Researches on regulatory mechanism of algal bloom size structure in eutrophic estuarine water
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摘要: 为探究富营养河口水体藻华粒级结构的调控机制，本研究利用枯水期珠江口上游河水、下游海水及其等比例混合水进行培养实验，跟踪监测水体中叶绿素a和营养盐的浓度变化，并利用稀释实验估算藻类生长速率（μ）和小型浮游动物的摄食速率（m），以阐明上行控制（营养盐刺激）和下行控制（摄食影响）对藻类粒级结构的影响。结果显示：营养加富能增加藻类的生物量，藻类群落的优势粒级由超微型和微型转换为小型；加富河水中μ维持2～3 d高值后下降，速率为（1.13±0.37）d−1，加富海水中μ逐步增加，速率为（1.06±0.16）d−1，加富混合水中μ轻微波动，速率为（0.58±0.14）d−1，总体上小型藻类μ最大。3组加富水体中m总体均先增大后下降，粒级差异不明显。藻类被小型浮游动物摄食率（m/μ）随粒级增大而减小，说明富营养刺激大粒级的生长，大粒级面临的被摄食压力较小。m/μ随藻类每日的比生长速率（µChl a）降低而增加，说明藻华前期由上行控制主导，后期下行控制作用相对加强。本研究表明，富营养化不仅能够改变藻华的生物量，而且能影响其粒级结构，初步阐明了富营养河口水体中藻华粒级结构的调控机制。Abstract: In order to examine the regulatory mechanism of size structure of algal blooms in eutrophic estuarine waters, we used river water, sea water and their mixed water in Zhujiang River Estuary during dry season and conducted incubation experiments to examine changes of nutrients and chlorophyll a (Chl a) concentrations. Algal growth rate (μ) and microzooplankton grazing rate (m) were estimated by dilution experiments to examine the effects of bottom-up (nutrients stimulation) and top-down control (microzooplankton grazing) on size structure of algal blooms. We found that nutrient additions increased the peak of Chl a concentration, and phytoplankton community dominance changed from picophytoplankton and nanophytoplankton to microphytoplankton. Generally, μ kept high in the first 2 to 3 days and then declined (1.13±0.37) per day in nutrient added river water; μ kept increasing (1.06±0.16) per day in nutrient added sea water and slightly fluctuated (0.58±0.14) per day in nutrient added mixed water with microphytoplankton having the highest μ. In contrast, m increased in the first 2 days or 3 days and then decreased, and there were no size differences in all treatments. The microzooplankton grazing vs algal growth (m/μ) increased from microphytoplankton, nanophytoplankton, to picophytoplankton, indicating that larger size phytoplankton were under less top-down control. In addition, m/μ increased as daily algal specific growth rate decreased, indicating that bottom-up control played a stimulating role at early stage, and the top-down control played a more important role in the late stage of algal blooms. This study suggests that eutrophication can make a difference in both the magnitudes and size structure of algal blooms in estuarine waters.
