolulu, Hawai`i 96822. 3 Current address: Department of Bioengineering, Faculty of Engineering, Soka University, 1-236 TangiCho, Hachiouji, Tokyo 192-8577, Japan. Paci®c Science (2001), vol. 55, no. 1:1±15 : 2001 by University of Hawai`i Press

A seasonal study of size fractionated chlorophyll α concentration was conducted weekly in Monbetsu Harbor from October 1996 to November 1997 to investigate the annually persistent occurrence of the spring peak of the chlorophyll α concentration in the >10μm size fraction immediately after the retreat of sea ice, as described by K. Hamasaki et al. (Plankton Biol. Ecol., 45,151,1998). Species composition of natural phytoplankton assemblages was also investigated to study whether phytoplankton or ice algae were responsible for the spring peak in the coastal water. The spring peak occurred immediately after the retreat of sea ice but timing of the occurrence was different between the stations occupied in the present study. The spatial heterogenity in occurrence of the spring peak seemed to be related to the sea ice distribution between the stations. New sea ice provided only a small supply of ice algae due to the relatively short growth period inside of the harbor. Large ice floes provided for a large supply of ice algae due to the long growth period outside of the harbor. The magnitude of the spring peak was related to sea ice growth. However, those ice algae seemed to sink to the bottom with little contribution to phytoplankton assemblage in the harbor, while ice algae contributed significantly to the spring peak outside of the harbor. Species composition revealed relatively fast response of phytoplankton to the environmental change after the disappearance of sea ice. Surface assemblages of phytoplankton including ice algae seemed to respond fully to the regional optical condition by changing in the species composition.

UVR and PAR wavelengths are attenuated to different extents within the water column, causing variations in spectral composition with depth. The present investigation (a) describes the variability of UVR and PAR penetration at a station in the temperate coastal waters of Sagami Bay and determines (b) the characteristics of relative UVR penetration to the euphotic zone. Examination of the seasonal irradiance profile measurements indicated eight measurements displaying two distinct attenuation coefficients (K d ) for specific UVR wavelengths and PAR. The two attenuation coefficients observed from specific wavelengths in the water column may be caused not only by chlorophyll pigments, but also by dissolved organic material in the upper layer. The 1% depth of surface UVR at 305, 320, 340, and 380 nm averaged 10.8 ± 5.7, 14.9 ± 9.5, 19.8 ± 12.1, and 30.4 ± 17.6 m, respectively. The depth of euphotic layer displayed less variability averaging 62 ± 15 m throughout the entire study. Relative UVR penetration within the euphotic zone averaged 17.8 ± 8.1, 22.9 ± 10, 30.5 ± 13.8, and 46 ± 46.9% for 305, 320, 340, and 380 nm, respectively. A large variation of the relative transmission of UVR within the euphotic zone was found although the spectral composition was relatively stable in the air throughout the study.

An assessment of the environmental processes influencing variability in the recruitment and density of Antarctic krill (Euphausia superba) is important, as variability in krill stocks affects the Antarctic marine ecosystem as a whole. We have assessed variability in krill recruitment and density with hypothesized environmental factors, including strength of westerly winds (westerlies) determined from sea level pressure differences across the Drake Passage, sea ice cover, and ozone depletion. We found a significant positive correlation between krill recruitment in the Antarctic Peninsula area and the strength of westerlies during 1982–1998. Years with strong westerlies during the austral summer season resulted in high krill recruitment in 1987/1988, 1990/1991, and 1994/1995, while the years of weak westerlies resulted in low krill recruitment in 1982/1983, 1988/1989, 1992/1993, and 1996/1997. The strength of westerlies was significantly related to recruitment of 1-year-old krill (r = 0.57) and 2-year-old krill (r = 0.69) with a level of significance of 5%. In addition, the strength of westerlies also had a strong correlation with chlorophyll a (r = 0.63) and sea ice cover with a 1-year time lag (r = 0.67). The strength of westerlies is considered to be a key environmental factor. We also found significant correlations between krill density in the Antarctic Peninsula area and the Antarctic ozone depletion parameters during 1977–1997 (e.g., total ozone in October at Faraday/Vernadsky Station of r = 0.76 with a level of significance of 1%). We suspect that ozone depletion impacts directly and/or indirectly on the variability in krill density.

Cyanobacteria were relatively small contributors to carbon biomass (0.97-18%) in the euphotic zone. However, a higher contribution to production obtained at the surface water (16-45%) implies that they contribute more to carbon cycling than is expected from their biomass.

