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1.
ABSTRACT Dissolved nutrient uptake and metabolism by periphyton in a central North Island gravel-bed river were investigated using recirculating in-situ chambers. Dissolved inorganic nitrogen (DIN) uptake was correlated with photosynthesis and chlorophyll but N uptake and carbon fixation were partly de-coupled indicating storage. Dissolved reactive phosphorus (DRP) uptake was only weakly correlated with photosynthesis. Diatoms and green algae relied on DRP in the water, but Cyanobacteria met part of their P needs from storage. Dissolved organic nutrients were excreted in both light and dark incubations, with approximately 50% of DIN uptake during photosynthesis excreted as DON. To simulate diurnal variations in nutrients, oxygen and pH existing computer models need to de-couple photosynthesis from nutrient uptake, allow for variable stoichiometry and better quantify recycling of organic nutrients. 相似文献
2.
Edward A. Drew John F. Ireland Colin Muir William A. A. Robertson John D. Robinson 《Marine Ecology》1982,3(4):335-355
Abstract. The population of Laminaria ochroleuca in the current swept Straits of Messina was investigated regarding its age structure and photosynthesis. Age structure appears to be determined by sporadic recruitment and the limitation of growth due to peak currents decapitating older plants, which is corroborated by drag force resistance calculations. The calculation of a carbon budget from measurements of photosynthesis and dark respiration both in the laboratory and in situ shows that L. ochroleuca cannot satisfy its carbon demands for growth and respiration at 50 m depth and no satisfactory explanation can be given for its rapid growth between 50 and 100 m. 相似文献
3.
Physiology of Laminaria 总被引：1，自引：0，他引：1
Abstract. Sporophytes of Laminaria digitata and L. saccharina were collected from the shore at different times of year. Intact sporophytes of both species, and discs cut from L. digitata lamina tissue were maintained for several weeks in laboratory cultures under various nitrate, phosphate, temperature and daylength regimes. Substrate-saturated uptake rates of approximately 24 μgN g dry weight-1 h-1 from 20 μM nitrate and 8 μgP g dry weight-1 h-1 from 10 μM phosphate were more than sufficient to account for internal nitrogen and phosphorus accumulation. Other nitrogen sources - nitrite, ammonium and urea - were also taken up, independently of each other, and supported growth. During the late spring decline of ambient nutrient levels, when growth rates on the shore also decline markedly, enrichment with nitrate (15 μM) and phosphate (3μ) together prevented this decline and also maintained peak photosynthetic rates (net photosynthesis = 10.4 μlO2 cm-2 h-1) which otherwise dropped to 4.5 μO2 cm-2 h-1 over 47 days at ambient nutrient levels (0.5 μM nitrate and phosphate). Slow summer growth rates in June/July were enhanced to greater than spring peak values by combined nitrate (7.5 μM) and phosphate (1.8 μM) enrichment; neither was sufficient alone, although the individual nutrients were accumulated internally. A lesser, but significant enhancement was also achieved in September. In midwinter, nutrient enhancement itself (10.5 μM nitrate and 3.0 μM phosphate) had a small effect on growth rates only if summer water temperature (15°C) was used, but the dramatic effect of an increased photoperiod (7.5 to 17.5 h) was in excess of that expected for the increased radiant energy available. This was found to be due, at least in L. digitaia discs, to the re-establishment of a surface meristoderm in the dormant winter tissue; this was particularly active with high phosphate supply. Growth of the new lamina in January on the shore was much reduced if the old lamina was removed, although the time of initiation of new growth remained unchanged. In the laboratory, the old lamina was found to be a source of nitrogen for new lamina but not of fixed carbon or phosphorus. New lamina photosynthesis, manifest as mannitol accumulation, was directly proportional to phosphate supply up to at least 7.5 μM phosphate. Mannitol accumulation was then suppressed by a nitrate supply above 12 um, presumably by diversion of fixed carbon to other biosynthetic pathways. 相似文献
4.
