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1.
Seasonal and interannual variations in physicochemical properties (i.e., temperature, salinity, dissolved oxygen and dissolved inorganic nutrients), chlorophyll a (Chl-a), particulate carbon and nitrogen (PC and PN, respectively), and primary production were investigated in the neritic area of Sagami Bay, Kanagawa, Japan, from January 2002 to December 2008. These abiotic/biotic variables, except for NH4 +–N, repeated similar seasonal variations for all 7 years. On the basis of the analysis of data obtained on 167 sampling dates, depth-integrated primary production in this water can be easily estimated from Chl-a at the surface using the regression equations obtained in the present study. Intermittently high values of dissolved inorganic nutrients, Chl-a, PC, PN and primary productivity at the surface during the summer stratified period were induced by high freshwater discharge from the rivers after rainfalls and by the expansion of nutrient-rich Tokyo Bay Water. Temperature, salinity and dissolved inorganic nutrients showed drastic variations within a scale of a few days and/or weeks, and these variations were related to sea levels that represent the intrusion of the Kuroshio Water, Intermediate Oyashio Water or deep water from the continental slope. However, there was no consistent trend in the variations in Chl-a, PC, PN and primary production due to the complex effects of these waters.  相似文献   

2.
A 24 hour time series survey was carried out during a spring tide (tidal range ca.2 m) of May 1995 on a tidal estuary in the Seto Inland Sea, Japan, in the context of an integrated program planned to quantify the dynamics of biophilic elements (carbon, nitrogen and phosphorus) and the roles played by the macrobenthos on the processes. Three stations were set along a transect line of about 1.4 km, which linked the river to the rear to the innermost part of the subtidal zone. Every hour, at each station, measurements were made of surface water temperature, salinity and dissolved oxygen concentration, and surface water was collected for the determination of nutrients [NH4 +−N, (NO3 −+NO2 −)−N, PO4 3−−P and Si (OH)4−Si]. During the ebb flow, riverine input of silicate and nitrate+nitrite significantly increased the concentrations of both the intertidal and the subtidal stations. Conversely, during the high tide, river nutrient concentrations were lowered by the mixing of fresh water with sea water. As a result, best (inverse) correlations were found at the river station for salinity against silicate (y=-2.9 Sal.+110.7,r 2=0.879) and nitrate+nitrite (y=-1.3 Sal.+48.4,r 2=0.796). In contrast, ammonium nitrogen concentrations were higher at intermediate salinities. Indeed, no significant correlation was found between salinity and ammonium. The effect of the macrobenthos, which is abundant on the intertidal flat, is discussed as a biological component that influences the processes of nutrient regeneration within the estuary. The effect of the tidal amplitude is an important one in determining the extent of the variations in nutrient concentrations at all three stations, which were stronger between the lower low tide and the higher high tide.  相似文献   

3.
Concentrations of particulate organic nitrogen (PN), dissolved inorganic nitrogen (DIN), and their nitrogen isotope ratios (δ 15N) in the Kiso-Sansen Rivers were determined from monthly observations over the course of a year to assess variations in the form and sources of riverine nitrogen discharged into Ise Bay. The δ 15N values of NO3 − observed in the Kiso-Sansen Rivers showed a logarithmic decreasing trend from 8 to 0‰, which varied with the river discharge, indicating mixing between point sources with high δ 15N and non-point sources with low δ 15N. The influence of isotope fractionation of in situ biogeochemical processes (mainly DIN assimilation by phytoplankton) on δ 15N of NO3 − was negligible, because sufficient concentrations of NH4 + for phytoplankton demand would inhibit the assimilation of NO3 −. A simple relationship between river discharge and δ 15N of NO3 − showed that the fraction of total NO3 − flux arising from point sources increased from 4.0–6.3% (1.1–1.8 tN day−1) during higher discharge (>600 m3 s−1) to 30.2–48.3% (2.6–4.1 tN day−1) during lower discharge (<300 m3 s−1). Riverine NO3 − discharge from the Kiso-Sansen Rivers can explain 75% of the variations in surface NO3 − at the head of Ise Bay over the year.  相似文献   

