黄海水产研究所在鳗草幼苗培育技术方面取得突破

正近日,中国水产科学研究院黄海水产研究所与荣成东楮岛水产有限公司联合开展的海草床生态系统重建项目通过专家组阶段性现场验收。海草床生态系统是三大典型生态系统之一,也是"蓝碳"的重要组成部分,具有重要的生态服务功能。例如,海草床能为生物提供栖息、育幼场所,丰富周围生物多样性。因此,在全球海草资源日趋衰退的背景下,海草资源的恢复和保护是重建其生态服务功能的重要途径之一。然     

海草植株扩繁理论及其定植效应的研究进展

海草(Seagrasses)是地球上一类经陆生植物演化，发展到可以完全在海洋环境中生活的高等被子植物，具有重要的生态功能和经济价值。本文综述了近年来国内外对海草植株扩繁理论及其定植效应的研究进展，总结了影响海草植株生长扩繁的环境因素，探讨了定植间距、定植阶段、施肥处理等定植理论和技术对海草植株定植效应的影响，并对目前存在的科学问题进行归纳总结，就未来我国沿岸受损海草床生态系统的规模化修复研究提出了展望。     

海草对营养盐的吸收过程及其与附生藻类的竞争机制

海草床是近岸海域重要的生态系统,具有显著的生态服务功能,但近岸海域的富营养化已对海草床生态系统的结构与功能构成严重威胁。本文从营养盐与海草生长的关系、海草叶片和根部对营养盐的摄取过程、海草与附生藻类的营养盐竞争及其影响等三个方面,综述了海草对营养盐的吸收过程及其与附生藻类的竞争机制。最后提出如下重点研究方向:1)在不同环境条件下,海草叶与根对营养盐摄取的贡献;2)附生藻类对海草生长的影响机制;3)海草营养吸收与竞争的生态环境效应。     

海草床的产卵场功能及其形成机理研究进展

正海草是一类能够在海洋环境生存,具有典型根、茎、叶结构的高等单子叶植物,其整个生活史的开花、传粉和结种等过程均在海水中进行,主要分布于沿岸浅水区域~([1])。全球已知海草种类有72种,中国现存22种,其中鳗草属(Zostera)和喜盐草属(Halophila)的海草种类最多,分别为5种和4种~([2-3])。海草床作为滨海三大典型生态系统之一,     

荣成天鹅湖海草床及其邻近裸沙区浮游生物的时空变化特征

海草床是近海典型生态系统之一,为了解山东省荣成市天鹅湖鳗草(Zostera marina)海草床及其邻近裸沙区的浮游生物群落结构及时空变化特征,于2019年2月、5月、8月和11月,对天鹅湖鳗草海草床及其邻近裸沙区的浮游生物、海草床生态学特征及关键环境因子进行了周年调查,并应用典范对应分析(CCA)和冗余分析(RDA)探究了环境因子对浮游生物优势种的影响。结果显示,共发现浮游植物38种,隶属3门25属,其中,硅藻门(Bacilariophyta)种类最多(89.4%),甲藻门(Dinophyta)次之(7.8%);共发现浮游动物18种,幼虫3类,以甲壳动物(71.4%)为主;浮游生物种类数呈现显著的季节变化,且在11月达到最大值;海草床浮游植物和浮游动物的年平均丰度分别为5.4×104 cells/m3和1.6×104 ind./m3,是裸沙区浮游植物和浮游动物年平均丰度的1.4倍和1.5倍;典范对应分析和冗余分析显示,海草床浮游生物优势种主要与水温、海草床的植株密度及生物量显著相关,而裸沙区浮游生物优势种则主要与水温、pH值及氨氮含量等环境因子显著相关。结果表明,天鹅湖海草床相比裸沙区具有更丰富的浮游生物。本研究为深入了解海草床生态系统的结构和功能提供了基础数据。     

