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1.
海藻营养代谢研究进展——海藻营养代谢的调节 总被引：3，自引：1，他引：3
介绍影响海藻 (尤其是大型海藻 )主要营养盐 ( N,P,C)吸收的环境因子 (如光照、温度及水流 )对营养盐主动吸收过程中的能量提供 ,酶含量和活性的影响以及水流对藻体周围营养盐离子进入细胞的调节 ;化学因素 (营养盐离子或分子的浓度、形式、海水介质的 p H)对海藻选择吸收不同形式营养盐离子及其相互作用的调节过程 ;生物因素 (藻体形态、组织的类型及海藻的年龄和营养史 )通过细胞内不同水平营养库的积累和相互转变而对海藻营养吸收和同化的调节 ;N代谢与 C代谢的生化偶连关系。 相似文献
2.
海洋藻类是海洋中的初级生产者,在其生长发育过程中体内各种各样的酶不断地催化着无数的生化反应,完成其新陈代谢过程,而决定这些酶促反应强弱的酶活性的高低会直接或间接地受到外界环境条件的影响.简要概述了物理因素(如光照、温度及水流)、化学因素(营养盐离子或分子的浓度、形式、海水介质的pH)、生物因素(藻体形态、组织的类型及海藻的年龄)对海洋藻类酶含量和活性的影响及其应用前景. 相似文献
3.
海洋藻类是海洋中的初级生产者,在其生长发育过程中体内各种各样的酶不断地催化着无数的生化反应,完成其新陈代谢过程,而决定这些酶促反应强弱的酶活性的高低会直接或间接地受到外界环境条件的影响.简要概述了物理因素(如光照、温度及水流)、化学因素(营养盐离子或分子的浓度、形式、海水介质的pH)、生物因素(藻体形态、组织的类型及海藻的年龄)对海洋藻类酶含量和活性的影响及其应用前景. 相似文献
4.
陆源排污对邻近海域底栖海藻群落的影响 总被引：1，自引：0，他引：1
伴随着经济的发展，我国沿海海域富营养化日趋严重。为了明确富营养化对底栖海藻群落的影响及作用机制，本文选择了与大连凌水河口(污水河)毗邻的海藻床作为野外观测点，研究底栖海藻群落对营养盐自然衰减梯度的响应规律；在实验室内，选择了在排污口附近优势分布、营r-生态策略的绿藻缘管浒苔和仅在寡营养区域分布、营k-生态策略的红藻柔质仙菜作为实验材料，开展了营养吸收动力学和生长动力学研究。通过二者在营养盐吸收、利用和繁殖策略方面的比较研究，剖析了底栖海藻群落对不同营养环境的响应机制。结果显示:随着海水中营养盐浓度的降低，底栖海藻群落呈现种类数增加、优势种覆盖度降低的趋势。根据底栖海藻在群落水平对氮源营养的响应，认为现行海水水质标准中无机氮一类水质标准的限值应该由目前的14.29 μmol/L降低为6.69 μmol/L。在富营养环境中，营养盐浓度的上升促进了r-策略海藻幼体的竞争力和种群繁殖力，使其占据了大量的生态位，形成优势种群，导致底栖海藻多样性较低；在寡营养环境中，由于得不到充足的营养盐供应，r-策略海藻幼体的竞争力和种群繁殖力都受到制约，占据的空间生态位有限，为其他种类的生存提供了条件，而那些对营养盐需求较低但利用效率高的k-策略海藻则表现出更强的竞争力，在竞争中取得优势，能快速突破早期环境筛的限制，形成成体，因此，在寡营养海域，底栖海藻的多样性比较丰富。 相似文献
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采用实验室生态学研究方法,进行了藻体部位、藻质量、碳源质量浓度及水流流速对铁钉菜(Ishige foliaceaokamurai)和羊栖菜(Sargassum fusiforme)氮磷营养盐吸收影响的研究。结果表明:2种大型海藻不同部位对营养盐的吸收速率不同,铁钉菜下部的吸收速率最大,其次是固着器;羊栖菜顶部的吸收速率最大,其次是中部。铁钉菜藻质量1.0g的吸收速率最大,其次是1.5g;羊栖菜藻质量0.5 g的吸收速率最大,其次是1.0g;2种藻类2.0g和2.5g的吸收速率相差不多。碳源质量浓度为1200mg/L时,铁钉菜的吸收速率最大,其次是碳源800mg/L;碳源质量浓度为800mg/L时,羊栖菜的吸收速率最大,其次是碳源400mg/L;2种海藻对照组的吸收速率均相对较低。相同流速下,2种海藻均以PO4-P对照组的吸收速率最大;NO3-N、NH4-N吸收速率在流速为50cm/s时最大。 相似文献
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光照和营养盐胁迫对龙须菜生长及生化组成的影响 总被引：9，自引：0，他引：9
以龙须菜(Gracilaria lemaneiformis)为实验材料,分别研究了光照强度、营养盐胁迫对其生长及生化组成的影响。结果表明,在800～3000lx的范围内随光强的升高,龙须菜生长率增加,但藻红素(PE)、叶绿素a、蛋白质和可溶性总糖含量却降低,即低光强更利于龙须菜生化组分的积累。饥饿处理组、饱和处理组及正常对照组的生长率分别为0.9%,5.01%,3.06%。饥饿处理组的总C含量最高,总N及C/N比值高(>15),饱和处理组则相反,C/N比值<10,即存在C高N低、N高C低的现象。表明水体营养状况对龙须菜生长、体内生化组分有显著影响。总C、总N及C/N比都能很好地反映藻体的营养状态。饱和处理组藻体呈现深红色,饥饿处理组藻体色泽为浅黄色,因此也可根据藻体色泽的变化来估计藻体的营养状态。 相似文献
8.
