印度洋浮游生态系统的特点及其对全球变暖的响应

与太平洋和大西洋相比,印度洋有独特的季风和洋流系统和由此驱动的浮游生物分布及生产规律.在全球变暖的背景下,印度洋的变暖趋势比太平洋和大西洋更为显著,是研究变暖对海洋浮游生态系统影响的热点海区之一.文章结合国内外文献,评述印度洋浮游生态系统的现状、特点及对全球变暖的响应,包括印度洋的浮游生物地理分布、南北印度洋浮游生态系...     

印太交汇区浮游植物和浮游动物生态学研究进展

海洋浮游植物和浮游动物是海洋生态系统中的重要组成部分,支撑了整个海洋生态系统的正常运转.因此,海洋浮游植、动物的生态学研究有利于我们全面认识和了解一个海洋生态系统的状况.印太交汇区作为全球最大的海洋生物多样性中心,是国际上生物多样性研究的热点区域,但该区域对浮游生物生态学方面的研究较少,不利于我们深入认识该区域生物多样...     

Chlorophyll, photosynthesis and new production in the Southern California Bight

The study of phytoplankton distributions and processes in these waters has been stimulated in recent years (1) by the synoptic views of surface pigment afforded by the Coastal Zone Color Scanner (CZCS) aboard the NIMBUS-7 satellite; (2) by rapid developments in bio-optical oceanography toward the estimation of in situ photosynthetic rate; (3) by use of sediment traps and geochemical tracers to determine the flux of organic matter from the euphotic zone; and (4) by measurements of new production based on the utilization of nitrate by the plankton. The evolution and rationale of the Joint Global Ocean Flux Study of ocean biogeochemical cycles and ocean climate changes serve to focus much of the work. In that context, a major goal is to assess new/export production on large time and space scales accessible to date only by remote sensing.     

上层海洋浮游生物地理分布

确定海洋浮游生物的分布区域是海洋浮游生态学研究的首要任务之一,本文总结了上层海洋(0-200 m)浮游生物地理分布的研究历史、已有的认知及全球变化的影响.对浮游生物地理分布的研究可以分为19世纪末期至20世纪70年代、20世纪80年代至2000年,以及2000年以后三个时期.根据分布区资料的时间长短,浮游生物分布区分为...     

Wind wave breaking under the conditions of inhomogeneous currents and of the atmospheric boundary layer

As known fromin situ observations, inhomogeneities of flows and of the atmospheric boundary layer produce variations of the intensity of wind wave breaking. A relevant phenomenological model is suggested here, describingin situ data on the breaking of waves in the presence of internal waves. The response of the wave breaking to the flow's inhomogeneity enhances with the growth of its spatial or temporal scale. For the mesoscale (10–100 km) inhomogeneities, the model is essentially simplified—wave breakings depict the local energy inputs to wind waves. The model allows us to compute currents of various type in the wave breaking intensity field. The results may have practical implications, in terms of remote sensing of the ocean. Translated by Vladimir A. Puchkin.     

The uranium content and the activity ratio234U/238U in marine organisms and sea water in the western North Pacific

The uranium content and activity ratio A²³⁴U/A²³⁸U were determined in open ocean water, marine plankton, marine algae and sea water in the environment in which plankton and algae live. The average uranium content of 3.34±0.28×10⁻⁶ g/l and the average activity ratio of 1.13±0.04 were obtained in open ocean water. The uranium contents in plankton and algae were respectively from 1.7 to 7.8×10⁻⁷ g/g and 0.4 to 23.5×10⁻⁷ g/g on dry basis with the respective concentration factors of 48 to 260 and 10 to 733. The activity ratio in plankton and algae ranged from 1.07 to 1.18 which coincided well with those in the environmental sea water.     