The light-saturated maximum value (P B max) and initial slope (α) of the photosynthesis-irradiance (P-E) curve were examined in a warm streamer, a cold streamer and a warm core ring off the Sanriku area in the subarctic western North Pacific Ocean during an ADEOS/OCTS Sanriku field campaign in early May 1997. BothP B max and α were within the ranges of temperate populations. A regional difference was apparent inP B max: populations in the warm streamer tended to show higher value ranging between 1.92 and 4.74 mgC (mgChla)−1h−1 than those in the cold streamer and the warm core ring (1.35–2.87 mgC (mgChla)−1h−1). A depth variation was also observed in α in both the warm streamer and the warm core ring: shallow populations tended to have lower α than deep populations. The depth variations in bothP B max and α resulted in a lower light intensity of the light saturation in a deeper population than that of a shallower one. These depth-related variations in the P-E parameters were likely a manifestation of “shade-adaptation” of photosynthesis. Photoinhibition was not observed over in situ surface light intensity varying below ca 1600 μmol photon m−2s−1. Water-column primary productivity was biooptically estimated to be 233 to 949 mgC m−2d−1 using vertical distributions of the P-E parameters, chlorophylla, phytoplankton light absorption and underwater irradiance. Applicability of surface data sets for estimation of water-column productivity is discussed.

Taxonomic composition, size composition, standing stock, and chemical composition of mesozooplankton were determined to examine the contribution of their fecal pellets to the vertical flux of organic carbon at the outside, the edge, and the center of the warm core ring. The warm core ring significantly affects not only their taxonomic composition and size composition but also their standing stock and chemical composition. The zooplankton at the center of the warm core ring was characterized by the absence of carnivores at the top of the size-trophic relation and filter feeding planktonic tunicates at the bottom. Zooplankton carbon biomass at the outside of the ring was one-third less than that at the center of the ring. The vertical flux of fecal pellets obtained from the pellet volume (12.3 mgC m−2d−1) contributed 19 to 96% of the flux (13 to 64 mgC m−2 d−1) estimated from the body carbon and the fecal pellet production rate. The estimated flux of fecal pellets was 6 to 27% of vertical carbon flux (236 mgC m−2d−1) determined by the sediment traps. Microscopic determination of fecal pellets and plankton in the sediment trap samples indicated high grazing activity during the sinking process. Those observations might suggest that particles other than fecal pellets contributed significantly to the vertical carbon flux and fecal pellets were settled directly without loss or being recycled within the surface mixed layer.

The spring bloom of phytoplankton is a well-established, regular, seasonal event in the western subarctic Pacific and is considered one of the most important conditions of massive production of pelagic fishes. A series of 12 cruises was conducted from 1990 to 1992 to examine the timing and magnitude of the spring phytoplankton bloom in the Oyashio region, the western subarctic Pacific off Hokkaido, Japan. An interannual variability in the bloom events was also analysed. On the basis of hydrographical characteristics, the study area was divided into three water masses: the Oyashio Water Mass, the Mixed Water Mass, and the Coastal Water Mass. Spring blooms were observed first in April in the Oyashio and the Coastal Water Masses, and continued to May in 1991 and 1992. However, no bloom was recorded in the Mixed Water Mass. High nutrient supply into the surface mixed layer during winter is likely to be one of the factors supporting an intense spring bloom in the Oyashio Water Mass. A significant positive relationship between log-transformed surface chlorophyll a concentration and maximum density gradient (MDG) within the euphotic layer was obtained in April, indicating the importance of vertical stability of the water column in the initiation of spring blooms in the Oyashio and the Coastal Water Masses. The spring blooms in 1991 were much more extensive and lasted longer than in 1990. It is suggested that meteorological conditions and abundance of grazers were responsible for this interannual difference.

The seasonal development of algal biomass and dissolved organic carbon (DOC) in bottom ice was determined for two widely separated areas of annual sea ice, Saroma-ko in northern Japan and Resolute Passage in the Canadian High Arctic, to determine the importance of DOC to estimates of primary production in sea ice communities. As algal biomass, measured either as chlorophyll a (Chl a) or particulate organic carbon (POC), increased, DOC concentrations increased to extremely high values (up to 40 mg Cl−1 DOC). The highest algal biomass and DOC concentrations were observed at Resolute under thin (4–8 cm) snow cover. Highly significant double-log linear relationships (r2 = 62–80%, p < 0.01) existed between DOC and both Chl a and POC, suggesting much of the DOC originated from the ice algae. A highly significant global relationship between DOC and POC (r2 = 74%, p