Temperature and light tolerance of representative brown, green and red algae in tumble culture revealed by chlorophyll fluorescence measurements 总被引：2，自引：0，他引：2
Laminaria japonica, Undaria pinnatifida, Ulva lactuca, Grateloupia turuturu and Palmaria palmata are suitable species that fit the requirements of a seaweed-animal integrated aquaculture system in terms of their viable biomass, rapid growth and promising nutrient uptake rates. In this investigation, the responses of the optimal chlorophyll fluorescence yield of the five algal species in tumble culture were assessed at a temperature range of 10 - 30℃. The results revealed that Ulva lactuca was the most resistant species to high temperature, withstanding 30℃ for 4 h without apparent decline in the optimal chlorophyll fluorescence yield . While the arctic alga Palmaria palmata was the most vulnerable one, showing significant decline in the optimal chlorophyll fluorescence yield at 25℃ for 2 h. The cold-water species Laminaria japonica, however, demonstrated strong ability to cope with higher temperature （24 -26℃ ） for shorter time （within 24 h） without significant decline in the optimal chlorophyll fluorescence yield . Grateloupia turuturu showed a general decrease in the optimal chlorophyll fluorescence yield with the rising temperature from 23 to 30℃ , similar to the temperate kelp Undaria pinnatifida. Changes of chlorophyll fluorescence yields of these algae were characterized differently indicating the existence of species-unique strategy to cope with high light. Measurements of the optimal chlorophyll fluorescence yield after short exposure to direct solar irradiance revealed how long these exposures could be without significant photoinhibition or with promising recovery in photosynthetic activities. Seasonal pattern of alternation of algal species in tank culture in the Northern Hemisphere at the latitude of 36°N was proposed according to these basic measurements. 相似文献
5.
In order to investigate the mechanism of eutrophication in Atsumi Bay which is a shallow and partially mixed estuary, distributions of temperature, salinity and concentrations of nitrogen and phosphorus in all their chemical forms were observed once a month throughout a year. Supplies of freshwater and nutrients are estimated and balances of salt and nutrients are examined using a modified box model. The deduced estuarine hydrography and calculated values of photosynthesis, decomposition, deposition and sedimentation are compared with those obtained byin situ observations and laboratory experiments. It is found that the factors responsible for the appearance of heavy eutrophication include not only the general increase of nutrient supply from land but also nutrient accumulation in the rainy season just before summer, the N/P ratio of the supply from land being favourable for uptake by phytoplankton, formation of semi-closed circulations of the nutrients associated with stratification and vertical circulation of estuarine water, and possibly the inorganic turnover of phosphorus (PO4-P) under aerobic and anaerobic conditions. The usefulness of the modified box model for obtaining a synoptic understanding of the estuarine system is also demonstrated. 相似文献
6.
7.
F.T. Short M.W. Davis R.A. Gibson C.F. Zimmermann 《Estuarine, Coastal and Shelf Science》1985,20(4):419-430
The seagrass Syringodium filiforme was examined in an ecological analysis of plant nutrient requirements and nutrient resource availability. Assessment of the sediment geochemistry in a San Salvador Island seagrass bed indicated that phosphorus was not readily accessible to the plants. Ammonium regeneration in the fine-grained carbonate sediments was high, and interstitial concentrations averaged ca. 100 μM while phosphate replenishment to interstitial water was low, and concentrations were generally less than 2 μM. Analysis of the seagrass leaf tissue content (C : N : P = 1390 : 47 : 1, atomic wt) suggested that nitrogen and phosphorus were both depleted relative to carbon. However, this high N : P for S. filiforme and the low concentration of phosphate available in the interstitial water established the likelihood that plant acquisition of phosphorus was limited. The finding of high root biomass relative to leaf biomass in these seagrass beds corroborates this evidence by depicting a method of plant adaptation that increases nutrient absorptive root surface area. 相似文献
8.
KANG Yanyu LIANG Junrong GAO Yahui LIN Rongcheng GAO Hu XING Xiaoli MA Jie LUO Qiaoqi 《海洋学报(英文版)》2007,26(5):107-115
The growth and interspecies competition of two red tide algal species Thalassiosira pseudonana Hasle et Heimdal and Gymnodinium sp.were studied under different concentration ratios of nitrogen to phosphorus,and the algal batch culture experiments were conducted.The physiological and biochemical indexes were measured periodically,including the maximum comparing growth rate,relative growth rate,average double time and chlorophyll a concentration.The results showed that when the concentration ratio of nitrogen to phosphorus was 16:1,the maximum comparing growth rate,relative growth rate and chlorophyll a concentration of Thalassiosira pseudonana all reached the highest,and average double time was the shortest.This implied that the optimal concentration ratio of nitrogen to phosphorus of Thalassiosira pseudonana is 16:1.When the concentration ratio of nitrogen to phosphorus was 6:1,the maximum comparing growth rate,relative growth rate and the chlorophyll a concentration of Gymnodinium sp.reached the highest,and average double time was the shortest,so the optimal concentration ratio of nitrogen to phosphorus of Gymnodinium sp.is 6:1.From the growth curves as indicated both in the cell density and the chlorophyll a concentration,it is suggested that the influence of concentration ratio of nitrogen to phosphorus on the chlorophyll a concentration and the cell density are almost the same.Different concentration ratios of nitrogen to phosphorus had weak influence on community succession and the competition between the two algae.Gymnodinium sp.may use the phosphorus in vivo for growth,so it is important to pay attention to the concealment of phosphorus,in order to avoid the outbreak of red tide.On the basis of the importance of nitrogen and phosphorus and the ratio of their concentration,the possible outbreak mechanism of red tide of the two algae was also discussed. 相似文献
9.
