2017年春、夏季黄海35°N共发的绿潮、金潮和赤潮

于2017年4月至6月,沿南黄海35°N断面出现了罕见的绿潮、金潮和赤潮等有害藻华共发现象。本研究通过现场定时定速拖网等方法,对黄海35°N断面不同站位的大型漂浮藻类进行了定量观测,并对赤潮区浮游植物进行了显微镜观察。结果表明：沿35°N断面的漂浮绿藻和马尾藻生物量具有明显的时空变化特征,4月下旬漂浮绿藻和马尾藻开始零星出现,5月下旬生物量和分布范围明显增加,在6月上旬达到最大,随后在6月下旬降低。漂浮绿藻和马尾藻的分布区域存在差异,120°30''—122°30''E为两者共同分布海域,向西以漂浮绿藻为主,向东则以马尾藻为主。分别于5月下旬和6月下旬在黄海35°N断面发现了1次米氏凯伦藻（Karenia mikimotoi）赤潮和1次赤潮异弯藻（Heterosigma akashiwo）赤潮。基于现场获取的水文数据,本文对南黄海海域的环境条件及其对有害藻华分布的影响进行了讨论。沿35°N断面共发的绿潮、金潮和赤潮现象表明黄海海域正面临严峻的海洋生态问题,通过对该海域赤潮、金潮和绿潮的长期观测,可望揭示这些藻华灾害形成机制和演变规律,为针对性地开展有害藻华预报、预警和防控提供科学依据。     

Diet composition and resource partitioning in two small flatfish species in the German Bight

Since the late 1980s, the small-sized non-commercial flatfish species solenette (Buglossidium luteum) and scaldfish (Arnoglossus laterna) have increased in abundance in the southern North Sea. Because these species are considered as possible competitors for prey of commercial flatfish, this study aimed at advancing knowledge of their feeding ecology.Between January 2009 and January 2010 stomach contents of solenette and scaldfish and benthic infauna were sampled seasonally in a study area in the German Bight. The objectives were to investigate the seasonal variability of feeding activity and diet composition of both flatfish species related to benthic prey availability.For both flatfish, the highest feeding activity was found in summer, at the same time that the highest prey densities occurred in the study area. A reduced feeding activity was observed during the winter of 2010, but not in the winter of 2009, probably related to higher 2009 water temperatures.In all seasons, diet composition of solenette was dominated by meiofauna, mainly harpacticoid copepods. Macrofauna prey species, namely juveniles of bivalves and echinoderms became important in spring. An increase in amphipods and cumaceans was found in the stomach contents during summer and autumn, simultaneously with their increased abundance in the benthic infauna. In contrast, polychaetes were rarely found in the diet, but dominated the infauna during all seasons.Diet composition of scaldfish was dominated by larger and mobile prey, and, during all seasons, was mainly comprised of crustaceans. Amphipods characterised the diet in both winters, while decapods such as Crangon spp. and Liocarcinus spp. were the dominant prey from spring to autumn. Additionally, juveniles of flatfish (Pleuronectids) and bivalves were found in the scaldfish diet in spring, replaced by cumaceans in summer. No dietary overlap between both flatfish species was found across seasons, indicating partitioning of prey resources between solenette and scaldfish. Their different feeding strategies and prey preferences, in turn were influenced by the seasonal variability of available prey.     

Association of picophytoplankton distribution with ENSO events in the equatorial Pacific between 145°E and 160°W

Climatological variability of picophytoplankton populations that consisted of >64% of total chlorophyll a concentrations was investigated in the equatorial Pacific. Flow cytometric analysis was conducted along the equator between 145°E and 160°W during three cruises in November–December 1999, January 2001, and January–February 2002. Those cruises were covering the La Niña (1999, 2001) and the pre-El Niño (2002) periods. According to the sea surface temperature (SST) and nitrate concentrations in the surface water, three regions were distinguished spatially, viz., the warm-water region with >28 °C SST and nitrate depletion (<0.1 μmol kg⁻¹), the upwelling region with <28 °C SST and high nitrate (>4 μmol kg⁻¹) water, and the in-between frontal zone with low nitrate (0.1–4 μmol kg⁻¹). Picophytoplankton identified as the groups of Prochlorococcus, Synechococcus and picoeukaryotes showed a distinct spatial heterogeneity in abundance corresponding to the watermass distribution. Prochlorococcus was most abundant in the warm-water region, especially in the nitrate-depleted water with >150×10³ cells ml⁻¹, Synechococcus in the frontal zone with >15×10³ cells ml⁻¹, and picoeukaryotes in the upwelling region with >8×10³ cells ml⁻¹. The warm-water region extended eastward with eastward shift of the frontal zone and the upwelling region during the pre-El Niño period. On the contrary, these regions distributed westward during the La Niña period. These climatological fluctuations of the watermass significantly influenced the distribution of picophytoplankton populations. The most abundant area of Prochlorococcus and Synechococcus extended eastward and picoeukaryotes developed westward during the pre-El Niño period. The spatial heterogeneity of each picophytoplankton group is discussed here in association with spatial variations in nitrate supply, ambient ammonium concentration, and light field.     

