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1.
Laboratory experiments of bioassay with Pltaeodaetytum tricornutum, Chatoceros didymus, Chaetoreros calcitraus and Heterogtoea sp. sampled from the Changjiang Estuary in spring and summer, 1986, indicated that both N and P limit phytoplankton growth in the medium with N : P ranged between 8-30, and N limits phytoplankton production in the medium with N: P<8, while P is the limitary nutrient in the N : P>30. Generally, N : P in the Changjiang Estuary waters is 2 times higher than Redfield ratio. The bioassay experiments with high N : P water samples collected from Changjiang Estuary show that phytoplankton production is limited by P. Phytopiankton appears to give priority to the uptake of P at all periods of time. And the optimum N:P for phytoplankton growth is determined to be 18. 相似文献
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Zhang Shuijin 《海洋学报(英文版)》1995,14(1):73-83
ＥｃｏｌｏｇｉｃａｌｆｅａｔｕｒｅｓｏｆｐｈｙｔｏｐｌａｎｋｔｏｎｉｎｒｅｄｔｉｄｅｏｕｔｂｕｒｓｔａｒｅａｉｎｔｈｅＸｉａｍｅｎＨａｒｂｏｒ￥ＺｈａｎｇＳｈｕｉｊｉｎ（ＲｅｃｅｉｖｅｄＪｕｎｅ２０，１９９４；ａｃｃｅｐｔｅｄＳｅｐｔｅｍｂｅｒ２，１... 相似文献
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During June 1997 cruise by R/V Science No.l, observations on temporal and spatialvariations of the size-fractionated phytoplankton standing stock and primary production were carried out in the Bohai Sea. The size-fractionated chlorophyll a (Chl a) and primary production, photosynthet-ically available radiation (PAR), as well as the related physico-oceanographic and zooplanktonic parameters were measured at five time-series observation stations representing sub-areas of the sea. Results obtained show that there were the marked features of spatial zonation of Chl a and primary production in the Bohai Sea. The values in the Laizhou Bay, the Liaodong Gulf and the Bohai Gulf were high and showed close relation with tidal fluctuations, i.e. high Chl a concentration occurred during high tide in the Laizhou Bay, and during low tide in the Liaodong Gulf and the Bohai Gulf. In the strait and the central region of the Bohai Sea, the values were relatively low and no relationship with tidal fluctuation could be foun 相似文献
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Vivienne Cassie 《新西兰海洋与淡水研究杂志》2013,47(2):153-166
In a 1973–74 survey of preserved phytoplankton from Lakes Rotoiti, Rotoehu, Rotoma and Waikaremoana, 205 algal taxa (including 111 Chlorophyta, 56 Chrysophyta, 17 Cyanophyta, 16 Pyrrhophyta, and 5 Euglenophyta) were found. The greatest number of species was found in Lake Rotoehu, but monthly maxima based on cell counts were usually greater in Lake Rotoiti. A summer bloom of the toxic blue‐green alga Aphanizomenon flos‐aquae occurred in Lake Rotoehu. Each lake had its own pattern of dominance. Surface and subsurface samples showed marked differences in species composition and abundance. Diatoms were important winter and spring components, with desmids forming conspicuous subordinates. Cemtium hirundinella was prominent in subsurface layers of Lakes Rotoma and Waikaremoana. Compound indices (ratios of number of species of most other algae to that of desmids) point to Lake Rotoehu as extremely eutrophic, to Lake Rotoma as moderately eutrophic, and to Lakes Rotoiti and Waikaremoana as oligotrophic rather than meso‐ or eutrophic. 相似文献
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There is a low nutrient level in the Aoshan Bay. In June 1999, the chemical adjustmentand control experiment was made in the Aoshan Bay. Following tracts investigation was carried out before the experiment and on the 1st, 2nd, 4th, 5th, 6th and 45th day/after the experiment. While the variance of amount of phytoplankton, the replacement of superior species and the species composition of phytoplankton were researched. The results show that the amount of phytoplankton in the Aoshan Bay rises gradually after the experiment. Ceratium macroceros Cleve of pyrophyta was the dominant species before the experiment, its dominant index was 37.7％. Six days after the experiment, its dominant index dropped to 17.6％ . Meanwhile the dominant index of Asterionella japanics Cleve rose from 7.1％ to 39.2％ , it became the first dominant species. Forty-five days after the experiment, the amount of phytoplankton in the Aoshan Bay was 5.15 to 137.32 times more than that in 1997. 相似文献
