CO2濃度升高對(duì)三角褐指藻和旋鏈角毛藻種群生長(zhǎng)的影響*

毛雪微， 劉光興, 2， 王為民， 陳洪舉, 2**

(中國(guó)海洋大學(xué) 1. 環(huán)境科學(xué)與工程學(xué)院； 2. 海洋環(huán)境與生態(tài)教育部重點(diǎn)實(shí)驗(yàn)室, 山東 青島 266100)

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CO2濃度升高對(duì)三角褐指藻和旋鏈角毛藻種群生長(zhǎng)的影響*

毛雪微1， 劉光興1, 2， 王為民1， 陳洪舉1, 2**

(中國(guó)海洋大學(xué) 1. 環(huán)境科學(xué)與工程學(xué)院； 2. 海洋環(huán)境與生態(tài)教育部重點(diǎn)實(shí)驗(yàn)室, 山東 青島 266100)

摘要：采用室內(nèi)模擬CO2加富培養(yǎng)的方式研究了2種pCO2(395和1000μatm)對(duì)三角褐指藻(Phaeodactylum tricornutum)和旋鏈角毛藻(Chaetoceros curvisetus)這2種硅藻的種群生長(zhǎng)和溶解性無(wú)機(jī)碳的影響。研究表明：CO2濃度升高顯著促進(jìn)了三角褐指藻和旋鏈角毛藻種群的生長(zhǎng)。三角褐指藻實(shí)驗(yàn)組的平均比生長(zhǎng)率比對(duì)照組高出33.1%，旋鏈角毛藻實(shí)驗(yàn)組的平均比生長(zhǎng)率比對(duì)照組高出13.4%。同時(shí)，CO2加富引起培養(yǎng)環(huán)境中溶解性無(wú)機(jī)碳(DIC)濃度升高，據(jù)此推測(cè)，未來(lái)海洋酸化將使藻生長(zhǎng)的碳限制得到緩解。海洋酸化會(huì)促進(jìn)旋鏈角毛藻種群密度增加，這預(yù)示著在未來(lái)酸化的環(huán)境下暴發(fā)赤潮的概率將增加，這將對(duì)海洋生態(tài)系統(tǒng)的穩(wěn)定性和生物多樣性構(gòu)成威脅。

關(guān)鍵詞：海洋酸化； 浮游植物； 硅藻； 種群生長(zhǎng)； 三角褐指藻； 旋鏈角毛藻

MAO Xue-Wei, LIU Guang-Xing, WANG Wei-Min, et al. Effects of elevated CO2on the population growth ofPhaeodactylumtricornutumandChaetoceroscurvisetus[J].Periodical of Ocean University of China, 2016, 46(3)： 60-66.

近年來(lái)，海洋酸化成為各沿海國(guó)家及國(guó)際研究組織日益關(guān)注的問(wèn)題，并成為海洋科學(xué)領(lǐng)域的研究熱點(diǎn)之一。冰芯記錄表明，工業(yè)革命以前的80萬(wàn)年中大氣CO2平均濃度基本上沒(méi)有高過(guò)280ppm[1-2]，表層海洋的pH平均為8.2[3]。工業(yè)革命以來(lái)，大氣CO2平均濃度升高了40%，這期間海洋吸收了人為排放CO2的30%，致使海洋表層pH值平均下降了0.1，引起海洋酸化[4-6]。2013年全球大氣CO2的平均濃度約為395.31ppm[7]，到21世紀(jì)末大氣CO2濃度可能達(dá)到1000ppm(基于典型濃度路徑RCP8.5下的CMIP5 ESMs模型預(yù)估)[5]，逐增的CO2排放可能會(huì)導(dǎo)致表層海水[H+]增加100%~150%、海洋pH降低到3億年以來(lái)從未經(jīng)歷過(guò)(極端災(zāi)害性氣候事件除外)的酸度值[4]。

