Elemental composition of individual pico- and nano-sized marine detrital particles in the northwestern Mediterranean Sea

The elemental composition of individual < 10 μm detrital particles from Mediterranean surface waters was analysed using a Transmission Electron Microscope (TEM) equipped with an energy dispersive X-Ray microanalyser. Results show that carbon and phosphorus content per detritus volume are much higher in pico-detrital particles < 2 μm (42 kg C m⁻³ and 1 kg P m⁻³) than in 5–10 μm detrital particles (20 kg C m⁻³ and 0.1 kg P m⁻³). The C:N:P atomic ratios for different sized fractions of the detrital particles were found to be 82:10:1 for < 2 μm particles, 120:29:1 for 2–5 μm particles and 308:37:1 for 5–10 μm particles. The average ratio for all size classes of detrital particles (< 10 μm) was 132:23:1. The differences in elementary compositions of the detrital particles studied here suggest that the different size fractions probably have different origins. The role and origins of < 10 μm detrital particles within the biogeochemical cycles are discussed.     

Chemical characteristics and estimation on the vertical flux of N, P, Si in upwelling area of Taiwan Strait

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Emergence in the deep sea: Evidence from harpacticoid copepods

In coastal waters, individuals of many benthic species make temporary excursions into the water column, a behavior called emergence. The reasons for this behavior are not well established, but some that have been suggested apply equally well to the deep sea, and some sediment-trap data suggest that emergence occurs in the deep sea. To investigate this possibility, we collected sediment cores and placed inverted-funnel traps at 3087 m depth on the continental slope off central California (36°41.91′N 123°0.14′W) for 36 days and investigated a representative taxon, the harpacticoid copepods. Although our methods probably produced underestimates, at least 4 of 55 species emerged, so conceptualizations about the ecology of deep-sea-sediment communities should include the idea that some benthic species use the near-bottom flow to change locations.     

First observation of Karlodinium veneficum from the East China Sea and the coastal waters of Germany

Harmful algal blooms often occurred in the East China Sea (ECS) and the German coastal waters of the North Sea but Karlodinium veneficum had not been taxonomically reported. Two strains of Karlodinium (LAMB090611 and LAMB010601) were isolated from the two areas in 2009. The morphological characteristics and molecular phylogeny of two strains are compared on the basis of observation of a light microscope, a scanning electron microscope (SEM), a laser scanning micro-scope (LSM) and an internal transcribed spacer (ITS) sequence data. The mean cell length of strain LAMB090611 is (14.2 ± 1.8) μm (range 11.1-18.7 μm) and mean width is (10.8 ± 1.5) μm (range 8.2- 14.7 μm). The mean cell length of strain LAMB010601 is (15.1 ± 1.2) μm (range 12.7-17.9 μm) and the mean width is (11.4 ± 1.1) μm (range 9.1-14.7 μm), respectively. The two strains are similar in morphological characteristics, including a straight apical groove, distinct ventral pore, sulcal extension, cingulum displacement, two or four irregular shaped chloroplasts within the cell and almost equal sized epicone and hypocone. The large and round nucleus is located at the center or at the hypocone of the cell. The sequence length of the ECS strain LAMB090611 and the German strain LAMB010601 is 640 and 646 bp, respectively. The GC content is 49%. The nucleotide similarity of the two strains is 98.1%. The sequence divergence is 0.003. Both strains are confirmed as Karlo-dinium veneficum (D. Ballantine) J. Larsen and this is the first taxonomic report from China and Germany coastal waters. The population dynamics of this toxic species in the ECS and German coastal waters needs to be investigated in the near future.     

山东半岛南部近岸全新世泥质区表层沉积物

泥质区沉积记录是全新世海洋环境演变的重要信息载体。中国近海沿岸发育着若干小型泥质沉积体,比较明确的有南海西部近海的泥质区,但尚未进行研究。通过对山东半岛南部近岸海域采集的浅地层剖面资料精细解释后发现,在该区近岸海域存在一个小型泥质沉积区,主要分布在青岛崂山头以北至乳山口附近的近岸海域,整体上平行海岸线呈条带状分布,由近岸向海逐渐变薄,等厚深度分布平行于岸线,沉积中心位于鳌山湾海域,沉积中心最厚可达22.5 m。AMS¹⁴C测年结果表明,该泥质区形成于全新世。本文利用在泥质区采集的表层沉积物的粒度、黏土矿物、碎屑矿物、地球化学元素等分析测试结果,对比研究区周边主要入海中小河流物质成分和黄河物质成分,探讨了山东半岛南部近岸海域泥质沉积区的沉积特征和物源情况。结果表明,该泥质区的形成是黄河与周边入海河流共同作用的结果。     