Enrichment experiments with ammonium, nitrate and silicate were conducted to determine their effects on the photosynthate allocation by ice algae collected during the spring of 1992 from Resolute Passage, Canadian Arctic. Ammonium concentrations of 100 μM inhibited the synthesis of protein, which was the largest fraction in the end products for the ammonium and nitrate enrichment experiments. No inhibition was detected for up to 200 μM of added nitrate. Silicate enrichment of >5 μM combined with 50 μM ammonium increased photosynthate allocation to protein to more than 45%. However, protein synthesis showed no regular pattern of increase or decrease with enrichments of varying concentration of silicate plus 50 μM of nitrate. The dominant fraction in the silicate plus nitrate experiment was polysaccharide and nucleic acids, which accounted for more than 35% of the total photosynthesis. The total lipid fraction was only slightly affected by nitrogen or silicate, but neutral lipids decreased while membrane-associated polar lipids increased with silicate plus ammonium enrichment. Our findings indicate that ice algae in Resolute Passage were likely limited by ammonium and silicate during the declining period of the algal bloom in 1992.

Seasonal variations in under-ice microalgal sedimentation and plankton dynamics in Saroma-ko, a shallow seasonally ice-covered lagoon (Sea of Okhotsk, Hokkaido, Japan), were followed during a 4-week period at the end of winter. At 3–4 day intervals, sediment traps were deployed at three depths from the undersurface of the ice and water column samples were collected. Sampled variables included chlorophyll a (chl a) and pheopigments, particulate organic carbon and nitrogen (POC, PON), cell identification and enumeration, biogenic silica and dissolved inorganic nutrients. POC/PON, POC/chl a and Si/chl a ratios for suspended biomass as well as cell counts showed the presence of a diversified phytoplankton assemblage with a high microheterotrophic biomass. A major peak in algal sedimentation occurred at the end of the sampling season (chl a flux ca. 5 mg m−2 d−1); the sedimented algae included both ice algae and phytoplankton species. Ice algae did not remain suspended in the plankton biomass, but sedimented rapidly upon release from the ice matrix. Results show that Saroma-ko had a rather special food web structure at the end of winter, when both high microalgal export and water column recycling simultaneously occurred under the ice cover.

The vertical flux of ice algae was determined with a multiple sediment trap at 4 m depth at the central station in Saroma Ko lagoon, Hokkaido, Japan. Collection was done in 5-day intervals from March 1 to April 24, 1994. The sea ice started breaking at the end of that period, from April 10 to 14,1994 and disappeared completely from the lagoon on April 17, 1994. The average fluxes of CHLa, PHEO, POC, PON, and BioSi during the melting season of sea ice were 20±6.5 mg CHLa, 2.0±1.0 mg PHEO, 630±190 mg C, 110±39 mg N, and 490±170 mg Si m^ d^, respectively. The average % loss rates, determined by the ratio of the average vertical flux to the average ice algal production estimated from the standing stock and the growth rate, was calculated as 100% d^ for CHLa during the ice melting period. Once the sea ice started breaking and disappeared, they increased by at least 1.5 fold. A relatively high increase was observed for PHEO (2.5 fold) and BioSi (2.3 fold) compared to the lowest increase of CHLa (1.5 fold). This implies that either the vertical flux of CHLa has been depressed due to unfavorable physical conditions, such as low salinity produced by a combination of melting sea ice and runoff of fresh water and exposure to high light provided by a disturbed position of broken sea ice, or the vertical flux of BioSi has been accelerated through physical breakage of ice algal cells by heterotrophic grazing and possibly resuspension of PHEO-rich water induced by wind forced mixing, evidenced by a significant increase of PHEO under the ice free water. Wind-forced resuspension should be considered in any study of vertical flux of ice algae when sea ice disappears in shallow water.

Experiments were conducted during January 1995 in the Southern Ocean to examine the impact of enhanced solar ultraviolet-B radiation (UVBR) on the biosynthesis and composition of organic compounds in Antarctic marine phytoplankton. Our results revealed distinct changes in the biochemical composition of phytoplankton attributable to UVBR exposure. Fatty acid concentrations increased in the presence of UVBR, mainly on account of a large increase in the content of saturated fatty acids within the cells. On the other hand, polyunsaturated fatty acids declined in cells exposed to UVBR. Amino acid concentrations were higher in the UVBR exposed samples, attributable largely to a UVBR induced increase in cellular concentrations of glutamic' acid (glutamic acid+glutamine) and aspartic acid. Monosaccharide constituents of cellular storage and structural carbohydrates, however, showed a decline in the cells exposed to UVBR. Except for the decline in structural monosaccharides, these changes in the patterns of organic compounds observed in Antarctic phytoplankton were remarkably similar but, greater in magnitude in comparison to those observed in temperate phytoplankton exposed to UVBR.

