Detection of Prorocentrum donghaiense using sandwich hybridization integrated with nuclease protection assay

Prorocentrum donghaiense is an important harmful algae bloom (HAB) causing creature in China’s seas, and the conventional visual detection can not cope with long-term monitoring and high-throughput sampling projects. An assay for P. donghaiense with sandwich hybridization integrated with nuclease protection assay (NPA-SH) was established. Tests with mixed samples and spiked field ones confirmed its good specificity and sensitivity. The cell number of P. donghaiense correlated well with the optical density, ...     

Detection of DNA damage in mussels and sea urchins exposed to crude oil using comet assay

The single-cell microgel electrophoresis assay or the comet assay was used to evaluate DNA damage of dispersed crude oil on sea urchins (Strongylocentrotus droebachiensis) and mussels (Mytilus edulis L.). Sea urchins were exposed to 0.06 and 0.25 mg/L dispersed crude oil in a continuous flow system, while the mussels were exposed to 0.015, 0.06 and 0.25 mg/L dispersed crude oil. Sea urchin coelomocytes and mussel haemocytes were sampled after 4 and 5 weeks exposure, respectively. In the sea urchin coelomocytes, there was a significant concentration-related increase in the percentage of DNA in comet tail. In mussel haemocytes, there was a significantly higher percentage of DNA in comet tail for all treatments compared to the control. The responses were concentration-related up to 0.06 mg/L oil. The two highest exposure concentrations of mussels were not significantly different from each other. These results indicate that the comet assay can be used for biomonitoring of DNA damage in marine invertebrates following oil contamination.     

Assessing DNA damage in cnidarians using the Comet assay

The assessment of DNA damage by the Comet assay has been described as a useful non-specific general biomarker of stress in many marine organisms. In field situations it has successfully been employed to distinguish between reference and polluted sites and in the laboratory it has been widely used as a mechanistic tool to determine pollutant effects and mechanisms of DNA damage. To date a wide range of marine vertebrates and invertebrates have been used, however, the usefulness of this assay as a biomarker in cnidarians has not yet been assessed. The aims of this study were to optimize the Comet assay for cnidarian cells and to assess its utility for detecting genotoxic damage in these cells. Cells were isolated from the North American pacific coast temperate sea anemone Anthopleura elegantissima using a non-enzymatic dissociation procedure and viability was determined to be in excess of 90%. Cells were incubated either with (1 h acute exposures) hydrogen peroxide (H(2)O(2)), ethylmethanesulphonate (EMS) or benzo(a)pyrene (B[a]P). In comparison to other marine species, anemone cells exhibited high control or background levels of DNA strand breaks. Despite this, however, we observed dose responses for each of the study chemicals with no reduction in cell viability. This study demonstrates that anemone cells respond to known DNA damaging agents, including B[a]P which requires metabolism to exert its genotoxic effect, and that the Comet assay may prove to be a useful biomarker of stress in cnidarian species.     

Comet assay in phytoplankton as biomarker of genotoxic effects of environmental pollution

The alkaline comet assay was tested on different microalgae: the dinoflagellates, Karenia mikimotoi and Alexandrium minutum, and the diatom, Chaetoceros gracilis. The microalgae were exposed during their exponential growth to the model direct genotoxicant, hydrogen peroxide (1h, 5 and 100muM H2O2). Following H2O2 exposure, the comet assay was validated only for K. mikimotoi for which genotoxicity was observed from the lowest tested concentration of 5 microM with a concentration-dependent effect. C. gracilis was too small in size (4 microm) to be correctly analysed. For A. minutum, our lysis buffer was not strong enough to digest the cellulosic thecal plates. For K. mikimotoi, the comet assay was thus applied for the study of the genotoxic effects of different pesticides: epoxiconazole (as Opus formulation), chlorpyriphos-ethyl (as Dursban formulation) and endosulfan at 1, 10 and 100 microg of active substance/L for 24h. Exposure to epoxiconazole in formulation resulted in an increase in the extent of DNA strand breaks at the highest tested concentration icro/L. Endosulfan exposure resulted in DNA damage for K. mikimotoi nuclei. Genotoxicity was observed from 1 microg/L of endosulfan and was not concentration dependent.     