Aluminum in the East China Sea and Okinawa Trough, marginal sea areas of the Western North Pacific

The distribution of aluminum (Al) in seawater has been investigated in the continental slope and the Okinawa Trough areas of the East China Sea, which is one of the marginal seas in the western North Pacific Ocean. Aluminum concentration in waters over the slope and the Trough ranged from 5.6 to 25 nmol/kg in the surface layer (0–100 m), and had a minima of 1.1 nmol/kg between 400 and 500 m depth and ranged from 1.3 to 9.7 nmol/kg in the deep or bottom waters. Aluminum values were higher than in the surface waters of the central North Pacific, while minimum values were similar to levels in the intermediate or deep waters of the central North Pacific, except for the bottom water over the slope. This suggests that the high Al concentration in the surface reflects the large atmospheric input of Asian dust around the western side of the North Pacific region. On the continental slope, Al concentrations in the upper 500 m depth decreased slopeward. This horizontal gradient of Al can be explained from the combination of dilution by upwelling of Al-poor water originated from the North Pacific Intermediate Water (NPIW) which intrudes into the mid-depth of the Okinawa Trough and the scavenging of Al by biogenic particles in the continental slope zone.     

Seasonal variations in temperature,salinity and density in the southern coastal waters of the Caspian Sea

Variability in water temperature, salinity and density was investigated based on field measurements near Anzali Port, in the Southern Caspian Sea in 2008. Seasonal changes of seawater properties were mainly observed through the upper 100 m layer, while below this layer seasonal variations of the parameters were minor. Vertical structure of the temperature in the southern coastal waters of the Caspian Sea is characterized by a significant seasonal thermocline between 20–50 m depths with vertical variation in temperature about 16°C in midsummer (August). Decrease of the thermocline occurs with the general cooling of the air and sea surface water, and deepening of the mixed layer during late of autumn and winter. Seasonal averages of the salinity were estimated in a range of 12.27–12.37 PSU. The structure of thermocline and pycnocline indicated agreement between changes of temperature and density of seawater. Seasonal pycnocline was observed in position of the thermocline layer.     

Horizontal distribution of particulate matter and its characterization using phosphorus as an indicator in surface coastal water,Harima-Nada,the Seto Inland Sea,Japan

To study the horizontal distribution and characterization of suspended particulate matter (SPM) in the coastal environment, the distribution and seasonal variation of particulate phosphorus (PP), divided as organic (POP) and inorganic (PIP) fractions with POC, PON, and Chl.a, in 4 seasons throughout Harima-Nada of the Seto Inland Sea, Japan, were investigated. A high concentration of PIP was observed not only in the northern coastal area, which received much freshwater discharge, but also in the channel parts. In winter, when Δσt was low, the difference between surface and bottom σt, resuspension of sinking particles or/and surface sediment which has a high PIP/PP ratio seems to have occurred, and then a high concentration of PIP in surface water was observed. In spring and summer, PIP/PP ratios (0.24) of surface waters were close to those of phytoplankton (0.1–0.2). On the other hand, PIP/PP ratios in autumn and winter, when Δσt was low, were similar to those of surface sediment in Harima-Nada (0.32–0.39). SPM in Harima-Nada showed higher PP contents than other coastal environments, and its mean value of 9.10 mg P/g was close to the phytoplankton P content of 9.75 mg P/g. This suggests that SPM in Harima-Nada was strongly affected by phytoplankton. The C/N ratio in Harima-Nada in spring was high (11), although high Chl.a and low PIP/PP were observed, possibly resulting from preferential decomposition of nitrogen in comparison with carbon. We consider that the PIP/PP ratio is a good indicator to characterize SPM and to predict its origin as well as the C/N.     