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Key words:
- algal blooms /
- size structure /
- bottom-up control /
- top-down control /
- eutrophic estuary
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图 1 自然和营养加富的海水、混合水和河水中3种粒级叶绿素a的浓度
误差线代表标准偏差
Fig. 1 Concentrations of three size fractionation chlorophyll a in natural and nutrient added sea water, mixed water and river water
The error bars indicate standard deviation
图 2 培养实验中自然和营养加富的海水、混合水和河水中3种粒级藻类每日的比生长速率（µChl a）
Fig. 2 Daily algal specific growth rates (µChl a) for three size fractionation phytoplankton during the incubation in natural and nutrient added sea water, mixed water and river water
图 3 培养实验中营养加富的海水、混合水和河水中3种粒级藻类和总体的生长速率（µ）、小型浮游动物的摄食速率（m）以及藻类被小型浮游动物的摄食率（m/μ）
误差线代表标准偏差
Fig. 3 Microzooplankton grazing rates (m), algal growth rates (µ) and the consumption ratios of phytoplankton by microzooplankton (m/µ) for three size fractionation phytoplankton and total phytoplankton during the incubation in nutrient added sea water, mixed water and river water
The error bars indicate standard deviation
图 4 在营养加富的海水、混合水和河水中小型浮游动物的摄食速率（m）和藻类的生长速率（µ）关系
实线代表显著相关（p<0.05），在加富混合水和河水中相关性不显著，在加富海水显著相关（R2=0.389），在3类盐度水体中总体（黑线）显著相关（R2=0.137）
Fig. 4 Relationships between microzooplankton grazing rates (m) and algal growth rates (µ) in nutrient added sea water, mixed water and river water
The solid line indicates a significant regression (p<0.05), the regressions are not significant in both nutrient added mixed water and river water, but significant in nutrient added sea water (R2=0.389) and the total three-salinity water (black line) (R2=0.137)
图 5 在营养加富的海水、混合水和河水中3种粒级的藻类被小型浮游动物摄食率（m/µ）（A）及3种粒级藻类叶绿素a浓度在培养初始和结束时各自占比（B）
误差线代表标准偏差，不同字母代表显著性差异
Fig. 5 Ratios of three size fractionation phytoplankton consumed by microzooplankton (m/µ) (A) and percentages of three size fractionation Chl a concentration to total Chl a concentration in the initial and end incubation (B) in the nutrient added sea water, mixed water and river water
The error bars indicate standard deviation; different letters indicate significant differences
图 6 在营养加富的海水、混合水和河水中藻类的比生长速率（µChl a）和其被小型浮游动物摄食率（m/µ）的关系
实线代表显著相关（p<0.05），R2=0.385
Fig. 6 Relationships between algal specific growth rates (µChl a) and their ratios consumed by microzooplankton (m/µ) in the nutrient added sea water, mixed water and river water
The solid line indicates a significant regression (p<0.05) and R2=0.385
表 1 培养实验中自然和营养加富的河水、混合水和海水的总无机氮（TIN）、磷酸盐（P）的浓度变化（平均值±标准偏差，单位：µmol/kg）
Tab. 1 The concentrations (mean±SD, unit: µmol/kg) of total inorganic nitrogen (TIN) and phosphate (P) during the incubation in natural and nutrient added river water, mixed water and sea water
培养时间/d 河水 加富河水 混合水 加富混合水 海水 加富海水 总无机氮（TIN） 0 150.32±2.53 200.18±3.12 90.66±1.85 206.95±3.51 26.36±2.52 144.89±3.60 1 124.31±3.18 169.01±1.04 89.64±0.08 178.95±6.10 20.49±1.69 131.06±0.41 2 84.63±1.30 144.69±1.14 72.05±7.12 141.77±0.66 15.68±0.53 116.64±2.49 3 72.24±1.37 123.19±1.62 68.49±2.56 113.16±1.01 12.19±1.11 108.28±0.57 4 48.21±2.45 113.38±9.48 66.49±5.05 107.85±1.88 11.37±1.09 104.78±2.17 5 47.05±4.65 103.14±0.49 48.45±3.65 89.55±2.41 1.25±0.05 86.10±1.23 磷酸盐（P） 0 0.80±0.11 7.01±0.12 0.57±0.04 6.83±0.24 0.38±0.02 6.56±0.20 1 0.26±0.01 6.68±0.62 0.31±0.01 6.64±0.13 0.28±0.02 6.38±0.41 2 0.12±0.01 6.02±0.48 0.29±0.01 4.85±0.22 0.34±0.01 6.01±0.34 3 0.12±0.01 3.51±0.29 0.26±0.01 4.55±0.05 0.33±0.03 5.87±0.17 4 0.15±0.02 1.19±0.10 0.28±0.01 3.30±0.05 0.34±0.01 5.60±0.06 5 0.18±0.02 0.56±0.02 0.31±0.01 1.14±0.21 0.30±0.02 5.08±0.05 
