深圳海域近20年赤潮发生的特征分析

本文根据深圳海域1981-2002年发生的93起赤潮记录,综合分析了赤潮发生的特征,可归纳为5点：①深圳海域的赤潮多发区位于大鹏湾、大亚湾和深圳圳湾,其中大鹏湾的盐田水域、大亚湾两部的东山和坝光水域、深圳湾的后海与东角头水域为赤潮多发地段;②赤潮发生的频率增高,赤潮持续时间延长;③全年中有两个赤潮多发季节,主要集中在3～5月,其次为9～11月;④赤潮引发种类丰富,约有39种,其中甲藻最多,其次为硅藻,具有一定的区域分布特征;⑤赤潮引发种类具有明显的演替规律,不断有新的种类引发赤潮。     

香港及珠江口海域有害赤潮发生机制初步探讨

回顾了香港及珠江口海域赤潮发生和藻毒素污染的历史及研究状况,结合3种代表赤潮藻种最适光温盐生长实验,4种不同形态氮营养盐对几种常见赤潮藻种生长影响实验,以及不同营养盐,温度,盐度条件下赤潮藻群落变化过程实验,初步探讨了物理,化学,生物等环境因子在香港和珠江口海域赤潮发生中的作用机制。     

东海近海海域营养盐分布特征及其与赤潮发生关系的初步研究

根据2002年4月25日～5月2日的调查数据,分析了东海近海海域营养盐(NO3--N,PO4^3-P,SiO3^2-Si,NH4-N等)的分布特征,并初步探讨了营养盐分布与赤潮发生的关系．结果表明,调查海区营养盐浓度较高,与国家一类海水水质相比,无机氮和无机磷的超标率分别为46％和60％,长江口及杭州湾附近海域富营养化程度比较严重．调查海域由于受沿岸长江等河流输入的影响。营养盐浓度自近岸向外海快速递减,等值线几乎与海岸线平行．根据调查结束后赤潮发生的特点和区域,表明营养盐浓度的增加,尤其是DIN和PO4^3-P的增加,与赤潮的发生有一定关系。但本次赤潮并不是发生在营养盐浓度最高的海区,因此,富营养化并不是诱发本次赤潮发生的唯一环境因素．     

微微型藻华爆发海域硅酸盐与叶绿素a分布特征研究

以南戴河近岸海域为研究对象,分析了该海域2009年5~10月份硅酸盐和叶绿素a的时空分布特征,并初步探讨了它们与微微型藻华的关系。结果表明:整个调查期间该海域硅酸盐平均含量为0.67±0.31 mg·L^-1,叶绿素a平均含量为2.06±1.16 ug·L^-1;其平面分布呈现近岸高、远岸低的特点;硅酸盐平均含量9月最高、5月最低;叶绿素a平均含量在8~9月高、5~6月低;微微藻赤潮期间海域硅酸盐和叶绿素a平均含量明显高于未发生微微藻赤潮的2008年同期。叶绿素a与硅酸盐浓度呈现出正相关关系,在微微藻赤潮爆发期间尤为显著,可能是因为微微型浮游植物大量生长抑制了硅藻等消耗硅酸盐藻类的正常生长繁殖所致。     

我国近海赤潮多发区域及其生态学特征

根据有关的研究资料,分析我国近海赤潮多发区分布、主要赤潮生物种类、环境状况及赤潮发生生态学特点.结果表明,我国辽东湾、渤海湾、莱州湾、大连湾、长江口、舟山海域、杭州湾、厦门湾、柘林湾、大鹏湾、珠江口等为赤潮多发区.引发赤潮的因素较多,它与气象、水动力、营养盐及生物环境的变化密切相关,人类活动(如海水养殖、陆源污水排放等)影响加剧近海富营养化是引发赤潮的重要因素;但富营养化并非发生赤潮的唯一条件,低营养海区也可能发生赤潮.目前对诱发赤潮的关键因子及赤潮发生机理,应加强定点长期监测和开展深入研究.     

