Phytoplankton pigments from the nimbus-7 coastal zone color scanner: comparisons with surface measurements

The removal of atmospheric effects from Nimbus-7 Coastal Zone Color Scanner (CZCS) images reveals eddy-like ocean turbidity patterns not apparent in the original calibrated images. Comparisons of the phytoplankton pigment concentrations derived from the corrected CZCS radiances with surface measurements agree to within less than 0.5 log C, where C is the sum of the concentrations of chlorophyll a plus phaeopigments a (in milligrams per cubic meter).     

断根对冬小麦光合特性及耐旱性的影响

[目的]采用叶绿素荧光分析技术探讨断根对冬小麦光合特性的影响,并对不同断根程度冬小麦的耐旱性进行比较。[方法]在对水分敏感的冬小麦花期开展试验。断根处理分小断根(A1)与大断根(A2)两种。小断根为单面刀在距小麦主茎一侧2 cm处垂直切下,深度为10 cm。大断根为单面刀在距小麦主茎两侧2 cm处垂直切下,深度为10 cm。于花期(2013年4月19日)给予各处理冬小麦一次性充分供水(土壤含水量占田间持水量的80%),此后不再供水任其水分胁迫自然加重并避免降水影响,测定供水后1、4、7、10、13 d各处理冬小麦旗叶叶绿素荧光参数。[结果]冬小麦叶绿素荧光对水分胁迫非常敏感,其参数的变化与水分胁迫的加剧密切相关。通过叶绿素荧光数据对比,在胁迫加剧的过程中断根处理小麦比对照小麦具有更强的耐旱能力,而双侧断根处理较单侧断根具有更强的耐旱力。[结论]该研究可为旱地节水农业的持续发展提供理论及实践依据。     

Artificial Neural Network to Predict Leaf Population Chlorophyll Content from Cotton Plant Images

Leaf population chlorophyll content in a population of crops, if obtained in a timely manner, served as a key indicator for growth management and diseases diagnosis. In this paper, a three-layer multilayer perceptron （MLP） artificial neural network （ANN） based prediction system was presented for predicting the leaf population chlorophyll content from the cotton plant images. As the training of this prediction system relied heavily on how well those leaf green pixels were separated from background noises in cotton plant images, a global thresholding algorithm and an omnidirectional scan noise filtering coupled with the hue histogram statistic method were designed for leaf green pixel extraction. With the obtained leaf green pixels, the system training was carried out by applying a back propagation algorithm. The proposed system was tested to predict the chlorophyll content from the cotton plant images. The results using the proposed system were in sound agreement with those obtained by the destructive method. The average prediction relative error for the chlorophyll density （μg cm^-2） in the 17 testing images was 8.41%.     

LED水下集鱼灯光场分布数值模拟分析

为探究水下LED集鱼灯光色、功率、放置深度和海水叶绿素浓度对光场分布的影响,本文基于蒙特卡罗模拟方法建立了水下光束传输数值计算模型,通过控制变量法计算了不同条件下的水下光场分布,并提出以0.1~10 lx等值线所包围的面积与计算截面面积比值为相对有效光照范围(Relative effective illumination range,REIR)。以REIR为评价指标,对不同条件组合下的光场分布进行了分析,结果显示：(1)相同功率条件下,REIR依次为：绿光>白光>蓝光,以功率420 W、叶绿素浓度0.1 mg/m^3 为例三种光色的REIR比值为1.58:1.31:1;(2)相同光色条件下,当叶绿素浓度0.1 mg/m^3 时,灯具功率从420 W增至1200 W,蓝绿白三种光色灯具的REIR分别从31.68%、50.27%、41.78%增至38.59%、56.91%、50.15%,功率增加近3倍,但REIR增幅有限;(3)随着灯具放置深度增加,REIR先增加后稳定;以叶绿素浓度1.0 mg/m^3 、功率为420 W为例,绿光与白光灯REIR的最大值约为9.69%~9.84%,出现在水深20 m左右,而蓝光灯的REIR最大值约为5.60%,出现在放置深度为15 m左右;(4)当灯具功率为420 W,海水叶绿素浓度从0.1 mg/m^3 增至5.0 mg/m^3,蓝绿白三种光色灯具的REIR分别从31.89%、48.25%、42.05%减少至1.65%、2.09%、2.22%。研究结果可为水下灯具光色功率选型、深度放置以及有效光场分布范围估算提供参考。     