威海双岛湾海域海草分布及其生态特征

2016年8月，现场调查并分析了山东省威海市双岛湾海域的海草资源及其生态特征，发现分布面积为442.19 hm2的海草床，种类为鳗草(Zostera marina)和红纤维虾形草(Phyllospadix iwatensis) 2种。鳗草的分布面积约为434.46 hm2，占总面积的98.3%，主要分布在双岛湾中部东侧及海参池，其平均植株密度和生物量分别为(174.2±9.2) shoots/m2和(337.7±17.5) g DW/m2。红纤维虾形草的分布面积约为7.73 hm2，占总面积的1.7%，主要分布在双岛湾湾口东侧及向东约3 km的近岸礁石浅水区，呈明显的带状分布，其平均植株密度和生物量分别为(889.1±17.1) shoots/m2和(605.9±18.1) g DW/m2。双岛湾海草床平均水深约为1.6 m，鳗草草床底质坚硬，平均底质粒径约为(4.3±0.2) mm。本调查表明，双岛湾海草床受到陆源污染物排放、围海养殖和捕捞作业等人类活动的严重威胁，提出了保护双岛湾海草床的建议和对策，为我国海草床现有资源提供数据补充。     

海南新村湾泰来草形态和生理指标特征及环境影响因素

海草具有重要的生态系统服务功能,其形态和生理指标受到各种环境因素的影响。本研究在2019年对海南陵水新村湾泰来草(Thalassia hemprichii)海草床进行了6次采样调查,研究了一年内1月、3月、5月、7月、9月和11月的海草形态和生理特征,分析了环境因素对泰来草形态和生理特征的影响。结果显示,泰来草形态指标叶长、叶宽、根状茎直径、根长在不同月份间存在显著差异,叶长最大值和最小值分别出现在5月[(15.05±6.13) cm]和9月[(7.19±2.55) cm];叶宽最大值和最小值分别出现在11月[(11.93±1.68) mm]和9月[(8.73±1.96) mm];根状茎直径最大值和最小值分别出现在11月[(5.22±1.71) mm]和3月[(4.06±0.74) mm]。泰来草地下组织碳含量在不同月份间存在显著差异,最大值和最小值分别出现在11月[(31.23±0.94)%]和3月[(24.90±3.48)%]。相关性分析显示,海水温度与泰来草叶宽、地下组织碳含量呈显著正相关;盐度与叶长和根状茎长呈显著正相关,与地下组织碳含量呈显著负相关;海水pH与叶长、叶宽、地下组织碳含量和地下组织氮含量呈显著正相关。海水中的溶解无机氮、氨氮和硝酸氮对海草生理指标有显著影响。沉积物有机碳含量与叶长、叶宽和根状茎长呈显著负相关。研究表明,新村泰来草的生长受到温度、盐度、pH的影响较大,高营养盐水平可能对泰来草产生负面影响,应该限制该地区营养盐输入。本研究可为保护新村湾泰来草海草床以及修复受损海草床生态提供数据支撑和科学依据。 海南省近岸海洋生态环境过程与碳汇重点实验室 海南 三亚 572022     

我国首个全球海草科学监测站在北海市建立

世界海草协会全球海草监测网日前将一套全球标准化海草监测工具赠予广西红树林研究中心，与广西红树林研究中心合作在北海市设立中国首个全球海草科学监测站。全球海草科学监测站是全球海草监测网设立的海草监测机构，使用统一的方法和工具，对各海域的海草资源现状进行监测，为保护海草场提供科学依据。     

海草种子结构的研究进展

海草（seagrass）是生活于热带和温带海域浅水中的单子叶植物,一般分布于低潮带和潮下带6m以上（少数可深达30m）的浅水生境。海草具有发达的根系和地下茎,能进行水媒传粉,也可以通过根茎进行无性繁殖,它的耐盐性极强,而且植物体具有发达的通气组织,能完全生长于沉水环境中。在适宜的条件下,海草可以形成大面积的海草床。     

大叶藻种子萌发与幼苗培育、种植方法的初步研究

<正>海草(Seagrasses)是生活于热带和温带海域浅水中的单子叶植物。目前全世界共发现有海草约12属67种,在中国共分布有5科11属21种海草[1]。大叶藻(Zostera marina L.)作为海草的一个典型代表,生于潮间带和潮下带的浅海中,通常形成广大的群落—海草床。海草能完全生长于沉水环境,有很发达的根状茎,有稳定沉积物、稳定底泥、抵御风浪对近岸底质的侵蚀作用,同时海草的叶片可以捕捉悬浮     

