Nitrogen uptake and primary productivity rates in the Mid-Atlantic Bight (MAB)

Nutrient concentrations, primary productivity, and nitrogen uptake rates were measured in coastal waters of the Mid-Atlantic Bight over a two-year period that included measurements from all four seasons. In order to assess carbon productivity and nitrogen demand within the context of the physical environment, the region was divided into three distinct hydrographic regimes: the Chesapeake and Delaware Bay outflow plumes (PL), the southern Mid-Atlantic shelf influenced by the Gulf Stream (SS), and the mid-shelf area to the north of the Chesapeake Bay mouth (MS). Annual areal rates of total nitrogen (N) uptake were similar across all regions (10.9 ± 2.1 mol N m⁻² y⁻¹). However, annual areal rates of net primary productivity were higher in the outflow plume region (43 mol C m⁻² y⁻¹), than along the Mid-Atlantic shelf and in areas influenced by the Gulf Stream (41 and 34 mol C m⁻² y⁻¹, respectively). Rates of net primary productivity were not well correlated with Chl a concentrations and were uncoupled with net N uptake rates. Seasonally averaged annual areal rates of net primary productivity for the Mid-Atlantic Bight measured in this study were higher than those calculated in previous decades and provide important validation information for biogeochemical models and satellite remote sensing algorithms developed for the region.     

Nutrient concentrations and fluxes in the Changjiang Estuary during summer

In June 2003 and 2006 concentrations of nutrient were determined in the Changjiang Estuary. The data indicated that phosphate and nitrate did not behave conservatively in the estuary, but silicate behaved conservatively. An important mobilization of phosphate and nitrate was observed from the river up to halfway in the estuary. Both input flux (from river to estuary) and output flux (from estuary to coastal zone) of phosphate, silicate and nitrate were calculated from statistical interpretations of the salinity profiles. There was a large discrepancy between input and output fluxes of phosphate and nitrate. The river fluxes of silicate, phosphate and nitrate (f_r) are augmented 5.3%, 28.9% and 36.6% in June 2003 and 1.0%, 62.5%, 31.7% in June 2006 by internal inputs (f_i). The phosphate and nitrate fluxes are enhanced through the estuarine process, while silicate flux is unaltered. The authors present some long-term data for nutrient concentrations and the ratios of silicon to nitrogen to phosphorus in the Changjiang Estuary. Silicate level falled in the last two decades, while concentration of nitrate increased. Phosphate concentration had no significant change.     

庙岛群岛北五岛生态系统净初级生产力与景观格局时空分布异质性研究

利用ArcGIS10.2、ENVI5.1、SPSS26等软件,本文基于经典CASA模型估算了2005年、2010年、2017年庙岛群岛北五岛的净初级生产力(Net Primary Productivity, NPP),从季节、岛屿、景观类型、地形梯度等多种角度分析了NPP的时空分布异质性;进而分析了2005年、2010年、2017年北五岛的景观格局时空分布异质性;探讨了NPP与景观格局时空变化之间的关系及其原因。结果表明：庙岛群岛北五岛平均全年NPP总量为7 520.54 t/a(以碳计),平均密度为406.07 g/(m²·a) (以碳计);NPP分布呈明显的时空分异性;各景观类型平均面积由大到小依次为：针叶林、阔叶林、建设用地、草地、耕地;其NPP平均密度由大到小依次为：阔叶林、针叶林、耕地、草地、建设用地;各景观NPP平均密度随坡度和高差的增大先上升后出现平缓下降态势;坡向对林地NPP影响较大,半阴坡林地NPP平均密度最大;不同地形梯度的NPP年平均密度随时间推移总体呈下降态势;NPP高值出现在山林区域,低值主要在建设用地区域;由于自然地理条件、植物自身生长条件和人类活动强度等原因,NPP时空异质性分布受季节差异、景观格局时空异质性和地形因子影响显著。     

