Phytoplankton, nutrients and hydrography in the frontal zone between the Southwest Indian Subtropical gyre and the Southern Ocean

A survey was made of the Southwest Indian Ocean frontal region between 30 and 50°E containing the Agulhas Return, Subtropical and Subantarctic Fronts. From CTD, SeaSoar and extracted samples the distribution of nitrate, silicate and chlorophyll a is shown to be strongly linked to the front and water mass structure, varying zonally and meridionally. Surface chlorophyll a concentrations were low to the north and south leaving a band of elevated chlorophyll between the Subtropical and Subantarctic Fronts. The low concentration of chlorophyll a to the north, in Subtropical Water, was clearly due to nitrate limitation. Between the Subtropical and Subantarctic Fronts, where the chlorophyll a concentrations were highest, the surface layer showed silicate depletion limiting diatom growth. South of the Subantarctic Front there were deep extending, low concentrations of chlorophyll a, but despite plentiful supplies of macro-nutrients and a well-stratified surface layer, high concentrations of chlorophyll a were absent. Changes from west to east were associated with the meandering of the Southern Ocean Fronts, especially the Subtropical Front, and their strength and proximity to each other. Concentrations of chlorophyll a peaked where the Agulhas Return, Subtropical and Subantarctic Fronts were in close proximity. Combined frontal structures appear to have particularly pronounced vertical stability and are associated with enhanced upwelling of nutrients and leakage of nutrients across the front. Light levels are high within the shallow stable layer. Such conditions are clearly favourable for biological growth and support the development of larger-celled phytoplankton communities.     

海洋湍流的测量及相关分析

对海洋湍流速度脉动的一维概率密度作了测量，并把测量结果与高 斯分布进行了比较。比较的结果表明，一个接近于高斯分布而另一个却差别较 大。计算到直至五阶湍流相关函数并与网格湍流进行了比较，结果都表明小时 间间隔中测量结果与网格湍流的结果近似一致，而大时间间隔中却相差很大。 以上结论说明了较长的测量时间的必要性。     

A Preliminary Study of Oceanic Bomb Radiocarbon Inventory in the North Pacific during the Last Two Decades

Radiocarbon and total carbonate data were obtained near the 1973 GEOSECS stations in the North Pacific along 30°N and along 175°E between 1993 and 1994. In these stations, we estimated radiocarbon originating from atomic bomb tests using tritium, trichlorofluoromethane and silicate contents. The average penetration depth of bomb radiocarbon during the two decades has deepened from 900 m to 1300 m. Bomb radiocarbon inventories above the average value for the whole North Pacific were found widely in the western subtropical region around 30°N both in the 1970s and 1990s, and its area in the 1990s was broader than that in the 1970s. In most of the North Pacific, while the bomb radiocarbon has decreased above 25.4, the bomb radiocarbon flux below 25.4 was over 1 × 10¹² atom m^-2yr^-1 in the subtropical region around 30°N. In the tropical area south of 20°N, the bomb radiocarbon inventory below 25.4 increased from zero to over 10 × 10¹² atom m^-2 during the last three decades. These distributions suggest that the bomb radiocarbon removed from the surface is currently accumulated with bomb ¹⁴C flux of over 1 × 10¹² atom m^-2yr^-1 below 25.4 in the subtropical region, mainly by advection from the higher latitude, and that part of the accumulated bomb ¹⁴C gradually spread southward with about 30 years.     

山东半岛东北部海域悬浮体季节分布及控制因素

基于2018年山东半岛东北部海域冬、夏两季悬浮体浓度、浊度及水温和盐度调查资料,分析了研究区水体悬浮体浓度的季节性变化,探讨了其控制因素。结果表明：夏季浊度在0.2～37.8FTU之间变化,冬季浊度在1.5～100.1FTU之间变化,均表现为底高表低、东高西低的特征。夏季水温分层明显,表现为表层高、底层低的特征,盐度整体无明显变化;冬季温盐垂向上混合均匀,平面上表现为近岸低温低盐水体向远岸高温高盐水体的过渡。悬浮体浓度分布受潮流、波浪、温跃层和温盐锋面等因素影响。夏季,悬浮体垂向上受到温跃层影响,底层悬浮体难以向表层输运;平面上潮混合和波浪差异性作用阻碍了悬浮体的水平输运。冬季,强风浪促使悬浮体垂向混合剧烈,表层悬浮体浓度明显较夏季变高;平面上沿岸流和黄海暖流形成的温、盐锋面阻碍了水团间悬浮体的输运。     

"政社分开"大背景下社会组织创新发展的思考与建议 ——以海洋社会组织为例

党的十九大以来,随着我国社会组织的不断发展和政府职能转变的逐步推进,社会组织面临着前所未有的机遇与挑战。文章以海洋社会组织为例,研究在"政社分开"过程中遇到的问题。研究表明,"政社分开"后,社会组织遇到的困难一是失去物质资源,难以正常开展活动;二是失去"主心骨",难以建立公信力;三是失去主要业务来源,发展内生动力不足。为新形势下社会组织如何更好地健康发展,提出了建立健全社会组织法律法规、加强对社会组织的扶持力度、拓展社会组织经费来源结构等对策建议。     