浮游植物貢獻(xiàn)了幾乎整個(gè)海洋生態(tài)系統(tǒng)和全球約50%的初級(jí)生產(chǎn)力，是自然界物質(zhì)循環(huán)和能量流動(dòng)的基礎(chǔ)，在全球氣候調(diào)節(jié)、碳封存和產(chǎn)氧方面起著重要的作用[8-9]。有學(xué)者指出大氣CO2升高導(dǎo)致的海洋酸化會(huì)提高海洋浮游植物的凈初級(jí)生產(chǎn)量(Net primary production, NPP)[10]。海洋酸化對(duì)浮游植物各類(lèi)群影響的研究近年來(lái)逐步開(kāi)展。早期海洋酸化的實(shí)驗(yàn)對(duì)象大部分集中在鈣化藻類(lèi)[11],例如：赫氏圓石藻(Emilianiahuxleyi)和大洋橋石藻(Gephyrocapsaoceanica)的鈣化量隨CO2濃度增加而降低[12]，但顆石藻Coccolithuspelagicus和Calcidiscusleptoporus的種群生長(zhǎng)速率在培養(yǎng)環(huán)境pH為7.80~8.70不隨環(huán)境pH降低而發(fā)生明顯變化[13]。另外，Dason等研究發(fā)現(xiàn)甲藻Amphidiniumcarterae和Heterocapsaoceanica在高CO2濃度和低pH條件下生長(zhǎng)受到抑制[14]。隨著海洋酸化研究的開(kāi)展，硅藻作為浮游植物的重要類(lèi)群，也逐漸受到關(guān)注[15-17]；pCO2水平增加至700μatm會(huì)促進(jìn)牟氏角毛藻(Chaetocerosmulleri)生長(zhǎng)并使其單位細(xì)胞光合速率增加[18]，而對(duì)中肋骨條藻(Skeletonemacostatum)的研究則發(fā)現(xiàn)海洋酸化對(duì)該藻生長(zhǎng)和光合固碳量的影響，取決于陽(yáng)光UV輻射和海洋酸化正、負(fù)效應(yīng)的綜合作用[19]；近岸種假微型海鏈藻(Thalassiosirapseudonana)受CO2濃度增加的影響同樣顯著[20]；但有研究稱(chēng)CO2加富使得直舟形藻(Naviculadirecta)的比生長(zhǎng)率降低[21]。顯然，不同種類(lèi)浮游植物對(duì)海洋酸化的響應(yīng)存在差異。浮游植物對(duì)海洋酸化響應(yīng)的差異性和研究種類(lèi)的局限性，使得目前海洋酸化對(duì)浮游植物影響的認(rèn)識(shí)還存在爭(zhēng)議，也表明加大海洋酸化研究的范圍和深度是十分必要的。

本研究所選擇的三角褐指藻(Phaeodactylumtricornutum)是實(shí)驗(yàn)室硅藻研究中的典型模式種[22]，旋鏈角毛藻(Chaetoceroscurvisetus)廣泛分布于中國(guó)近海，是比較常見(jiàn)的赤潮藻種[23]，研究海洋酸化條件下這2種硅藻種群生長(zhǎng)的響應(yīng)及對(duì)無(wú)機(jī)碳利用的機(jī)制，將為進(jìn)一步揭示海洋酸化對(duì)海洋生態(tài)系統(tǒng)的影響提供科學(xué)依據(jù)。

1材料與方法

1.1 實(shí)驗(yàn)設(shè)計(jì)

藻種來(lái)源實(shí)驗(yàn)所用的三角褐指藻取自中國(guó)海洋大學(xué)水產(chǎn)學(xué)院藻種室，旋鏈角毛藻取自中國(guó)海洋大學(xué)環(huán)境科學(xué)與工程學(xué)院赤潮分子生物學(xué)實(shí)驗(yàn)室。