Limpets as prey: Lipophrys pholis choice for size

Patellid limpets are key species on rocky shores, structuring intertidal assemblages through their grazing. Their role as prey for fish is, however, often overlooked in studies of intertidal ecosystem functioning. The shanny Lipophrys pholis is a common predator of limpets on rocky shores in Northern Europe and, in this study, we examined the characteristics of its predation on limpets based on prey size. The limpet size range that adult L. pholis (10–12.5 cm) can eat was examined in the laboratory using Patella depressa in 0.2 cm classes, varying between 0.5 cm and 3.0 cm in maximum shell length. There was a limpet size refuge above 1.8 cm, while all smaller sizes were readily consumed by the shanny. The predator attacking behaviour was also examined and found to vary with prey size. Limpets up to 0.8 cm were crushed by the jaw‐constricting force and eaten whole, whereas larger prey were prised from the substratum and the body subsequently separated from the shell. To examine whether there was a L. pholis preference for P. depressa size, a two‐stage laboratory experiment was done using two size classes defined as small (0.7–0.8 cm maximum shell length) and large (1.5–1.6 cm maximum shell length). In the first stage, the predator was given each limpet size class separately. In the second stage, the fish was given a choice between the two classes. Lipophrys pholis was shown to have a preference for the large size class (1.5–1.6 cm). The average number of limpets consumed by the shanny was examined for the duration of one high‐tide typical of the central region of Portugal (≈ 4 h). On average, approximately five limpets (up to an eight limpet maximum) were consumed. The present study shows that L. pholis has a feeding preference based on limpet size, which suggests that the limpet population structure and intra‐ and inter‐specific interactions may be influenced by the shanny predation.     

不同产地浒苔对幼刺参生长、消化和非特异性免疫的影响

为探究不同产地浒苔型饵料对幼刺参生长、消化和非特异性免疫的影响,本实验将青岛浒苔与宁波浒苔的干粉与海泥分别按一定质量比例混合,开展刺参饲喂实验,并与刺参天然饵料马尾藻进行对比。结果表明,青岛浒苔饵料和马尾藻饵料喂养的刺参的粗蛋白含量分别为14.31%±0.10%和15.43%±1.41%,显著高于宁波浒苔饵料(11.17%±0.63%),粗脂肪和灰分含量无显著差异;青岛浒苔组、宁波浒苔组和马尾藻组的增重率分别为22.65%±5.68%、3.03%±1.17%和20.47%±2.01%,特定生长率分别为(1.44±0.33)、(0.21±0.08)、(1.33±0.12)%/d,青岛浒苔组和马尾藻组刺参的增重率和特定生长率显著高于宁波浒苔组;青岛浒苔组、宁波浒苔组和马尾藻组刺参肠道淀粉酶、胃蛋白酶、胰蛋白酶和纤维素酶活力无显著差异;马尾藻组刺参体腔液碱性磷酸酶活力为(17.57±4.56)金氏单位/100mL,显著高于青岛浒苔组[(5.56±1.32)金氏单位/100mL]和宁波浒苔组[(2.83±0.75)金氏单位/100mL],超氧化物歧化酶和酸性磷酸酶活力无显著差异。由此可见,绿潮暴发时,通过打捞浒苔用以配制刺参饵料,既有助于缓解绿潮的生态灾害,又能够补充刺参饵料来源,具有广阔的生态效益和市场前景,但是其营养成分影响因素较为复杂,配制饵料时应充分考虑不同品种、采集时间和生长地点的差异,并通过一些前处理手段充分发挥浒苔的饵料价值。     