Ventilation of the glacial deep Pacific Ocean

Measurements of the age difference between coexisting benthic and planktic foraminifera from western equatorial Pacific deep-sea cores suggest that during peak glacial time the radiocarbon age of water at 2-kilometers depth was no greater than that of today. These results make unlikely suggestions that a slowdown in deep-ocean ventilation was responsible for a sizable fraction of the increase of the ratio of carbon-14 (14C) to carbon in the atmosphere and surface ocean during glacial time. Comparison of 14C ages for coexisting wood and planktic foraminifera from the same site suggests that the atmosphere to surface ocean 14C to C ratio difference was not substantially different from today's.     

加气渗灌下灌水定额和棉秆还田深度对棉花生长和产量的影响

为探究加气渗灌模式下灌水定额和秸秆还田深度对棉花生长和产量的影响,本文以“新陆中88号”为研究对象,探究灌水定额和秸秆还田深度对棉花株高、茎粗、干物质量以及叶绿素相对量的调控效应,棉花受灌水定额影响较大,植株株高、茎粗、植株干物质量和叶片叶绿素相对量均随着灌水定额的增大呈增加趋势。同一灌水定额条件下,D2处理的叶绿素相对量大于D1和D3处理,且在灌水定额相同条件下,秸秆还田深度为25cm时,棉花株高、茎粗以及单株棉花籽棉产量均为最佳,为南疆棉秆还田和水气渗灌技术提供了一定技术参考。     

渤海湾口虾蛄假蚤状幼体的密度分布及影响因素研究

为研究渤海湾影响口虾蛄Oratosquilla oratoria假蚤状幼体分布的主要因素,分别于2015年和2016年的5、6、7、8、10月开展了10个航次的调查,选取的影响因子为月份、经度、纬度、表层水温、水深、表层盐度、溶解氧、无机氮、活性磷酸盐、化学耗氧量、叶绿素a,并采用广义加性模型(Generalized additive model,GAM)分析了口虾蛄假蚤状幼体的密度分布和上述影响因素间的关系。结果表明:2015年和2016年,渤海湾口虾蛄假蚤状幼体平均资源密度为0.095 ind./m~2,出现时间为6—8月,存在年际变化;GAM分析表明,不论将月份、经度和表层纬度视为分类变量还是数值变量,最优的GAM模型均由表层水温、纬度、月份和水深组成,各影响因素对口虾蛄假蚤状幼体影响程度的重要性依次为表层水温月份纬度水深。本研究结果可为口虾蛄渔业资源开发和保护提供技术支撑。     

Remote sensing of the fram strait marginal ice zone

Sequential remote sensing images of the Fram Strait marginal ice zone played a key role in elucidating the complex interactions of the atmosphere, ocean, and sea ice. Analysis of a subset of these images covering a 1-week period provided quantitative data on the mesoscale ice morphology, including ice edge positions, ice concentrations, floe size distribution, and ice kinematics. The analysis showed that, under light to moderate wind conditions, the morphology of the marginal ice zone reflects the underlying ocean circulation. High-resolution radar observations showed the location and size of ocean eddies near the ice edge. Ice kinematics from sequential radar images revealed an ocean eddy beneath the interior pack ice that was verified by in situ oceanographic measurements.     

Manganese flux from continental margin sediments in a transect through the oxygen minimum

The flux of manganese from continental margin sediments to the ocean was measured with a free-vehicle, benthic flux chamber in a transect across the continental shelf and upper slope of the California margin. The highest fluxes were observed on the shallow continental shelf. Manganese flux decreased linearly with bottom water oxygen concentration, and the lowest fluxes occurred in the oxygen minimum zone (at a depth of 600 to 1000 meters). Although the flux of manganese from continental shelf sediments can account for the elevated concentrations observed in shallow, coastal waters, the flux from sediments that intersect the oxygen minimum cannot produce the subsurface concentration maximum of dissolved manganese that is observed in the Pacific Ocean.     