辽河三角洲滨海湿地水域初级生产力研究进展

滨海湿地位于海洋与陆地生态系统的交错过渡带,具有极高的生产力和光合固碳效率,是海岸带蓝色碳汇的重要组成部分。滨海湿地生产力不仅由芦苇、翅碱蓬、红树林等陆上植被提供,水体中浮游植物的光合固碳也是提供初级生产力的重要途径。以往较多的调查和研究集中在陆上植被,而对于滨海湿地水域浮游植物和底栖微藻的报道较少。近年来随着各国政府和学者对二氧化碳排放和气候变化的关注,滨海湿地多圈层生态系统的碳循环和碳汇过程成为研究热点,而湿地水域生产力和光合固碳过程作为多圈层碳循环中重要的一个环节亦应受到足够的重视。以中国北方典型的盐沼湿地区域——辽河三角洲滨海湿地为案例,对湿地水域生产力研究进展进行综述,并对其影响因素进行讨论,以期为国家碳循环与碳中和目标调查提供参考资料。     

南沙群岛海域溶解氧垂直分布最大值的季节特征

根据“八五”、“九五”国家科技专项南沙群岛海域综合科学考察的现场调查资料,对南沙群岛海域溶解氧垂直分布最大值现象的分布特征、季节变化规律作了较为全面的分析和研究,同时比较了东海、黄海海域春、夏季溶解氧垂直分布出现的最大值现象及其特征.研究结果表明南沙群岛海域溶解氧垂直分布的最大值现象与我国东海、黄海海域的溶解氧垂直分布最大值现象无论在地理分布、深度、强度、季节性变化还是存在条件的特征化方面,均有着较大的差别.反映影响南沙群岛海域溶解氧垂直分布最大值形成的原因,均与东海、黄海海域溶解氧垂直分布最大值形成的原因有所不同     

Export Production in the Equatorial and North Pacific Derived from Dissolved Oxygen, Nutrient and Carbon Data

A global ocean inverse model that includes the 3D ocean circulation as well as the production, sinking and remineralization of biogenic particulate matter is used to estimate the carbon export flux in the Pacific, north of 10°S. The model exploits the existing large datasets for hydrographic parameters, dissolved oxygen, nutrients and carbon, and determines optimal export production rates by fitting the model to the observed water column distributions by means of the “adjoint method”. In the model, the observations can be explained satisfactorily with an integrated carbon export production of about 3 Gt C yr⁻¹ (equivalent to 3⋅10¹⁵ gC yr⁻¹) for the considered zone of the Pacific Ocean. This amounts to about a third of the global ocean carbon export of 9.6 Gt C yr⁻¹ in the model. The highest export fluxes occur in the coastal upwelling region off northwestern America and in the tropical eastern Pacific. Due to the large surface area, the open-ocean, oligotrophic region in the central North Pacific also contributes significantly to the total North Pacific export flux (0.45 Gt C yr⁻¹), despite the rather small average flux densities in this region (13 gC m⁻²yr⁻¹). Model e-ratios (calculated here as ratios of model export production to primary production, as inferred from satellite observations) range from as high a value as 0.4 in the tropical Pacific to 0.17 in the oligotrophic central north Pacific. Model e-ratios in the northeastern Pacific upwelling regions amount to about 0.3 and are lower than previous estimates. This revised version was published online in July 2006 with corrections to the Cover Date.     

The size-fractionated chlorophyll a and primary productivity in the Bering Sea during the summer of 2003

1Introduction Thephytoplanktonistheprimaryproducerofor- ganicsubstancesintheoceanandplaysanimportant roleinthesubstancecycleandenergyconversionof marineecosystem.Chlorophyllaconcentration(Chla) isanimportantindexmanifestingthelightenergy-au- totrophicbiomassinthesea.Primaryproductivityre- flectstheabilitytoconvertinorganiccarbonintoor- ganiccarbonbythephytoplanktonintheocean.Both Chlaandprimaryproductivityaretheimportantcon-tentsbeingstudiedinthemarineecosystemaswellas theimportantfoundationa…     

福建北部主要港湾的初级生产力

福建北部主要港湾（三沙、罗源、兴化和湄洲湾）2000年5、8、11月的初级生产力调查表明：三沙湾叶绿素a生物量和初级生产力低、变化幅度小,罗源湾和兴化湾8月均出现高的叶绿素a生物量和初级生产力,较之早期的可比资料表明,除三沙湾外,其他各港湾的初级生产力有明显的增加并出现局部的“藻华”.     

