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1.
A three-dimension ecological dynamic model was established to numerically study the relationship of HAB and environmental conditions.The numerical experiments showed that the growth of diatom,the dominant HAB specie,was mainly restricted by phosphate and silicate.If the concentrations of phosphate and silicate reach 17-25 μg/L and 300-375 μg/L respectively,the water is in a state of eutrophication.When phosphate and silicate up to 26-32 μg/L and 350-500 μg/L respectively,HAB could be induced.The major regions of HAB occurrence are Jiaozhou Bay mouth,coastal bays,and coastal area from Maidao to Shilaoren.To avoid HAB occurrence,concentration of phosphate and silicate should not exceed 17-20 μg/L and 300 μg/L as a whole.Reasonable control of pollutant discharge is a key point to prevent water eutrophication and HAB occurrence. 相似文献
2.
Structure of the phytoplankton communities and primary production in the Ob River estuary and over the adjacent Kara Sea shelf 总被引：1，自引：0，他引：1
The material was collected in the Ob River estuary and over the adjacent shallow Kara Sea shelf between 71°14′0 and 75°33′0N
at the end of September 2007. Latitudinal zoning in the phytoplankton distribution was demonstrated; this zoning was determined
by the changes in the salinity and concentration of nutrients. Characteristic of the phytocenosis in the southern desalinated
zone composed of freshwater species of diatom and green algae were the high population density (1.5 × 106 cells/l), biomass (210 μgC/l), chlorophyll concentration (4.5 μg/l), and uniform distribution in the water column. High primary
production (∼40 μgC/l/day) was recorded in the upper 1.5-m layer. The estuarine frontal zone located to the north contained
a halocline at a depth of 3–5 m. Freshwater species with low population density (2.5 × 105 cells/l), biomass (24 μgC/l), and chlorophyll concentration (1.5 μg/l) dominated above the halocline. Marine diatom algae,
dinoflagellates, and autotrophic flagellates formed a considerable part of the phytocenosis below the halocline; the community
characteristics were twofold lower as compared with the upper layer. The maximal values of the primary production (∼10 μgC/l
per day) were recorded in the upper 1.5-m layer. The phytocenosis in the seaward zone was formed by marine alga species and
was considerably poorer as compared with the frontal zone. The assimilation numbers at the end of the vegetation season in
the overall studied area were low, amounting to 0.4–1.0 μgC/μgChl/h in the upper layer and 0.03–0.1 μgC/μgChl/h under the
pycnocline. 相似文献
3.
The present investigation was targeted at diatom composition studies in the surface sediments (0–1 cm) sampled in the Sea of Okhotsk and the northwest Pacific in the depth range from 130 to 6110 m. The taxonomic analysis, as well as the quantitative (the diatom cell abundance per sediment dry weight unit) content and ecological group definition, was applied. Ten diatom taxa are the main body (80–100%) of the diatom assemblages: Bacterosira bathyomphala, Chaetoceros spp. (spores), Actinocyclus curvatulus, Thalassiosira latimarginata (group), T. antarctica (spores), Neodenticula seminae, Rhizosolenia hebetata f. hiemalis, Thalassiothrix longissima, Coscinodiscus marginatus, Coscinodiscus oculus iridis. The relative content of these species reflects the sedimentation conditions for different parts of the sea: the shelf, the continental slope, the open sea, and the ocean. The highest diatom content (45.6.3–60.0 106 per g of dry weight) was found for the surface sediments in the central part of the Sea of Okhotsk and the continental slope of western Kamchatka. 相似文献
4.
Abstract. .The phosphate uptake kinetics of single cells and colonies of the haptophycean alga Phaeocystis pouchetii were investigated in short- and long-term experiments. In phosphate-deprived cultures, the highest nutrient uptake rate (Vmax ) of both growth forms appeared to be similar. However, the half-saturation constant for phosphate uptake of the cells embedded in a colony (Ks = 3.08 μM) was considerably higher than that of the single cells (Ks = 0.31 μM). This is consistent with the existence of a diffusion barrier formed by the colony membrane and colonial mucus. Over a 24 h light/dark cycle, the phosphate assimilation rate in moderately limited colonies and single cells was nearly identical during the light period. In the following dark phase, colony cells maintained this uptake rate, whereas the uptake of the single cells diminished by 70 %. The high dark uptake rate in colonies ran parallel with the absorption and degradation of intracolonial carbon compounds, suggesting that the dissimilation of these compounds covers the energy requirements for phosphate uptake in the dark. In Phaeocystis cultures during a transition to phosphate depletion, a significant amount of phosphate was found in the colonial mucus, isolated by selective filtration. The possible absorption of phosphate by the mucus and the role of mucus in the energy budget seem to be an essential feature of phosphate uptake of colonies. Short-term measurement of phosphate uptake in colony cells may therefore underestimate the phosphate uptake of the whole colony. 相似文献
5.