4种大型海藻单养和两两混养条件下生长以及营养盐的吸收利用 总被引：2，自引：0，他引：2
《海洋湖沼通报》2017,(2)
近年来海水富营养化导致近海海域大型海藻过量繁殖,为研究大型海藻与营养盐的相互关系,我们采用实验生态学的方法研究了4种大型海藻(孔石莼、小珊瑚藻、缘管浒苔、石花菜)单养和两两混养条件下的生长、营养盐(PO4-P和NO3-N)含量变化以及营养盐吸收利用情况。结果表明,单养条件下,孔石莼的湿重增长最多(46.4%),其相对增长率显著高于缘管浒苔、小珊瑚藻、石花菜。孔石莼+缘管浒苔、孔石莼+小珊瑚藻、孔石莼+石花菜混养体系中,孔石莼的相对增长率显著高于缘管浒苔、小珊瑚藻、石花菜,其他混养体系中两种大型海藻的相对增长率无显著差异。在单养条件下培养10d,海藻对PO4-P、NO3-N的利用率分别以孔石莼(85.4%)、缘管浒苔(72.6%)为最大,而石花菜对两种营养盐的利用率均最小(51.1%和57.1%)。在混养条件下,PO4-P、NO3-N的最高利用率分别出现在孔石莼+小珊瑚藻(86.3%)和缘管浒苔+小珊瑚藻(81.7%)体系中。无论单养还是混养,海藻对PO4-P和NO3-N的吸收速率都在第2d达到峰值。因此,大型海藻可以有效地去除营养盐,4种藻中,孔石莼和缘管浒苔分别是去除PO4-P和NO3-N的最佳大型海藻。本研究结果可以为利用大型海藻进行环境污染的治理提供支持。 相似文献
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不同配比饲料对刺参C、N、P营养盐收支的影响 总被引：1，自引：0，他引：1
本实验采用5种含有不同比例(即20∶80、40∶60、60∶40、80∶20和100∶0)的鼠尾藻和海泥的颗粒饲料喂养刺参(Apostichopus japonicus),并比较了不同饲料条件下刺参C、N、P营养盐的收支过程。结果表明:刺参C、N、P营养盐收支过程和饲料中鼠尾藻的含量显著相关(P<0.05)。刺参的摄食率和排粪率随着饲料中鼠尾藻含量的增加而显著降低(P<0.05);刺参的耗氧率、排氨率、排磷率,以及对C、N、P营养盐的摄入率、生长余力和吸收效率均随着饲料中鼠尾藻含量的增加而显著变大(P<0.05)。当饲料中鼠尾藻添加量大于60%时,刺参对营养元素的生长余力和吸收效率无显著变化(P>0.05),因此对于成参而言,饲料中鼠尾藻和海泥的比例为60∶40是较为理想的配制比例,既可以满足刺参生长代谢所需要的主要营养元素,又能够最大限度地减少刺参养殖活动营养盐的排放。 相似文献
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探究微藻的氮代谢通路对了解其对不同氮源利用的分子机制具有重要意义。本研究利用Illumina高通量测序技术对两种氮素营养条件下(硝酸氮和尿素)多形微眼藻的转录组进行分析,通过基因功能注释及数字基因表达谱分析,研究了多形微眼藻细胞内氮代谢的调控机制。结果检测出15种参与氮代谢的酶,对应76个编码基因,构建了多形微眼藻的氮代谢通路图。其中10个酶编码基因在两种不同氮素营养条件下存在差异表达,最显著的是谷氨酸合成酶、谷氨酸脱氢酶和谷氨酰胺合成酶相关基因。有机氮源(尿素)实验组中,多形微眼藻细胞内的硝酸盐还原酶、亚硝酸盐还原酶等基因的差异表达明显高于无机氮源(硝酸钠)实验组,表明当环境中的氮源为尿素时,会对多形微眼藻细胞内硝酸盐的转化和利用有一定影响。本研究初步阐述了硝酸盐、尿素的吸收转运对多形微眼藻细胞内氮代谢的影响机制,可为硅藻在不同氮素营养条件下的吸收利用机制及氮代谢响应研究提供依据。 相似文献
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The source and significance of three nutrients – nitrogen, phosphorous and silicon – were investigated by a modified dilution method performed on seawater samples from the Central Yellow Sea (CYS), in spring blooming period of 2007. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrients supplied through remineralization by microzooplankton grazing. The results indicate that phytoplankton growth during the bloom is mostly contributed by internal nutrient pools (KI=0.062–1.730). The external nutrient pools (KE=<0–0.362) are also of importance for phytoplankton growth during the bloom at some sampling sites. Furthermore, the contribution of the recycled-nutrient pool by remineralization (KR=<0–0.751) is significant when microzooplankton grazing rate was higher than 0.5 d−1 during the spring phytoplankton blooms in the Central Yellow Sea. Compared with internal phosphorus, internal nitrogen and silicon contribute more to the phytoplankton production at most sampling stations. 相似文献
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Jacco Kromkamp 《新西兰海洋与淡水研究杂志》2013,47(3):457-465
The most common storage products of cyanobacteria are polyphosphate as a phosphorus storage compound, cyanophycin or phycobilin protein pigment as nitrogen storage products, and glycogen as a storage product of both carbon and energy. Nutrient uptake kinetics are regulated by the storage pools, and the patterns of regulation have a feedback effect on the amount of accumulated nutrient in the cells. Besides having a storage function the nutrient storage products are likely to act as metabolic sinks during conditions of energy stress. Regulation of storage products is especially strict in light‐limited cultures. By increasing the rate of polysaccharide formation during growth with short photoperiods, cyanobacteria are able to sustain relatively high growth rates. This effect is enhanced by keeping respiratory losses very low. 相似文献
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The source and significance of two nutrients, nitrogen and phosphorous, were investigated by a modified dilution method performed on seawater samples from the Jiaozhou Bay, in autumn 2004. This modified dilution method accounted for the phytoplankton growth rate, microzooplankton grazing mortality rate, the internal and external nutrient pools, as well as nutrient supplied through remineralization by microzooplankton. The results indicated that the phytoplankton net growth rate increased in turn from inside the bay, to outside the bay, to in the Xiaogang Harbor. The phytoplankton maximum growth