深圳市污染物排放总量与其东部水体赤潮发生的关系

探讨了深圳市污染物排放总量对深圳东部海域赤潮发生的影响.结果表明：深圳市总氮(TN)、总磷(TP)净排放量以及排污中的N∶P与东部海域甲藻赤潮发生频率呈明显正相关;推算出东部甲藻赤潮爆发的TP、TN年排污阈值分别为3.917×10³ t和2.123×10⁴ t;而近岸排污与硅藻赤潮发生的相关性不明显.举例说明了深圳排污总量控制的具体方式.     

北海区海洋生态灾害的主要类型及分布现状研究

本文将海洋生态灾害定义为局部海域一种或少数几种海洋生物数量过度增多引起的海洋生态异常现象,包括赤潮、绿潮、水母旺发和外来种入侵等,根据相关研究及调查资料,探讨了北海区赤潮、绿潮、水母、外来生物入侵等生态灾害发生特点及趋势。结果表明,北海区赤潮和绿潮灾害频发,影响面积较大,渤海北部秦皇岛附近海域赤潮灾害严重,黄海西部山东半岛近岸海域浒苔绿潮灾害严重;水母灾害呈上升趋势,对人体健康威胁较大,北海区滨海城市都曾发生过水母蛰伤致死案例;黄河三角洲区域米草和泥螺入侵扩展速度较快。面对这些海洋生态灾害巨大威胁,北海区亟需加强海洋生态灾害防控研究。     

山东海域赤潮灾害特征及预警报管理

掌握赤潮灾害时空分布规律是科学设计赤潮监控方案、提高防灾管理效率的基础和依据。本文统计分析了1990—2010年间山东海域的76次赤潮灾害事件数据。结果表明:赤潮灾害频率显著地分为4个波段,且峰值呈递增趋势;灾害面积呈现周期性倒U型曲线变化;每年的5—10月是赤潮灾害的多发期,其中,8月的灾害次数和灾害面积均占全年总数的30%以上;灾害空间分布集中在莱州湾海域、青岛近海、庙岛群岛的北隍城海域,烟台四十里湾的赤潮灾害最频繁;夜光藻(Noctiluca scintillans)和球型棕囊藻(Phaeocystis globosa)引发的赤潮灾害面积最高,夜光藻和红色裸甲藻(Gymnodinium sanguineum)致灾次数最多。本文从赤潮监测与信息采集、赤潮预报方法以及赤潮灾害预警报管理机制3个方面分析总结了山东海域赤潮灾害预警报业务化管理现状,结合山东海域赤潮灾害特征和预警报管理实践,提出了以控制污染和修复生态环境为根本的赤潮防控建议。     

一次陆源降雨污水引起血红哈卡藻赤潮的成因

以2007年烟台四十里湾海域血红哈卡藻(Akashiwo sanguinea Hirasaka)赤潮为对象,研究赤潮消长与水环境因子的关系。研究发现大量陆源降雨污水输入后,海水盐度急剧下降、营养盐大幅增加,特别是活性磷酸盐浓度明显增加,促进了血红哈卡藻的生长繁殖并最终形成赤潮。赤潮发生前海区第一优势种为尖刺拟菱形藻(Pseudo-nitzschia pungens Halse),优势度0.47(0.42—0.52),多样性指数2.63(2.43—2.89);赤潮发生时血红哈卡藻密度范围1.05×105—4.10×106个/L,优势度0.92(0.83—0.99),多样性指数0.27(0.15—0.64);赤潮消退后中肋骨条藻(Skeletonema costatum Cleve)为第一优势种,优势度0.49(0.43—0.55),多样性指数2.46(2.19—2.84)。赤潮的发生、发展、消亡与化学需氧量(COD)、无机氮(DIN)、活性磷酸盐(DIP)、富营养化指数(E)呈显著正相关(P<0.05),与盐度呈显著负相关(P<0.01)。赤潮前、后该海域为贫营养、P限制、叶绿素a含量中等,赤潮期间该海域为富营养、P限制、叶绿素a含量高。通过影响力评定,活性磷酸盐、COD、盐度是此次赤潮发生的主要诱发因子,当活性磷酸盐含量低于0.3μmol/L时,硅藻逐渐取代甲藻,此次赤潮消散。     