Major contribution from mesopelagic plankton to heterotrophic metabolism in the upper ocean

Measurements of plankton respiration and heterotrophic bacterial abundance and production were made at seven deep water stations within the upper 500 m of the Gulf of Mexico during the summer of 1995. Bacterial abundance [(1.1–4.6)×108 1⁻¹] and rates of bacterial production (2–19 nM C h⁻¹) and plankton respiration (50–245 nM O₂ h⁻¹) decreased with depth by four- to nine-fold, and were similar to those reported for oligotrophic waters. Bacterial turnover times increased with depth from approximately 1 to 5 days. Bacterial growth efficiencies decreased from 15% at the surface to 8% at 500 m. Depth-integrated plankton respiration exceeded known estimates of primary production for the region, suggesting that heterotrophic utilization of previously and concurrently produced organic matter (e.g. spring phytoplankton growth, and summer blooms of Trichodesmium sp.) was occurring during the summer. Estimates for the upper 500 m showed that roughly half of the bacterial biomass (56%), bacterial production (49%), and plankton respiration (60%) occurred below the euphotic zone. Routine oceanographic studies have focused exclusively on the metabolic activity occurring within the euphotic zone. Our measurements, however, indicate that mesopelagic plankton also contribute substantially to heterotrophic metabolism and nutrient cycling in the ocean.     

现代海洋环境监测体系和海洋管理背景下的浮游生物监测

浮游生物在海洋生态系统中处于基础性地位,为促进我国浮游生物监测工作的发展,文章在现代海洋环境监测体系和海洋管理的背景下,从海洋生态系统保护、全球变化研究和现代海洋管理3个方面,系统梳理和分析浮游生物监测的意义和价值,并对我国相关领域的工作提出启示和展望。研究结果表明:浮游生物的恶性暴发和入侵对海洋生态系统造成严重影响,各类国际公约和政府间协议都将浮游生物监测作为保护海洋生物多样性的重要内容;浮游生物的分类信息以及其分布区和物候学特征对气候变化和海水温度的指示信息,可作为全球变化研究的重要指标;浮游生物监测已被广泛应用于国内外现代海洋管理中,主要包括海洋生态系统服务评价、海洋环境影响评价和海洋生物资源评价3个方面;我国浮游生物监测工作在浮游生物分类和鉴定以及大数据应用方面存在不足,未来应加强相关能力考核、标准化计量认证、数据整合共享和新技术手段运用。     

Nutrient limitation in two marine diatoms inhibits release of bromoform

Bromoform released from phytoplankton and kelp in the ocean is the largest known carrier of bromine to the atmosphere. The photoproducts of atmospheric bromoform catalyse ozone depletion. Laboratory investigations were conducted into the link between nutrient limitation and bromoform production using axenic cultures of two warm-water diatoms (Chaetoceros neogracile and Phaeodactylum tricornutum). During exponential growth the bromoform production was 2 000–3 000 nmol bromoform (g Chl a)?1 h?1, i.e. 10–100 times higher than earlier values for temperate and cold-water diatoms. Bromoform production decreased down to zero under CO2 and nitrate limitation for both species. These results suggest that the bromoform production could be directly related to bromoperoxidase activity (and irradiance) only during exponential growth, whereas compounds other than bromoform might be formed under nutrient limitation.     

The seasonal cycle of surface chlorophyll in the Peruvian upwelling system: A modelling study

The seasonal variability of surface chlorophyll in the northern Humboldt Current System is studied using satellite data, in situ observations and model simulations. The data show that surface chlorophyll concentration is highest in austral summer and decreases during austral winter, in phase opposition with coastal upwelling intensity. A regional model coupling ocean dynamics and biogeochemical cycles is used to investigate the processes which control this apparently paradoxical seasonal cycle. Model results suggest that the seasonal variability of the mixed layer depth is the main controlling factor of the seasonality. In winter, the mixed layer deepening reduces the surface chlorophyll accumulation because of a dilution effect and light limitation. In summer, biomass concentrates near the surface in the shallow mixed layer and nitrate limitation occurs, resulting in a biomass decrease in the middle of summer. Intense blooms occur during the spring restratification period, when winter light limitation relaxes, and during the fall destratification period, when the surface layer is supplied with new nutrients. Model sensitivity experiments show that the seasonal variations in insolation and surface temperature have little impact on the surface chlorophyll variability.     