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[1] Strom S. Novel interactions between phytoplankton and microzooplankton: their influence on the coupling between growth and grazing rates in the sea[J]. Hydrobiologia, 2002, 480(1/3): 41−54. doi: 10.1023/A:1021224832646 [2] Kirchman D L. Growth rates of microbes in the oceans[J]. Annual Review of Marine Science, 2016, 8: 285−309. doi: 10.1146/annurev-marine-122414-033938 [3] Huang Bangqin, Xiang Weiguo, Zeng Xiangbo, et al. Phytoplankton growth and microzooplankton grazing in a subtropical coastal upwelling system in the Taiwan Strait[J]. Continental Shelf Research, 2011, 31(6): S48−S56. doi: 10.1016/j.csr.2011.02.005 [4] Strom S L, Fredrickson K A. Intense stratification leads to phytoplankton nutrient limitation and reduced microzooplankton grazing in the southeastern Bering Sea[J]. Deep-Sea Research Part II: Topical Studies in Oceanography, 2008, 55(16/17): 1761−1774. [5] Sun Jun, Feng Yuanyuan, Zhang Yaohong, et al. Fast microzooplankton grazing on fast-growing, low-biomass phytoplankton: a case study in spring in Chesapeake Bay, Delaware Inland Bays and Delaware Bay[J]. Hydrobiologia, 2007, 589(1): 127−139. doi: 10.1007/s10750-007-0730-6 [6] Froneman P W, McQuaid C D. Preliminary investigation of the ecological role of microzooplankton in the Kariega Estuary, South Africa[J]. Estuarine, Coastal and Shelf Science, 1997, 45(5): 689−695. doi: 10.1006/ecss.1996.0225 [7] Strom S L, Brainard M A, Holmes J L, et al. Phytoplankton blooms are strongly impacted by microzooplankton grazing in coastal North Pacific waters[J]. Marine Biology, 2001, 138(2): 355−368. doi: 10.1007/s002270000461 [8] Zhou L, Tan Y, Huang L, et al. Seasonal and size-dependent variations in the phytoplankton growth and microzooplankton grazing in the southern South China Sea under the influence of the East Asian monsoon[J]. Biogeosciences, 2015, 12(22): 6809−6822. doi: 10.5194/bg-12-6809-2015 [9] Lie A A Y, Wong C K. Selectivity and grazing impact of microzooplankton on phytoplankton in two subtropical semi-enclosed bays with different chlorophyll concentrations[J]. Journal of Experimental Marine Biology and Ecology, 2010, 390(2): 149−159. doi: 10.1016/j.jembe.2010.05.001 [10] Liu Xiangjiang, Tang C H, Wong C K. Microzooplankton grazing and selective feeding during bloom periods in the Tolo Harbour area as revealed by HPLC pigment analysis[J]. Journal of Sea Research, 2014, 90: 83−94. doi: 10.1016/j.seares.2014.02.017 [11] Lehrter J C, Pennock J R, McManus G B. Microzooplankton grazing and nitrogen excretion across a surface estuarine-coastal interface[J]. Estuaries, 1999, 22(1): 113−125. doi: 10.2307/1352932 [12] Sun Jun, Feng Yuanyuan, Zhou Feng, et al. Top-down control of spring surface phytoplankton blooms by microzooplankton in the central Yellow Sea, China[J]. Deep-Sea Research Part II: Topical