Abstract. Coastal Patagonian sea waters had been differentially nutrient-enriched to determine (i) the magnitude of the algal biomass supported and (ii) which species were able to best compete for the available nutrients. Nitrogen was found to be the nutrient limiting growth of the natural phytoplankton population. The addition of NO3 at 25 μg at 1-1 led to a 10 to 30 μg 1-1 increase in chlorophyll a in all but those treatments containing trace metal additions. The best yield coefficients were obtained when a chelator (EDTA) was added with NO3 . A pool of nine diatom species were common in the N03 supplemented waters and the addition of vitamins along with NO3 allowed two of the nine species to dominate. 相似文献
6.
The uptake of zinc and cadmium by a species of marine diatom Thalassirosira weissflogii and the nutrient variation (phosphorus and silicon) in the culture medium were estimated when exposed to zinc and cadmium stress under controlled laboratory conditions.It was found that low cadmium addition could stimulate the culture to grow with a relatively high rate and exert its toxicity at the elevated concentration.The cellular uptake of zinc and cadmium by the diatom varied in the ranges of 1.21~3.75 and 0.060~0.629 fmol per cell respectively in the whole cultivation period.The mean cellular phosphorus and silicon drawdowns were constant with 0.26~0.42 and 0.30~0.46 pmol per cell respectively in those healthy cultures.It is illustrated that the algal cells can adjust some physiological mechanisms to decrease metal accumulation and keep metal homeostasis in the organism.The correlation analysis results further indicate that the cellular cadmium uptake might be closely related with the cellular phosphorus, silicon drawdown and the growth rate of diatom (P<0.05, 0.001, 0.01); and the cultures grow better in good conditions, the lower amount of phosphorus, silicon materials are consumed by a single cell to keep a high efficiency of utilization. 相似文献
7.
I. A. Nemirovskaya 《Oceanology》2010,50(5):716-728
Data are presented on the content of aliphatic and polycyclic aromatic hydrocarbons (AHC and PAH, respectively) in the interstitial
waters and bottom sediments of the Kara Sea compared to the distribution of the particulate matter and organic carbon. It
was found that the AHC concentrations within the water mass (16 μg/l on average) are mainly formed by natural processes. The
AHC distribution represents the variability of the hydrological and sedimentation processes in different regions of the sea.
The widest ranges of the concentrations were registered in the Ob Bay-Kara Sea section: in the water (10–310 μg/l for the
AHC and 0.4–7.2 ng/l for the PAH) and in the surface layer of the bottom sediments (8–42 μg/l for the AHC and 9–94 ng/g for
the PAH). The differentiation of the hydrocarbons (HC) in the different media follows the marginal filter’s regularities;
therefore, no oil and pyrogenic compounds are supplied to the open parts of the sea. In the sediment mass, the HC content
is determined by the variations in the oxidative conditions in the sediment and its material’s composition. 相似文献
8.
The influences of macronutrient enrichment on iron absorption, adsorption, and the bioconcentration factor (BCF) of iron by coastal diatoms were examined. In addition, the distribution of different iron size fractions in seawater in relation to two diatom species exposed to nutrient enrichment over an extended period (6 days for Thalassiosira weissflogii, and 4 days for Skeletonema costatum), was investigated. Iron concentrations were measured of seven size fractions: particles (>0.4 μm), colloidal particles (0.4 μm–100, 100–50, 50–30, 30–10, 10–3 kDa), and soluble species (<3 kDa).The absorption, adsorption, uptake, BCF of iron by the diatoms, and the iron species distribution in seawater were affected by the diatom species, as well as the nitrate (N) and phosphate (P) concentration. The addition of P could affect the iron internalization strategy. The content of soluble iron species was positively correlated with the amount of iron absorption by T. weissflogii, but it was not suitable for S. costatum. 相似文献
9.