rates and microzooplankton grazing mortality rates were 1.14 and 0.92 d-1 outside the bay, 0.42 and 0.32 d-1 inside the bay and 0.98 and 0.62 d-1 in the harbor respectively. Outside the bay, the remineralized nitrogen (Kr=24.49) had heavy influence on the growth of the phytoplankton. Inside the bay, the remineralized phosphorus(Kr=3.49) strongly affected the phytoplankton growth. In the harbor, the remineralized phosphorus (Kr=3.73) was in larger demand by phytoplankton growth. The results demonstrated that the different nutrients pools supplied for phytoplankton growth were greatly in accordance with the phytoplankton community structure, microzooplankton grazing mortality rates and environmental conditions. It is revealed that nutrient remineralization is much more important for the phytoplankton growth in the Jiaozhou Bay than previously believed. 相似文献
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Marianne Holmer Ole Pedersen Dorte Krause-Jensen Birgit Olesen Malene Hedegrd Petersen Stephanie Schopmeyer Marguerite Koch Bente Aa. Lomstein Henning S. Jensen 《Estuarine, Coastal and Shelf Science》2009,85(2):319-326
Sulfur and oxygen dynamics in the seagrasses Thalassia testudinum and Syringodium filiforme and their sediments were studied in the US Virgin Islands (USVI) in order to explore sulfide intrusion into tropical seagrasses. Four study sites were selected based on the iron concentration in sediments and on proximity to anthropogenic nutrient sources. Meadow characteristics (shoot density, above- and below-ground biomass, nutrient content) were sampled along with sediment biogeochemistry. Sulfide intrusion was high in T. testudinum, as up to 96% of total sulfur in the plant was derived from sediment-derived sulfides. The sulfide intrusion was negatively correlated to the turnover of sulfides in the sediments regulated by both plant parameters and sediment sulfur pools. Sediment iron content played an indirect role by affecting sulfide turnover rates. Leaf production was negatively correlated with sulfide intrusion suggesting that active growth reduced sulfide intrusion. Sulfide intrusion was lower in S. filiforme (up to 44%) compared to T. testudinum consistent with a higher internal nighttime oxygen concentrations found for S. filiforme. When S. filiforme can take advantage of its ability to maintain high internal oxygen concentrations, as was the case on the USVI, it could increase its success in colonizing unvegetated disturbed sediments with potentially high sulfide concentrations. 相似文献
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S. Lan Smith Naoki Yoshie Yasuhiro Yamanaka 《Deep Sea Research Part I: Oceanographic Research Papers》2010,57(3):394-408
During the SERIES iron-enrichment experiment in the eastern subarctic Pacific, after addition of iron and its subsequent depletion, the Si:N drawdown ratio increased at approximately the time that diatoms became iron limited. Laboratory studies have reported that this results from a decrease in the rate of N uptake together with a more moderate decrease in the rate of Si uptake for iron-limited cultures compared to iron-replete cultures. However, for SERIES Boyd et al. (Limnol. Oceanogr. 50 (2005)) reported an unexplained increase in the rate of Si uptake at the onset of iron limitation and suggested that studies of nutrient uptake kinetics should be undertaken in search of an explanation. We compare the classic Michealis–Menten (MM) kinetics to the recently developed optimal uptake (OU) kinetics (the SPONGE: Smith and Yamanaka. Limnol. Oceanogr. 