培養(yǎng)條件取培養(yǎng)至對(duì)數(shù)生長(zhǎng)期藻液接入盛“f/2”培養(yǎng)基[24]的1000mL錐形瓶中進(jìn)行培養(yǎng)。三角褐指藻初始密度設(shè)為4.6×105cells/mL，旋鏈角毛藻初始密度設(shè)為5.0×105cells/mL。培養(yǎng)溫度為(20±1)℃，鹽度30，光照條件(139±20)μmol·m-2·s-1，光暗比例為12L∶12D。實(shí)驗(yàn)用海水為青島石老人海水浴場(chǎng)砂濾海水，經(jīng)0.45μm微孔濾膜過(guò)濾，高溫高壓(121℃, 0.12MPa, 20min)滅菌后，冷卻至室溫備用。

實(shí)驗(yàn)分組每種藻各設(shè)置實(shí)驗(yàn)組和對(duì)照組，每組各設(shè)3個(gè)平行。對(duì)照組通入過(guò)濾自然空氣(395μatmCO2，2013年全球大氣CO2濃度平均水平，來(lái)自NOAA/ESRL數(shù)據(jù))。實(shí)驗(yàn)組通入含1000μatm CO2(2100年大氣平均CO2濃度預(yù)測(cè)水平)[5，7]的過(guò)濾混合空氣。通氣流量均控制在0.1L/min，通氣至體系底部。實(shí)驗(yàn)過(guò)程中的CO2濃度和通氣流量由CO2加富器(CE100-6型, 武漢瑞華儀器設(shè)備有限責(zé)任公司)控制。

1.2 參數(shù)測(cè)算

培養(yǎng)環(huán)境pH的測(cè)定接種后通氣，對(duì)藻種進(jìn)行適應(yīng)性培養(yǎng)24h。從接種次日起(第1天)，每隔1d同時(shí)間取樣，取已搖勻藻液10mL，立即用pH計(jì)(PB-10型, Sartorius, 德國(guó))測(cè)定pH。

細(xì)胞計(jì)數(shù)pH測(cè)定完畢后，用中性魯哥氏液固定藻類(lèi)樣品，用血球計(jì)數(shù)板、光學(xué)顯微鏡(Nikon YS100)進(jìn)行藻密度計(jì)數(shù)。

比生長(zhǎng)率μ的計(jì)算根據(jù)以下公式計(jì)算比生長(zhǎng)率μ[25]：

μ=(lnN2-lnN1)/(t2-t1)。

式中：N1表示t1天藻密度；N2表示t2天藻密度。

培養(yǎng)環(huán)境溶解性無(wú)機(jī)碳(DIC)的測(cè)定從接種次日起(第1天)，每隔1d同時(shí)間取樣，取各組已搖勻藻液10mL，置于臺(tái)式高速冷凍離心機(jī)(5804R, eppendorf, 德國(guó))中離心2min (20℃，8000r/min)，取上清液，用總有機(jī)碳分析儀(TOC-VCPN，島津SHIMADZU，日本)測(cè)定其溶解性無(wú)機(jī)碳(以下簡(jiǎn)稱(chēng)DIC)含量。

1.3 數(shù)據(jù)處理

用SPSS 19.0軟件進(jìn)行數(shù)據(jù)處理，單因素方差分析(One-way ANOVA)進(jìn)行顯著性分析。用Origin 8.5軟件繪圖。

2結(jié)果

2.1 培養(yǎng)環(huán)境pH的變化

在整個(gè)實(shí)驗(yàn)過(guò)程中，CO2濃度升高引起三角褐指藻培養(yǎng)環(huán)境pH顯著降低(p<0.05) (見(jiàn)圖1a)。從第1天起至第7天，實(shí)驗(yàn)組環(huán)境pH極顯著低于對(duì)照組(p<0.01)，實(shí)驗(yàn)組培養(yǎng)環(huán)境平均pH降至7.94，比對(duì)照組pH (平均值8.37)低0.43。

CO2濃度升高同樣引起旋鏈角毛藻培養(yǎng)環(huán)境pH極顯著降低(p<0.01) (見(jiàn)圖1b)，實(shí)驗(yàn)組培養(yǎng)環(huán)境平均pH為8.01，與對(duì)照組(平均值8.47)相比降低了0.46。

(a.代表三角褐指藻組培養(yǎng)環(huán)境pH，b.代表旋鏈角毛藻組培養(yǎng)環(huán)境pH。*：p<0.05，**：p<0.01，誤差棒：標(biāo)準(zhǔn)偏差。a.pH inP.tricornutumculture medium ,b.pH inC.curvisetus. culture medium.*：p<0.05,**：p<0.01,Error bar:SD.)