Carbon and nitrogen primary productivity in three North Carolina estuaries

Uptake of inorganic carbon and ammonium by the plankton community of three North Carolina estuaries was measured using ¹⁴C and ¹⁵N isotope methods. At 0% light, C appeared to be lost via respiration, and at increasing light levels uptake of inorganic carbon increased linearly, saturated (mean I_k = 358±30 μEin m⁻² s⁻¹), and frequently showed inhibition at the highest light intensities. At 0% light NH₄⁺ uptake was significantly greater than zero and was frequently equivalent to uptake in the light (light independent); at increasing light levels NH₄⁺ uptake saturated (mean I_k = 172±44 μEin m⁻² s⁻¹) and frequently indicated strong inhibition. Light-saturated uptake rates of inorganic carbon and NH₄⁺ were a function of chlorophyll a (r² = 0·7−0·9); average assimilation numbers were 625 nmol CO₂ (μg chl. a)⁻¹ h⁻¹ and 12·9 nmol NH₄⁺ (μg chl. a)⁻¹ h⁻¹ and were positively correlated with temperature (r² = 0·3−0·7). The ratio of dark to light-saturated NH₄⁺ uptake tended to be near 1·0 for large algal populations at low NH₄⁺ concentrations, indicating near light independence of uptake; whereas the ratio was lower for the opposite conditions. These data are interpreted as indicative of nitrogen stress, and it is suggested that uptake of NH₄⁺ deep in the euphotic zone and at night are mechanisms for balancing the C:N of cellular pools. A 24-h study using summed short-term incubations confirmed this; the cumulative C:N of CO₂ and NH₄⁺ uptake during the daylight period was 10–20, whereas over the 24-h period the ratio was 6 due to dark NH₄⁺ uptake. Annual carbon and nitrogen primary productivity were respectively estimated as 24 and 4·0 mol m⁻² year⁻¹ for the South River estuary, 42 and 7·3 mol m⁻² year⁻¹ for the Neuse River estuary, and 9·6 and 1·6 mol m⁻² year⁻¹ for the Newport River estuary.     

2008年夏季白令海粒度分级叶绿素a和初级生产力

2008年7月我国第三次北极科学考察中在白令海不同区域设立BR断面、NB断面和BS断面,对200 m以浅海水进行叶绿素a浓度和初级生产力的现场观测,对部分观测站进行微型、微微型光合浮游生物的粒级结构分析,结果表明,在白令海叶绿素a和初级生产力区域性特征明显,深海海盆中BR断面表层叶绿素a浓度为0.190～0.976μg...     

Effects of physical phenomena on the distribution of nutrients and phytoplankton productivity in a coastal lagoon

Sea level, salinity, temperature, nitrate, nitrite, phosphate, silicate, chlorophylls a, b and c and their phaeophytins, phytoplankton abundance and phytoplankton productivity time series were generated for the mouth and three interior locations of Bahia San Quintin, Baja California, Mexico, for 10 days during summer of 1979. The samples were taken once every 2 h. This was done to describe space and time variability of these ecological properties and to elucidate the main factors that cause this variability. Upwelling events bring nutrient reach waters near the bay mouth and tidal currents propagate those waters throughout the bay. Nutrient remineralization at the sediments and the effect of turbulence induced by tidal currents and winds increase nutrient concentrations in the interiors of the bay. In comparison with available information on nutrients limited growth of planktonic algae, nutrients seemed not to be limiting to phytoplankton growth during the sampling period. Phytoplankton cell abundances at the extremes of the lagoon are an order of magnitude lower than at the mouth due to greater turbidity. Chlorophyll concentrations at the extremes are about one-third of those of the mouth. Primary productivity decreases from the mouth to the interiors in the same manner as chlorophyll does. There is not a significant difference in cell size between phytoplankton at the bay mouth and those at the extremes of the bay. Primary productivity in the bay is comparable to the productivity maxima of other upwelling areas. There is no clear permanent dominance of diatoms over dinoflagellates, or vice versa, at any location in the bay. The alternation of upwelling and non-upwelling played an important role, together with that of the spring-neap tide cycle, in producing low frequency (< 0.01 cycles h^?1) temporal variability of ecological properties throughout the bay.     