Linking pipefishes and seahorses to seagrass meadows in the Venice lagoon: Implications for conservation

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鳗草根际固氮菌的分离鉴定及培养条件的筛选

为了解鳗草(Zostera marina)根际微生物的共生固氮功能,并分离得到对海草有潜在促生效果的功能微生物,以山东荣城天鹅湖鳗草为研究对象,采用选择性固氮培养基从其根际分离得到了两株具较高固氮酶活性的菌株(3A和4G),从形态学、生理生化特性、16S rDNA和固氮基因nifH等方面对菌株进行筛选和鉴定,探讨菌株的最佳培养条件并获得了菌株典型生长曲线。结果表明,菌株3A为海旋菌(Thalassospira),革兰氏阳性菌,菌落圆形桔黄色,可利用的碳源:D-甘露糖,D-松三糖,L-鼠李糖等,最佳培养条件:盐度2.585%,pH 8.18,温度31.49℃;菌株4G为芽孢杆菌(Bacillus),革兰氏阴性菌,菌落圆形乳白色,可利用的碳源:D-纤维二糖,D-葡萄糖,D-麦芽糖,蔗糖,D-甘露醇,D-海藻糖等,最佳培养条件:盐度2.920%,pH 7.99,温度37.27℃。利用乙炔还原法测定二者的固氮酶活性,分别为252.21 nmol C_2H_4/(mL·h)和196.31 nmol C_2H_4/(mL·h)。研究证实两株菌株具有良好的固氮性能,可用于海草固氮肥的研制,在海草床生态系统恢复研究领域具有潜在的应用前景。     

The effects of distance from coral reefs on seagrass nursery use by 5 emperor fishes at the southern Ryukyu Islands,Japan

Whilst the importance of seagrass beds as nurseries for coral reef fishes has been clearly recognized, the vast majority of early studies on fish nursery habitats emphasized the close proximity of the latter to coral reefs. To determine the potential nursery role of isolated seagrass beds, we investigated the degree to which juvenile emperor fishes (Lethrinidae) utilized seagrass beds in the presence/absence of adjacent coral habitats at Ishigaki Island (southern Japan), such fishes being known to use seagrass beds as nurseries. Seagrass beds in close proximity to coral habitats (distance between the two habitats of 50–200 m) had greater densities of lethrinid juveniles than those without adjacent coral habitats (2.5–4 km) for 3 different sites investigated, although a significant difference was obtained only for 1 site. Juveniles of Lethrinus atkinsoni, L. obsoletus, L. harak, and L. nebulosus were observed in seagrass beds with and without adjacent coral habitats, whereas L. ornatus occurred only in the former. Overall, most lethrinid juveniles utilize seagrass beds irrespective of the presence of adjacent adult coral habitat, suggesting that both types of seagrass beds would contribute to lethrinid adult populations. Therefore, management efforts for lethrinid populations should be applied not only to contiguous coral-seagrass habitat systems but also to isolated habitats.     

Response of different benthic habitats to off‐shore fish cages

Off‐shore fish farming can increase the organic load of nearby coastal marine ecosystems due to the deposition of fish food and faeces on seabeds. Seagrass meadows are particularly affected by aquaculture activities but there are few empirical data showing differential effects of the same farming activity on multiple habitat types. Here, we assessed over a 2‐year period whether macrofaunal assemblages inhabiting sandy bare seabeds and Cymodocea nodosa meadows varied in their macrofaunal community structure to the fish farming activities. We observed high spatial and temporal variability in macrofauna composition and dynamics among seabed habitats and a limited impact of fish cages in their area of influence as compared with control areas. Seagrass meadows showed a higher abundance in macrofauna communities than sandy bare bottoms. Local marine currents could partially explain some results because of their influence on grain size composition. Differences in grain size resulted in higher abundances of the tanaid Apseudes talpa beneath fish cages and the absence of the sensitive amphipod Ampelisca brevicornis. Differences of resilience of seabeds (seagrass meadows and sandy bare bottoms) should be taken into account for environmental monitoring studies of off‐shore fish cages. Our results suggest that hydrodynamics are a key factor to determine buffer areas between fish cages and seagrass meadows.     