圖1不同pCO2培養(yǎng)條件下pH隨時(shí)間的變化

Fig.1The time course of changes for pH values under differentpCO2

2.2 培養(yǎng)環(huán)境溶解無(wú)機(jī)碳(DIC)的變化

CO2濃度升高導(dǎo)致2種硅藻培養(yǎng)環(huán)境中DIC濃度升高(見(jiàn)圖2)，其中三角褐指藻實(shí)驗(yàn)組升高更明顯，平均DIC濃度比對(duì)照組高出19.9% (p<0.05)。在三角褐指藻整個(gè)生長(zhǎng)階段中，隨著時(shí)間推進(jìn)，對(duì)照組DIC下降趨勢(shì)較實(shí)驗(yàn)組明顯，至第12天下降了18.0%，同時(shí)對(duì)照組pH上升趨勢(shì)較實(shí)驗(yàn)組明顯，但實(shí)驗(yàn)組DIC基本保持平穩(wěn)。相比之下，旋鏈角毛藻培養(yǎng)環(huán)境整體DIC濃度低于三角褐指藻培養(yǎng)環(huán)境，且隨著時(shí)間推移，其變化較平穩(wěn)，處于20~25mg/L之間，實(shí)驗(yàn)組與對(duì)照組間差異不明顯，僅在第13天有顯著差別。

(a.代表三角褐指藻組培養(yǎng)環(huán)境DIC濃度，b.代表旋鏈角毛藻組培養(yǎng)環(huán)境DIC濃度。* ：p<0.05，**：p<0.01，誤差棒：標(biāo)準(zhǔn)偏差。a. DIC concentration inP.tricornutumculture medium , b. DIC concentration inC.curvisetus. culture medium. *：p<0.05, **：p<0.01, Error bar: SD.)

圖2不同pCO2培養(yǎng)條件下溶解性無(wú)機(jī)碳(DIC)隨時(shí)間的變化

Fig.2The time course of danges for dissolved inorganic carbon(DIC) under differentpCO2

2.3 種群生長(zhǎng)

CO2濃度升高引起的酸化環(huán)境顯著促進(jìn)三角褐指藻種群的生長(zhǎng)，不僅提高藻的生長(zhǎng)速率，也使其生長(zhǎng)的最大藻密度增大(見(jiàn)圖3 a)。從第2天開(kāi)始，實(shí)驗(yàn)組藻密度顯著高于對(duì)照組(p<0.05)。第3天開(kāi)始，實(shí)驗(yàn)組和對(duì)照組都已進(jìn)入對(duì)數(shù)生長(zhǎng)期，但是實(shí)驗(yàn)組藻密度明顯高于對(duì)照組的藻密度(p<0.05)，第5天和第7天出現(xiàn)極顯著性差異(p<0.01)。隨著時(shí)間的推進(jìn)，實(shí)驗(yàn)組藻密度的增加更為明顯，至第13天，實(shí)驗(yàn)組藻密度達(dá)到5.15×106cells/mL與對(duì)照組藻密度3.52×106cells/mL相比高出46.3%。

CO2濃度升高引起的酸化環(huán)境同樣明顯促進(jìn)旋鏈角毛藻種群的生長(zhǎng)(見(jiàn)圖3 b)，培養(yǎng)至第13天，實(shí)驗(yàn)組最大藻密度(3.60×106cells/mL)極顯著高于對(duì)照組最大藻密度(2.81×106cells/mL) (p<0.01)。與三角褐指藻的實(shí)驗(yàn)結(jié)果不同的是，旋鏈角毛藻培養(yǎng)初期，實(shí)驗(yàn)組和對(duì)照組的藻密度只有微弱的差異，培養(yǎng)到第11天時(shí)，才顯示出顯著的差異性(p<0.05)，實(shí)驗(yàn)組藻密度高出對(duì)照組45.3%。至實(shí)驗(yàn)第13天，實(shí)驗(yàn)組藻密度比對(duì)照組高出28.1%。