海洋浮游植物初级生产力及碳生物量的检测技术研究进展

浮游植物是海洋生态系统中的主要初级生产者，构建海洋食物网、生物泵和元素循环（包括碳循环、氮循环和硅循环等）的基石。因此，海洋生态系统中的元素循环和能量流动均与浮游植物的生长和代谢息息相关。海洋碳循环是全球碳循环的关键环节，也是全球生态系统中生物地化循环的重要组成部分。尽管浮游植物在海洋碳循环中起着至关重要的作用，但是直接测定浮游植物的初级生产力和碳生物量依旧受到传统技术和方法的限制。本文详细介绍了有关浮游植物初级生产力和碳生物量检测的各种技术和方法，列举了其各自的优缺点。目前，测定海洋浮游植物初级生产力的主要方法有黑白瓶法、遥感估算法、碳同位素测定、快速重复率荧光法；测定海洋浮游植物碳生物量的主要方法有细胞体积转换法、流式细胞术、电子探针X射线显微分析、分位数回归模型估算法。通过对比分析发现碳同位素与快速重复率荧光法相结合可以更高效测定出初级生产力，而最具优势与应用前景的碳生物量检测方法是基于分位数回归模型估算法。其中，基于分位数回归模型估算法具有拟合异常值、测定结果准确等优势，能够实现现场浮游植物群落以及各个功能群碳生物量的估算，并能够与卫星遥感技术手段相结合，可以应用于大尺度和长时间序列的海洋浮游植物碳生物量估算。通过本文的综述，一方面为海洋浮游植物初级生产力和碳含量的研究提供一个基本和系统的认识，另一方面为深入研究浮游植物在海洋碳循环以及全球碳循环中的作用提供参考。     

象山港中、西部秋季浮游植物粒径分级、叶绿素a和初级生产力

１９９４年１０月结合水色遥感光谱实验,对象山港中、西部浮游植物细胞丰度、优势种类、叶绿素ａ浓度和初级生产力的分布做了现场观测。表层水中共鉴定出浮游植物２４种,隶属３门１７属,细胞丰度为１．０５×１０４±１．１４×１０４个／ｄｍ３;叶绿素ａ浓度为１．０７±０．５９μｇ／ｄｍ３,潜在初级生产力为３．８６±３．６０ｍｇＣ／（ｍ３·ｈ）。港区西部的浮游植物细胞丰度、叶绿素ａ浓度和初级生产力均高于港区中部;表层叶绿素ａ浓度高于中层和底层。浮游植物细胞粒径分级结果表明,微型和微微型浮游植物细胞（＜２０μｍ）对总叶绿素ａ的贡献占８６％,对初级生产力的贡献占８９％;小型浮游植物细胞（＞２０μｍ）对总叶绿素ａ的贡献占１４％,对初级生产力的贡献占１１％。     

Primary productivity in the western tropical Pacific and equatorial warm waters

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Distribution characteristics of size-fractionated chlorophyll a and primary productivity in Beibu Gulf

The distribution of the abundance of phytoplankton, chlorophyll a (Chl.a) concentration and primary productivity in the Beibu Gulf were observed from May 23 to June 4, 1994.The results show that there were marked featares of spatial zonation in the survey area due to the differences between the geographic environment and the hydrological conditions.Chlorophyll a and primary productivity were higher in the inshore than in the middle area and higher in the north than in the south of the Beibu Gulf.The average concentration of Chl.a, primary productivity and the abundance of phytoplankton were 0.94±0.45 μg/dm³, 351±172 mg/(m²·d) (C) and 0.97×10⁴-10.050×10⁴ ind./m³ in the area, respectively.There were 176 species belonging to 4 phyla and 56 genera based on microscope identification.The results of the size-fractionation show that the contribution of nanoplankton and picoplankton was 77% to total Chl.a and 91% to total primary productivity, which proved their importance to phytoplankton communities in the Beibu Gulf.     

Nutrient and Plankton Dynamics in the NE and NW Gyres of the Subarctic Pacific Ocean

The western subarctic gyre (WSG) and the eastern Alaska Grye (AG) on each side of the subarctic North Pacific, have many similarities. In both gyres, macronutrients are generally high and chl is low, and hence both gyres are High Nitrate, Low Chlorophyll (HNLC) regions. Despite the general similarities between these two gyres, there are many important differences. The time series station established at Stn KNOT on the southwest edge of the WSG and two in situ mesoscale iron enrichment experiments at each of the gyres has provided more information on iron concentrations, the dual role of iron and silicate limitation and seasonal cycles in the gyres. There is more seasonality in many parameters at Stn KNOT than at Stn P. There is an increase in Chl and primary productivity at Stn KNOT in May followed by increased iron limitation in summer. Low DIC:NO₃ ratios and high Si:NO₃ ratios in the WSG, indicate lower calcification and higher diatom production than at Stn P. The sources of iron for these areas are still not clear, but horizontal transport of iron rich coastal water and vertical transport could be important sources at certain times of the year in addition to dust input. Satellite images show that chl-rich coastal waters occasionally extend to the vicinity of Stn KNOT and therefore Stn KNOT may not always represent conditions in the main part of the WSG. This review focuses mainly on a comparison of Stn KNOT and Stn P, two time series stations on the edge of two very large gyres. At present, we have a limited understanding of the temporal and spatial variability within each of these large gyres. This revised version was published online in July 2006 with corrections to the Cover Date.     