超声波提取-固相萃取联用检测河鲀毒素的研究

使用热处理、震摇、超声波等手段改善水产品中的河鲀毒素提取率,利用多种固相萃取柱纯化提取液,采用高效液相色谱-紫外检测法进行检测,重点对河鲀毒素的提取和固相萃取纯化进行了研究。试验发现,结合振荡和加热双重作用的索氏提取法和超声波加热辅助提取法具有较高的提取能力,其中超声波(35kHz,强度100%,60℃)提取10min即可达到最好效果,耗时短,效率更高;比较SCX、PRS、WCX、C18、SAX 5种固相萃取柱对河鲀毒素的吸附作用,SCX、PRS、WCX柱则能够将河鲀毒素完全保留在其上。样品纯化试验结果显示,C18-WCX小柱的组合纯化样品的效果最好,回收率在75%—82%之间,相对标准偏差小于15%。研究结果对河鲀毒素的提取、纯化和检测工作具有重要的参考意义。     

不同藻类生态参数在反演沉积物环境中的应用比较

海洋沉积物中残留的硅壳、甲藻孢囊、类脂类化合物及生物硅等生态参数被广泛应用于反演和指示海洋古环境特征.本研究通过测定烟台四十里湾表层沉积物中的硅藻化石、甲藻孢囊、菜籽甾醇、甲藻甾醇及生物硅5种生态参数,比较不同生态参数的相关性及它们在反演海洋环境中的功能差异,建立了多参数综合应用的研究方法.研究发现,沉积物中的硅壳丰度与菜籽甾醇含量及生物硅含量存在明显正相关关系(P＜0.05),菜籽甾醇含量与生物硅含量可以较好的佐证与提高沉积物中硅壳对硅藻生物量指示的准确性;甲藻孢囊与甲藻甾醇含量相关性不明显(P＞0.05),相较而言,甲藻甾醇可以更准确的反演甲藻的生物量.因此,生物与化学参数的结合应用不仅可以提高生物量指示的精确性,而且有助于从物种组成角度更好的了解藻类对环境变化的响应特征.     

Detection of breaking waves using X-band pulse radar in the nearshore region

An X-band pulsed Doppler microwave radar has been used to determine the characteristics of breaking waves. Field experiments were conducted at the Shuang-Si estuary in the north of Taiwan in the winter of 2005. Analyses on maxima radar cross section and Doppler frequency shift are done to characterize wave breaking zones. Based on observations of breaking waves, the wave breaking zones are shown to be located at water depths of 1.8 to 2.2 m in the experimental site. In general, the results indicate that a radar system has the potential to delineate the spatial variation of breaking waves clearly and that this is sufficient to achieve a measurement operation for near-shore air-sea interaction events.     

Detection of buried targets using a synthetic aperture sonar

This paper presents observations of buried target detections made using a 20-kHz synthetic aperture sonar. At grazing angles below the critical angle, surprisingly high signal-to-noise detections were made of cylindrical targets buried at depths of 15 and 50 cm. During a separate set of measurements, buried spheres were clearly seen at steep grazing angles, but were generally not seen below the critical angle. Since scattering from wave-generated sand ripples may contribute to detections at grazing angles below critical angle, the information available on the ripple fields is discussed and used in acoustic backscatter simulations for the buried spheres. Lack of information on the ripple height precludes a definitive explanation for the absence of buried sphere detections at subcritical grazing angles.     