Implications of nutrient enrichment for the conservation and management of seagrass Zostera muelleri meadows

1. Nutrient overenrichment in aquatic environments, or eutrophication, is increasingly affecting seagrass habitats around the world, leading to the degradation of seagrass ecosystems and the loss of associated ecosystem services.
2. The resistance of seagrass to nutrient enrichment is believed to be site specific, yet the direct correlations between environmental factors and the resistance of seagrass meadows has not yet been adequately resolved. The response of seagrass beds to long‐term multiple‐level sediment nutrient enrichment represents a current research gap.
3. This study therefore assessed the in situ long‐term influence of four levels of sediment urea fertilizer addition on Zostera muelleri plants using a manipulative experimental design at three sites with diverse sediment characteristics. Specifically, this study investigated the response of porewater nutrient concentration, seagrass morphology indices, and seagrass plant tissue carbon and nitrogen contents under experimental nutrient stress levels.
4. Over a 13‐month experiment, sediment nutrient addition substantially increased the ammonium concentrations in the sediment porewater, significantly decreased seagrass morphology indices, and caused a carbon and nitrogen imbalance in plant tissues. Ammonium toxicity was more pronounced in seagrass meadows growing on sandy substrates with lower relative above‐ground biomass, which showed low resistance to eutrophication at sediment ammonium concentrations of up to 1 × 10⁴ μM. Plants growing in muddy sand substrates with higher relative above‐ground biomass were more resistant to nutrient impacts, however, with a delayed negative response observed in response to higher nutrient concentrations (up to 1 × 10⁵ μM).
5. Our findings suggest that seagrasses in low‐nutrient sandy environments show more rapid responses to eutrophication, although seagrasses in both sandy and muddy substrates exhibited declines in response to a long‐term elevation of sediment nutrient concentrations. While continuing to assess the relative susceptibility of seagrass habitats across differing environments to inform coastal management, conservation efforts should allocate resources accordingly and prioritize reducing nutrient overenrichment in sensitive seagrass meadows.

     

Do different seagrass species support distinct fish communities in south‐eastern Australia?

Between spring 1998 and autumn 1999, a fine mesh seine net was used to sample fish communities at three locations in south-eastern Australian estuaries, two located near Sydney [Botany Bay (BB) and Port Hacking (PH)] and one located approximately 150 km to the south [Sussex Inlet (SI)]. At each location, fish were collected from adjacent beds of the seagrasses Posidonia australis Hooker and Zostera capricorni Ascherson. These seagrass species differ markedly in morphology and life history. Fish communities displayed significant differences between seagrass species with respect to abundances and lengths of economically important species, and the structure of assemblages at locations in PH and BB, but not in SI. Differences appeared to be related to the recruitment of juveniles of several inshore species, such as Acanthopagrus australis (Günther), Rhabdosargus sarba (Forskaal) and Girella tricuspidata (Quoy & Gaimard) to Zostera beds at BB and PH during spring and early summer. These differences were not evident over the wider spatial scale, however, the SI location did support a distinct assemblage of fish compared with locations in PH and BB. These results suggested that local recruitment events and differences in estuarine geomorphology may be important in structuring these seagrass fish communities.     

Prioritizing localized management actions for seagrass conservation and restoration using a species distribution model

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移植大叶藻的形态、生长和繁殖的季节性变化

通过对移植2年后的大叶藻(Zosteramarina L.)的形态、生长和繁殖情况进行4个季度的观察和测量,发现在春季(3月和4月)和初夏(6月)大叶藻叶的叶绿素含量较低,而其他季节相对较高;根在冬季(12月和1月)和初春(3月)最发达;叶及叶鞘长度,叶宽和每株成体的生物量都在夏季达到最高值,而在秋季降到最低值;单株大叶藻叶生产率的最高值和最低值也分别出现在夏季和秋季;大叶藻侧生苗在冬季的萌发率最高,而夏季未观测到有侧生苗萌出。结果显示,光照影响大叶藻叶绿素的含量;水温对移植大叶藻的形态、生长和无性繁殖产生显著影响,夏季高水温对大叶藻生长的抑制作用比冬季低水温的影响更大。