深圳湾海域赤潮生物演变及赤潮预警关键因子分析

2020年5月初,深圳湾海域发生近5年来首次赤潮, 面积达到6 km2, 前期赤潮优势种为中肋骨条藻(Skeletonema costatum), 后期转变为赤潮异弯藻(Heterosigma akashiwo)。布放于深圳湾海域的海洋环境综合浮标自动监测到了赤潮发生过程的海水水质和生态数据变化: 赤潮发生前(4月底)硝酸盐和磷酸盐均大幅升高; 赤潮发生期间, 叶绿素a浓度迅速升高, 最高值达到127.1 μg·L-1(5月2日), 海水温度持续升高, 盐度整体下降; 5月4日开始, 赤潮逐渐消散, 当日水温日均值达到28 ℃以上, 风力也开始升高, 盐度则继续降低。经研究分析, 本次深圳湾赤潮的主要调控因素可能是水温, 活性磷酸盐大幅升高可能是引发中肋骨条藻大规模增殖的诱因, 而赤潮后期的陆源水体输入导致的悬浮物增加导致了赤潮快速消亡。本次赤潮优势种从硅藻到针胞藻的转变, 主要原因可能是赤潮前期磷酸盐快速消耗导致的磷供应不足。通过数据分析发现, 近十几年来, 深圳湾海域赤潮生物逐渐从硅藻转变为甲藻及其他藻类, 其原因与海域氮磷比持续升高、磷成为限制因子有关, 故海域赤潮监测预警应重点关注磷酸盐的变化。     

Temporal Occurrence and Spatial Distribution of Red Tide Events in China's Coastal Waters

Between the years 1933–2001, 460 red tide events were found in China's coastal water. The scope of red tide occurrence has extended over all the coastal provinces of China, and the three major areas with high red tide frequency are the Bohai sea, the sea area near the Shengsi Archipelago and Huaniaoshan Island on the outer side of the Changjiang River estuary and the Hangzhou Bay, and the coastal waters on the east side of the Zhujiang River estuary from Hong Kong to East Guangdong. In the past 20 years, the frequency of red tides has been tending upwards. The years of 1988–1990 and 1998–2001 saw the most serious red tides along China's coastal waters, with the latter period as the peak. The average area of a single red tide, i.e., the scale of red tides, is expanding every year, and in 2001 rose to about 500 km². Every year, China's red tides occur from south to north, with those in the South China Sea occurring from March to May, those in the East China Sea from April to August and those in the Bohai and Huanghai Seas from May to September.     

Eine “red tide” in der südlichen Nordsee und ihre Beziehungen zur Umwelt

Phytoplankton blooms have attracted attention since times of old, especially the red tides caused by peridinians. Observed in all regions of the world, red tides occur predominantly in the warmer seas (e. g. West Coast of Florida). An opportunity to study a bloom, caused by the non-toxic dinoflagellateCeratium furca, was provided in North Sea coastal waters of an area ranging from Belgium to Sweden. Its development could be followed from July to October 1981 with the aid of samples taken 5 days a week near the island of Helgoland. A decline in the bloom coincided with a drop in water temperature (increasing turbulence). This condition and the presence, right up to the end, of relatively high amounts of nutrients indicate that nutrient deficiency did not terminate the bloom. Similarly, there was no evidence for a dependence on micronutrients by freshwater input or by the preceding diatom bloom. Longterm investigations indicate that climatic changes coincide with an increase in the phytoplankton stock during all seasons (especially noticeable from July to September) and with a decrease in salinity (there was a minimum in 1981). The stratification of the sea water causes the peridinians to move to depths optimal for their growth which may bring about an aggregation at the surface. There are numerous indications in literature of similar changes of environmental conditions in the North Sea. One example from the Western Baltic Sea demonstrates that the presence of a high vertical density gradient in the sea leads to oxygen deficiency in deeper zones, which, however, is not directly correlated to the coincident phytoplanktonic bloom in the upper layers. It is probable that, under appropriate hydrographical conditions, “red tides” can occur repeatedly in the southern North Sea, produced by non-toxic as well as toxic species.     