4.
Time-series measurements of dissolved inorganic carbon (DIC) and nutrient concentrations were conducted in the northwestern North Pacific from October 2002 to August 2004. Assuming that data obtained in different years represented time-series seasonal data for a single year, vertical distributions of DIC and nutrients showed large seasonal variabilities in the surface layer (∼100 m). Seasonal variabilities in normalized DIC (nDIC) and nitrate concentrations at the sea surface were estimated to be 81–113 μmol kg−1 and 12.7–15.7 μmol kg−1, respectively, in the Western Subarctic Gyre. The variability in nutrients between May and July was generally at least double that in other seasons. In the Western Subarctic Gyre, estimations based on statistical analyses revealed that seasonal new production was 39–61 gC m−2 and tended to be higher in the southwestern regions or coastal regions. The seasonal new productions in the northwestern North Pacific were two or more times higher than in the North Pacific subtropical gyre and the northeastern North Pacific. It is likely that this difference is due to spatial variations in the concentrations of trace metals and the species of phytoplankton present. In addition, from estimations of surface pCO2 it was verified that the Western Subarctic Gyre is a source of atmospheric CO2 between February and May and a sink for CO2 between July and October.  相似文献   

5.
Partial pressure of CO2 in surface sea water (pCO2) was measured continuously off Sanriku in May, 1997 by a new pCO2 measurement system. We have examined the relation of pCO2 to physical factors such as temperature, salinity and density, chemical and biological factors such as nutrients and carbonate system and chlorophylla. In the Kuroshio region pCO2 was not correlated to physical, chemical and biological factors in the range of 260 to 290 μatom. In transition water (Tr1) between Kuroshio and the Oyashio second branch, pCO2 was weakly correlated to physical factors and strongly correlated to nutrients. In transition water (Tr2) between the Oyashio first and second branches, pCO2 was highly correlated to temperature (SD: 10.9 μatom) and salinity (SD: 8.6 μatom) and also to nutrients. In transition water (Tr1+Tr2), pCO2 was highly multivariately correlated to temperature (T), salinity (S), chlorophylla (CH) (or nitrate+nitrite (N)) as follows, pCO2(μatom)= 10.8×T(°C)+27.7×S+2.57CH(μg/1) −769, R2= 0.86, SD = 20.9, or pCO2(μatom)= 3.9×T(°C)+25.5×S+16.0NO3(μM) −686, R2= 0.99, SD = 6.4. Moreover, pCO2 was predicted by only two factors, one physical (S) and the other chemical/biological (N) as follows: pCO2 (μatom)=32.8×S+19.4N−908, R2=0.97, SD=8.4. The pH measured at 25°C was well correlated with normalized pCO2 at a fixed temperature. In the Oyashio region pCO2 was decreased to 160 μatom, probably because of spring bloom, but was not correlated linearly to chlorophylla. The results obtained showed the possibility of estimating pCO2 of the Oyashio and transition regions in May by satellite remote sensing of SST, but the problem of estimation of pCO2 in Kuroshio water remains to be solved.  相似文献   

6.
Data from the R/V Mirai cruise (May–June 2000) have been examined to discover how mesoscale processes associated with eddy dynamics direct affect the water masses, the distributions and the vertical fluxes of the dissolved oxygen, nutrients and dissolved inorganic carbon in the western subarctic Pacific. Using maps of the temperature, salinity, dissolved oxygen, nutrients, chlorophyll and sea-air pCO2 difference we show that the boundaries of the anticyclone eddies in the study region were composed of high productivity coastal Oyashio water. The coastal waters were wrapped around the anticyclone eddies (thus creating a high productivity belt) and intruded inside of them. Using SeaWifs data we demonstrate that temporal variations in the position and the strength of anticyclone eddies advected the Kuril island coastal high productivity waters to the pelagic part, resulting in temporal variations of the chlorophyll in the Oyashio region. Computed vertical fluxes of the dissolved oxygen (DO), inorganic carbon (DIC) and silicate show that the anticylonic eddies in the Kuroshio-Oyashio Zone are characterized by enhanced vertical fluxes of the DO and DIC between the upper (σθ = 26.7–27.0) and lower (σθ = 27.1–27.5) intermediate layer, probably due to the intrusions of the Oyashio waters into the eddies. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

7.
为了推动海水养殖的可持续发展,研究其中水动力过程对生态要素的影响,本文基于实测数据,研究了南麂列岛养殖功能海域秋季的潮致混合特征及其对营养盐浓度的影响。结果显示,该海域雷诺应力呈现出显著落潮占优的特点,而落潮阶段高、低潮附近的转流过程又分别具有正、斜压的特点,进一步导致高潮时雷诺应力峰值被限制于近底层,而低潮时雷诺应力峰值自底至表陆续出现。南麂列岛养殖功能海域营养盐浓度很高,其中NO2-、PO43-与Si O32-浓度受雷诺应力影响显著,而NO3-浓度与盐度相关性明显,主要受水团控制。  相似文献   