珠江广州河段枯水期富营养化状况调查研究

以珠江广州河段(雅岗大桥至琶洲大桥)水体富营养化状况为调查对象,布设6个采样监测点,检测分析叶绿素a、总氮、总磷、透明度及CODMn等污染指标,采用综合营养状态指数法评价该河段枯水期富营养化程度。结果表明,珠江广州河段枯水期处于重度富营养状态,主要污染物TP、TN和CODMn浓度均值超过国家《地表水环境质量标准》的V类水标准,属地表水劣V类水体。珠江上游的渔业养殖、周边城市的工业排放与广州市区生活污水是造成水体污染的主要原因,联防联治长效机制的建立将有助于珠江水环境问题的解决。     

长江口悬浮泥沙的MODIS影像遥感监测研究

通过对遥感监测泥沙原理和MODIS传感器特征的分析,应用不同时间的MODIS影像进行长江口及其附近海域的悬浮泥沙监测。结果表明:(1)长江口及其附近海域悬浮泥沙含量较高,其中杭州湾悬浮泥沙浓度高于长江口;(2)长江口及其附近海域水体中的泥沙由再悬浮形成,且冬季泥沙浓度和范围均大于春季;(3)入海径流与海洋动力是影响河口沿岸及近海水域水体悬浮泥沙含量的主要因素,其中海洋动力的潮流和波浪是主导控制因素。     

旱胁迫对春小麦叶绿素含量·RWL和OWC的影响及相关分析

[目的]探讨小麦（Triticum aestivum L.）叶绿素含量与抗旱性的关系。[方法]以旱地和水地小麦品种为供试材料,在不同灌水条件下对其叶绿素含量、离体叶片失水速率（RWL）及组织含水量（OWC）进行研究。[结果]旱地品种叶绿素含量、RWL及WOC低于水地品种,旱胁迫下旱地品种叶绿素含量、RWL和OWC降低值小于水地品种;叶绿素含量与RWL呈极显著正相关,与OWC呈显著正相关。[结论]小麦叶绿素含量与抗旱性关系密切,可以为小麦抗旱节水性鉴定提供参考。     

Isotopic composition of neodymium in waters from the drake passage

The isotopic composition of neodymium has been determined in seawaters from the Drake Passage. The Antarctic Circumpolar Current, which controls interocean mixing, flows through this passage. The parameter epsilon(Nd)(0) which is a function of the ratio of neodymium-143 to neodymium-144, is found to be uniform with depth at two stations with a value which is intermediate between the values for the Atlantic and the Pacific and indicates that the Antarctic Circumpolar current consists of about 70 percent Atlantic water. Cold bottom water from a site in the south central Pacific has the neodymium isotopic signature of the waters in the Drake Passage. By using a box model to describe the exchange of water between the Southern Ocean and the ocean basins to the north together with the isotopic results, an upper limit of approximately 33 million cubic meters per second is calculated for the rate of exchange between the Pacific and the Southern Ocean. Concentrations of samarium and neodymium were also determined and found to increase approximately linearly with depth. These results suggest that neodymium may be a valuable tracer in oceanography and may be useful in paleo-oceanographic studies.     

Rapid acidification of the ocean during the Paleocene-Eocene thermal maximum

The Paleocene-Eocene thermal maximum (PETM) has been attributed to the rapid release of approximately 2000 x 10(9) metric tons of carbon in the form of methane. In theory, oxidation and ocean absorption of this carbon should have lowered deep-sea pH, thereby triggering a rapid (<10,000-year) shoaling of the calcite compensation depth (CCD), followed by gradual recovery. Here we present geochemical data from five new South Atlantic deep-sea sections that constrain the timing and extent of massive sea-floor carbonate dissolution coincident with the PETM. The sections, from between 2.7 and 4.8 kilometers water depth, are marked by a prominent clay layer, the character of which indicates that the CCD shoaled rapidly (<10,000 years) by more than 2 kilometers and recovered gradually (>100,000 years). These findings indicate that a large mass of carbon (>2000 x 10(9) metric tons of carbon) dissolved in the ocean at the Paleocene-Eocene boundary and that permanent sequestration of this carbon occurred through silicate weathering feedback.     