Feeding of Aurelia sp. (Scyphozoa) and links to the microbial food web

The impact of the scyphomedusa Aurelia sp. on planktonic assemblages was experimentally studied in enclosures incubated in situ in the sea lake of Mljet Island (Big Lake, Southern Adriatic), where jellyfish are present throughout the year. In situ feeding experiments using plankton at natural densities indicated a reduction in abundance for small calanoid and cyclopoid copepods, copepodites, nauplii and ciliates in the presence of Aurelia sp. In addition to direct predatory pressure, Aurelia sp. exerted an indirect cascading effect on autotrophic and heterotrophic microbial plankton. Phytoplankton biomass increases of up to 0.5 μg C·l^?1·h^?1 were mainly related to 19′‐hexanoyloxyfucoxanthin‐ and 19′‐butanoyloxyfucoxanthin‐containing phytoplankton. Bacterial production was about twice as high in the presence of Aurelia sp. and biomass was also consistently higher. It appears that the top‐down effect of predation along with material release by Aurelia sp. results in increases in microbial biomass and production.     

利用志愿观测船提升表层海洋观测能力

对表层海洋动力学及其调控机制的认识对准确认识海洋自然变化过程及其未来对气候变化的响应具有重要意义。志愿观测船作为自动观测系统的载体和样品采集平台的优势使其在提升人类对于表层海洋的观测能力方面具有极大优势。本文系统性地回顾了志愿观测船的概念、发展历史、现状和未来发展趋势。基于志愿观测船的诸多海洋观测项目的成功显示了,随着快速发展的传感器技术,志愿观测船能够以经济有效的方式显著地提升表层海洋现场观测的时间和空间分辨率。未来的海洋观测系统应该综合利用包括志愿观测船在内的多种海洋观测平台的优势。     

Ocean Color Satellite Imagery and Shipboard Measurements of Chlorophyll a and Suspended Particulate Matter Distribution in the East China Sea

Satellite-derived ocean color data of Coastal Zone Color Scanner (CZCS) on board the Nimbus-7 and Ocean Color and Temperature Scanner (OCTS) on board the Advanced Earth Observing Satellite (ADEOS) are jointly used with historical in situ data to examine seasonal and spatial distributions of chlorophyll a (Chl-a) and suspended particulate matter (SPM) concentrations in the East China Sea. Ocean color imagery showed that Chl-a concentrations on the continental shelf were higher than those of the Kuroshio area throughout the year. Satellite-derived Chl-a concentrations are generally in good accordance with historical in situ values during spring through autumn (although no shipboard in situ measurement was conducted at nearshore areas). In contrast, ocean color imagery in winter indicated high Chl-a concentrations (4–10 mg m^–3) on the continental shelf where bottom depth was less than 50 m when surface water was turbid (2–72 g m^–3 of SPM at surface), while historical in situ values were usually less than 1 mg m^–3. This suggests that resuspended bottom sediment due to wind-driven mixing and winter cooling is responsible for the noticeable overestimation of satellite-derived Chl-a concentrations. The algorithm for ocean color needs to be improved urgently for turbid water.     

New Zealand lakes research, 1967–91

Research on New Zealand lakes over the past 25 years has focused mainly on eutrophication, measures of water quality, patterns, processes and production in plankton communities, and the spread and growth of submerged adventive macrophytes. Compared with most northern temperate lakes many New Zealand lakes show: low levels of inorganic nitrogen (N) and frequent N‐limitation of phyto‐plankton growth; diffuse, rather than point source, nutrient inflows; a great diversity of optical properties; unusual and often variable timing of plankton growth (attributed to the pervasive influence of New Zealand's oceanic climate); low productivity and biomass of zooplankton, which appear to be limited by food rather than predators; and sensitivity to invasion by adventive macrophytes. Notable research develop‐ments include improved methods of measuring nutrients, empirical predictive models that relate indices of eutrophication to nutrient loading, and significant advancements in methods of quantifying and measuring water colour and clarity.     