2.4 比生長(zhǎng)率μ

結(jié)果顯示，在培養(yǎng)初期(第1~7天)，CO2濃度升高能提升三角褐指藻的比生長(zhǎng)率(見(jiàn)圖3a)。但在培養(yǎng)后期促進(jìn)效果不明顯。整個(gè)培養(yǎng)期間，三角褐指藻實(shí)驗(yàn)組平均比生長(zhǎng)率為0.205d-1，高出對(duì)照組 (0.154d-1) 33.1%。相比之下，在培養(yǎng)初期(第1~5天)和第11天，CO2濃度升高對(duì)旋鏈角毛藻生長(zhǎng)有促進(jìn)作用(見(jiàn)圖3b)。在整個(gè)培養(yǎng)期間，旋鏈角毛藻實(shí)驗(yàn)組平均比生長(zhǎng)率為0.152d-1，對(duì)照組為0.134d-1。CO2加富引起旋鏈角毛藻平均比生長(zhǎng)率上升13.4%。

3討論

本研究的結(jié)果表明，在適宜溫度、光照條件下，CO2濃度升高對(duì)三角褐指藻和旋鏈角毛藻種群生長(zhǎng)有顯著的促進(jìn)作用，三角褐指藻實(shí)驗(yàn)組的平均比生長(zhǎng)率比對(duì)照組高出33.1%，旋鏈角毛藻實(shí)驗(yàn)組的平均比生長(zhǎng)率比對(duì)照組高出13.4% (見(jiàn)圖3)。不少研究同樣顯示CO2濃度升高促進(jìn)硅藻生長(zhǎng)：中肋骨條藻在高濃度CO2(20.6 μmol·L-1)培養(yǎng)條件下的生長(zhǎng)速率與低濃度CO2(4.5 μmol·L-1)相比提升了2‰~3‰[26]；對(duì)赤道太平洋和南大洋的浮游植物群落進(jìn)行CO2加富實(shí)驗(yàn)，發(fā)現(xiàn)CO2濃度增加會(huì)顯著提高浮游植物的生產(chǎn)力并促進(jìn)大型成鏈硅藻的生長(zhǎng)[27-28]。Wu等研究表明，在高CO2分壓((101.3±3.0) Pa, pH =7.80)條件下，三角褐指藻的生長(zhǎng)率比對(duì)照組(39.3±1.1) Pa, pH =8.15)高出5.2%[15]。相比較而言，本研究CO2加富引起三角褐指藻平均比生長(zhǎng)率上升33.1%(見(jiàn)圖3)，其種群促進(jìn)作用比Wu等研究更顯著。與硅藻的積極響應(yīng)不同的是，海洋酸化能夠?qū)е潞Ｋ瓹aCO3飽和度下降，降低多數(shù)鈣化藻類(lèi)的生長(zhǎng)和鈣化量[29-30]，影響鈣化生物的碳酸鈣外殼或骨架的生成，對(duì)鈣化生物產(chǎn)生負(fù)面影響，使得大部分的鈣化生物和部分甲藻因海洋酸化而遭到抑制和威脅[14, 31-34]。據(jù)此推測(cè)，未來(lái)海洋酸化環(huán)境下，硅藻種群生長(zhǎng)的促進(jìn)將進(jìn)一步影響到海洋生物群落的結(jié)構(gòu)和演替，對(duì)海洋生態(tài)系統(tǒng)的群落穩(wěn)定性造成一定影響。

(a.代表三角褐指藻組生長(zhǎng)曲線(xiàn)及比生長(zhǎng)率，b.代表旋鏈角毛藻組生長(zhǎng)曲線(xiàn)及比生長(zhǎng)率。* ：p<0.05，**：p<0.01，誤差棒：標(biāo)準(zhǔn)偏差。a. Growth curves and the specific growth rate inP.tricornutumculture medium , b. Growth curves and the specific growth rate inC.curvisetus. culture medium. *：p<0.05, **：p<0.01, Error bar: SD.)