《Journal of Sea Research》2004,51(1):21-35
Nitrate loading to coastal waters has increased over recent decades while silicon loading has remained relatively constant or decreased. As the N:Si ratio in coastal waters shifts due to these anthropogenic influences, silicate limitation of diatom biomass may become a feature of the biogeochemistry in coastal waters especially in regions of reduced exchange. Two sets of nutrient enrichment mesocosm experiments were conducted in successive years using a natural planktonic assemblage obtained from the Trondheimsfjord, Norway. The inorganic nutrient concentrations at the start of the experiments were manipulated to give a variety of N:Si concentrations at ratios representative of current and possible future values, should N loading continue. In June 1999 experiments were conducted with a gradient of inorganic N:Si ratios (1:2, 1:1, 2:1, 4:1) to investigate the influence of low and high N:Si ratio conditions and to determine the conditions that would generate Si limitation of diatom growth. In June 2000, based on 1999 data, highly replicated experiments were conducted at N:Si ratios of 1:1 and 4:1 which were expected to result in N and Si limitation of diatom growth, respectively; statistical differences in cellular composition were recorded. N limitation of diatom biomass increase was observed under the three lowest N:Si ratios: particulate carbon (C) accumulation continued to occur following N exhaustion resulting in an increase in the organic C:N ratio. Silicate limitation of diatom biomass increase only occurred at the highest N:Si ratio of 4:1. Silicate exhaustion was followed by continued nitrate uptake for several days, at a slower rate than previously. The resulting increase in organic N was accompanied by an increase in organic C such that the C:N ratio of the organic material at the highest N:Si ratio failed to increase to the extent observed under the N limited conditions. Statistically significant differences in chlorophyll-a yield per unit nitrate, C:chlorophyll-a ratios, C:N ratio and diatom cell yield per unit nitrate or Si were observed in Si compared to N limited conditions. All mesocosms became dominated numerically and in terms of biomass by the diatom Skeletonema costatum. The potential implications of changing N and Si regimes in coastal waters are discussed. 相似文献
10.
Seasonal and interannual variations in physicochemical properties were investigated in the neritic area of Sagami Bay, Kanagawa,
Japan, from December 2000 to December 2005. Physicochemical properties (i.e. temperature, salinity, density, dissolved oxygen
and dissolved inorganic nutrient concentration) revealed clear seasonal variations, which were similar to each other during
all 5 years. Temperature, salinity and dissolved inorganic nutrients showed rapid, drastic variations within a few days and/or
weeks. These variations are related to sea levels, principally due to the shifting effects of the Kuroshio Current axis: they
were strongly affected by the Kuroshio Water and other waters, when sea level difference was greater than ca. 35 cm and lower
than ca. 15 cm, respectively. Temperature difference (DF
T
) increased with sea level difference, and the difference of salinity and dissolved inorganic nutrients (NH4
+-N, NO3
−+NO2
−-N, NH4
++NO3
−+NO2
−-N, PO4
3−-P and SiO2-Si) increased and decreased with DF
T
, respectively. All these correlations are significant. Total dissolved inorganic nitrogen (N), phosphate (P) and silicate
(Si) revealed seasonal variations in the ranges of 0.57–16.08, 0.0070–0.91 and 0.22–46.38 μM, respectively. From the regression equations between these elements allowed the following relation to be obtained; Si:N:P
= 14.8:13.4:1. Dissolved inorganic nutrients were characterized by Si and/or P deficiency, especially in the upper layer (0–20
m depth) during summer. Single and/or combined elements are discussed on the basis of potential and stoichiometric nutrient
limitations, which could restrict phytoplankton (diatom) growth as a limiting factor. 相似文献
11.
A five-year study of the interannual changes observed in May–June during the mass reproduction of coccolithophorids was carried
out in the northeastern part of the Black Sea. The long-term dynamics were analyzed using the data on the phytoplankton collected
during the last 40 years. The fraction of coccolithophorids represents either 20 or 60% of the total biomass of the algae
and does not depend on either the previous winter conditions or the nitrogen content and the N: P ratio in the surface water
layer. Our studies have revealed the dependency between the phosphate content and the size of the coccolythophorids’ fraction
in the total phytoplankton biomass. The long-term population dynamics includes three periods. Until the mideighties, the coccolythophorid
fraction in the Black Sea phytoplankton was insignificant (3%). The average biomass was equal to 8 μg/l. In the late eighties,
the average biomass increased up to 106 μg/l. Since the midnineties, coccolythophorids often prevail in the number and mass
among the other phytoplankton species. The general tendency for the growth of the coccolythophorid fraction in the phytoplankton
cenoses coincides with the increase in the phosphate concentration in the near-surface water observed within the last 40 years.
This fact corresponds to the experimental results, which demonstrate that the coccolythophorid development during May–June
is phosphate-limited. 相似文献
12.