再生水灌溉对植物叶绿素含量的影响

[目的]为了研究再生水灌溉对植物叶绿素含量的影响。[方法]于2003～2005年进行盆栽和小区试验,测定不同水质灌溉下3种植物的叶绿素含量。[结果]同一年度内两种试验方法无显著性差异;3种水质灌溉的植物叶绿素含量均增高,顺序为:二级水>中水>自来水,中水、二级水处理无明显差异,相同的处理3种植物叶绿素增长率不同。在相同的试验方式下不同年度间的同一种草的叶绿素含量有随年度先增长后降低的变化趋势;不同年度间同一种草的不相同处理,呈逐年增长的趋势,无显著性差异。[结论]再生水灌溉能提高植物叶绿素的含量。     

Biospheric primary production during an ENSO transition

The Sea-viewing Wide Field-of-view Sensor (SeaWiFS) provides global monthly measurements of both oceanic phytoplankton chlorophyll biomass and light harvesting by land plants. These measurements allowed the comparison of simultaneous ocean and land net primary production (NPP) responses to a major El Ni?o to La Ni?a transition. Between September 1997 and August 2000, biospheric NPP varied by 6 petagrams of carbon per year (from 111 to 117 petagrams of carbon per year). Increases in ocean NPP were pronounced in tropical regions where El Ni?o-Southern Oscillation (ENSO) impacts on upwelling and nutrient availability were greatest. Globally, land NPP did not exhibit a clear ENSO response, although regional changes were substantial.     

行间生草对红地球葡萄园树体及土壤物理性状的影响

在夏季高温条件下,研究了葡萄园行间清耕及行间生白三叶草对红地球葡萄园树体生长及土壤物理性状的影响,为葡萄园行间生草提供试验依据。结果表明:生草处理的葡萄叶绿素(SPAD值)、叶面积、节间长、节间粗分别为35.53、366.80cm2、13.03cm、1.275cm,比清耕增加2.33%、0.55%、7.69%、6.25%,但差异不显著;夏季高温条件下,14:00-16:00时,生草处理对地表至地下10cm处的降温效果显著;生草处理0～10cm土壤容积含水量明显高于清耕处理,而30～40cm土壤容积含水量又略低于清耕处理;生草使土壤容重降低9.49%,总孔隙度提高4个百分点;生草还降低了葡萄叶片的温度及气孔导度。可见,葡萄园行间生草改善了土壤物理性状,促进了葡萄生长发育。     

喷水方式对葡萄叶片SPAD值和叶绿素含量及产量的影响

【目的】研究极端干旱区葡萄微喷条件下,不同喷水方式对葡萄叶片SPAD值和叶绿素含量及产量的影响,确定优质高产的喷水方式,为快速测定大田葡萄叶片叶绿素含量提供新方法。【方法】采用微喷灌溉,对不同喷水方式下,测定葡萄SPAD值、叶绿素含量及品质与产量,分析不同喷水方式处理下的SPAD值日变化及连日变化特征、SPAD值与叶绿素含量相关关系。【结果】在不同喷水时长条件下,各处理的SPAD值呈先减小后增大的变化趋势,日变化值在40.1~45.6 SPAD,其中,WP1的SPAD值(44.3)日平均值最高,其次是WP2(43.5)和WP3(42.9),CK(41.2)最低。葡萄SPAD值与叶绿素a、叶绿素b以及总叶绿素含量间的回归方程,分别为C_a=0.068 5VSPAD-0.890 2,C_b=0.045 4VSPAD-1.019 4,C_t=0.114VSPAD-1.909 6,在葡萄品质指标和产量上,采用微喷可以提高VC含量、多酚含量和单宁含量等多项品质指标,并使葡萄平均增产8.6%。【结论】不同喷水方式下,葡萄叶片SPAD值与叶绿素a、叶绿素b以及总叶绿素含量间均存在极显著正相关关系,利用SPAD值预测叶绿素a含量、b含量与总叶绿素含量是可行的。     

全海深ARV被动升沉补偿系统缆绳张力控制分析

本文以上海海洋大学深渊科学技术研究中心研发的11 000 m全海深复合型无人潜水器(ARV)的吊放为研究对象,考虑潜水器在大深度水深吊放与回收过程中的平稳性与安全性等问题,为消除母船升沉运动对潜水器吊放与回收的影响,防止带缆因张力不均而破坏甚至断裂,造成ARV损坏,结合特定海况下的吊放回收要求,提出了一种适应于全深海ARV吊放回收的被动升沉补偿系统。本文简述了被动升沉补偿系统的组成及其工作原理,对油缸进行了尺寸计算,利用AMESim软件对该系统进行了建模与仿真分析,并重点分析了缆绳的张力控制。数值计算和分析结果表明,该系统的缆绳张力满足全海深ARV吊放回收的使用要求,通过解决升沉补偿技术问题,分析了缆绳的张力控制。