8.
Concentrations of nutrients (NO3, NO2, Si(OH)4, PO4 and dissolved inorganic carbon (DIC) were measured in a series of seawater samples collected over approximately 15 months in 2005 and 2006 by an automatic water sampler (Remote Access Sampler, RAS) in the Northwestern North Pacific. Seasonal variability and concentrations of NO3 + NO2 (NOx and Si(OH)4 were comparable to previous shipboard observations, although there were small errors associated with measurements of PO4 and DIC. Concentrations of these nutrients began to decrease in late April. After the end of June, NOx and Si(OH)4 decreased rapidly, with large fluctuations. After October, these nutrients increased again until late spring 2006. The ratio of the decrease of Si(OH)4 to that of NOx suggests that numbers of biogenic opal-producing creatures, such as diatoms, increased after the end of June. This conclusion was supported by a rapid increase in biogenic opal flux recorded in a sediment trap at 150 m. The relationship between NOx concentrations at the RAS depth of 35 m and NOx integrated over the upper 100 m was determined using previous shipboard hydrocast data. This relationship was used to estimate integrated mixed layer NOx concentration from RAS data. Estimated new production based on seasonal drawdown of integrated NOx averaged approximately 156 mg-C m−2day−1 annually, which agrees with previous estimates. Thus, an automatic seawater sampler that documents annual maximum and minimum nutrient concentrations and episodic events such as storms and spring blooms, which might be missed by an ordinary research vessel, will contribute to time-series observations of nutrients and, by extension, biological pump activity.  相似文献   

9.
In the present study, we have investigated the conditions influencing encystment and excystment in the dinoflagellate Gyrodinium instriatum under laboratory conditions. We incubated G. instriatum in modified whole SWM-3 culture medium and in versions of modified SWM-3 from which NO3 −, PO4 3−, NO3 − + PO4 3−, or Si had been omitted and observed encystment. Percentage encystment was high in the media without N and without P, while the percentage encystment in the medium lacking both N and P was highest. Moreover, to investigate N or P concentration which induced the encystment, Gyrodinium instriatum was also incubated in media with different concentrations of inorganic N and P; the concentrations of NO2 − + NO3 − and PO4 3− were measured over time. The precursors of cysts appeared within 2 or 3 days of a decrease in NO2 − + NO3 − or PO4 3− concentration to values lower than 1 μM or 0.2 μM, respectively. When cysts produced in the laboratory were incubated, we observed excystment after 8–37 days, without a mandatory period of darkness or low temperature. We incubated cysts collected from nature at different temperatures or in the dark or light and observed excystments. Natural cysts excysted at temperatures from 10 to 30°C, in both light and dark, but excystment was delayed at low temperatures. These studies indicate that G. instriatum encysts in low N or P concentration and excysts over a wide temperature range, regardless of light conditions, after short dormancy periods.  相似文献   

10.
The importance of the nitrogen source for phytoplankton growth in a highly eutrophic embayment, Dokai Bay, was investigated. The DIN concentration often exceeded 100 μM of which 40–70% was NH4 +. During two incubation experiments, the natural assemblage of mainly diatoms took up NH4 + instead of NO3 −. The growth of two Skeletonema species isolated in Dokai Bay were significantly faster on NH4 + (1.86 and 1.27 div. d−1 respectively) than on NO3 − (1.55 and 1.04 div. d−1 respectively). Our results indicated that these diatoms could grow faster by using NH4 + compared to NO3 − in this eutrophic bay.  相似文献   