根据现场调查和室内试验工作, 计算珠江口水域浮游植物有效光合作用水体体积, 同时研究浮游动物摄食行为对磷再生的补偿作用, 进而对该水域磷的生物利用状况进行初步评估。分析珠江口2002—2003年的数据发现, 珠江口水域浮游植物有效进行光合作用水体的体积存在季节性变化, 枯水期约为9.7×104m3, 而丰水期约为6.6×104m3。该水域总初级生产量在枯水期约为36kg.d-1, 在丰水期约为31kg.d-1, 呈现枯水期大于丰水期的特点。浮游动物的摄食作用可促进水体中磷的再生, 这部分磷可满足浮游植物生长对磷需求的1.5%—15.6%, 并呈现丰水期大于枯水期的特点。浮游动物摄食作用直接释放的量远大于其自身生理周转释放的量。 相似文献
10.
《Oceanologica Acta》1998,21(6):923-935
As part of the Programme National d'Océanographie Côtière, the nutrient dynamics of the Bay of Seine were studied between 1992 and 1994 in order to complement work on ecological modelling. Firstly, the River Seine's nutrient fluxes were established: 80 000–130 000 t a−1 of dissolved inorganic nitrogen, 6 400–8 4001 a−1 of dissolved phosphorus and 20 000–77 000 t a−1 of dissolved silicium. Estuarine processes were taken into account. Consequences of nutrient loading for the bay were then evaluated at the pelagic level (nutrient and chlorophyll enrichments) and the benthic level (distribution of various phosphorus fractions in superficial sediments). The large continental inputs always induce concentration gradients in the water from the mouth of the river to the northwest of the bay. The northward spreading of fine particulate matter controls the distribution of adsorbed phosphate and iron-aluminium bound phosphate in sediments. In contrast, calcium bound phosphate, the main fraction in sediments, is not affected by river inputs. Organic phosphorus in sediments is related to phytoplankton blooms, with increasing concentrations during productive periods; afterwards the fast recycling prevents sedimentary accumulation. The nutrient depletions observed beyond the turbid plume during spring 1992 enabled the calculation of nutrient uptake rates, and the comparison of these rates with phytoplankton biomass (chlorophyll a + phaeopigments). Ratios of nutrient consumption to pigment concentration were estimated at 1 μmol μg−1 for nitrogen, 0.05 for phosphorus and 0.5 for silicate. These values, as N/P and Si/N uptake ratios (respectively 17.5 and 0.4), were similar to usual values. 相似文献
11.
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
12.
三十烷醇对海带叶绿体超微结构的效应 总被引：6，自引：0，他引：6
本文将经不同浓度三十烷醇处理的海带进行电镜切片观察,结果表明经三十烷醇处理后的海带,其叶绿体形态发生显著改变。与对照组相比,叶绿体中的类囊体片层增多,基质浓厚,其外形更为饱满,光合作用的强弱与类囊体片层的多少关系密切。文中从细胞学的水平上分析了三十烷醇促进海带增产的内在原因。 相似文献
13.
