Dark respiration in the light and in darkness of three marine macroalgal species grown under ambient and elevated CO₂ concentrations     

ZOU Dinghui  GAO Kunshan  XIA Jianrong 《海洋学报(英文版)》2011,30(1):106-112

Dark respiration (non-photorespiratory mitochondrial respiration),which occurs both in the light and in darkness,is vital for growth and survival of algae and plays a critical role in modulating the carbon balance of them.In the present study,we have investigated dark respiration in the light (R L) and in darkness (R D) in three marine macroalgal species,Hizikia fusiformis (phaeophyta),Gracilaria lemaneiformis (Rhodophyta) and Ulva lactuca (Chlorophyta),cultured at 20℃ using aeration with two CO 2 conditions:current ambient (CO 2 concentration about 380 μl/L) and elevated CO 2 (approximately 720 μl/L) air.R L was estimated by using the Kok method,whereas R D was determined as the rate of O 2 influx at zero light.The results showed that both R L and R D were unchanged for the elevated CO 2-grown algae relative to ambient CO 2 concentration for all the algal species tested.However,R L was significantly lower than R D across all the algal species and growth CO 2 treatments,demonstrating that daytime respiration was partly depressed by the light.The percentage of inhibition of respiration by light was similar between ambient and elevated CO 2 grown algae.The ratio of respiration to photosynthesis,which tended to decrease when estimated using R L instead of R D,was not altered for the elevated relative to ambient CO 2 concentration.The results suggest that R L,rather than R D,is a more accurate estimate of nonphotorespiratory carbon loss in marine macroalgae during the daytime.It would not be anticipated that elevated atmospheric CO 2 would exert a substantial influence on respiratory flux either in the light or in darkness in these particular marine macroalgal species.  相似文献   

Mapping benthic macroalgal communities in the coastal zone using CHRIS-PROBA mode 2 images   总被引：2，自引：0，他引：2  

G. Casal  T. KutserJ.A. Domínguez-Gómez  N. Sánchez-CarneroJ. Freire 《Estuarine, Coastal and Shelf Science》2011,94(3):281-290

The ecological importance of benthic macroalgal communities in coastal ecosystems has been recognised worldwide and the application of remote sensing to study these communities presents certain advantages respect to in situ methods. The present study used three CHRIS-PROBA images to analyse macroalgal communities distribution in the Seno de Corcubión (NW Spain). The use of this sensor represent a challenge given that its design, build and deployment programme is intended to follow the principles of the “faster, better, cheaper”. To assess the application of this sensor to macroalgal mapping, two types of classifications were carried out: Maximum Likelihood and Spectral Angle Mapper (SAM). Maximum Likelihood classifier showed positive results, reaching overall accuracy percentages higher than 90% and kappa coefficients higher than 0.80 for the bottom classes shallow submerged sand, deep submerged sand, macroalgae less than 5 m and macroalgae between 5 and 10 m depth. The differentiation among macroalgal groups using SAM classifications showed positive results for green seaweeds although the differentiation between brown and red algae was not clear in the study area.  相似文献   

Detection of deep water benthic macroalgae using image-based classification techniques on multibeam backscatter at Cashes Ledge,Gulf of Maine,USA   总被引：1，自引：0，他引：1  

Chris McGonigle  Jonathan H. Grabowski  Craig J. Brown  Thomas C. Weber  Rory Quinn 《Estuarine, Coastal and Shelf Science》2011

Benthic macroalgae form an important part of temperate marine ecosystems, exhibiting a complex three-dimensional character which represents a vital foraging and spawning ground for many juvenile fish species. In this research, image-based techniques for classification of multibeam backscatter are explored for the detection of benthic macroalgae at Cashes Ledge in the Gulf of Maine, USA. Two classifications were performed using QTC-Multiview, differentiated by application of a threshold filter, and macroalgal signatures were independently extracted from the raw sonar datagrams in Matlab. All classifications were validated by comparison with video ground-truth data. The unfiltered classification shows a high degree of complexity in the shallowest areas within the study site; the filtered demonstrates markedly less variation by depth. The unfiltered classification shows a positive agreement with the video ground-truth data; 82.6% of observations recording Laminaria sp., 39.1% of Agarum cribrosum and 100.0% (n = 3) of mixed macroalgae occur within the same acoustically distinct group of classes. These are discrete from the 8.1% recorded agreement with absences and nulls (>40 m) of macrophytes (n = 32) from a total of 86 ground-truth locations. The results of the water column data extraction (WCDE) show similar success, accurately predicting 78.3% of Laminaria sp. and 30.4% of A. cribrosum observations.  相似文献   