11.
为探讨海马齿(Sesuvium portulacastrum)对水域环境修复作用,本文研究了水培海马齿对不同盐度水质的碳汇作用以及不同形态氮的利用情况。实验设计0、10、20、30、35盐度梯度,海马齿水培时间82 d,然后测定植株干重、营养元素含量以及积累速率,最后在抑菌与不抑菌条件下研究海马齿根际与铵态氮(NH4+-N)、硝态氮(NO3--N)、无机磷(PO43-)以及色氨酸(Trp)吸收转化关系。研究结果表明,盐度10条件下海马齿植株干重、有机元素含量以及积累速率最高,有机碳、有机氮与有机磷积累速率分别为(5.572±1.611)、(0.313±0.058)、(0.057±0.013)mg/(d·ind.),而高盐环境35盐度条件下对海马齿生长造成一定胁迫。盐度0～35范围,海马齿均未出现死亡现象。不同盐度抑菌培养条件下,色氨酸与无机氮共存时均能被能被海马齿利用,色氨酸利用量远高于硝态氮、铵态氮;不抑菌条件下铵态氮则表现出增加的结果。海马齿作用在盐度...  相似文献   

12.
The influence of macronitrogen (NO - 3 and NH + 4 ) addition with Ulva pertusa on dissolved inorganic carbon system in seawater was studied. The results indicate that p(CO 2 ) and HCO 3 concentration decrease significantly, while pH and CO 2- 3 concentration increase significantly. When the concentration of NO 3 was less than 71 μmol/dm 3 or NH + 4 was less than 49.7 μmol/dm 3 , dissolved inorganic carbon (DIC) absorption rates by Ulva pertusa generally increased with the increasing of nitrogen concentration. The DIC decreased 151 μmol/dm 3 with the addition of 71 μmol/dm 3 NO 3 and decreased 232 μmol/dm 3 with the addition of 49.7 μmol/dm 3 NH + 4 after the experiment compared with DIC measured without nitrogen addition. A significant negative-correlation was found between c(DIC) and growth rate (μ) of Ulva pertusa (r = -0.91, P <0.000 1, n=11). NH + 4 had more influence on the species of inorganic carbon system than NO 3 .  相似文献   

13.
从上行控制角度,通过野外采样和围隔培养实验,研究了水母的代谢及分解过程对水体环境中pH、溶解氧、营养盐组成的影响,以及该过程中浮游植物的变化。实验结果表明,沙海蜇在代谢过程中短时间内会大量消耗水体中的溶解氧（dissolved oxygen,DO）,使水体出现低氧和轻度酸化。代谢过程释放出大量营养盐,使水体中的溶解无机氮（dissolved inorganic nitrogen,DIN）浓度在24h内增加为原来的12倍,溶解无机磷（dissolved inorganic phosphorus,DIP）浓度增加了40多倍,进而引起水体中叶绿素a（chlorophyll a,chl a）浓度的增加。沙海蜇的分解过程使水体表现出明显的低氧（缺氧）和酸化现象。沙海蜇生物量越大,分解时间越长,对水体的改变程度越明显,此外,还释放出大量的营养盐并改变原有的营养盐结构,可以刺激甲藻和绿藻的生长,甚至可能引发藻华。  相似文献   

14.
Six newly developed floats, which were set to drift on the 26.7 σθ isopycnal surface and to profile temperature, salinity and pressure above 1000 dbar once a week, were deployed in the Oyashio and Kuroshio Extension (KE) in order to examine the circulation, formation site and time scale of newly formed North Pacific Intermediate Water (NPIW). The floats were deployed in February or May 2001, and the data from their deployments to December 2002 are analyzed here. Four of the six floats were deployed near the KE axis at around the first meander crest, and they moved eastward to 157°E–176°W at latitudes of 30°N–45°N. The other two floats deployed in the Oyashio water with low-potential vorticity near the south coast of Hokkaido moved southward to reach the KE front and then moved eastward to the same region as the first four floats. The temperature and salinity at 26.7 σθ measured by the profiling floats indicate that the source waters of NPIW, Oyashio and Kuroshio waters are drastically mixed and modified in the mixed water region west of 160°E. The floats were separated into the three paths east of 160°E between the Kuroshio Extension front and the north of Water-Mass front (nearly subarctic front). New NPIW is judged to be formed along these three paths since the vertical profiles of temperature and salinity are quite smooth, having a salinity minimum at about 26.7σθ along each path. Kuroshio-Oyashio isopycnal mixing ratios of the new NPIW are 7:3, 6:4 and 5:5 at 26.7σθ along the southern, middle and northern paths, respectively. Potential vorticity converges to about 14–15 × 10−11 m−1s−1 along these paths. The time scale of new NPIW formation is estimated to be 1–1.5 years from the merger of Oyashio and Kuroshio waters to the formation of the new NPIW. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