鼎湖山人工马尾松第1代与自然更新代生长动态比较

应用年轮分析法研究马尾松栽种的第1代和自然更新代的动态。结果表明,本区域马尾松第1代在贫瘠土壤上能正常生长,并在成熟期有较高的生长量,因此不失为较好的造林绿化的先锋树种。从经济利用的角度出发,应在生长量高峰期后采伐最为合理,在本区域采伐期可选择在树龄40年左右。但马尾松的更新代严重退化,表明本区域在土地利用上不能连续栽种马尾松,最佳方式是在35年林龄左右进行林分改造。     

A hierarchy of conceptual models of red-tide generation: Nutrition,behavior, and biological interactions

Red tides – discolorations of the sea surface due to dense plankton blooms – occur regularly in coastal and offshore waters along much of the world's coastline. Red tides often cause large-scale mortalities of fish and shellfish and significant losses to the aquaculture and tourist industries of many countries. Therefore, understanding and predicting the mechanisms controlling the outbreak, persistence, spread, and decline of red tides are important concerns to scientists, officials, industry, and the public. With increasing knowledge of red-tide species and red-tide events, new mechanisms have been discovered. Based on the nutrition and behaviors of red-tide organisms and biological interactions among them, red-tide outbreaks can be categorized into a hierarchy of four generation mechanisms (GM1–GM4). In the simplest, GM1, all phototrophic red-tide species were treated as exclusively autotrophic organisms without the ability to swim. However, this GM cannot explain red-tide outbreaks in oligotrophic surface waters offshore. Vertical migration (considered in GM2) and mixotrophy (GM3) enable red-tide flagellates to acquire growth factors from nutrient-rich deep waters or co-occurring prey, respectively. In natural environments, all red tides occur by those species outgrowing co-occurring organisms; red-tide species dominate communities by eliminating other species or reducing their abundances. Thus, GM4 contains the direct biological interactions (i.e., inhibition by physical contact or chemical effects) and indirect biological interactions (i.e., acquiring resources faster than others) that can affect the dominance of red-tide species under given conditions. Correctly choosing one of these four GMs for red tides dominated by one causative species is important because the accuracy of predictions may be outweighed by the costs and time required to acquire the relevant information. In this study, mechanisms describing the outbreak, persistence, and decline of red tides were reviewed, the advantages and limitations of each mechanism were evaluated, and insights about the evolution of the mechanisms were developed.     

Microgrowth patterns in the shell of the Malaysian cockle Anadara granosa (L.) and their use in age determination

Marked specimens of the Malaysian cockle Anadara granosa (L.) were placed in buried cages (filled with sediment from the surrounding substratum) which were located in intertidal and subtidal environments in an area between Penang Island and mainland West Malaysia. In the majority of cockle shells examined the number of growth bands deposited was close to the number of tidal periods. Bands in the shells of intertidal animals were more strongly defined than those in shells continuously immersed. The banding pattern in shells from the subtidal environments showed narrow increments during spring tides alternating with a few wider increments during neap tides. The growth increments between bands correspond to tidal periods so they can be used to record growth rates and provide estimates of the ages of the shells. Samples of cockles collected from four sites in a commercial cockle-culture area off the coast of West Malaysia were aged. Two of the sites were located in an estuary where the cockles were periodically exposed to fluctuating salinities during the intermonsoon period. Cockles from the other two sites were situated away from the estuary and experienced full strength sea water. There was good agreement between the calculated estimates of the ages determined from the tidal bands and their known ages. Shells of cockles from the estuary had characteristically marked banding patterns which may be related to shell deposition during the intermonsoon period when the cockles were exposed to sea water of low salinity. Cockle shells collected outside the estuary did not display these patterns.     

Flooding regimes increase avian predation on wildlife prey in tidal marsh ecosystems

Within isolated and fragmented populations, species interactions such as predation can cause shifts in community structure and demographics in tidal marsh ecosystems. It is critical to incorporate species interactions into our understanding when evaluating the effects of sea‐level rise and storm surges on tidal marshes. In this study, we hypothesize that avian predators will increase their presence and hunting activities during high tides when increased inundation makes their prey more vulnerable. We present evidence that there is a relationship between tidal inundation depth and time of day on the presence, abundance, and behavior of avian predators. We introduce predation pressure as a combined probability of predator presence related to water level. Focal surveys were conducted at four tidal marshes in the San Francisco Bay, California where tidal inundation patterns were monitored across 6 months of the winter. Sixteen avian predator species were observed. During high tide at Tolay Slough marsh, ardeids had a 29‐fold increase in capture attempts and 4 times greater apparent success rate compared with low tide. Significantly fewer raptors and ardeids were found on low tides than on high tides across all sites. There were more raptors in December and January and more ardeids in January than in other months. Ardeids were more prevalent in the morning, while raptors did not exhibit a significant response to time of day. Modeling results showed that raptors had a unimodal response to water level with a peak at 0.5 m over the marsh platform, while ardeids had an increasing response with water level. We found that predation pressure is related to flooding of the marsh surface, and short‐term increases in sea levels from high astronomical tides, sea‐level rise, and storm surges increase vulnerability of tidal marsh wildlife.     