北斗系统3个频段信号反演潮位高度技术研究

全球性海平面的上升可能会对沿海地区的社会活动产生重大的影响,因此,监测和了解海平面变化显得非常重要。本文依据信号的信噪比（SNR）测高原理,通过分析2014年9月5-31日,在中国浙江省舟山市的大洋山岛上所收集的北斗3个频段的卫星信号,成功地实现潮位高度反演。其中,B1频段反演结果的标准差（STD）为33.82 cm,相关系数为95.98%;B2频段反演结果的STD为38.48 cm,相关系数为94.68%;B3频段的反演结果的STD为34.56 cm,相关系数为96.08%。这是首次关于北斗3个频段信号的SNR测高研究。本次实验论证了该方法在北斗系统上的可行性,同时对北斗B1、B2、B3频段的信号在SNR测高中的性能作了对比分析。     

Detection and characteristics analysis of the western subarctic front using the high-resolution SST product

Oceanic front plays a significant role in the ocean vertical mixing and the regulation of air-sea interaction, among others. The western branch of the subarctic front(WSAF) located in the Northwest Pacific has attained lots of attention given its strong intensity and widespread influence on this region. In this study, we take advantage of the merged sea surface temperature(SST) at a high spatial resolution of 0.05° to investigate the characteristics of WSAF. The front detection algorithm that co...     

Detection of objects on the sea bottom using backscatteringcharacteristics dependent on the observation point

Sector-scanning sonar systems image the sea bottom to detect objects that can be distinguished from the background structure of the sea bottom. In current systems, images are displayed and discarded as new image data become available, In this paper, a method for improving sonar detection by utilizing all images in a sequence is investigated. The proposed method requires that sonar data are acquired with a sector-scanning sonar in a side-looking configuration. It is demonstrated that these data can be used to detect observation-point-dependent changes in sea-bottom backscattering characteristics. These changes provide additional cues for discrimination that can improve the detection of objects on the sea bottom. Results of applying the method to experimental data are presented     

Marine environmental quality assessment using polychaete taxocene characteristics in Vancouver Harbour

Polychaete taxocene characteristics from seven stations in Vancouver Harbour obtained during the PICES Practical Workshop are presented. Thirty families and 79 polychaete species were identified. Polychaete density ranged from 194.0 individuals m(-2) in Port Moody Arm to 846.0 individuals m(-2) in the Central Harbour, with a mean abundance over the seven stations of 428.9 individuals m(-2). Biomass varied from 3.0 g wet wt. m(-2) to 28.5 g wet wt. m(-2), with a mean biomass for the seven stations of 12.9 g wet wt. m(-2). High species diversity and richness of polychaete taxocene were observed at two stations, the West Vancouver Laboratory in the Outer Harbour and at a far field reference station in Thornborough Cannel. Sediment quality assessment indicated severe adverse effects at two sites in Port Moody Arm, where high concentrations of chlorinated hydrocarbons and some trace metals were found. A limited number of species, dominance of pollution-tolerant Tharyx multifilis, and the lowest values of polychaete biomass and indices of richness and diversity were detected in Port Moody Arm. Rich species composition and domination of pollution-sensitive species provided evidence of unstressed communities at the far field reference station. Sites in the Outer Harbour, Central Harbour and Indian Arm were characterised by intermediate pollutant exposure.     

Determination of nitrate in the blood of the hydrothermal vent tubeworm Riftia pachyptila using a bacterial nitrate reduction assay

The vestimentiferan tubeworm Riftia pachyptila derives most or all of its nutrition from intracellular chemosynthetic bacterial symbionts. Because purified preparations of symbionts respire nitrate, possibly nitrite, and oxygen, host transport of nitrate is a topic of interest. In the present study, we have developed a nitrate detection assay that utilizes a nitrite reductase-deficient Escherichia coli strain for the reduction of nitrate to nitrite, which is then determined spectrophotometrically. Nitrate and nitrite concentrations were measured in the blood and coelomic fluids of R. pachyptila collected from hydrothermal vent sites at 9°N and 13°N. The blood was shown to have nitrate concentrations up to one hundred times that of ambient sea water (40 μM). Blood nitrate levels reached concentrations of>1 mM, while nitrite was measured in the range of 400-700 μM. The concentrations of nitrate and nitrite in the coelomic fluids were 150-240 μM and <20 μM, respectively. The nitrate determination technique we present here is simple, applicable for laboratory and shipboard use on sea water or biological fluids, and works reliably within the 0.5 to 2000 μM range.     