春、秋季南黄海浮游纤毛虫丰度及生物量的分布差异

Seasonal variation of marine plankton spatial distribution is important in understanding the biological processes in the ocean.In this study,we studied spatial distribution of planktonic ciliate abundance and biomass in the central deep area(station depth greater than 60 m) and the coastal shallow area(station depth less than 60 m) of the southern Yellow Sea(32°–36.5°N,121°–125°E) in spring(April) and autumn(October–November) of 2006.Our results showed that both ciliate abundance and biomass in the surface waters were higher in spring((1 490±2 336)ind./L;(4.11±7.81) μg/L) than in autumn((972±823) ind./L;(1.11±1.18) μg/L,calculated by carbon).Ciliate abundance and biomass in the surface waters of the coastal shallow area were similar in spring and autumn.However,in the central deep area,those values were much higher in spring((1 878±2 893) ind./L;(5.99±10.10)μg/L) than in autumn((738±373) ind./L;(0.74±0.76) μg/L).High values of ciliate abundance and biomass occurred in the central deep area in spring and in the coastal shallow area in autumn.Mixotrophic ciliate Laboea strobila was abundant in the central deep area in spring,when a phytoplankton bloom occurred.However,in autumn,L.strobila was abundant in the coastal shallow area.Boreal tintinnid Ptychocyli obtusa was found in spring.Both L.strobila and P.obtusa were concentrated in the surface waters when their abundance was more than 1 000 ind./L.Peaks of these species were in the subsurface waters when their abundance was less than 400 ind./L.This study showed that both high abundance and biomass of ciliates occurred in different areas in southern Yellow Sea seasonally.     

Zooplankton Distribution and Dynamics in a North Pacific Eddy of Coastal Origin: I. Transport and Loss of Continental Margin Species

Zooplankton from coastal/continental margin environments can be transported long distances seaward into the subarctic North Pacific by the large (100–200 km diameter) anticyclonic eddies that form annually in late winter along the eastern margin of the Alaska Gyre. One recurrent region for eddy formation is off the southern tip of the Queen Charlotte Islands (near 52°N 132°W). Eddies from this source region (termed ‘Haida eddies’) propagate westward into open ocean waters during the subsequent 1–3 years, often to about 140°W, occasionally to mid gyre. Each eddy contains a core of anomalously low density water, and produces an upward doming of the sea surface detectable by satellite altimetry, thereby aiding repeated ship-based sampling. The zooplankton community in the eddies is a mixture between shelf/slope species (transported from the nearshore formation region) and subarctic oceanic species (which colonize the eddy from the sides and below). This paper reports sequential observations (late winter, early summer and fall seasons of 2000, and early summer and fall of 2001) of the abundance and distribution of continental-margin zooplankton in the Haida eddies that formed in late winters of 2000 and 2001. Shelf-origin species declined in abundance over time. Species that appeared to have a continental slope origin sometimes declined but sometimes persisted and flourished. Transport and retention within the eddy appeared to be especially effective for species that undergo diel vertical migration. This revised version was published online in August 2006 with corrections to the Cover Date.     

南海北部表层沉积物碳酸盐含量和δ18O及δ13C的空间与粒径分布特征及其控制因素

为深入研究南海北部表层沉积物中碳酸盐的来源及其控制因素,采用湿筛法,对南海北部珠江口、陆架、陆坡及海盆表层沉积物中碳酸盐的含量、δ18O和δ13C及其粒度分布特征进行了研究。结果表明,南海北部表层沉积物中的碳酸盐可能主要以海洋自生碳酸盐为主,其含量在空间上以陆坡显著高于海盆、陆架及珠江口为特征。粒度上,陆架(水深80 m)和浅陆坡(水深550 m)处碳酸盐的粒度分布相对平均,但在珠江口及730 m以深,76.9%~84.5%的碳酸盐分布于小于32 μm的粒级中。另外,珠江口和陆架与陆坡和海盆碳酸盐δ18O和δ13C的空间及粒度分布特征显著不同。珠江口陆架区,在空间上从珠江口向陆架,全样碳酸盐的δ18O和δ13C由轻变重。粒度上,碳酸盐的δ18O和δ13C随着粒径的增大而变重,并且δ18O和δ13C之间正相关,主要受珠江淡水的δ18O及其δ13C_DIC控制。陆坡海盆区,空间上,从陆坡向海盆,δ18O略有变轻,δ13C基本不变。粒度上,碳酸盐的δ18O和δ13C随着粒度的增大没有明显的变化趋势,并且δ18O与δ13C之间不相关或负相关。其δ18O可能主要受表层海水的温度控制,其δ13C可能主要受海水δ13C_DIC控制。     