The response of ice algae to low salinity was determined at three levels of silicate enrichment during the winter of 1992 in Saroma-ko Lagoon, Hokkaido, Japan. Regardless of the silicate concentration, the chlorophyll a content decreased by 50% of its initial value within the first day of exposure to low salinity water (22 psu) and continued to decrease gradually thereafter. The degree of decrease after the first day was a function of silicate concentration. The size distribution of the ice algae at the beginning of the incubation was 52% in the size class > 10 μm, 39% in 10-2 μm and 9% in 2-0.2 μm. Within two weeks of silicate enrichment, the 2-0.2 μm fraction decreased to less than 1% while the > 10 μm fraction increased to more than 90%. Low salinity and low silicate concentrations reduced the chlorophyll a biomass and photosynthetic activity. Silicate enrichments, even at the low salinity, enhanced photosynthetic activity and the relative abundance of the > 10 μm cells. Our results suggest that ice algae may not survive if trapped in the low salinity lens that is present immediately below the ice during melting because of possible osmotic damage associated with silicate deficiency. However, ice algal cells may recover from the damage when they sink into the high salinity and silicate-rich underlying water in Saroma-ko Lagoon. The ecological role of low salinity water is discussed in relation to vertical flux of ice algae.

A long-term nutrient enrichment bioassay was used to test the hypothesis that silicon is the potential limiting nutrient for growth of bottom ice algae in the Canadian High Arctic and to determine the physiological response of the algae to nutrient deprivation. All measures of algal response (chlorophyll a , particulate organic carbon, cell concentration and carbon allocation) indicated that nitrogen rather than silicon was the principal potential limiting nutrient. Silicon was not present in great excess, however, and significantly influenced the growth of most of the dominant species. Algal growth slowed and ultimately stopped in all treatments except for the combined (P, δi and N) addition. Carbon allocation shifted toward lipid and away from protein as growth was slowed by nutrient depletion, with neutral lipids increasing while membrane-associated lipids declined. There was no evidence of carbon storage in polysaccharides. The biosynthetic response of the algae thus confirmed that nutrient limitation can cause lipid accumulation in ice algal communities.

We used the 13C tracer technique in conjunction with gas chromatography-mass spectrometry to examine the impact of ultraviolet radiation (UVR) on the patterns ofbiosynthesis and composition of monosaccharides in natural assemblages of phytoplankton photoadapting to high light intensities. Exposure to UVR resulted in a decrease in the rates of phytoplankton photosynthesis and a marked reduction in the rates of production and pool sizes of neutral monosaccharides within the storage carbohyd-ate fraction (operationally defined as carbohydrates soluble in hot water). In contrast, the biosynthesis of r:eutral monosaccharides associated with cell wall or structural carbohydrates (operationally defined as the fraction of carbohydrates insoluble in hot water) showed an increase in the presence of UVR, which, although marginal, was consistent from stalion to station. The decline in pool sizes of monosaccharides within the storage carbohydrate fraction was largely responsible for the decline in the overall carbohydrate content of the cells. The diminution in the rates of synthesis and pool sizes of glucose within this fraction represented one of the most significant differences compared to phytoplankton shielded from UVR. In the structural carbohydrate fraction, the synthesis of several component monosaccharides was consistently higher in phytoplankton exposed to UVR.

In situ diel feeding behavior of neritic copepods was investigated using the gut fluorescence method, during spring and fall bloom periods in Akkeshi Bay, on the eastern coast of Hokkaido, Japan. Acartia omorii and Paracalanus sp. were the dominant species during the fall, and Pseudocalanus spp. and A. longiremis during the spring. During both bloom periods, diel rhythms were always observed for the gut pigment contents of these dominant copepods, although there were interspecific differences in the pattern. The maximum gut pigment content was always observed during the night and the minimum during the day. For all species, except Paracalanus sp., the average gut pigment content during the night was significantly higher (p