基于时空矩阵方法对福建省海湾水质变化特征分析 总被引：1，自引：1，他引：0
基于2005—2011年8月和2012—2015年5月、8月的水质监测数据,应用水质指标的主成分分析结果,对福建省海湾划分环境单元,通过时空矩阵方法对福建省海湾水质指标变化特征进行了分析。结果显示:（1）通过主成分分析,4个水质指标聚成两类成分,磷酸盐和叶绿素a聚为一类主成分,硝酸盐和溶解氧聚为另一类主成分;（2）以主成分权重值为坐标,划分福建省海湾表层水体为6个环境单元,以此建立水质指标相对含量的时间序列组合矩阵,对福建省海湾水质指标变化分析;（3）水质指标时空矩阵表现出一定的周期性变化趋势,环境单元的指标变化模式具有同步性,指标含量变化的绝对值从叶绿素a到营养盐再到溶解氧呈轻微增长;（4）两类主成分具有一定相关性,营养水平高低影响营养-浮游植物动态关系,当磷酸盐含量高于0.03 mg/L、硝酸盐含量高于0.25 mg/L,且营养盐时间周期变化显著时,叶绿素a时间周期变化与营养盐发生同步联动效应;（5）夏季福建省海湾水体生产力较低,大量陆源有机物输入、降解耗氧,表层溶解氧含量降低明显;（6）福建省海湾主要受两种性质差异很大的水体影响,富含高营养盐径流水团影响了河口及邻近海域的环境单元,而福建省南部海湾主要受台湾暖流及上升流影响,台湾暖流是东海海域磷酸盐的重要来源。 相似文献
13.
Abstract. Organic substances are suspected to influence the unpredictable, episodic blooms which characterize the planktonic pennate diatom Asterionella glacialis in certain coastal waters. Experiments to test its general responsiveness to organic enrichments in terms of growth rate and colony formation were carried out. An axenic clone was grown at 10° C, 0.039 l min-1 ,12:12 LD cycle in G uillard's f/2 medium enriched with eight different organic substances. Growth rates in organically-enriched media during exponential phase usually exceeded those in f/2 medium alone. Cell yields after 12 days in media enriched with glycyl-glycin and trypticase + yeast extract were significantly greater than in the other treatments. Longer chain lengths accompanied organic enrichment, notably with trypticase + yeast extract and 100ppm soil extract. These results suggest that Asterionella glacialis is positively responsive to elevated levels of certain organic substances. A potential effect of organic substance - trace metal - silica interactions on colony-size is suggested. 相似文献
14.
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。 相似文献
15.
R.J. Morris M.J. McCartney A.G. Howard M.H. Arbab-Zavar J.S. Davis 《Marine Chemistry》1984,14(3):259-265
Dissolved inorganic arsenic and phosphate levels present in an enclosed experimental ecosystem have been studied during the course of a natural spring diatom bloom. Whilst phosphate levels dropped rapidly to almost zero as the bloom developed, arsenic levels remained constant even when arsenate levels exceeded the dissolved phosphate. Certain diatom species (Thalassiosira spp., Chaetoceras spp. and Skeletonema costatum) therefore appear to be capable of discriminating, either by uptake or excretion, between phosphate and arsenate. The implications of such findings are discussed. 相似文献
16.
Detailed analysis of the lipids present in seawater medium before and after growing cultures of the diatom Chaetoceros simplex calcitrans Paulsen in them has been carried out and compared with the lipids found in the diatom itself.Fatty Acids. The seawater contained 1.0 μg fatty acids/ml, C 16:0, C 18:0 and C 18:1 being the predominant components. After removal of 12-day cultures of the diatom, the medium contained 1.1 μg fatty acids/ml and showed 47% decrease of the C 18:0 acid, and decreases of 37% in the C 13:0 and 56% in the C 15:1 contents. The diatom itself contained 10.7% fatty acids of the dry weight, among which C 16:1, C 16:0 and C 14:0 predominated.Sterols. Cholesterol dominated the sterol composition of seawater, which was found to contain 0.15 μg total sterols/ml. The filtered culture medium contained 0.18 μg total sterols/ml, had lost some of its cholesterol content, but contained a significant amount of 24-methylene-cholesterol. Other minor sterols in seawater both prior to and after growing diatoms cultures in it were β-sitosterol, stigmasterol and campesterol.The diatom itself contained 0.47% total sterols of the dry weight with cholesterol and 24-methylene-cholesterol making up ca. 40% of the total each. Minor sterols found were stigmasterol (or fucosterol), campesterol and β-sitosterol. 相似文献
17.