52 (2007)) within a variable-composition model, which employs cell quotas for each relevant nutrient, applied to the multi-element (C, N, Si, Fe) dynamics during SERIES. Using the Monte Carlo Markov Chain, we fit two versions of the model (differing only in the equations for nutrient uptake) to the available data for nutrient concentrations, chlorophyll, biogenic silica and particulate organic carbon and specific growth rates.With either uptake kinetics, the model reproduces observed concentrations well for nutrients and somewhat less well for chlorophyll. The different uptake kinetics yield greater differences in modeled elemental composition of phytoplankton and biomass of phytoplankton and zooplankton, which are not directly constrained by data. MM kinetics cannot reproduce the observed increase in Si uptake rate as a function of the decreasing trend in concentration of silicic acid, and it predicts Si limitation throughout nearly all of the experiment after iron-fertilization. In contrast, OU kinetics reproduces the increase in Si uptake rate and matches the observation-based estimate for the timing of the return to iron limitation. The key assumption of the SPONGE, that uptake rates of all nutrients depend on physiological acclimation by phytoplankton as a function of the ambient concentration of the growth-limiting nutrient, was originally formulated for modeling chemostat experiments. We show that it also agrees with the observations from this field experiment and provides an explanation for the increases in Si uptake rate and Si:N drawdown ratio. 相似文献
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João Magalhães Neto Mogens René Flindt João Carlos Marques Miguel Ângelo Pardal 《Estuarine, Coastal and Shelf Science》2008
Although mitigation programmes have been implemented in huge eutrophied estuarine systems, satisfactory results are not always immediately achieved. External loadings are reduced but the nutrient pools still existing in the sediments (due to decades of external supply) start to deplete only slowly, to reach the lower steady state level related to the new external loading. In the Mondego Estuary, this situation could be seen from the mass balance calculations including different nutrient fractions (dissolved, SPM and bound in vegetation). Different nutrient fractions quantified over the year showed the retention capacity and supplying capacity of these estuarine systems, and also the seasonal dynamics those fractions can present. External loading of nitrogen was largely dominated by DIN, but after its incorporation by benthic primary producers nitrogen export occurred essentially as SPM-N. Phosphorus loading was dominated by SPM-P, but during warmer periods P-efflux increased DIP concentration inside the system and was afterwards exported through the outer boundary. Although nutrients bound in vegetation were not significant to total mass balance, depending on the occurrence of occasional macroalgal blooms, the vegetation fraction can significantly increase its contribution to the overall balance. 相似文献
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The impact of milkfish fish pens on the distribution of the alpheid shrimp Alpheus macellarius was studied in the Bolinao area, Philippines. In addition, the impact of the alpheid shrimp on sediment biogeochemistry, including organic matter mineralization, nutrient and sulfur cycling was compared in sediments affected and unaffected by fish farming. The fish farming activity had negative impact on the distribution of shrimps by reducing the abundance up to 60% in the vicinity of the net pens, and to almost absence inside the net pens. At a farm site abandoned seven month prior to sampling the abundance of shrimps was still low and sediment pools of reduced sulfur high, indicating a slow benthic recovery. The shrimp had large physical impact on the sediments, and the mineralization rates were stimulated by the presence of the shrimp in pristine sediments, whereas the fish farm impacted sites showed high mineralization rates both in sediments with and without the presence of the shrimp suggesting that the organic matter enrichment stimulated the mineralization in these low-organic sediments, whereas the shrimp had less impact. Sulfate reduction rates and in particular pools of sulfides increased in the farm impacted sediments, and sulfate reduction was an important process for organic matter mineralization (>67%) in all sediments. Although the shrimp had minor effect on the organic matter mineralization and nutrient fluxes in the farm impacted sediments, they appeared to increase the oxidation of sulfides by increasing the zone of oxidized surface sediment and thereby improving the sediment conditions for recolonization after fish farming has ceased. 相似文献