Joji Ishizaka 《Journal of Oceanography》1991,47(5):226-239
I reviewed my research on analysis of temporal and spatial variability of phytoplankton by physical-biological models. This paper was prepared for a lecture of the member awarded the Okada Prize for 1991 from the Oceanographical Society of Japan.Temporal change of phytoplankton in a local upwelling was studied by simulated upwelling experiments conducted with natural phytoplankton communities under natural surface light conditions. Results of the culture experiments was explained by a simple model. This model allows to predict the chlorophyll and nutrient concentration changes in a given upwelled water mass.Above model was verified by a local upwelling observed off Izu, Japan, on May, 1982. Phytoplankton growth and nutrient decrease in surface water of the local upwelling were observed within two days followed by decrease of phytoplankton concentration under depleted nutrient environment. The phytoplankton growth and nutrient decrease could explained by the model with phytoplankton removal rate of about half of the growth rate. Centric diatom was the dominant phytoplankton group and pennate diatom showed less abundance in the upwelled water. Pennate diatom showed fast growth rate when nutrient was abundant and fast decreasing rate after nutrient depleted. On the other hand, flagellate and monads showed relatively slow change of biomass under the change of nutrient concentrations. Furthermore, resting spore formation of centric diatom,Leptocylindrus danicus, was observed in a response to nutrient depletion.Temporal and spatial variability of phytoplankton in the southeastern U.S. continental shelf ecosystem was studied by physical-biological models. First, differences of the biological responses to frontal eddy upwelling during spring and to intrusion during summer was considered by Lagrangian particle tracing experiments with optimally-interpolated flow fields. In spring, particles showed residence time of a few days; however, particles in summer intrusion stayed on the shelf nearly 30 days. It was concluded that difference of particle residence time of upwelled water make the difference of plankton communities. Similar flow fields and particle tracing experiments were used to trace the features in chlorophyll distributions during spring of 1980 derived by Coastal Zone Color Scanner (CZCS). Phytoplankton patchness were created and deformed by frontal eddy events. Eularian physical-biological model was constructed to understand the CZCS-chlorophyll distributions. Statistical comparisons with series of numerical experiments indicate that horizontal advection is an important process for the chlorophyll distributions and that upwelling and associated phytoplankton growth are responsible for the across-shelf gradients and maintenance of concentrations. Furthermore, the CZCS data were assimilated to the model to improve the phytoplankton concentrations, and phytoplankton carbon flux across shelf was estimated. Processes causing the time changes of chlorophyll concentrations were estimated with the model and satellite data further indicated that the both physical and biological forcing is important for the time chages. Several other studies conducted presently were mentioned. 相似文献
14.
Batch cultures of water and algae from Lake Rotorua were subjected to nitrogen, phosphorus, and trace element additions, singly and in combination, at monthly intervals between June 1975 and May 1976. The algal responses to the additions were assayed after 5 d incubation, by extracting the chlorophyll from the algae and estimating the concentration by fluorescence. The chlorophyll production consistently responded positively to the addition of nitrogen, while responses to the addition of phosphorus and trace elements were minor by comparison. Although the chlorophyll responses to nitrogen may not have been paralleled by actual growth, the consistent pattern of behaviour by algae in the batch cultures was interpreted as evidence of persistent shortage of nitrogen in the Lake Rotorua environment. 相似文献
15.
Primary production rates, chlorophyll a and nutrient concentrations, particulate carbon, nitrogen and phosphorus concentrations, Secchi depths and submarine light levels were measured at stations within, and near, the zone of mixing of the Sand Island and Mokapu Point ocean sewage outfalls near the island of Oahu in the Hawaiian Islands. Multiyear averages of several parameters indicated that the Sand Island outfall had no adverse impact on phytoplankton communities or water quality. The major effect of the Mokapu Point outfall was a reduction in photosynthetic rates, probably due to the rapid uptake of nutrients introduced into the mixed layer with the secondarily treated sewage. The Sand Island outfall, which discharged coarsely screened raw sewage within the thermocline, had less of an impact because the inorganic nutrient concentrations in the sewage were lower and because the sewage rarely rose into the mixed layer. The results indicate that, under appropriate conditions, ocean outfalls may be preferable to estuarine or freshwater outfalls and that secondary treatment is not always necessary to reduce the impacts of ocean outfalls to an acceptable level. 相似文献
16.
印度洋海水营养盐添加模拟实验中浮游植物生长的营养盐限制作用 总被引：1，自引：0，他引：1
借助"中国首次环球科学考察航次",在印度洋海区进行了N、Fe、N+Fe以及N+Fe+P的营养盐添加模拟实验。通过对实验过程中水体营养盐浓度、叶绿素a(Chl-a)浓度以及温度等参数进行分析,探讨了添加不同营养盐对该实验海区浮游植物生长的影响。结果表明,N的添加会引起浮游植物的快速爆发,而单独添加Fe并不能刺激浮游植物快速生长,N、P联合作用对浮游植物生长的影响远远大于单独N的作用。另外,在实验海区浮游植物优先利用海水中的硝酸盐,在硝酸根耗尽后,海水中可被利用的P会促进浮游植物的生长。实验过程中水体N/P比值的变化同叶绿素a浓度以及浮游植物生长速度(R)没有可对比性,而且N/P比值与后两者之间的相关性都差,所以认为水体中N/P比值并不能单独决定浮游植物生长。此外,实验水体温度同Chl-a浓度和R值之间相关性分析表明,水体温度虽对浮游植物生长有重要作用,但不能控制浮游植物生长。 相似文献
17.