15.
In order to examine the formation, distribution and transport of North Pacific Intermediate Water (NPIW), repeated hydrographic observations along several lines in the western North Pacific were carried out in the period from 1996 to 2001. NPIW formation can be described as follows: (1) Oyashio water extends south of the Subarctic Boundary and meets Kuroshio water in intermediate layers; (2) active mixing between Oyashio and Kuroshio waters occurs in intermediate layers; (3) the mixing of Oyashio and Kuroshio waters and salinity minimum formation around the potential density of 26.8σθ proceed to the east. It is found that Kuroshio water flows eastward even in the region north of 40°N across the 165°E line, showing that Kuroshio water extends north of the Subarctic Boundary. Volume transports of Oyashio and Kuroshio components (relative to 2000 dbar) integrated in the potential density range of 26.6–27.4σθ along the Kuroshio Extension across 152°E–165°E are estimated to be 7–8 Sv (106 m3s−1) and 9–10 Sv, respectively, which is consistent with recent work. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

16.
朱明  刘峰  陈璐  刘兆普 《海洋与湖沼》2018,49(5):975-982
我国黄海出现的绿潮发源于黄海南部苏北辐射沙洲紫菜养殖区,苏北沙洲区濒临的沿岸河网众多,来自沿岸径流的淡水携带大量氮磷等营养盐间歇性入海,导致海水的富营养化并伴随着盐度的周期性波动。本研究通过模拟实验研究低盐度(15和5)对浒苔吸收氮盐(NO_3~–-N和NH_4~+-N)和磷盐(PO_4~(3–)-P)的影响,主要发现:与盐度30相比,在低盐度(15和5)时,浒苔对NO_3~–-N的1h最大吸收速率(V_(max))和亲和力(V_(max)/Ks)分别提高280%和350%左右,半饱和常数(Ks)下降15%左右,并能够维持对NO_3~–-N的高效吸收(24h);盐度15和5时,浒苔对NH_4~+-N的1h最大吸收速率(V_(max))分别提高40%和200%,亲和力(V_(max)/Ks)分别提高20%和180%, Ks分别提高15%和30%,但是盐度降低对NH_4~+-N的长效吸收产生负面影响,甚至在盐度5条件下出现吸收高浓度NH_4~+-N后再释放的现象;与盐度30相似,盐度15条件下浒苔能够快速吸收PO_4~(3–)-P,而盐度5则导致藻细胞内的PO_4~(3–)-P在早期阶段快速流失,并在后期不能有效吸收PO_4~(3–)-P。本实验的结果表明,降低盐度有利于浒苔对氮源的快速吸收,在盐度15下浒苔能够实现对硝酸盐和磷盐的高效吸收。  相似文献   

17.
长江水体溶解态无机氮和磷现状及长期变化特点   总被引：2，自引：0，他引：2  
于2006年2、5、8和11月对长江从攀枝花至河口和上游的两条支流雅砻江和嘉陵江的溶解态无机氮(NO-3-N、NO-2-N和NH+4-N)和磷酸盐(PO43--P)进行了取样调查,同时结合长江营养盐的历史数据,分析了长江水体中溶解态无机氮、磷的长期变化特点。结果表明,长江NO-3-N、NH+4-N、DIN(包括NO-3-N、NO-2-N和NH+4-N)和PO3-4-P浓度从上游到下游显示出增加趋势,但存在季节差异;NO2-N浓度总体较低,在长江中下游(武汉—南京)浓度较高。长江从上游到下游DIN通量的变化主要受径流量的影响,从上游到下游单位面积年产N量逐渐升高;PO3-4-P输送通量从上游往下游呈增加趋势,也主要受径流量控制,但从季节变化来讲,PO3-4-P的月输送通量受其浓度的控制更加明显。自20世纪60年代来,长江水体中NO3--N、NO2--N、DIN和PO3-4-P的浓度都处于缓慢上升趋势,但到80年代上升速度明显加快;不同阶段DIN和34PO-P的季节变化特点也不尽相同,反映了其来源的差异。目前,长江水体中溶解态无机氮、磷浓度与国内及国际河流相比处于中等水平。  相似文献   