Rapid visualization of plankton abundance and taxonomic composition using the Video Plankton Recorder

Traditional methods for determining spatial distributions of planktonic taxa involve net, pump, and bottle collections followed by the tedious and time-consuming task of plankton sample analysis. Thus, plankton ecologists often require months or even years to process samples from a single study. In this paper, we present a method that allows rapid visualization of the distribution of planktonic taxa while at sea. Rapid characterization of plankton distributions is essential in the dynamic physical environment, where biological and physical patterns can change quickly. Such a “sample-and-observe” capability is necessary for mapping ephemeral features (such as patches, eddies, jets, plumes) and determining appropriate locations to conduct more localized sampling, including in situ observational studies. We describe the techniques used in imaging the plankton, analyzing the video, and visualizing the data. We present an example of at-sea data analysis conducted aboard R.V. Columbus Iselin on Georges Bank in May 1994 and visualizations of the 3-dimensional distribution of selected planktonic taxa in a 2 × 2 km × 90 m volume of seawater. A video of the image processing and visualization is included on the CD-ROM accompanying this volume and is an essential part of this paper.     

Impacts of elevated CO2 on particulate and dissolved organic matter production: microcosm experiments using iron-deficient plankton communities in open subarctic waters

Response of phytoplankton to increasing CO₂ in seawater in terms of physiology and ecology is key to predicting changes in marine ecosystems. However, responses of natural plankton communities especially in the open ocean to higher CO₂ levels have not been fully examined. We conducted CO₂ manipulation experiments in the Bering Sea and the central subarctic Pacific, known as high nutrient and low chlorophyll regions, in summer 2007 to investigate the response of organic matter production in iron-deficient plankton communities to CO₂ increases. During the 14-day incubations of surface waters with natural plankton assemblages in microcosms under multiple pCO₂ levels, the dynamics of particulate organic carbon (POC) and nitrogen (PN), and dissolved organic carbon (DOC) and phosphorus (DOP) were examined with the plankton community compositions. In the Bering site, net production of POC, PN, and DOP relative to net chlorophyll-a production decreased with increasing pCO₂. While net produced POC:PN did not show any CO₂-related variations, net produced DOC:DOP increased with increasing pCO₂. On the other hand, no apparent trends for these parameters were observed in the Pacific site. The contrasting results observed were probably due to the different plankton community compositions between the two sites, with plankton biomass dominated by large-sized diatoms in the Bering Sea versus ultra-eukaryotes in the Pacific Ocean. We conclude that the quantity and quality of the production of particulate and dissolved organic matter may be altered under future elevated CO₂ environments in some iron-deficient ecosystems, while the impacts may be negligible in some systems.     

Effects of temperature and chlorinity on the microdistribution ofFavella taraikaensis Hada (Ciliata) in Maizuru Bay

Continuous sampling of the plankton with a pump sampler was carried out along a 960 m straight-line course in Maizuru Bay. The 25 collections of plankton were successively obtained at a depth of 1.5 m along the course, each of the collections covering a horizontal distance of 38 m. Vertical samplings of the plankton were done at five different depths (90, 120, 150, 180 and 210 cm) at 13 stations along the course. In both kinds of samplings temperature and chlorinity were measured.In the horizontal distribution ofF. taraikaensis, it was demonstrated that the counts of plankton had no correlation with the temperature and chlorinityin situ. There was a correlation between the counts and the differences of temperature and chlorinity between two successive sampling stations. It seemed thatF. taraikaensis was most abundant in the locations where the temperature difference was greater than +0.2C and the chlorinity difference was greater than +0.04 . This species was more abundant around the steep thermocline and the steep halocline. When the vertical profiles of temperature and chlorinity did not show steep gradients, this species was more abundant near the surface.     

Mesoscale features and phytoplankton biomass at the GoodHope line in the Southern Ocean during austral summer

Two sets of high-resolution subsurface hydrographic and underway surface chlorophyll a (Chl a) measurements are used, in conjunction with satellite remotely sensed data, to investigate the upper layer oceanography (mesoscale features and mixed layer depth variability) and phytoplankton biomass at the GoodHope line south of Africa, during the 2010–2011 austral summer. The link between physical parameters of the upper ocean, specifically frontal activity, to the spatially varying in situ and satellite measurements of Chl a concentrations is investigated. The observations provide evidence to show that the fronts act to both enhance phytoplankton biomass as well as to delimit regions of similar chlorophyll concentrations, although the front–chlorophyll relationships become obscure towards the end of the growing season due to bloom advection and ‘patchy’ Chl a behaviour. Satellite ocean colour measurements are compared to in situ chlorophyll measurements to assess the disparity between the two sampling techniques. The scientific value of the time-series of oceanographic observations collected at the GoodHope line between 2004 to present is being realised. Continued efforts in this programme are essential to better understand both the physical and biogeochemical dynamics of the upper ocean in the Atlantic sector of the Southern Ocean.     