Detection of changes in variance of oceanographic time-series using changepoint analysis

Changepoint analysis is used to detect changes in variability within GOMOS hindcast time-series for significant wave heights of storm peak events across the Gulf of Mexico for the period 1900-2005. To detect a change in variance, the two-step procedure consists of (1) validating model assumptions per geographic location, followed by (2) application of a penalized likelihood changepoint algorithm. Results suggest that the most important changes in time-series variance occur in 1916 and 1933 at small clusters of boundary locations at which, in general, the variance reduces. No post-war changepoints are detected. The changepoint procedure can be readily applied to other environmental time-series.     

Detection of mines in acoustic images using higher order spectral features

A new pattern-recognition algorithm detects approximately 90% of the mines hidden in the Coastal Systems Station Sonar0, 1, and 3 databases of cluttered acoustic images, with about 10% false alarms. Similar to other approaches, the algorithm presented here includes processing the images with an adaptive Wiener filter (the degree of smoothing depends on the signal strength in a local neighborhood) to remove noise without destroying the structural information in the mine shapes, followed by a two-dimensional FIR filter designed to suppress noise and clutter, while enhancing the target signature. A double peak pattern is produced as the FIR filter passes over mine highlight and shadow regions. Although the location, size, and orientation of this pattern within a region of the image can vary, features derived from higher order spectra (HOS) are invariant to translation, rotation, and scaling, while capturing the spatial correlations of mine-like objects. Classification accuracy is improved by combining features based on geometrical properties of the filter output with features based on HOS. The highest accuracy is obtained by fusing classification based on bispectral features with classification based on trispectral features.     

基于河口潮间带底栖微藻群落水平的环境质量状态评价

The feasibility of community-based bioassessment of environmental quality status was studied using microphytobenthos(MPB) in estuarine intertidal ecosystems.The sediment samples of MPB were collected monthly during a 1-year cycle(September 2006–August 2007) at four sampling stations in the Nakdong River Estuary,Korea.Environmental variables,such as salinity,radiation,grain size of sediment,Si(OH)_4(Si),nitrate(NO_3~–),nitrite(NO_2~–),ammonium(NH_4~+) and phosphates(PO_4~(3–)),were measured synchronously for comparison with biotic parameters.The statistical analyses were carried out for assessment the relationship between biotic and environmental parameters.The results showed that:(1) the MPB community structures were significant differences among four sampling stations;(2) spatial variation in the MPB communities were significantly correlated with environmental variables,especially the nutrient NH_4+ in combination with salinity and grain size;(3) three species(Navicula lacustris,Pleurosigma anglulatum and Fragilaria sp.1) were significantly correlated with nutrients and/or Si;and(4) the species richness and diversity were significantly correlated with the grain size.It is suggested that MPB communities may be used as a potentially robust bioindicator for assessing environmental quality status in estuarine intertidal ecosystems.     

基于产卵场环境因子的阿根廷滑柔鱼资源补充量预报模型研究

西南大西洋阿根廷滑柔鱼Illex argentinus是短生命周期种类,其资源量极易受到海洋环境变化的影响。根据2003—2011年我国鱿钓船队在西南大西洋的生产统计数据,以及产卵场海洋表面温度(SST)、海表温度距平值(SSTA),计算分析了阿根廷滑柔鱼在产卵期产卵场各月最适表层水温范围占总面积的比例(用PS表示)以及表征海流强度的SST、SSTA等多种环境变量因子与单位捕捞量渔获量(CPUE)的相关性,建立多种基于主要环境因子的资源补充量预报模型,同时分析比较预报模型的优劣。相关性分析表明:6月份有3片连续区域的SST与CPUE之间存在强相关性,分别为38°~39°S、54°~55°W,40.5°~41.5°S、51°~52°W,39.9°~40.4°S、42.6°~43.1°W。利用6月份此3片连续区域SST与次年CPUE建立的三元线性模型,模型符合统计检验,偏差解释率为82.4%。在此基础上加入7月份PS影响因子建立3种方案下的误差反向传播(EBP)神经网络模型。结果认为,包含了福克兰寒流与巴西暖流表温信息的方案3模型优于其他两种模型,其准确率可以达到90%以上。     