紫菜养殖筏架上定生浒苔对黄海绿潮的贡献

Green tides caused by the unusual accumulation of high floating Ulva prolifera have occurred regularly in the Yellow Sea since 2007. The primary source of the Yellow Sea green tides is the attached algae on the Pyropia aquaculture rafts in the Subei Shoal. Ulva prolifera and Blidingia(Italic) sp. are the main species observed on Pyropia aquaculture rafts in the Subei Shoal. We found that U. prolifera has strong buoyancy and a rapid growth rate, which may explain why it is the dominant species of green tides that occur in the China's sea area of the Yellow Sea. The growth rate of floating U. prolifera was about 20%–31% d–1, which was much higher than Blidingia(Italic) sp. There were about 1.7 × 10~4 t of attached algae on the Pyropia aquaculture rafts in May 2012. We found that 39% of attached algae could float when the tide rose in the Subei Shoal, and U. prolifera accounted for 63% of the floating algae. Our analysis estimated that about 4 000 t of attached U. prolifera floated into the surrounding waters of the Subei Shoal during the recycling period of aquaculture rafts. These results suggest that the initial floating biomass of large-scale green tides in the Yellow Sea is determined by the U. prolifera biomass attached to Pyropia aquaculture rafts, further impacting the scale of the green tide.     

乳铁蛋白对大黄鱼仔鱼生长、存活和抗应激能力影响的研究

用不同水平(分别为T1组:0 mg/L;T2组:50 mg/L;T3组:100 mg/L;T4组:150 mg/L)乳铁蛋白(lactoferrin,简称LF)强化的卤虫(Artemia franciscana)幼体投喂9~23日龄大黄鱼(Pseudosciaena crocea)仔鱼。结果表明,摄食LF强化卤虫幼体的大黄鱼仔鱼其生长无明显改善(P0.05),但大黄鱼仔鱼的成活率和抗应激能力显著提高,T3(60%)和T4(80%)组的成活率显著高于T1(40%)和T2(30%)组(P0.05)。T4组大黄鱼仔鱼的耐干露能力最强,T4组和T3组的抗高盐度(65)应激能力明显的强于T1和T2组(P0.05),T4组和T3组之间无明显的差异(P0.05)。经4 h高温(32°C)曝露后,T1和T2组的仔鱼全部死亡,T4组和T3组的成活率分别为30%和23.3%。即仔鱼的成活率和抗应激能力受卤虫强化LF水平的影响显著,LF强化的有效剂量为不低于100 mg/L强化水体。     

黄海绿潮浒苔提取物的化感效应及化感物质的分离鉴定

化感作用是浒苔绿潮暴发的重要原因之一,目前,对于浒苔产生化感物质的结构、种类以及产量的研究鲜有报道。本文针对黄海浒苔绿潮致灾藻种,利用毒性鉴别程序（TIE）对其体内的化感物质进行分离提取及结构鉴定,明确了浒苔产生化感物质的主要成分。首先用石油醚、乙酸乙酯和甲醇3种有机溶剂分别对新鲜浒苔进行提取,得到3种不同溶剂粗提物,其中乙酸乙酯粗提物的抑藻活性最强,对测试物种中肋骨条藻的半数有效浓度（96h-EC₅₀）值为22.25 mg/L;其次对乙酸乙酯粗提物进行萃取分离得到初步提纯物,其对中肋骨条藻的96h-EC₅₀值为21.12 mg/L;然后用硅胶层析柱对上述初步提纯物进行分离,共得到6种组分,其中抑藻活性最强的组分对中肋骨条藻的96h-EC₅₀值为10.57 mg/L;最后,对新鲜浒苔提取物用红外光谱和气相色谱-质谱联用仪进行检测,实验结果表明主要化感物质为:4,7,10,13,16,19-二十二碳六烯酸、2-十六碳烯酸、棕榈酸、5,8,11,14,17-二十碳五烯酸、9,12-十八碳二烯酸、9,12,15-十六碳三烯酸、花生四烯酸、13-二十二碳烯酸等8种脂肪酸。研究结果对于系统阐释浒苔绿潮暴发机制具有重要意义。     