— The impact of ultraviolet-B radiation (UVBR) on the biosynthesis and the composition of intracellular dissolved free and combined amino acids was examined in nitrate-replete and nitrate-deficient cultures of Tetraselmis sp. Several similarities were observed in the response of Tetraselmis sp. to nitrogen deficiency and exposure to UVBR, in support of a view that UVBR affects amino acid synthesis in phytoplankton via its inhibitory effects on nitrogen assimilation into the cells. At levels that still permitted the uptake of carbon into the cells, both nitrogen deficiency and UVBR exposure resulted in a reduction in the overall rates of carbon incorporated into amino acids, an increase in the absolute concentrations of amino acids within the intracellular dissolved free amino acid (INDFAA) pool and a decrease in the total cellular amino acid (TCAA) pool. An examination of the patterns of carbon assimilation into individual amino acids in cells exposed to UVBR revealed similarities with the patterns in cells subject to nitrogen deficiency. The most conspicuous changes from the controls included an increased incorporation of 13C into glutamic' acid (glutamic acid + glutamine) and aspartic acid and a marked reduction into alanine and valine. Changes in the concentrations of amino acids within the INDFAA and TCAA pools were also similar in nitrate-deficient and UVBR-exposed cells and resembled the carbon assimilation patterns. These results strongly suggest that UVBR-induced changes in the biosynthesis and composition of amino acids are probably via its suppression of nitrogen assimilation into the cells.

Effects of vertical stability on spring blooms of phytoplankton were investigated for the western subarctic Pacific ocean using a one-dimensional (depth) ecosystem model. In the model, vertical stability was expressed by diffusion constants calculated from observed density distribution. Dynamics of phytoplankton in blooms was calculated by the model using the vertical diffusion. Then, the calculated results were compared with the Coastal Zone Color Scanner (CZCS) data. The comparison shows that the shallow surface mixed layer causes early start days of spring blooms at inshore (northern) stations. In addition, spring blooms continue long at inshore (northern) stations since a water column has weak stability. This is because weak stability of a water column causes large nutrient supply from a deep layer and large diffusive transport of phytoplankton biomass from the subsurface maximum.

The spatial distribution and seasonal variability of epipelagic chaetognaths along the Kurile Islands and off south-east Hokkaido, in the western subarctic Pacific Ocean. were investigated during the period from May 1990 to October 1992. Sagitta elegans was the dominant species among the epipelagic chaetognaths in the study area. Juvenile S. elegans were distributed mainly along the path of the mixed water which was determined by the acceleration potential anomaly (APA) at the iso-pycnal density surface of 26.6 σθ. The location of the path of The mixed water meandered around cyclonic and anticyclonic eddies. Catches of S. elegans were made at temperatures ranging from 4.5 to 22.2dC. The juvenile distribution, however, was mostly restricted to between 1 and 4dC of the potential temperature determined at the isopycnal density surface of 26.6 σθ. Variability in the juvenile abundance within the path of the mixed water could be caused by predation rather than by food limitation because microzooplankton, which are known to he prey for juveniles, were abundant enough to meet the food requirements of juveniles in the study area. Adults occurred in spring (April-May) and young individuals (juvenile and stage 1) were abundant in summer (June-July), when a strong thermocline developed. The main spawning period appears to be during April-May, with a possible second spawning period in the autumn.

Background Physical exercise effectively attenuates neuropathic pain, and multiple events including the inhibition of activated glial cells in the spinal dorsal horn, activation of the descending pain inhibitory system, and reductions in pro-inflammatory cytokines in injured peripheral nerves may contribute to exercise-induced hypoalgesia. Since fewer GABAergic hypoalgesic interneurons exist in the dorsal horn in neuropathic pain model animals, the recovery of impaired GABAergic inhibition in the dorsal horn may improve pain behavior. We herein determined whether the production of gamma-aminobutyric acid (GABA) and glutamic acid decarboxylase (GAD) in the dorsal horn is restored by treadmill running and contributes to exercise-induced hypoalgesia in neuropathic pain model mice. C57BL/6 J mice underwent partial sciatic nerve ligation (PSL). PSL-Runner mice ran on a treadmill at 7 m/min for 60 min/day, 5 days/week, from two days after PSL. Results Mechanical allodynia and heat hyperalgesia developed in PSL-Sedentary mice but were significantly attenuated in PSL-Runner mice. PSL markedly decreased GABA and GAD65/67 levels in neuropils in the ipsilateral dorsal horn, while treadmill running inhibited these reductions. GABA+ neuronal nuclei+ interneuron numbers in the ipsilateral dorsal horn were significantly decreased in PSL-Sedentary mice but not in PSL-Runner mice. Pain behavior thresholds positively correlated with GABA and GAD65/67 levels and GABAergic interneuron numbers in the ipsilateral dorsal horns of PSL-Sedentary and -Runner mice. Conclusions Treadmill running prevented PSL-induced reductions in GAD65/67 production, and, thus, GABA levels may be retained in interneurons and neuropils in the superficial dorsal horn. Therefore, improvements in impaired GABAergic inhibition may be involved in exercise-induced hypoalgesia.

第3回極域科学シンポジウム 横断セッション「南極海季節的海氷域における生物地球化学」11月26日（月） 統計数理研究所 セミナー室