Detection of rapid deposition of sea ice-rafted material to the Arctic Ocean benthos using the cosmogenic tracer Be

During three icebreaker cruises in the Arctic Ocean under different sea-ice conditions in 2002, undisturbed benthic surface sediments were collected and assayed for the presence of a short-lived (t_1/2=53 d), particle-reactive cosmogenic radionuclide, ⁷Be, that is solely derived from atmospheric deposition. Under largely ice-covered conditions in May–June 2002, we did not detect this radionuclide in benthic surface sediments, despite significant inventories present in ice-rafted snow on the overlying sea ice (mean=86.8 Bq m⁻²±32.0 SD; n=9). During the July–August 2002 Shelf–Basin Interactions (SBI) cruise aboard the USCGC Healy and during a simultaneous cruise of the CCGS Sir Wilfrid Laurier on the Bering and Chukchi Shelf, which occupied the same general region following retreat and dissolution of Arctic ice cover, the ⁷Be present in this snow as well as surface deposition on to the sea ice-free water surface was detected in many benthic surface sediments, including some as deep as 945 m in Barrow Canyon. Inventories of ⁷Be in sediments were as high (60 Bq m⁻²) as the entire decay-corrected inventory present earlier in some snow samples collected on the sea-ice cover. Other deposition indicators such as the inventories of sediment chlorophyll, sediment oxygen respiration rates and ²³⁴Th-derived export fluxes also showed post-ice melt particle deposition and vertical transport, but in most cases the ⁷Be deposition was not tightly correlated with these other indicators, suggesting that ⁷Be sedimentation may not be controlled by the same processes. Our observations indicate that materials in sea ice, including contaminants, particulate organic, and mineral matter originating from atmospheric deposition or entrained in continental shelf sediments and rafted onto sea ice, can be rapidly transported to depth. The re-distribution of these materials as sea-ice drifts and eventually melts has the potential for impacting Arctic Ocean biogeochemical cycles and contaminant concentrations in areas of the Arctic remote from the original point of deposition.     

基于FlowCam影像和YOLOv3深度学习模型的多纹膝沟藻检测

海洋中的有害藻华,包括微藻形成的赤潮和褐潮以及大型藻类形成的绿潮和金潮,已成为一类突出的海洋生态灾害问题。2021年11—12月,山东半岛东北部海域发生多纹膝沟藻(Gonyaulax polygramma)形成的大规模赤潮,导致海带养殖严重受损,亟待构建有针对性的赤潮监测预警体系。本文以多纹膝沟藻为对象,尝试应用流式影像仪(FlowCam)结合卷积神经网络模型YOLOv3,分别对含有多纹膝沟藻的浓缩海水样品、含有多纹膝沟藻和链状亚历山大藻(Alexandrium catenella)的浓缩海水样品,以及含有多纹膝沟藻活细胞及空壳的浓缩海水样品进行了检测实验,探究了基于藻种影像的深度学习模型在赤潮原因种检测方面的应用潜力。结果表明,在以FlowCam获取的影像数据集训练3万次后,YOLOv3对多纹膝沟藻表现出较好的识别能力,对浓缩海水样品中目标藻种识别的平均精度为88.2%;当样品中存在与多纹膝沟藻形态相似的链状亚历山大藻时,模型对多纹膝沟藻识别的平均精度下降为76.6%,对两种微藻同时进行训练和检测,可将对多纹膝沟藻识别的平均精度提高至84.6%。对于低温下出现脱壳现象的多纹膝沟藻,模型对海水中活细胞识别的平均精度为86.7%,对空壳识别的平均精度87.8%,将多纹膝沟藻活细胞与空壳分别识别的平均精度均值(87.3%)高于将两者统一作为多纹膝沟藻进行检测的识别精度(84.2%),整体识别精度提升3.1%。综合相关结果可以看出,FlowCam与深度学习模型相结合在赤潮监测和研究中具有重要应用潜力。