南沙海域初级生产力与水柱垂直稳定度的关系

海洋中浮游植物利用光能吸收水体中的CO₂和营养盐合成有机物,不但为海洋食物链的运行提供物质和能量基础,而且还通过海一气界面气体交换影响着大气CO₂浓度.水柱垂直稳定度对海洋初级生产力有重要影响,对此人们早已认识,但通过实测数据分析两者定量关系的文章至今仍极为罕见.此外,南沙海域是世界最大的边缘海之一,然而有关该海域的初级生产力仅见报道过两个测站的实测数据[1].     

长江口邻域叶绿素a和初级生产力的分布

海水中的叶绿素a浓度是浮游植物现存量的重要指标,其分布反映出了水体中浮游植物的丰度及其变化规律.初级生产力反映了水域初级生产者通过光合作用生产有机碳的能力,是海洋生物链的第一个环节,是海洋生态系统研究的重要内容,也是海域生物资源评估的重要依据.河口及其邻近海域是人类活动较为频繁的海域,也是生物海洋学研究过程的重要区域.长江口是陆源物质输入东海的主要场所,径流把大量的悬浮泥沙和丰富的溶解营养盐带入海洋,造成了长江口邻近海域独特的生态环境特征,成为了诸多研究的焦点.     

湛江湾真光层深度与初级生产力的时空变化及其影响因素

基于2016−2017年4个季节航次数据,分析了湛江湾真光层深度与初级生产力的时空变化特征及其影响因素。结果表明,湛江湾真光层深度平均值为（6.95±3.17）m,空间变化比季节变化明显,K_d(PAR)与浊度存在显著的正相关关系,建立的线性回归模型R²为0.73（p<0.01）,表明悬浮颗粒物对湛江湾真光层深度的影响占主导地位。利用VGPM模型得到初级生产力（以碳计）的平均值为（639.53±427.95）mg/(m²·d),其时空特征与真光层深度基本保持一致,真光层深度比叶绿素a浓度更能解释初级生产力的时空分布模式。     

High primary productivity and f-ratio in summer in the Ulleung basin of the East/Japan Sea

To better understand the cause of high summer primary productivity in the Ulleung Basin located in the southwest part of the East/Japan Sea, the spatial dynamics of primary, new, and regenerated productivities (PP, NP, and RP) were examined along the path of the Tsushima Warm Current system in summer 2008. We compared hydrographic and chemical parameters in the Ulleung Basin with those of the Kuroshio Current in the Western Pacific Ocean and the East China Sea. In summer, integrated primary productivity (IPP, 0.37–0.96 g C m⁻² d⁻¹) and integrated new productivity (INP, 26–221 mg N m⁻² d⁻¹) within the euphotic zone in the Ulleung Basin were higher than those in the East China Sea and the Western Pacific Ocean (0.17–0.28 g C m⁻² d⁻¹, 2−5 mg N m⁻² d⁻¹, respectively). In contrast, there was no pronounced spatial variation in integrated regenerated productivity (IRP, 43–824 mg N m⁻² d⁻¹). Strong positive correlations between IPP and INP (also the f-ratio), and between nitrate uptake rate in the mixed layer and nitrate upward flux through the top of pycnocline in summer in the Ulleung Basin imply that the high IPP was mainly supported by supply of nitrate from the underlying water in the euphotic zone. Shallowing of the pycnocline depth as the current enters the East/Japan Sea facilitates nitrate supply from the nutrient-replete cold water immediately below the pycnocline through nitrate upward flux. A subsurface maximum in PP at or above the pycnocline and a high f-ratio further support the importance of this source of nitrate for maintaining the high summer PP in the Ulleung Basin. In comparison, the high PP layer was observed at the surface in the following fall and spring in the Ulleung Basin. Our results demonstrate the importance of hydrographic features in enhancing PP in this oligotrophic Tsushima Warm Current system.