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The carbon cycle of lower trophic level in the Bohai Sea is studied with a three-dimensional biological and physical coupled model. The influences of the processes (including horizontal advection, river nutrient load, active transport etc. ) on the phytoplankton biomass and its evolution are estimated. The Bohai Sea is a weak sink of the CO2 in the atmosphere. During the cycle, 13.7% of the gross production of the phytoplankton enter the higher trophic level and 76.8 % of it are consumed by the respiration itself. The nutrient reproduction comes mainly from the internal biogeochemical loop and the rem-ineralization is an important mechanism of the nutrient transfer from organic form to inorganic. Horizontal advection decreases the total biomass and the eutrophication in some sea areas. Change in the nutrient load of a river can only adjust the local system near its estuary. Controlling the input of the nutrient, which limits the alga growth, can be very useful in lessening the phytoplankton biomass. 相似文献
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Preliminary study on seasonal succession and development pathway of phytoplankton community in the Bohai Sea 总被引：5，自引：3，他引：5
IThe Phytoplankton spoteS succession is a major characteristic Of PhytOPlankton behavior inthe an, and is Of major swificance tO PhytOPlankton d~cs and in coupling the PhytOPlankton cornxnunity to hasher trophic levels (Smayda, 1980). But another conception species ence that be defined by BraarUd often confUSeS with speCies sucCeSSion. Spotes su~ is thechange of speCies compeition within a given water mass resulting from changing physical,chemical and biological factors within the wa… 相似文献
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We conducted studies of phytoplankton and hydrological variables in a semi-enclosed bay in northern China to understand the spatial–temporal variability and relationship between these variables. Samples were collected during seven cruises in Jiaozhou Bay from November 2003 to October 2004, and were analyzed for temperature, nutrients and phytoplankton pigments. Pigments from eight possible phytoplankton classes (Diatoms, Dinoflagellates, Chlorophyceae, Prasinophyceae, Chrysophyceae, Haptophyceae, Cryptophyceae and Caynophyceae) were detected in surface water by high performance liquid chromatography (HPLC). Phytoplankton pigment and nutrient concentrations in Jiaozhou Bay were spatially and temporally variable, and most of them were highest in the northern and eastern parts of the sampling regions in spring (May) and summer (August), close to areas of shellfish culturing, river estuaries, dense population and high industrialization, reflecting human activities. Chlorophyll a was recorded in all samples, with an annual mean concentration of 1.892 μg L−1, and fucoxanthin was the most abundant accessory pigment, with a mean concentration of 0.791 μg L−1. The highest concentrations of chlorophyll a (15.299 μg L−1) and fucoxanthin (9.417 μg L−1) were observed in May 2004 at the station close to the Qingdao Xiaogang Ferry, indicating a spring bloom of Diatoms in this area. Although chlorophyll a and other biomarker pigments showed significant correlations, none of them showed strong correlations with temperature and nutrients, suggesting an apparent de-coupling between the pigments and these hydrological variables. The nutrient composition and phytoplankton community composition of Jiaozhou Bay have changed significantly in the past several decades, reflecting the increasing nutrient concentrations and decline of phytoplankton cell abundance. The unchanged total chlorophyll a levels indicated that smaller species have filled the niche vacated by the larger species in Jiaozhou Bay, as revealed by our biomarker pigment analysis. 相似文献
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Abstract Uptake rates of ammonium (NH4 + ), nitrate (NO3 ? ), and urea by three subgroups of phytoplankton (< 200, < 20, < 2 μm) off Westland, were measured using 15 N tracer techniques in midwinter 1988, after a recent upwelling. For all size fractions at surface irradiance (I100), nitrogen (N) was taken up primarily as NO3 ?. This accounted for 67–85% of total N uptake (SρN), whereas at 40 and 7% of surface irradiance, the regenerated N (NH4 + ) and urea) made up 31–72% of SρN. Depth profile experiments for all three size components showed that uptake of NO3 ? was most light‐sensitive, followed by that of NH4 + and urea. The irradiance and nutrient availability plot indicated that light was substantially more important than the nutrient concentrations in controlling the assimilation of N by microplankton (20–200 μm). Nano‐ (2–20 μm) and picoplankton (< 2 μm) however, were not as sensitive to either light or nutrient concentrations. High winds and the resulting deep mixing, combined with offshore and alongshore advection in the midwinter, were suggested to be the major cause of the low biomass and N productivity. 相似文献