Mass Stranding of Marine Birds Caused by a Surfactant-Producing Red Tide

In November-December 2007 a widespread seabird mortality event occurred in Monterey Bay, California, USA, coincident with a massive red tide caused by the dinoflagellate Akashiwo sanguinea. Affected birds had a slimy yellow-green material on their feathers, which were saturated with water, and they were severely hypothermic. We determined that foam containing surfactant-like proteins, derived from organic matter of the red tide, coated their feathers and neutralized natural water repellency and insulation. No evidence of exposure to petroleum or other oils or biotoxins were found. This is the first documented case of its kind, but previous similar events may have gone undetected. The frequency and amplitude of red tides have increased in Monterey Bay since 2004, suggesting that impacts on wintering marine birds may continue or increase.     

Lunar synchronization of spawning in sea bass, Lates calcarifer (Bloch): effect of luteinizing hormone-releasing hormone analogue (LHRHa) treatment

Based on egg collection records, spontaneous spawning activity of sea bass, Lates calcarifer (Bloch), reared in floating net cages followed a semilunar cycle. The peak of multiple spawnings coincided with declining spring tides of quarter moon periods. Maximum diameter of intra-ovarian, ripe oocytes (0.51–0.55 mm) occurred in synchrony with the quarter moon periods. Smaller oocytes (0.44–0.47 mm) were sampled during the new and full moon periods. Two structural analogues of luteinizing hormone-releasing hormone (LHRHa) (des-Gly¹⁰, d -Ala⁶-LHRH ethylamide and d -Ala⁶, Pro⁹-Nethylamide-LHRH), in pelleted or dissolved form, induced mature female sea bass with a mean egg diameter of at least 0.40 mm to spawn at any day during the lunar cycle. The onset of spontaneous and LHRHa-induced spawnings occurred during low tides in the evening until dawn (from 19.00 to 05.00 hours). These results demonstrate that LHRHa can effectively induce mature sea bass to spawn independent of the highly predictable semilunar spawning rhythm. In addition, the occurrence of both spontaneous and hormone-induced spawnings at a precise period of the day suggest a tidal and diurnal cue entraining spawning of mature female sea bass.     

Rectal gland morphology of freshwater and seawater acclimated bull sharks Carcharhinus leucas

To compare rectal gland morphology of bull sharks Carcharhinus leucas , animals captured in the freshwater reaches of the Brisbane River, Australia, were acclimated to sea water over 17 days with 1 week in the final salinity. A control group was left in fresh water for 17 days. Animals in fresh water and sea water were strongly hyper- and hypo-ionic with respect to plasma Na⁺ and Cl^–, respectively. This difference necessitates NaCl secretion by the rectal gland in sea water and conservation of NaCl in fresh water. Structural differences in the rectal gland of freshwater and seawater acclimated bull sharks were limited. There was no difference in rectal gland cross-sectional area, lumen area, rectal gland vein area, number of secretory tubules or secretory cells per secretory tubule in freshwater and seawater acclimated animals. At a cellular level, there was no difference between the degree of basolateral and lateral folding, number of mitochondria or number of desmosomes per tight junction. Tight junction width was significantly greater in seawater acclimated animals. The number of red blood cells in the interstitial tissue was also significantly higher in seawater acclimated animals, possibly as a result of increased blood perfusion of the secretory epithelia. The lack of major structural changes in the rectal glands of bull sharks acclimated to fresh water and sea water most likely represents the salinity gradient in the Brisbane River where animals are found throughout the river and can experience large fluctuations in salinity over short distances. Differences in rectal gland morphology of bull sharks in fresh water and sea water are discussed in terms of their relevance to osmoregulation in elasmobranchs.