Winter water mass distributions in the western Gulf of Mexico affected by a colliding anticyclonic ring

The winter water mass distributions in the western Gulf of Mexico, affected by the collision of a Loop Current anticyclonic ring, during January 1984 are analyzed. Two principal modes of Gulf Common Water (GCW) formation, arising from the dilution of the Caribbean Subtropical Underwater (SUW), are identified. Within the western gulf continental slope to the east of Tamiahua, the GCW is formed by the collision of anticyclonic rings. During these collision events, the SUW, entrapped at the core (200 m depth) of these features, is diluted by low salinity (36.1S36.3) water from the uppermost layer of the main thermocline. The end product of this mixture is GCW, which is further diluted by low salinity coastal water within the western gulf continental shelf. The second GCW formation mode is associated to the northerly wind stress which propagates over the western gulf during winter. During January, 1984, this wind stress gave rise to a 175 m mixed layer. This convective mixing destroyed the static stability of the summer thermocline and allowed for the partial dilution of the SUW with low salinity (S36.3) water from the western gulf continental shelf. Within the western gulf's upper 2000 m, the following water masses were identified to be present: GCW, SUW, Tropical Atlantic Central Water and associated dissolved oxygen minimum stratum, Antarctic Intermediate Water remnant, a mixture of the Caribbean Intermediate Water and the upper portion of North Atlantic Deep Water (NADW), and the NADW itself. The topographic distribution of these water masses' strata was dictated by the cyclonic-anticyclonic baroclinic circulation that evolved from the anticyclone's collision to the east of Tamiahua. Between the cyclonic and anticyclonic domains, the maximum pressure differential of these water masses' core occurrences was 150 to 280 dbar. The topographic transition zone defined by these strata occurred between the cyclonic and anticyclonic domains and coincided unambiguously with the anticyclone's collision zone. Within the continental shelf, we identified low temperature (12°C) and low salinity (31) coastal waters contributed by river runoff. Driven by the northerly wind stress, these coastal waters were advected toward the south hugging the coastline. The coastal and continental shelf waters demarcated a sea surface temperature, salinity, and dissolved oxygen discontinuity region that coincided with the horizontal baroclinic flow transition zone associated to the anticyclone's collision.     

Standing stock and community structure of photosynthetic picoplankton in the northern South China Sea

1 Introduction Forthe lastm ore than 20 a,ow ing to the develop-m ent of observation and experim ent technologies form arine m icroorganism s,m arine biologistshave discov-ered m any m icroorganism s w hich are difficult to beobserved by com m on m icroscope before. T hus, thecognition to the m arine phytoplankton com m unitiesand the structure of food chains has achieved im por-tantprogress.E specially,w ith the developm entand ap-plication of epifluorescence m icroscopy and flow cy-tom etry…     

Biogeochemical evolution of the outflow of the Mediterranean deep-lying particulate organic matter into the northeastern Atlantic

Small- and large-size particles were collected in January and August 1989 throughout the water column (50–3000 m) in a northeastern Atlantic area where deep Mediterranean waters outflowing through the Strait of Gibraltar are incorporated at mid-depth into Atlantic waters. Particles collected by water filtration (0.7 μm pore size) and by vertical hauls of a plankton net (50 μm mesh size) were analysed for their organic carbon and lipid composition, namely fatty acids, hydrocarbons, aliphatic and alicyclic alcohols and ketones, and pigments. Small-size particles exhibited POC concentrations two to three orders of magnitude higher (5–50 μg/l) than large particles (0.01–0.32 μg/l). Strong spatial and temporal variations were also observed. Surface small particles collected in January accounted for 15–50 μg/l of POC, whereas in August, these represented only 5–15 μg/l following the seasonal variability of primary production. Concurrently, the variety of lipid components was larger in January.The lipid components of large-size particles were dominated by zooplankton markers, whereas small particles showed evidence of a mixed algal composition (mainly of haptophytes and moderately of diatoms, prasinophytes, chrysophytes and dinoflagellates) with a bacterial contribution. The vertical profiles of the different lipid classes showed a general decrease with depth, particularly significant in the upper 200 m, consistently with the POC contents. Compositional changes were more evident in small particles and included the loss of unsaturated compounds and the increase of diagenetic and bacterial markers. Unusual increases were observed at mid-depths indicating additional particle inputs, either by in situ formation or by advective transport from the Mediterranean. The latter was recognized because small particles in Mediterranean waters entrained large quantities of continental detritic materials that were also found in the Mediterranean water lenses in the Atlantic. From these observations, it was inferred that the outflow of the Mediterranean deep-lying particulate organic matter might still preserve its signature in the mid-depth northeastern Atlantic waters.     