Seasonality of oceanic primary production and its interannual variability from 1998 to 2007

The seasonality of primary productivity plays an important role in nutrient and carbon cycling. We quantify the seasonality of satellite-derived, oceanic net primary production (NPP) and its interannual variability during the first decade of the SeaWiFS mission (1998 to 2007) using a normalized seasonality index (NSI). The NSI, which is based upon production half-time, t(1/2), generally becomes progressively more episodic with increasing latitude in open ocean waters, spanning from a relatively constant rate of primary productivity throughout the year (mean t(1/2) ~5 months) in subtropical waters to more pulsed events (mean t(1/2) ~3 months) in subpolar waters. This relatively gradual, poleward pattern in NSI differs from recent estimates of phytoplankton bloom duration, another measure of seasonality, at lower latitudes (~40°S–40°N). These differences likely reflect the temporal component of production assessed by each metric, with NSI able to more fully capture the irregular nature of production characteristic of waters in this zonal band. The interannual variability in NSI was generally low, with higher variability observed primarily in frontal and seasonal upwelling zones. The influence of the El Niño–Southern Oscillation on this variability was clearly evident, particularly in the equatorial Pacific, where primary productivity was anomalously episodic from the date line east to the coast of South America in 1998. Yearly seasonality and the magnitude of annual production were generally positively correlated at mid-latitudes and negatively correlated at tropical latitudes, particularly in a region bordering the Pacific equatorial divergence. This implies that increases of annual production in the former region are attained over the course of a year by shorter duration but higher magnitude NPP events, while in the latter areas it results from an increased frequency or duration of similar magnitude events. Statistically significant trends in the seasonality, both positive and negative, were detected in various patches. We suggest that NSI be used together with other phenomenological characteristics of phytoplankton biomass and productivity, such as the timing of bloom initiation and duration, as a means to remotely quantify phytoplankton seasonality and monitor the response of the oceanic ecosystem to environmental variability and climate change.     

Southern elephant seal trajectories, fronts and eddies in the Brazil/Malvinas Confluence

This study describes the association between transient, mesoscale hydrographic features along the axis of the Brazil–Malvinas Confluence, in the SW Atlantic, and the foraging behavior of 2–3-year-old (focal) juvenile southern elephant seals, Mirounga leonina, from Península Valdés, Argentina. Departing from the dominant pattern of foraging on predictable bathymetric fronts on the Patagonian shelf and slope, three females out of 12 satellite-tracked juveniles remained at the edge of young warm-core eddies and near the outer core of cold-core eddies, coinciding with the most productive areas of these temperature fronts. Seal trajectories along high-temperature gradients were always consistent with the speed and direction of surface currents inferred from the temperature distribution and confirmed by surface drifters. Movements of foraging seals were compared with those of surface drifters, coinciding in time and space and yielding independent and consistent data on regional water circulation parameters. The diving pattern recorded for one focal seal yielded shallower dives and a loose diel pattern in the eddy, and a marked diurnal cycle compatible with foraging on vertically migrating prey in the cold waters of the Malvinas Current. Pre-reproductive females that use the mesoscale fronts of the Argentine Basin as an alternative foraging area would benefit from lower competition with more experienced seals and with other top predators that reproduce along the coast of Patagonia.     

“Trends” and variations of global oceanic evaporation data sets from remote sensing

The variability in global oceanic evaporation data sets was examined for the period 1988-2000. These data sets are satellite estimates based on bulk aerodynamic formulations and include the NASA/Goddard Space Flight Center Satellite-based Surface Turbulent Flux version 2 （ GSSTF2）, the Japanese-ocean flux using remote sensing observations （J-OFURO）, and the Hamburg Ocean-Atmosphere Parameters and Fluxes from Satellite version 2 （HOAPS2）. The National Center for Environmental Prediction （NCEP） reanalysis is also included for comparison. An increase in global average surface latent heat flux （SLHF） can be observed in all the data sets. Empirical mode decomposition （EMD） shows long-term increases that started around 1990 for all remote sensing data sets. The effect of Mt. Pinatubo eruption in 1991 is clearly evident in HOAPS2 but is independent of the longterm increase. Linear regression analyses show increases of 9.4%, 13.0%, 7. 3%, and 3.9% for GSSTF2, J-OFURO, HOAPS2 and NCEP, for the periods of the data sets. Empirical orthogonal function （EOF） analyses show that the pattern of the first EOF of all data sets is consistent with a decadal variation associated with the enhancement of the tropical Hadley circulation, which is supported by other satellite observations. The second EOF of all four data sets is an ENSO mode, and the correlations between their time series and an SO1 are 0.74, 0.71,0.59, and 0.61 for GSSTF2, J-OFURO, HOAPS2, and NCEP in that order. When the Hadley modes are removed from the remote sensing data, the residue global increases are reduced to 2.2% , 7. 3%, and 〈 1% for GSSTF2, J-OFURO and HOAPS, respectively. If the ENSO mode is used as a calibration standard for the data sets, the Hadley mode is at least comparable to, if not larger than, the ENSO mode during our study period.