Two processes are generally explained as causes of temporal changes in the stoichiometric silicon/nitrogen (Si/N) ratios of
sinking particles and of nutrient consumption in the surface water during the spring diatom bloom: (1) physiological changes
of diatom under the stress of photosynthesis of diatom and (2) differences of regeneration between silicon and nitrogen. We
investigated which process plays an important role in these changes using a one-dimensional ecosystem model that explicitly
represents diatom and the other non-silicious phytoplankton. The model was applied to station A7 (41°30′ N, 145°30′ E) in
the western North Pacific, where diatom regularly blooms in spring. Model simulations show that the Si/N ratios of the flux
exported by the sinking particles at 100 m depth and of nutrient consumptions in the upper 100 m surface water have their
maxima at the end of the spring diatom bloom, the values and timings of which are significantly different from each other.
Analyses of the model results show that the differences of regeneration between silicon and nitrogen mainly cause the temporal
changes of the Si/N ratios. On the other hand, the physiological changes of diatoms under stress can hardly cause these temporal
changes, because the effect of the change in the diatom's uptake ratio of silicon to nitrogen is cancelled by that in its
sinking rate. 相似文献
18.
The regeneration of pore water nutrients was studied and the contribution of benthic nutrient fluxes to the overlying water
was evaluated on the basis of field specific observations conducted in September–October 1998 and April–May 1999 in the Bohai
Sea. Nutrient concentrations in sediment pore waters were examined by incubating sediment core samples with overlying seawater
in air and/or nitrogen conditions. Nutrient diffusion fluxes calculated by diagenetic equations were within a factor of 2
during incubations. The factors affecting nutrient diffusion across sediment/water interface include bioturbation, nitrification,
denitrification, adsorption, and dissolution. The regeneration of nutrients from sediments will increase nutrient loads of
the Bohai Sea and affect nutrient atomic ratios in this region. Among nutrient sources from riverine input, atmospheric deposition
and sediment regeneration, ammonium and phosphate mainly came from atmospheric deposition (>50%); nitrate was mainly transported
by riverine input into the Sea, silicate from sediment regeneration accounts up to 60%. This demonstrates that nutrient regeneration
in sediments contributes more silicate than riverine input and atmospheric deposition together, but benthic flux contributes
very much less phosphate and nitrate relative to riverine input and atmospheric deposition. The benthic fluxes of nutrients
may lead to a decrease of the amount of nitrate, an increase of phosphate, ammonia and silicate in the water column. The release
of silicate from sediments may compensate the decrease of silicate due to the reduction of riverine discharge. Nutrient regeneration
in sediment may have an important influence on the eutrophic character of coastal waters in this region.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
南海北部和中部硅藻通量季节性变化及其对季风气候的响应 总被引：2，自引：2，他引：0
通过对南海北部和中部两套时间序列沉积物捕获器中的颗粒物样品进行硅藻分析,揭示了南海北部和中部硅藻通量的季节变化规律及其区域差异和各自对东亚季风气候的响应.研究表明在南海北部和中部海域,硅藻通量可以在一定程度上指示海洋初级生产力水平,其中南海北部硅藻通量明显低于中部,这可能与北部颗粒物样品采集期间发生的E1 Ni(n)o... 相似文献
20.
Frank A. Whitney 《Journal of Oceanography》2011,67(4):481-492
Data collected primarily from commercial ships between 1987 and 2010 are used to provide details of seasonal, interannual
and bidecadal variability in nutrient supply and removal in the surface ocean mixed layer across the subarctic Pacific. Linear
trend analyses are used to look for impacts of climate change in oceanic domains (geographic regions) representing the entire
subarctic ocean. Trends are mixed and weak (generally not significant) in both winter and summer despite evidence that the
upper ocean is becoming more stratified. Overall, these data suggest little change in the winter resupply of the mixed layer
with nutrients over the past 23 years. The few significant trends indicate a winter increase in nitrate (~0.16 μM year−1) in the Bering Sea and in waters off the British Columbia coast, and a decline in summer phosphate (0.018 μM year−1) in the Bering. An oscillation in Bering winter nutrient maxima matches the lunar nodal cycle (18.6 years) suggesting variability
in tidal mixing intensity in the Aleutian Islands affects nutrient transport. Nitrate removal from the seasonal mixed layer
varies between 6 μM along the subarctic–subtropical boundary and 18 μM off the north coast of Japan, with April to September
new production rates in the subarctic Pacific being estimated at 2 and 6 moles C m−2. Changes in nutrient removal in the Bering and western subarctic Pacific (WSP) suggest either the summer mixed layer is thinning
with little change in new production or new production is increasing which would require an increase in iron transport to
these high-nutrient low-chlorophyll (HNLC) waters. Si/N and N/P removal ratios of 2.1 and 19.7 are sufficient to push waters
into Si then N limitation with sufficient iron supply. Because ~3 μM winter nitrate is transferred to reduced N pools in summer,
new production calculated from seasonal nutrient drawdown should not be directly equated to export production. 相似文献