冬夏季南海西部固氮蓝藻

本研究分析了冬季东北季风期(2006年11月27日-12月16日)及夏季西南季风期(2007年8月11日-9月16日)南海西部越南沿岸区域(10°~17°N,108°~115°E)的网采浮游植物样品,探讨了冬夏两季南海西部固氮蓝藻的物种、丰度及分布特征,以及影响固氮蓝藻丰度与分布的环境因素。冬夏两季南海西部固氮蓝藻主要有束毛藻(Trichodesmium)和胞内植生藻(Richelia intracellularis),束毛藻物种包括铁氏束毛藻(Trichodesmium thiebaultii)、红海束毛藻(Trichodesmium erythraeum)以及汉氏束毛藻(Trichodesmium hildebrandtii),其中铁氏束毛藻为优势种,胞内植生藻主要与根管藻(Rhizosolenia sp.)共生。冬季时束毛藻藻丝体平均丰度为0.194×104 filaments/L,束毛藻细胞平均丰度为0.172×106 cells/L,胞内植生藻细胞平均丰度为0.255×104 cells/L,与笔尖形根管藻(Rhizosolenia styliformis)共生的胞内植生藻居多;蓝藻主要分布在调查海域的北部。夏季时束毛藻藻丝体平均丰度为2.995×104 filaments/L,束毛藻细胞平均丰度为6.007×106 cells/L,胞内植生藻细胞平均丰度为2.198×104 cells/L,与笔尖根管藻共生的胞内植生藻占优势。夏季时固氮蓝藻丰度高于冬季,胞内植生藻宿主更为多样化。本研究中温度及冷窝对蓝藻的分布有重要影响,而盐度单独对蓝藻分布的影响不大,与温度结合时表现出一定的限制作用。     

The impact of overfishing and El Niño on the condition factor and reproductive success of Peruvian hake, Merluccius gayi peruanus

In this study we examine physiological responses of Peruvian hake (Merluccius gayi peruanus) to changes in their population structure and physical environment during the period 1971–2004. In particular, we assess the relative investment of energy in growth and/or reproduction of small (20–35 cm) and large (35–50 cm) hake. We calculated the (i) condition (Fulton’s K), (ii) gonad and (iii) gut fullness indices for 42,761 female hakes sampled from commercial landings; these indices indicate fish somatic, reproductive and feeding condition, respectively. Using Generalized Additive Models we then examined potential relationships between these indices and sea surface temperature anomalies and date. Drastic energy exhaustion and a decrease in female hake fecundity were observed during El Niño events. The long-term trend showed a general increase in condition factor and a decrease in gonad index for large hake between 1971 and 2004. Small hake exhibited a different trend with an increase in reproductive activity, which was accompanied by an earlier maturation. We hypothesise that the observed low investment of energy in reproduction by large female hake might be related to the lack of large males, due to a sex-selective fishery and the impact of El Niño. We suggest that fishing diminished hake reproductive capacity, modified the sex ratio in favour of females and increased population vulnerability to environmental stress, in particular to the El Niño. The impact of multidecadal variability and predators like the squid, Dosidicus gigas, remain unresolved until longer time series become available.     

Intra-plant differences in seaweed nutritional quality and chemical defenses: Importance for the feeding behavior of the intertidal amphipod Orchestoidea tuberculata

As a result of their morphological complexity, large macroalgae show intra-thallus variations in their nutritional composition and secondary metabolite content, which influences the trophic ecology of herbivorous invertebrates, and ultimately their fitness. In this study, we evaluated for the first time the variability in nutritional quality (protein content, carbohydrates, lipids, and total organic matter), secondary metabolites (phlorotannins), and structure (shape and toughness) between blades and stipes of the macroalgae Durvillaea Antarctica. Specifically, we looked at their effect on feeding preference, rate of consumption, absorption efficiency, and growth rate of the amphipod Orchestoidea tuberculata, one of the most abundant organisms on Chilean sandy beaches. Proteins, carbohydrates, total organic matter and phlorotannin contents were significantly higher in blades than in stipes. Preference experiments revealed that the amphipods preferred blades when fresh pieces of blades and stipes were offered at the same time. Similar results were found when artificial food (in which structures of both parts of the alga were standardized) was offered, suggesting that shape and toughness of the two different parts of the alga did not influence preference patterns of O. tuberculata. Absorption efficiency of O. tuberculata was higher on blades compared to stipes. When the amphipods were kept with each of the algal parts separately (i.e. no choice), they consumed a significantly higher amount of stipe, which suggests that O. tuberculata used food quantity to compensate for the lower nutritional quality of stipes. The higher nutritional values of blades compared to stipes appears to explain observed preference patterns by O. tuberculata. Phlorotannin content did not appear to inhibit blade consumption, suggesting that the nutritional quality of the food could be more important than chemical defense in determining food choice in O. tuberculata. Growth did not differ between the amphipods maintained with either blades or stipes (i.e. no choice), which is consistent with the hypothesis of compensatory feeding. To conclude, O. tuberculata can actively select specific parts of an alga and this selection appears to be based on nutritional quality. The capacity for using different feeding strategies allow O. tuberculata, in some cases, to successfully exploit food types with different nutritional qualities.     