南海西北部夏冬季浮游介形类的分布及其影响因素

海洋浮游介形类(Ostracods)是一类分布较广的小型甲壳动物, 在海洋碳循环中起重要作用。目前国内海洋浮游动物采样常使用505μm网目孔径的浮游生物网, 从而导致个体较小的介形类被忽略。文章根据2006年7—8月(夏季)和2006年12月—2007年1月(冬季)在南海西北部海域分别使用网目孔径为505μm和160μm浮游生物网采集的样品, 比较不同网目所获浮游介形类种类和丰度的差异, 分析介形类种类和丰度的分布特征, 探讨环境因素对其时空分布的影响。160μm网目采集的浮游介形类种类和丰度均高于505μm。基于160μm网目数据分析浮游介形类群落结构: 1) 鉴定浮游介形类32种, 其种数由近岸向外海递增, 等深线100m以浅海域的种数显著高于100m以深海域(p<0.01); 2) 夏季浮游介形类的丰度高于冬季, 夏季丰度高值区主要出现在雷州半岛东部和琼东近岸, 显著高于外海(p<0.05), 冬季介形类丰度分布较为均匀; 3) 优势种针刺真浮萤(Euconchoecia aculeata)是近岸高丰度的主要贡献种; 4) 介形类种数与温度和水深呈显著正相关, 丰度与叶绿素a浓度呈正相关, 而与温度和盐度呈负相关。夏季琼东沿岸上升流和粤西沿岸流有助于浮游介形类在雷州半岛和海南岛东部近岸海域形成较高的丰度, 最高达1252个·m^-3。同时, 建议今后研究浮游介形类采用网目孔径小的浮游生物网进行采集以便全面评估其群落结构特征。     

基于水淘选分级的长江口及邻近海域表层沉积物中磷的形态分布和迁移转化

磷是一种重要的生源要素,在河口、边缘海的初级生产中发挥重要作用,了解沉积物中磷的形态分布和迁移转化有助于深入了解该区域生态系统动力学。于2013年3月在长江口及邻近海域采集了表层沉积物样品,利用水淘选方法对沉积物进行了分级,并采用化学连续提取法分析了未分级和分级沉积物样品中的6种磷形态含量:可交换态磷、活性有机磷、铁结合态磷、自生磷灰石磷、碎屑磷和难分解有机磷,讨论了该区域沉积物中磷的形态分布、选择性输运过程和迁移转化。沉积物中总磷含量在14.0~18.4 μmol/g,其中碎屑磷是其主要成分,占54.5%,其次是有机磷和难分解有机磷,分别占到15.1%和13.1%。不同粒级沉积物中磷形态含量不同,可交换态磷、活性有机磷、铁结合态磷、自生磷灰石磷和难分解有机磷随粒级增加含量逐渐降低,而碎屑磷主要集中在粗粒级（大于32 μm）沉积物中。基于各粒级磷形态的质量分布,发现小于32 μm粒级的沉积物中各磷形态含量从长江口向浙闽沿岸逐渐增加,向外海方向逐渐减小,而大于32 μm沉积物的变化趋势与此相反,体现了不同形态磷的选择性输运。随粒径增大,总有机碳对有机磷比值（TOC/Or-P）先降低后升高,在大粒级沉积物中,TOC/Or-P比值较高主要是因为陆源有机碳贡献较高,而在小粒级沉积物中,主要是由于有机磷的迁移和转化更为活跃,体现了细颗粒物中有机磷相对有机碳的优先分解。本研究表明,从分级的角度可以对河口、边缘海的磷循环有一个更全面的认识。     