Studies in Oceanography, 2013, 97: 51−60. doi: 10.1016/j.dsr2.2013.05.005 [13] Grattepanche J D, Vincent D, Breton E, et al. Microzooplankton herbivory during the diatom—Phaeocystis spring succession in the eastern English Channel[J]. Journal of Experimental Marine Biology and Ecology, 2011, 404(1/2): 87−97. [14] Tsuda A, Saito H, Machida R J, et al. Meso- and microzooplankton responses to an in situ iron fertilization experiment (SEEDS II) in the northwest subarctic Pacific[J]. Deep-Sea Research Part II: Topical Studies in Oceanography, 2009, 56(26): 2767−2778. doi: 10.1016/j.dsr2.2009.06.004 [15] Fileman E S, Leakey R J G. Microzooplankton dynamics during the development of the spring bloom in the north-east Atlantic[J]. Journal of the Marine Biological Association of the United Kingdom, 2005, 85(4): 741−753. doi: 10.1017/S0025315405011653 [16] George J A, Lonsdale D J, Merlo L R, et al. The interactive roles of temperature, nutrients, and zooplankton grazing in controlling the winter-spring phytoplankton bloom in a temperate, coastal ecosystem, Long Island Sound[J]. Limnology and Oceanography, 2015, 60(1): 110−126. doi: 10.1002/lno.10020 [17] Behrenfeld M J. Abandoning Sverdrup’s critical depth hypothesis on phytoplankton blooms[J]. Ecology, 2010, 91(4): 977−989. doi: 10.1890/09-1207.1 [18] Lucas L V, Koseff J R, Monismith S G, et al. Processes governing phytoplankton blooms in estuaries. II: the role of horizontal transport[J]. Marine Ecology Progress Series, 1999, 187: 17−30. doi: 10.3354/meps187017 [19] 张景平, 黄小平, 江志坚, 等. 2006−2007年珠江口富营养化水平的季节性变化及其与环境因子的关系[J]. 海洋学报, 2009, 31(3): 113−120.Zhang Jingping, Huang Xiaoping, Jiang Zhijian, et al. Seasonal variations of eutrophication and the relationship with environmental factors in the Zhujiang Estuary in 2006−2007[J]. Haiyang Xuebao, 2009, 31(3): 113−120. [20] 曾丹娜, 牛丽霞, 陶伟, 等. 夏季珠江口水域营养盐分布特征及其富营养化评价[J]. 广东海洋大学学报, 2020, 40(3): 73−82. doi: 10.3969/j.issn.1673-9159.2020.03.010Zeng Danna, Niu Lixia, Tao Wei, et al. Nutrient dynamics in Pearl River Estuary and their eutrophication evaluation[J]. Journal of Guangdong Ocean University, 2020, 40(3): 73−82. doi: 10.3969/j.issn.1673-9159.2020.03.010 [21] 苏芯莹, 钟瑜, 李尧, 等. 珠江口典型海岛周边水域浮游植物分布特征及其影响因素[J]. 热带海洋学报, 2020, 39(5): 30−42.Su Xinying, Zhong Yu, Li Yao, et al. Distribution characteristics and influencing factors of phytoplankton in waters around typical islands in the Pearl River Estuary[J]. Journal of Tropical Oceanography, 2020, 39(5): 30−42. [22] Yin Kedong. Influence of monsoons and oceanographic processes on red tides in Hong Kong waters[J]. Marine Ecology Progress Series, 2003, 262: 27−41. doi: 10.3354/meps262027 [23] 林凤翱, 关春江, 卢兴旺. 近年来全国赤潮监控工作的成效以及存在问题与建议[J]. 海洋环境科学, 2010, 29(1): 148−151. doi: 10.3969/j.issn.1007-6336.2010.01.033Lin Feng’ao, Guan Chunjiang, Lu Xingwang. Effects of red tide events monitoring, existence questions and suggestions in coastal areas in recent years in China[J]. Marine Environmental Science, 2010, 29(1): 148−151. doi: 10.3969/j.issn.1007-6336.2010.01.033 [24] 田媛, 李涛, 胡思敏, 等. 广东省沿岸海域藻华发生的时空特征[J]. 