Effect of low salinity on the survival of recently hatched veliger of Nassarius reticulatus (L.) in estuarine habitats: A case study of Ria de Aveiro

The effect of low salinity on the survival of recently hatched veliger of the gastropod Nassarius reticulatus (L.) was studied under laboratory conditions at 17 °C ± 1 °C. Significant mortality occurred for salinities ≤ 17 psu and the LS₅₀ (salinity that causes 50% mortality) varied from 14.5 psu to 17.2 psu for exposures between 1 h and 48 h, respectively. The results were included in a mathematical model in order to estimate the mortality of N. reticulatus veliger in Ria de Aveiro under different salinity scenarios determined by numerical simulation. The model predicts a massive mortality of veliger immediately after their eclosion (1 h) in Ria de Aveiro during spring tide when the river input reaches its expected maximum — a situation that has been observed occasionally and may overlap a massive eclosion of veliger in the water. Except in this extreme situation, the mortality in Ria de Aveiro is generally restricted to the upstream limits of the channels. The results indicate that N. reticulatus recruitment in estuaries may strongly depend on the prevailing salinity regime.     

夜光藻配子细胞实时荧光定量PCR检测方法的建立与应用

夜光藻是我国广泛分布的赤潮原因种之一,其有性繁殖在种群增长中的作用尚不明确,定量分析配子细胞是研究夜光藻有性繁殖过程的重要手段。利用实时荧光定量PCR技术,以夜光藻rRNA基因的18S-ITS1为靶区域,建立了定量检测夜光藻配子细胞的方法。以配子细胞基因组DNA和含目的片段的重组质粒分别建立标准工作曲线,二者均呈现良好的线性响应,检出限分别为每反应0.17个细胞和10²个拷贝,满足定量检测应用需求。应用该方法对2015年逐月采集的胶州湾环境样品进行检测,并首次对夜光藻配子细胞的季节变化、水平分布与垂直分布进行了研究。结果表明,调查海域夜光藻配子丰度呈冬末春初、夏季双峰分布,范围为18.12~9.70×10⁵ cells/L;在水深小于10m的湾内近岸站位,配子丰度较低,垂直分布均匀;在湾中心、湾口和湾外的深水站位,配子丰度较高,仅在2~3月、7月和11月出现垂向差异。夜光藻配子细胞对种群增长和存续有潜在的积极意义,其丰度在营养细胞丰度高值期相对较高,在营养细胞丰度极低时仍可普遍检出。丰富了对近岸海域夜光藻配子细胞时空分布的认识,为深入研究夜光藻的种群增长模式、进一步探究其赤潮暴发的内在机理奠定了基础。     

Larval fish distribution in shallow coastal waters off North Western Iberia (NE Atlantic)

Monthly sampling for ichthyoplankton was conducted at three stations very near to the coast (near to shore shallow stations before the surf zone in direction to the shoreline) of Atlantic northwestern Portugal within contrasting localities: rocky shore, in front of a sandy beach receiving an estuary and a fishing port with heavy anthropogenic impact. Sampling was conducted from August 2002 to October 2003, always at full moon, at low tide and high tide in daylight hours, at the water column using a 48 cm diameter plankton net with 335 μm mesh. Analysis of the physico-chemical parameters pointed out the spatial (horizontal) homogeneity of the sampling area. Fish larvae from 41 taxa belonging to 17 families were identified; Blenniidae, Labridae, Ammodytidae, Clupeidae, Gobiidae, Soleidae and Gobiesocidae were the most representative during the study period. Parablennius gattorugine, Ammodytes tobianus, Symphodus melops, Sardina pilchardus, Lipophrys pholis and Coryphoblennius galerita were the most representative species (percentage contribution to total abundance). Peak abundance of fish eggs occurred during May, June and August 2003 and fish larvae occurred during May and July 2003 and August 2002 and 2003; there was a pronounced winter/early spring (March 2003) peak in larval abundance dominated by the small sandeel A. tobianus. This study identifies the occurrence of a conspicuous assemblage of larval fishes at very nearshore shallow environments of a variety of species with different adult habitats: the fish larvae assemblage was dominated by intertidal species. The present study has shown that temporal and spatial variations in the larval fish assemblage are related to environmental conditions and biological dynamics: the results suggest that abiotic conditions mediate biotic parameters, and that both abiotic and biotic characteristics regulated the larval fishes at very nearshore shallow environments.     