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Vivienne Cassie 《新西兰海洋与淡水研究杂志》2013,47(1):98-123
Between, May 1966 and May 1967, 110 preserved samples of the phytoplankton of Lake Rotorua, New Zealand, were examined. Species and cell counts have been compared with data from Lakes Rotoiti (21 samples) and Ohakuri (36 net samples). Brief comparisons have also been made with the flora of two of the Wellington City reservoirs and the oxidation ponds at Mangere, Auckland. In Lake Rotorua the autumn, maximum was more pronounced than the spring maximum. Cell numbers inshore at Kawaha Point were consistently lower than those further out in the open lake. The phytoplankton is classified as a eutrophic formation of the diatom type, with Chlorophyceae as main subordinates. Dominants include Melosira granulata Ralfs (winter, spring, and autumn), Melosira distans (Ehr.) Kütz. (spring, summer, and autumn), and Asterionella formosa Hass. (summer and autumn). 相似文献
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Ｈｏｗ ｔｈｅ ｐｏｌｌｕｔｉｏｎ ｓｔｒｅｓｓ ａｃｔｉｎｇ ｏｎ ｔｈｅ ｐｈｙｔｏｐｌａｎｋｔｏｎ ｐｏｐｕｌａｔｉｏｎｓ ──ａｎ ｏｂｓｅｒｖａｔｉｏｎ ｂｙ ｔｈｅ ｅｘｐｅｒｉｍｅｎｔａｌ ｅｎｃｌｏｓｅｄ ｅｃｏｓｙｓｔｅｍＴａｎｇＳ... 相似文献
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INTRODUCTIONAsthefundamentalbasisofthewholebiogeOChemicalcyclingofcarbon,primaryproduction.TIsWOrkwassupportedbyfUndsfmtheStateEducation~ssboandFujianaudienceFOUndstion.processesswitchontheflowofmaterialsandenergyintheoceanicecosystem,supportlargeamountoffisheryproductiononwhichourhumanbeingsrelyonfacesupply.Althoughconsistingonly8%oftheglobaloceanarea,coastalregionssupply26%oftheglobaloceanicbiologicalproductsand2/3--3/4oftotalfisheryresources.Therefore,theinvestigationsonphytoplank… 相似文献
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C.S. Law M.J. SmithC.L. Stevens E.R. Abraham M.J. Ellwood P. HillS. Nodder J. Peloquin S. PickmereK. Safi C.M. Walkington 《Deep Sea Research Part II: Topical Studies in Oceanography》2011,58(6):786-799
An in situ iron addition experiment (SAGE) was carried out in high-nitrate low-chlorophyll low-silicic acid (HNLCLSi) sub-Antarctic surface waters south-east of New Zealand. In contrast to other iron addition experiments, the phytoplankton response was minor, with a doubling of biomass relative to surrounding waters, with the temporal trends in dissolved iron and macronutrients instead dominated by physical factors such as mixing and dilution. The initial increase in patch surface area indicated a lateral dilution rate of 0.125 d−1, with a second estimate from a model of the decline in peak SF6 concentration yielding a higher lateral dilution rate of 0.16-0.25 d−1. The model was tested on the SOIREE SF6 dataset and provided a lateral dilution of 0.07 d−1, consistent with previous published estimates. MODIS ocean colour images showed elevated chlorophyll coincident with the SF6 patch on day 10 and 12, and an elevated chlorophyll filament at the SAGE experiment location 3-4 days after ship departure, which provided additional lateral dilution estimates of 0.19 and 0.128 d−1. Dissolved iron at the patch centre declined by 85% within two days of the initial infusion, of which dilution accounted for 50-65%; it also decreased rapidly after the 2nd and 3rd infusions but remained elevated after the fourth infusion. Despite decreases in nitrate and silicic acid from day 7 and 10, respectively, the final nutrient concentrations in the patch exceeded the initial concentrations due to supply from lateral intrusion and mixed-layer deepening. The low Si:N loss ratio suggested that the observed limited response to iron was primarily by non-siliceous phytoplankton. Algal growth rate exceeded the minimum dilution rate during two periods (days 3-6 and 10-14), and coincided with net chlorophyll accumulation. However, as the ratio of algal growth to dilution was the lowest reported for an iron addition experiment, dilution was clearly a significant factor in the SAGE experiment recording the lowest phytoplankton response to mesoscale iron addition. 相似文献