海洋环境科学, 2020, 39(1): 1−8. doi: 10.12111/j.mes20200101Tian Yuan, Li Tao, Hu Simin, et al. Temporal and spatial characteristics of harmful algal blooms in Guangdong coastal area[J]. Marine Environmental Science, 2020, 39(1): 1−8. doi: 10.12111/j.mes20200101 [25] Yin Kedong, Song Xiuxian, Sun Jun, et al. Potential P limitation leads to excess N in the Pearl River Estuarine coastal plume[J]. Continental Shelf Research, 2004, 24(16): 1895−1907. doi: 10.1016/j.csr.2004.06.014 [26] 柯志新, 谭烨辉, 黄良民, 等. 2009年秋季旋沟藻赤潮爆发期间珠江口表层水体的环境特征[J]. 海洋环境科学, 2012, 31(5): 635−638.Ke Zhixin, Tan Yehui, Huang Liangmin, et al. Environmental characteristics in surface water of the Zhujiang Estuary during the period of Cochlodinium blooms in fall, 2009[J]. Marine Environmental Science, 2012, 31(5): 635−638. [27] Lu Zhongming, Gan Jianping. Controls of seasonal variability of phytoplankton blooms in the Pearl River Estuary[J]. Deep-Sea Research Part II: Topical Studies in Oceanography, 2015, 117: 86−96. doi: 10.1016/j.dsr2.2013.12.011 [28] Landry M R, Hassett R P. Estimating the grazing impact of marine micro-zooplankton[J]. Marine Biology, 1982, 67(3): 283−288. doi: 10.1007/BF00397668 [29] Chen B, Zheng L, Huang B, et al. Seasonal and spatial comparisons of phytoplankton growth and mortality rates due to microzooplankton grazing in the northern South China Sea[J]. Biogeosciences, 2013, 10(4): 2775−2785. doi: 10.5194/bg-10-2775-2013 [30] Knap A H, Michaels A, Close A R, et al. Protocols for the joint global ocean flux study (JGOFS) core measurements[R]. Paris: UNESCO-IOC, 1994: 19. [31] 孙军, 宁修仁. 海洋浮游植物群落的比生长率[J]. 地球科学进展, 2005, 20(9): 939−945. doi: 10.3321/j.issn:1001-8166.2005.09.003Sun Jun, Ning Xiuren. Marine phytoplankton specific growth rate[J]. Advances in Earth Science, 2005, 20(9): 939−945. doi: 10.3321/j.issn:1001-8166.2005.09.003 [32] Boss E, Behrenfeld M. In situ evaluation of the initiation of the North Atlantic phytoplankton bloom[J]. Geophysical Research Letters, 2010, 37(18): L18603. [33] Johansson M, Gorokhova E, Larsson U. Annual variability in ciliate community structure, potential prey and predators in the open northern Baltic Sea proper[J]. Journal of Plankton Research, 2004, 26(1): 67−80. doi: 10.1093/plankt/fbg115 [34] Marañón E. Cell size as a key determinant of phytoplankton metabolism and community structure[J]. Annual Review of Marine Science, 2015, 7: 241−264. doi: 10.1146/annurev-marine-010814-015955 [35] 张亚锋, 王旭涛, 殷克东. 南海台风引发藻华的生物机制[J]. 生态学报, 2018, 38(16): 5667−5678.Zhang Yafeng, Wang Xutao, Yin Kedong. Biological mechanisms of typhoon-induced blooms in the South China Sea[J]. Acta Ecologica Sinica, 2018, 38(16): 5667−5678. [36] Irigoien X, Flynn K J, Harris R P. Phytoplankton blooms: a ‘loophole’ in microzooplankton grazing impact?[J]. Journal of Plankton Research, 2005, 27(4): 313−321. doi: 10.1093/plankt/fbi011 [37] Calbet A, Landry M R. Phytoplankton growth, microzooplankton grazing, and carbon cycling in marine systems[J]. Limnology and Oceanography, 2004, 49(1): 51−57. doi: 10.4319/lo.2004.49.1.0051 [38] Schmoker C, Hernández-León S, Calbet A. Microzooplankton grazing in the oceans: impacts, data variability, knowledge gaps and future directions[J]. Journal of Plankton Research, 2013, 35(4): 691−706. doi: 10.1093/plankt/fbt023 -
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