不同体系改性粘土对浒苔(Ulva prolifera)微观繁殖体去除及萌发的影响

本文研究了2种无机改性粘土在3种不同改性配比下对浒苔微观繁殖体去除效果及萌发的影响。结果发现,去除率随改性粘土及改性剂用量的增加而升高,相同条件下硫酸铝(AS)改性粘土对浒苔微观繁殖体的去除效果优于聚合氯化铝(PAC)改性粘土,其中1:5 PAC改性粘土在0.5 g/L时去除率为62%,AS改性粘土则可达到80%。添加改性粘土后上层水体中浒苔微观繁殖体相对萌发率随改性粘土及改性剂用量的升高而降低,总体系相对萌发率表现为先升后降趋势,在改性剂浓度为0.1 g/L时相对萌发率达到最高。两种改性体系中微观繁殖体在1:3配比、1.0 g/L浓度下均未能萌发。该结果显示,改性粘土可以有效去除浒苔微观繁殖体并抑制其萌发,这为我国绿潮灾害的防控提供了一种新思路。     

短蛸对不同生物饵料利用的比较

为比较短蛸（Octopus ocellatus）对不同生物饵料的利用效果,以南美白对虾、肉球近方蟹、菲律宾蛤仔和玉筋鱼四种饵料进行了饲喂实验。结果表明：1）肉球近方蟹组短蛸增重率显著高于其他各组（P<0.05）,南美白对虾组脏体比显著高于玉筋鱼组（P<0.05）,各饵料组肝体比无显著差异;2）南美白对虾组和肉球近方蟹组短蛸肌肉的蛋白质含量显著高于菲律宾蛤仔组和玉筋鱼组（P<0.05）,肉球近方蟹组脂肪含量显著高于其余各组（P<0.05）,玉筋鱼组灰分含量显著低于其他各组（P<0.05）;3）南美白对虾组短蛸肝胰腺谷丙转氨酶活性显著高于其余各组（P<0.05）,肉球近方蟹组谷草转氨酶活性显著高于其余各组（P<0.05）,玉筋鱼组谷氨酸脱氢酶活性显著低于其余各组（P<0.05）,菲律宾蛤仔组酸性磷酸酶活性显著高于其余各组（P<0.05）,玉筋鱼组胃蛋白酶活性显著高于其他各组（P<0.05）。综上,投喂肉球近方蟹可以显著提高短蛸的增重率;不同饵料对短蛸肌肉的蛋白质、脂肪和灰分含量有影响,对其肝胰腺功能和胃蛋白酶活性也有显著影响。     

2021～2022年荣成海域多相赤潮的分子鉴定

山东半岛濒临渤海和黄海,海岸带复杂,海岸线长,近岸海域赤潮事件频发。然而,由于部分赤潮物种的形态难以识别,或易降解不稳定,加上形态鉴定专业要求高,导致致灾赤潮物种未得到准确鉴定。2021年11月至2022年4月间山东荣成海域海带养殖区暴发严重赤潮事件,面积达1 440 km²,导致海带白化、溃烂,造成严重经济损失。对该海域水样固定样本的观察鉴定到两种致灾赤潮物种,红色赤潮藻(Akashiwo sanguinea)和多纹膝沟藻(Gonyaulax polygramma),二者均为山东近海常见的致灾赤潮物种。该研究通过对赤潮样本中活体单细胞的显微观察和单细胞测序分析,根据藻细胞形态特征与分子标记序列相似性鉴定到三种优势致灾赤潮物种,包括红色赤潮藻、多纹膝沟藻和灰白下沟藻(Katodinium glaucum)。其中灰白下沟藻由于在固定过程中不稳定而较少得到鉴定。对该赤潮海域水样开展宏条形码分析,除了发现上述三种致灾赤潮物种外,还发现了另外一个致灾赤潮物种纺锤环沟藻(Gyrodinium fusiforme)。纺锤环沟藻也由于在固定过程中不稳定而较少得到鉴定。由此可见,...     