Decomposition of Phytoplankton in Seawater. Part I: Kinetic Analysis of the Effect of Organic Matter Concentration

Decomposition experiments were conducted on cultured phytoplankton (Skeletonema costatum) in seawater containing decomposer and consumer of size less than 500 μm. We determined the decomposition rates of bulk particulate organic matter (POM), the ratio of labile to semi-refractory fractions in the POM, and the POM carbon/ nitrogen (C/N) ratio during decomposition. To identify the kinetic mechanisms involved in the reactions of different order (e.g., first- and second-order), we studied the sensitivity of reaction rates to the initial concentration of POM, ranging from 2.4 to 71 mg-C L⁻¹. The results showed that decomposition consists of two first-order reactions: decomposition of labile and of semi-refractory particulate organic carbon (POC). The decomposition rate constants found for labile (0.13 day⁻¹ at 20°C), and semi-refractory POC (0.008 day⁻¹ at 20°C), and the carbon weight ratio of semi-refractory POC (13% at 20°C), were insensitive to the initial organic matter concentration. The time-dependence of the C/N ratio was also independent of this initial concentration. The decomposition rate constants and the content of semi-refractory POC did not change, regardless of the absence or presence of 25–500 μm organisms in natural seawater. This revised version was published online in July 2006 with corrections to the Cover Date.     

东海颗粒有机物中的碳氮比

利用１９９４年中国ＪＧＯＦＳ计划在东海进行的春,秋两航次的资料,分析颗粒有机物中碳氮化的变化,结果表明,春季碳氮比明显低于秋季;春季表层海水中的碳氮比分布特点是,近海小于外海,北部海域小于南部海域;秋季分布特点是,东北部海域碳氮比高,西南部海域较低,这种分布变化是生物活动,水团运动及沉积物再悬浮等因素引起的,研究表表明,仅利用碳氮比判断有机物的来源是不可靠的,必须综合其它现场因素谨慎判断。     

2006—2007年夏、冬季浙东海域叶绿素a分布特征及其环境影响因子

为更清楚了解浙东海域浮游植物的初级生产力情况,于2006年8月(夏季)和2007年1月(冬季)在浙东海域28°00′～30°00′N、122°00′～127°30′E设置了3条调查断面,共布设25个观测站位,现场采用荧光连续法对叶绿素a进行测定,初步研究了该海域叶绿素a的空间分布特征,并探讨了水体温度、营养盐和浊度对叶绿素a分布的影响。结果表明:夏季,叶绿素a分布趋势为近岸(平均质量浓度为2.01μg/L)>外海(平均质量浓度为0.52μg/L),其主要垂直分布类型为递增型、递减型和单峰型;冬季,叶绿素a分布趋势为外海(平均质量浓度为0.50μg/L)>近岸(平均质量浓度为0.33μg/L),主要垂直分布类型为递增型、均匀型、单峰型和双峰型。夏季调查海域浮游植物叶绿素a平均质量浓度为0.93μg/L,明显高于冬季(0.46μg/L)。温度、营养盐和浊度是影响研究区夏、冬季叶绿素a分布的主要环境因子。     

闽南－台湾浅滩渔场N／P比值的空间分布

１９８７年１２月—１９８８年１１月对闽南－台湾浅滩渔场上升流生态系进行了调查研究。研究结果表明，本研究海区的海水Ｎ／Ｐ比值的空间分布与水团的分布具有密切的关系。各水团的Ｎ／Ｐ比值不遵守Ｒｅｄｆｉｅｌｄ常数１５：１，并且在水团间存在一定的差别。在研究水团的分布及划分中，Ｎ／Ｐ比值可作一较好的参考值。闽浙沿岸水、次表层水和中深层水的Ｎ／Ｐ比值大于１５；海峡南部混合水、海峡暖水、夏季近岸涌升水和浅滩南部涌升水的Ｎ／Ｐ比值小于１５。前者主要是入海径流及有机体的充分分解所致，后者则为浮游植物对ＮＯ３－Ｎ和ＰＯ４－Ｐ的大量吸收及ＮＯ３－Ｎ和ＰＯ４－Ｐ再生速率上差异的结果。本文还讨论了水团的分布对营养盐和叶绿素分布的影响。