圖3不同pCO2培養(yǎng)條件下的生長(zhǎng)曲線(xiàn)及比生長(zhǎng)率μ

Fig.3Diatom growth curves and the specific growth rate under differentpCO2

研究顯示，CO2濃度升高引起的海水碳源增加是導(dǎo)致三角褐指藻和旋鏈角毛藻種群生長(zhǎng)被促進(jìn)的主要原因。有研究指出，海洋藻類(lèi)的生長(zhǎng)和初級(jí)生產(chǎn)力會(huì)受大氣CO2濃度水平的限制[35-37]。CO2濃度升高可以緩解光能自養(yǎng)型非鈣化浮游植物的碳限制，從而促進(jìn)其種群的生長(zhǎng)。Riebesell等對(duì)圍隔生態(tài)系統(tǒng)的CO2加富實(shí)驗(yàn)結(jié)果表明，在CO2濃度為1 050 ppm時(shí)，12天內(nèi)浮游植物群落消耗的無(wú)機(jī)碳比CO2濃度為350 ppm時(shí)增加39%，浮游植物消耗的碳氮比從6升高到8，CO2加富使浮游植物耗碳量增加從而促進(jìn)初級(jí)生產(chǎn)力[38]。本研究數(shù)據(jù)顯示，隨著培養(yǎng)時(shí)間的推進(jìn)，三角褐指藻對(duì)照組培養(yǎng)環(huán)境中的溶解性無(wú)機(jī)碳量有下降趨勢(shì)，環(huán)境中所提供的碳量已不足以滿(mǎn)足植物種群的生長(zhǎng)需求；而實(shí)驗(yàn)組DIC處于相對(duì)飽和的穩(wěn)定趨勢(shì)，其環(huán)境中所提供的溶解性無(wú)機(jī)碳量足以供給植物種群生長(zhǎng)。對(duì)照組第12天的培養(yǎng)環(huán)境DIC濃度比第1天下降18% (見(jiàn)圖2 a)，培養(yǎng)環(huán)境pH有上升趨勢(shì)(見(jiàn)圖1 a)，藻密度顯著低于實(shí)驗(yàn)組(見(jiàn)圖3 a)，說(shuō)明海水中無(wú)機(jī)碳濃度限制了三角褐指藻的生長(zhǎng)；相比之下，實(shí)驗(yàn)組平均DIC濃度比對(duì)照組高出19.9%，平均比生長(zhǎng)率比對(duì)照組高出33.1%，海水DIC濃度升高緩解了三角褐指藻生長(zhǎng)所受到的的碳限制，從而促進(jìn)其種群的生長(zhǎng)。從第2天開(kāi)始，三角褐指藻實(shí)驗(yàn)組藻密度即顯著高于對(duì)照組(p<0.05) (見(jiàn)圖3 a)，三角褐指藻對(duì)溶解性無(wú)機(jī)碳升高表現(xiàn)出較高的敏感度。相比較而言，旋鏈角毛藻對(duì)CO2加富的敏感度較低，海洋酸化對(duì)三角褐指藻生長(zhǎng)速率的促進(jìn)作用更加顯著(見(jiàn)圖3)：CO2加富最終引起三角褐指藻平均比生長(zhǎng)率上升33.1%，高于旋鏈角毛藻的平均比生長(zhǎng)率(13.4%)。

本文模擬的CO2濃度升高顯著促進(jìn)了三角褐指藻和旋鏈角毛藻種群的生長(zhǎng)，碳源增加是促進(jìn)二者種群生長(zhǎng)的主要原因。海洋酸化可能通過(guò)緩解藻類(lèi)生長(zhǎng)的碳限制促進(jìn)硅藻生長(zhǎng)，并會(huì)使得某些獲益物種(例如旋鏈角毛藻等赤潮生物)生物量增加，提升了赤潮暴發(fā)的風(fēng)險(xiǎn)，對(duì)海洋生態(tài)系統(tǒng)的穩(wěn)定性構(gòu)成威脅。