Airborne imagery of a disintegrating Sargassum drift line     

George O. Marmorino  W.D. MillerGeoffrey B. Smith  Jeffrey H. Bowles 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(3):316-321

Airborne hyperspectral and thermal infrared imagery collected over the Florida Current provide a view of the disintegration of a Sargassum drift line in 5 m s⁻¹ winds. The drift line consists mostly of rafts 20-80 m² in size, though aggregations larger than 1000 m² also occur. Rafts tend to be elongated, curved in the upwind direction, and 0.1-0.5 °C warmer than the surrounding ocean surface. Long weed ‘trails’ extending upwind from the rafts are evidence of plants dropping out and being left behind more rapidly drifting rafts. The raft line may be a remnant of an earlier Sargassum frontal band, which is detectible as an upwind thermal front and areas of submerged weed. Issues are identified that require future field measurements.  相似文献   

Phaeocystis globosa Scherffel, a harmful microalga, and its production of dimethylsulfoniopropionate     

沈萍萍  齐雨藻  王艳  黄良民 《中国海洋湖沼学报》2011,29(4):869-873

The production of dimethylsulfoniopropionate (DMSP) and its cleavage products (DMS) are well studied in phytoplankton worldwide. However, less is known about their sources, distributions, and impacts in the coast of China. We examined the production of DMSP and DMS in Phaeocystis globosa Scherffel and other benthic macroalgae from the South China coast in relation to environmental conditions. P. globosa was a harmful marine microalgal species and its bloom took place in the eutrophic waters along the South China Sea frequently. It also produced high content of DMSP at different growth stages, with the highest concentration usually observed in the stationary period. Moreover, the production of DMSP in P. globosa was significantly affected by salinity and temperature with the highest contents associated with high salinity (e.g. 40) and low temperature (e.g. 20°C). In field benthic macroalgae, there was also a marked difference in the DMSP of various species or different samples of the same species. Chlorophyll a contents were also determined for each macroalgal species. The highest chlorophyll a (238.7 ng/g fresh weight) was recorded in Chlorophyta Ulva lactuca at Guishan Island (Zhuhai), while the lowest value (1.5 ng/g fresh weight) was found in Rhodophyta Gracilaria tenuistipitata in Zhanjiang. Further correlation analysis indicated that there was no significant relationship between the content of DMSP and chl-a in macroalgae samples (P > 0.05). All the results suggested that the production of DMSP in marine algae was not only species- and stage-related, but also greatly affected by various environmental factors.  相似文献   

Doushantuo Macrofossil Compressions Imply the Ediacaran Hiemalora as Attachment Disc of Algae     

TANG Feng  GAO Linzhi  YIN Chongyu 《《地质学报》英文版》2013,87(Z1):869-870

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一种评价重金属污染对大型海藻毒性效应的新方法   总被引：10，自引：2，他引：8  

于志刚  张经  史峰岩  吴超元 《海洋与湖沼》1999,30(2):199-205

提出一种监测污染物对大型海藻毒性效应的新方法。该方法仅需将在有害环境中生长或２的大型海藻置于一封闭的、经０．４５μｍ膜过滤的海水体系中,在一定条件下培养１ｈ（设白、黑二瓶）,之后测定白、黑二瓶ＰＨ值并设计其差值△ＰＨ,再同样测定对照组白、黑二瓶ＰＨ差值△ＰＨ,计算△ＰＨ／△ＰＨ,则此计算值可用来代表相对光合作用速率,并用于评价毒性效应大小,另外,还较详昼地论证了该方法的水化学依据。  相似文献   

Bivalves,Tributyltin and Green Tides: Ecosystem-Level Impact?     