18.
为获得反硝化脱氮效率较好的菌株,实验从海水螺旋藻培养体系中分离获得一株嗜碱兼性好氧反硝化菌, 通过观察细菌形态以及16S rRNA基因序列的同源性分析, 鉴定该菌株为海杆菌属, 命名为Marinobacter sp. B3。为明确该海杆菌的反硝化性能及氮转化途径, 研究开展了溶解氧(DO), 碳氮摩尔比(C/N), pH和温度等不同单因素对反硝化性能影响实验和氮平衡实验。单因素影响实验结果表明, 当硝酸钾(KNO3)作为唯一氮源, NO3--N的初始浓度为100 mg/L, 盐度32, 振荡速度为150 r/min (初始DO质量浓度是5.6 mg/L), C/N=10, pH=8.0±0.2, 温度为35 °C时, 可获得最大脱氮效果。氮平衡实验结果得出, 在好氧环境下, 有20.11%的NO3--N转化为胞内氮, 5.58 mg/L的NO3--N转化为其他形态(NO2--N、NO4+-N和有机氮), 74.72%转化为N2释放; 厌氧环境下, 有26.65%的NO3--N转化为胞内氮, 72.86%的NO3--N转化为气态产物释放。最终实验结果表明, Marinobactersp. B3在好氧和厌氧条件下, 48 h对NO3--N的去除率分别为99.89%和93.80%, 具有较好的反硝化脱氮能力, 且在好氧条件下NO3--N去除效率更高, 在海水工厂化循环水养殖尾水处理方面具有良好的应用前景。  相似文献   

19.
The coastal sea level propagating westward along the south coast of Japan and the impact of the disturbance on the generation of the Kuroshio small meander have been examined. The propagation occurs in sea level variations for periods shorter than 10 days and is remarkable for periods of 4–6 days. Characteristics of the 4–6 day component have been studied using the extended empirical orthogonal function (EEOF). The first and second modes of EEOF are almost in-phase throughout the south coast of Japan. The higher four modes of EEOF are significantly excited when the Kuroshio takes the non-large-meander path, and propagate westward with phase speeds of 2.8 m s−1 (third and fourth modes) and 1.6 m s−1 (fifth and sixth modes) in the Kuroshio region west of Mera in the Boso Peninsula. The analysis shows that more than 70% of the small meanders generate in two months after a significant propagating disturbance reaches south of Kyushu when the velocity of the Kuroshio is high. This effect of coastal disturbance is examined by numerical experiments with a 2.5-layer model in which coastal disturbance is excited by vertical displacement of the upper interface. The result is that offshore displacement of the Kuroshio occurs southeast of Kyushu only in the case of significant upward displacement of the interface under the influence of a high Kuroshio velocity. The significant coastal disturbance, which is associated with upward displacement of the density interface, and a high Kuroshio velocity can therefore be important factors in generating small meanders.  相似文献   

20.
The biochemical effects of a cold-core eddy that was shed from the Kuroshio Current at the Luzon Strait bordering the South China Sea (SCS) were studied in late spring, a relatively unproductive season in the SCS. The extent of the eddy was determined by time-series images of SeaWiFS ocean color, AVHRR sea surface temperature, and TOPEX/Jason-1 sea surface height anomaly. Nutrient budgets, nitrate-based new production, primary production, and phytoplankton assemblages were compared between the eddy and its surrounding Kuroshio and SCS waters. The enhanced productivity in the eddy was comparable to wintertime productivity in the SCS basin, which is supported by upwelled subsurface nitrate under the prevailing Northeastern Monsoon. There were more Synechococcus, pico-eucaryotes, and diatoms, but less Trichodesmium in the surface water inside the eddy than outside. Prochlorococcus and Richelia intracellularis showed no spatial differences. Water column-integrated primary production (IPP) inside the eddy was 2–3 times that outside the eddy in the SCS (1.09 vs. 0.59 g C m−2d−1), as was nitrate-based new production (INP) (0.67 vs. 0.25 g C m−2d−1). INP in the eddy was 6 times that in the Kuroshio (0.12 g C m−2d−1). IPP and INP in the eddy were higher than the maximum production values ever measured in the SCS basin. Surface chlorophyll a concentration (0.40 mg m−3) in the eddy equaled the maximum concentration registered for the SCS basin and was higher than the wintertime average (0.29 ± 0.04 mg m−3). INP was 3.5 times as great and IPP was doubled in the eddy compared to the wintertime SCS basin. As cold core eddies form intermittently all year round as the Kuroshio invades the SCS, their effects on phytoplankton productivity and assemblages are likely to have important influences on the biogeochemical cycle of the region.  相似文献   

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