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責(zé)任編輯朱寶象

Effect of Elevated CO2on the Population Growth ofPhaeodactylumtricornutum

andChaetoceroscurvisetus

MAO Xue-Wei1, LIU Guang-Xing1,2, WANG Wei-Min1, CHEN Hong-Ju1,2

(Ocean University of China, 1. College of Environmental Science and Engineering； 2. Key Laboratory of Marine Environment and Ecology, Ministry of Education, Qingdao 266100, China)

Abstract:Ocean acidification is increasingly become one of research hotspots of marine science. Many scholars have investigated the effect of ocean acidification on phytoplankton populations. However, there still exist academic controversy on the influence of ocean acidification on the growth characteristics and response of phytoplankton populations because of the limitation and uncertainty of ocean acidification studies. We studied two of the typical diatom species, Phaeodactylum tricornutum and Chaetoceros curvisetus (harmful algae) to assess the effect of future CO2-driven ocean acidification (the future level of the year 2100) on the growth of phytoplankton populations, aiming to predict the response of marine diatoms to future global climate change and provide data base to the research of elevated CO2 impact on marine organisms and biodiversity. CO2 enrichment experiments were carried out under specific CO2 concentrations. The control groups were bubbled with CO2 of 395μatm (ambient atmosphere level) and the experimental groups were 1,000 μatm (future scenario of 2100 year). Results showed that the environmental pH in experimental groups had reduced since the effect of CO2-driven ocean acidification and the average pH level reduced approximately 0.3~0.4. The growth of P. tricornutum and C. curvisetus was promoted significantly by elevated CO(2 )concentration. The average specific growth rate (μ) of P. tricornutum groups and C. curvisetus groups had increased by 33.1% and 13.4%, respectively, compared to their control groups. CO2-driven ocean acidification can lead to the increase of dissolved inorganic carbon (DIC) concentration in the culture environment and relieve the limitation of inorganic carbon utilization during the growing period. Then, the growth can be promoted. Since diatoms account for a large part of marine primary productivity, the positive effect of ocean acidification on their growth may have ecological consequences in marine food chain in future. Additionally, elevated CO2 may lead to the break out of harmful algal blooms (such as C. curvisetus blooms) and be a threat to the stability of marine ecosystem and biodiversity.

Key words:ocean acidification; phytoplankton; diatom; population growth; Phaeodactylum tricornutum; Chaetoceros curvisetus

DOI：10.16441/j.cnki.hdxb.20150052

中圖法分類(lèi)號(hào)：Q948.112

文獻(xiàn)標(biāo)志碼：A

文章編號(hào)：1672-5174(2016)03-060-07

作者簡(jiǎn)介：毛雪微(1990-)，女，碩士生，從事海洋浮游生物生態(tài)學(xué)研究。E-mail: maoxuewei_ouc@163.com**通訊作者： E-mail: hongjuc@ouc.edu.cn

收稿日期：2015-03-11；

修訂日期：2015-06-04

*基金項(xiàng)目：國(guó)家自然科學(xué)基金青年基金項(xiàng)目(31101875) ；高等學(xué)校博士學(xué)科點(diǎn)專(zhuān)項(xiàng)科研基金項(xiàng)目(20110132120027)資助

引用格式：毛雪微， 劉光興， 王為民， 等. CO2濃度升高對(duì)三角褐指藻和旋鏈角毛藻種群生長(zhǎng)的影響[J]. 中國(guó)海洋大學(xué)學(xué)報(bào)(自然科學(xué)版)， 2016, 46(3)： 60-66.

Supported by Youth Fund Project of Natural Science Foundation of China, Grant (31101875); Specialized Research Fund for the Doctoral Program of Higher Education of China, Grant (20110132120027)