Jose M. Ruiz 《Marine Ecology》1999,20(1):1-9

Filter feeders such as bivalves are increasingly being shown to control phytoplankton blooms in eutrophic estuaries. The possibility of such a top-down effect on macroalgae, however, has not been considered previously even though most green tide algal species reproduce by pelagic swarmers that are equivalent to phytoplankton. This work presents circumstantial evidence from an oyster-culturing French embayment where, despite eutrophication since the mid-1970s, macroalgae did not proliferate until 1982. This was also the year when tributyltin pollution from antifouling paints dropped substantially following a world-wide prime ban that was implemented to save the shellfish industry. From the recorded evolution of the oyster stock, it is shown how tributyltin reduced the bivalve filter capacity within those years and resulted in Enteromorpha swarmers being much more likely to germinate and bloom. This suggests that the green tides had been successively contained by the biological activity and the chemical pressure. The effects of the latter on the former would thus have cascaded to ecosystem-level changes, and so the functional role of bivalves should be evaluated and preserved wherever relevant.  相似文献   

Distribution of green algal mats throughout shallow soft bottoms of the Swedish Skagerrak archipelago in relation to nutrient sources and wave exposure     

Leif Pihl  Anders Svenson  Per-Olav Moksnes  Hkan Wennhage 《Journal of Sea Research》1999,41(4):1550

Distribution and biomass of green algal mats were studied in marine shallow (0–1 m) soft-bottom areas on the Swedish west coast from 1994 to 1996, by combining aerial photography surveys with ground truth sampling. Filamentous green algae, dominated by species of the genera Cladophora and Enteromorpha, were generally present throughout the study area during July and August, and largely absent in late April and early May. These algae occurred at 60 to 90% of the locations investigated during the summer, and were estimated to cover between 30 and 50% of the total area of shallow soft bottoms of the Swedish Skagerrak archipelago. The distributional patterns were similar during the three years of the investigation and appeared unrelated to annual local nutrient inputs from point sources and river discharge. We postulate that the apparent lack of such a relationship is due to an altered state of nutrient dynamics throughout the archipelago. Mechanisms are likely to involve long-term, diffuse elevations in nutrient levels in coastal waters of the Skagerrak and the Kattegat over several decades leading to current eutrophic conditions, exceeding nutrient requirements for abundant filamentous algal growth. Patterns of algal abundance in our study were largely related to physical factors such as exposure to wind, waves and water exchange under conditions where nutrient loads among embayments seemed to be unlimited. Further, our results show that sediments covered by algal mats had higher carbon and nitrogen contents than unvegetated sediments. We hypothesise that sustained high nutrient loads, manifested in extensive biomass of filamentous algae during summer months, are re-mineralised via decay and sedimentation in the benthic realm. Hence, accumulated carbon and nutrients in the sediment could, in turn, constitute the basic pool for future algal mat production overlying soft bottoms in areas where tidal exchange is limited.  相似文献   

六种大型藻浸提液对中肋骨条藻的抑制及活性成分分离     

别聪聪  李锋民  李媛媛  赵雅菡  王震宇 《中国海洋大学学报(自然科学版)》2011,(Z2):107-112

为比较大型藻抑制赤潮藻的能力,研究了孔石莼、羊栖菜、长浒苔、马尾藻、蜈蚣藻和裙带菜的干粉末海水浸提液对中肋骨条藻的化感抑制作用并从长浒苔中分离出具有强抑制作用的组分。分析6种大型藻浸提液对中肋骨条藻的生长抑制率(Inhibitory rate,IR%)和120 h的半效应浓度(Effect concentration,EC50,120 h)发现,孔石莼、羊栖菜、长浒苔、马尾藻和蜈蚣藻的浸提液在浓度达到2.4 g/L时可在实验周期内使中肋骨条藻全部致死,抑制率达到100%,全部致死所需时间分别为96、120、96、144和144 h,当浓度达到4.8 g/L时,6种大型藻均可全部杀死中肋骨条藻,6种大型藻对中肋骨条藻的EC50,120 h分别为1.0、1.0、1.1、1.4、1.5和4.7 g/L。从长浒苔浸提液中分离的乙酸乙酯萃取组分具有强抑藻效果,受试条件下,其EC50值为0.08 mg/L。乙酸乙酯相气相色谱-质谱分析表明,组分至少包含14种物质,其中9-十八炔和邻苯二甲酸二异丁酯是含量最大的2种物质,各物质的抑藻活性尚需进一步研究。长浒苔具有很强的抑藻效果,具有应用于赤潮藻控制的潜力,研究结果为分离鉴定抑制中肋骨条藻的化感物质奠定了基础。  相似文献