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We analyzed oceanographic, hydrologic and atmospheric conditions in the northern Adriatic (section between the Po River delta and Rovinj) from 1990 to 2004 in which extreme phytoplankton blooms appeared. The largest blooms occurred in February, March, July and October, and were higher in surface layers and in the western, more eutrophic part of the region. They often appeared when the Istrian Coastal Countercurrent (ICCC; strong southward current indicating a “closure” of the northern Adriatic circulation system) was pronounced. They seem to be related to the intensities of surface fluxes and Po River discharge rates. The blooms can float over the northern Adriatic for a long period (up to 30 days; typical for March) and can appear simultaneously in separate circulation systems with a different species distribution. Finally, we present a hypothesis based on comparisons of geostrophic currents and fish stock that specific February northern Adriatic oceanographic conditions play the key role in the Adriatic anchovy stock. 相似文献
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Narumi K. Tsugeki Michinobu Kuwae Yukinori Tani Xinyu Guo Koji Omori Hidetaka Takeoka 《Journal of Oceanography》2017,73(3):309-320
We examined fossil pigments in a 210Pb-dated sediment core to document the temporal variations in phytoplankton biomass over the past 150 years in a semi-enclosed bay, Beppu Bay, in the western Seto Inland Sea, Japan. The flux of fossil pigments was used as an index of phytoplankton biomass, which we reconstructed after removing the effect of post-burial degradation on the concentrations of fossil pigments. The flux doubled from the 1960s to the early 1970s, decreased or remained stable in the early 1980s, and increased again from the late 1980s to the early 1990s. The first increase in phytoplankton biomass during the 1960s was likely caused by eutrophication due to an increase in terrestrial nutrient fluxes from watersheds. The decreasing phytoplankton biomass in the early 1980s was likely related to the establishment of a sewage treatment system that reduced the terrestrial nutrient fluxes to the sea. However, the terrestrial nutrient fluxes could not explain the second increase from the late 1980s to the early 1990s. Intensification of the influx of nutrients from the shelf slope to the sea was likely the cause of the second increase in phytoplankton biomass. This is supported by the inverse relationship between phytoplankton biomass and sea level at the shelf slope, the latter being an index of the intensity of the influx of oceanic nutrients from the shelf slope to the sea. The supply of oceanic nutrients may be therefore a critical factor in the determination of primary production in the western Seto Inland Sea. 相似文献
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Based on the data of the Jiaozbou Bay Ecosystem Dynamic Research,cell volume and surface area of 87 common phytoplankton species in China sea waters were calculated with assignment of the similar geometric form.The cell plasma volume,live weight,carbon mntent and nitrogen content were also calculated with the methods of Mullin et al.(1966),5trathmann(1967),Eppley et al.(1970),arid Taguchi(1976).After comparing these methods,we chose the method of Eppley et al.(1970) as the best method for calculating phytoplankton carbon content in China sea waters. 相似文献
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Lin Lu Tao Jiang Yong Xu Yaoyang Zheng Bijuan Chen Zhengguo Cui Keming Qu 《Journal of Oceanography》2018,74(4):381-392
Phytoplankton is a key component in the functioning of marine ecosystems, phytoplankton community structures are very sensitive to their environment. This study was conducted in the central Bohai Sea in the spring and early summer of 2015. Spatial variations in phytoplankton functional groups were examined through high-performance liquid chromatography pigment–CHEMTAX analysis. Results suggested that the phytoplankton biomass (chlorophyll a [Chl a]) in spring was mainly derived from the diatom community and was 3.5-fold higher than that in the summer. Meanwhile, the phytoplankton in the early summer sustained more diverse marker pigments than that in the spring. Despite the overwhelming predominance of microsized phytoplankton in the spring, some smaller phytoplankton (pico- or nanosized), including flagellates, such as prasinophytes, chlorophytes, and cryptophytes, highly contributed to the total Chl a in the summer. Various physico-chemical variables were recorded, and their correlations with phytoplankton density were established by redundancy analysis. Temperature, water stratification, nutrient availability, and even nutritive proportion influenced the succession of phytoplankton functional groups from diatom dominance in the spring to flagellate (mainly haptophytes and prasinophytes) dominance in the early summer. In conclusion, our work comprehensively evaluated the phytoplankton diversity and dynamics in the central Bohai Sea and suggests the need for long-term monitoring for further investigation. 相似文献