Modelling the response of the planktonic food web to iron fertilization and warming in the NE subarctic Pacific

A one-dimensional ecosystem model with two explicit size classes of phytoplankton was developed for the NE subarctic Pacific to investigate variations in the export of organic particles to the ocean interior due to potential changes in the environment. Specifically, the responses of the planktonic ecosystem to permanent removal of iron limitation and to warming (of 2 and 5 °C) were explored. The ecosystem model consists of five components (small and large phytoplankton, microzooplankton, detritus and nitrogen), and includes grazing by mesozooplankton that varies in time according to long-term observations at Ocean Station Papa (OSP). The model addresses the role of iron limitation on phytoplankton growth and includes temperature dependence of physiological rates. The ecosystem model was forced with annual wind and solar heating from OSP. The model best reproduced the low chlorophyll high nitrate conditions of the NE subarctic Pacific when both small and large phytoplankton were limited by iron such that their maximum specific growth rate was reduced by 10 and 70%, respectively. Sensitivity analysis showed that model results depended on the value of the iron limitation parameter of large phytoplankton (L_Fe-L) and the grazing parameters of micro- and mesozooplankton. To explore the effect of iron limitation, simulations were carried out varying the iron limitation parameters while maintaining the nitrogen flux at the base of the model constant and the grazing pressure by mesozooplankton unchanged. In the warming case, simulations were carried out increasing ocean temperatures by 2° and 5 °C applied only to the ecological components, the flux of nitrate at the base of the model was increased to obtain a steady annual cycle, and grazing by mesozooplankton remained constant. When compared with the standard case, model simulations indicated that both permanent removal of iron limitation and warming cause changes in food web structure and the carbon cycle. The response was more dramatic in the iron-replete case where the phytoplankton community structure in spring changed from one dominated by pico- and nanoplankton to one dominated by large phytoplankton, and primary production increased until it consumed all the external nutrient (N) supply to the upper layer. However, reducing iron deficiency actually led to lower annual primary production due to a decrease in the regeneration of nitrogen in the euphotic zone. These changes in food web structure influenced the magnitude, composition and seasonal cycle of sinking particles.     

西太平洋卡罗琳M4海山区悬浮体分布及其影响因素

海山可以通过与洋流的相互作用改变水体结构,促进悬浮体以及海洋生物的再分配,进而影响海洋生物地球化学过程,促进大洋物质和能量交换。西太平洋有着复杂的环流结构,也是海山分布最多的海区之一。为研究西太平洋海山区的悬浮体分布及其控制机制,2017年夏季在西太平洋卡罗琳M4海山区进行现场调查,利用扫描电镜分析了该海山区悬浮体样品的物质组成及分布,并结合温度、盐度和荧光叶绿素a浓度数据,讨论了海山对悬浮体分布的影响。结果表明,M4海山区的悬浮体由生物碎屑、矿物颗粒和絮凝体等组成。海水的强烈层化阻碍了该海山区下层营养物质的上涌,使上层水体呈现出寡营养的特征,导致大部分站位悬浮体丰度较低;但在海山顶部,潮流和海山地形相互作用在山顶上方形成反气旋环流,不仅促进了深水的营养物质向上扩散,使得荧光叶绿素a浓度升高,同时对平流输送来的以及从深水中上涌的悬浮体起到了滞留作用,使山顶上方的悬浮体丰度远高于离山顶较远的位置。随着水深的增大,温、盐跃层的强度减弱,水体中的营养盐浓度升高,为浮游生物的生长提供了适宜的环境,进而使生物碎屑及絮凝体的丰度升高。北赤道潜流挟带来自西太平洋近岸海区的陆源矿物颗粒到达M4海山区,...