Nutrient composition and distributions in coastal waters impacted by the Changjiang plume 总被引：1，自引：1，他引：0
WANG Xiulin WANG Baodong ZHANG Chuansong SHI Xiaoyong ZHU Chenjian XIE Linping HAN Xiurong XIN Yu WANG Jiangtao 《海洋学报(英文版)》2008,27(5):111-125
Four cruises were conducted during 2002--2003 in the Changjiang Estuary and adjacent coastal areas. The data presented show a clear coast to open sea gradient in nutrients related to the river inputs. Maximum values of chlorophyll a were typically observed at intermediate salinities at surface water and coincided with non-conservative decreases in nutrients along the salinity gradient, indicating that removal of nutrients was related to phytoplankton uptake. The seasonal variations of nutrient concentrations were just opposite to those of chlorophyll a, indicating that the seasonal variations of nutrients were mainly controlled by phytoplankton uptake, whereas riverine inputs merely weakened or balanced its extent. During the estuarine mixing, phosphate demonstrated some remobilization during all the four cruises; whereas both conservative and non-conservative behaviors for dissolved inorganic nitrogen and silicate were observed in the study area, indicating that both biotic and abiotic events may affect their behaviors during the estuarine mixing. Under the influence of freshwater inputs with high value of ratio of nitrogen to phosphorus, the estuarine and coastal waters impacted by the Changjiang plume were high （ 〉 30） in ratio of nitrogen to phosphorus, but rates of primary production were apparently not constrained by any kind of nutrient elements. However, the low （ 〈 1 ） ratio of silicate to nitrogen in most of the study area might be linked with the rapidly increasing frequency of harmful algal bloom （HAB） incidents in recent years in the coastal waters impacted by the Changjiang plume. 相似文献
18.
We studied the hypersaline stress responses of the Mediterranean seagrass Posidonia oceanica to determine if the species was tolerant to salinity increases that occur in coastal waters by the desalination industry. Water relations, amino acids, carbohydrates, ions, photosynthesis, respiration, chlorophyll a fluorescence, leaf growth and morphology, and plant mortality were analysed after exposing the mesocosm P. oceanica to a salinity level of 43 for one and three months followed by a month for recovery. One-month saline-stressed plants exhibited sub-lethal effects, including a leaf cell turgor pressure reduction, loss of ionic equilibrium and decreased leaf growth. There were also changes in photoprotective mechanisms, increased concentrations of organic osmolytes in leaves and reduced leaf ageing. All these dysfunctions recovered after removing the stress. After the longer exposure of three months, stress symptoms were much more acute and plants showed an excessive ionic exclusion capacity, increased leaf cell turgor, reduced plant carbon balance, increased leaf aging and leaf decay and increased plant mortality, which indicated that the plant had entered a stage of severe physiological stress. In addition, the long-term saline-stressed plants were not able to recover, still showing sustained injury after the one-month recovery period as reflected by unbalanced leaf ionic content, persistently impaired photosynthesis, decline in internal carbon resources and decreased leaf growth that resulted in undersized plants. In conclusion, P. oceanica was not able to acclimate to the saline conditions tested since it could not reach a new physiological equilibrium or recover after a chronic exposure of 3 months. 相似文献
19.
营养盐因子对龙须菜和菊花江蓠氮磷吸收速率的影响 总被引：17，自引：0，他引：17
本文在实验室条件下,研究了营养盐因子对龙须菜和菊花江蓠N、P吸收速率的 影响,分别对不同氮和磷的浓度、氮磷比及不同化合态氮对这两种藻类氮、磷吸收速 率的影响进行了实验与分析．结果表明:在适宜范围内,两种海藻对氮、磷的吸收速率 随介质中氮、磷浓度的增加而增加;不同氮磷对两种海藻N吸收速率的影响不存在 显著差异,但对磷吸收速率的影响非常显著,最高对磷吸收速率在介质的氮磷比为 10:1时;海藻对NH4-N的吸收速率随着NO3-N／NH4-N比的降低而增加,对PO43-P的 吸收速率与对NH4-N的吸收相似,而对NO3-N的吸收速率与对NH4-N的吸收相反． 相似文献
20.
养殖海带的生长模型研究 总被引：1，自引：0，他引：1
国内外关于海带生长和光合作用与其生长环境因素的关系研究开展的较多,但缺乏有效的模型来预测评估环境条件变化对海带生长和产量的影响.因此,根据海带生理生态学实验数据、现场观测的光照强度、温度和营养盐等影响海带生长与光合作用的环境参数和海带生长测定数据,运用动态模拟手段,建立了一个数学模型,并利用视窗化模型软件Stella9.0TM构建和运行了上述模型,用来模拟和预测海带(Laminaria japonica)的生长过程.同时,对模拟值和实测值进行了相关性分析及其检验,结果表明,该模型较好地模拟了生长海带的长度和干重,可以为相关研究和管理提供服务. 相似文献