Vertical Migrations and Feeding Rhythms of Acartia clausi and Pseudodiaptomus hessei (Copepoda: Calanoida) in a Tropical Lagoon (Ebrié, Côte d'Ivoire)

Diel changes in vertical distribution and gut pigment contents of Acartia clausi andPseudodiaptomus hessei were studied during several 24-h time series performed between 1993 and 1997 in four sites of the Ebrié Lagoon (Côte d'Ivoire). The sites differed by their morphology and their hydrological structure and by the vertical distribution of chlorophyll biomass. Both species showed classical diel vertical migrations (DVM). Copepodites and adult stages of P. hessei were almost benthic during the day and evenly distributed through the water column at night. The amplitude of DVM of A. clausi increased from copepodites I–III to adults. Copepodites and adults of A. clausi increased significantly their gut fluorescence at night, whereas those of P. hessei showed no clear diel feeding rhythm (DFR). These results suggest that A. clausi feed mostly at night on phytoplanktonic particles and P. hessei feed mostly on benthic algal particles during the day and on sestonic particles at night. No relationship was observed between DFR and DVM because both patterns occurred when food was either vertically homogeneous or vertically stratified. The daily average gut fluorescence of A. clausi increased with ambient chlorophyll concentration until around 12–15 μg l⁻¹, whereas no relationship was found for P. hessei. The implication of these patterns on the adaptation capacities and the behaviour of the two species are discussed. The DVM of P. hessei should explain its rarity in the estuarine area. The comparison of our results with previous ones suggests an evolution of A. clausi DFR between 1981–1982 and 1996–1997, in relation to an intensification of eutrophication.     

多肽菌素在长牡蛎人工育苗生产中的应用

多肽菌素作为一类具有抗菌活性的生物短肽,是一种可以替代抗生素的生物肽。为了推广多肽菌素在水产养殖中的应用,本研究以长牡蛎(Crassostreagigas)人工育苗为基础,以添加2×10_(–6) mol/L青霉素钠为对照组,以添加5个不同浓度(2×10_(–6)、4×10_(–6)、6×10_(–6)、8×10_(–6)、10×10_(–6) mol/L)多肽菌素为实验组,研究多肽菌素在长牡蛎人工育苗生产中的应用。结果显示:(1)在长牡蛎种贝培育方面,培育前8天各组差异不显著(P 0.05),培育后期添加6×10_(–6) mol/L多肽菌素组存活率均最高,对照组最低,且培育至32天时该实验组均显著高于其他组(P0.05)。(2)在长牡蛎幼虫培育方面,幼虫壳高日增长量在添加6×10_(–6) mol/L多肽菌素组中最大,为11.57μm/d,而对照组仅为9.61μm/d;幼虫存活率方面对照组始终最低,而添加6×10_(–6) mol/L与8×10_(–6) mol/L多肽菌素组均保持较高存活率,显著高于对照组(P 0.05)。(3)在长牡蛎幼虫附着变态方面,添加6×10_(–6) mol/L多肽菌素组附着率最高、附着时间最短,且均与对照组差异显著(P0.05)。(4)在长牡蛎稚贝培育方面,稚贝壳长日增长量实验组均高于对照组,且随添加浓度的上升,日增长量也随之增加;稚贝存活率在添加6×10_(–6) mol/L多肽菌素组达到最高,与对照组差异显著(P0.05)。结果表明,使用多肽菌素与使用青霉素钠相比,多肽菌素显著提高了整个牡蛎培育过程中的存活率、生长速度、及附着变态率,这也为多肽菌素在贝类育苗生产中的推广提供了基础依据。     

海洋酸化对青蛤免疫指标的影响

通过向水体中通入CO_2的方法模拟海洋酸化环境,测定青蛤(Cyclina sinensis)在酸化条件下各免疫指标的变化情况。结果显示:将青蛤置于酸化的海中(pH分别为7.4和7.7),并以自然海水做对照组(pH 8.1)后,血细胞总数随海水酸化胁迫时间的延长,表现为下降趋势,且差异显著(P0.05);海水pH降低抑制了溶菌酶的活性,但差异性不显著(P0.05);ACP活性总体呈下降趋势,对照组活性要高于酸化组,而ALP活性表现为上升趋势。酸化胁迫初期诱导SOD活性升高,后期SOD活性受到抑制,而CAT变化却截然相反;脂质过氧化产物MDA在酸化后期出现显著降低(P0.05)。