Length‐weight relationships of 69 fish species in the Beibu Gulf,northern South China Sea

Sixty‐nine fish species belonging to 41 genera from 29 families and seven orders were collected during 2006–2007 by otter trawl in Beibu Gulf, northern South China Sea, for analysis of their length‐weight relationships (WLRs). The analysis included 19 species for which no previous WLR estimates were available in FISHBASE.     

南海北部表层沉积物中原核微生物多样性

[目的]为研究南海北部沉积物原核微生物的多样性和群落结构.[方法]从南海北部XSCS13站位表层沉积物中扩增古菌和细菌的16S rDNA并构建文库,随机挑出阳性克隆子进行测序,选出所有的OTU构建系统进化树,进行系统发育学分析.[结果]多数克隆子来自于未培养原核微生物,沉积物中的古菌分属3大门类:泉古菌(Crenarchaeota)、奇古菌(Thaumarchaeota)和广古菌(Euryarchaeota),其中泉古菌(Crenarchaeota)为主要门类,占71％;广古菌(Euryarchaeota)最少,只有3个克隆子.泉古菌(Crenarchaeota)又以MG Ⅰ为主要类群,占61％.细菌多样性明显高于古菌,共9个门类:变形杆菌(Proteobacteria)(32.6％)、疣微菌(Verrucomicrobia)(3.0％)、拟杆菌门(Bacteroidete)(5.2％)、酸杆菌(Acidobacteria)(4.4％)、绿弯菌(Chloroflexi)(6.0％)、厚壁菌(Firmicute)(3.7％)、浮霉菌(Planctomycete)(5.2％)、芽单胞菌(Gemmatimonadete)(11.1％)、放线细菌(Actinobacteria)(4.4％).变形杆菌为优势类群(包括α-Proteobacteria、γy-Proteobacteria和δ-Proteobacteria 3个亚群),其中γ-Proteobacteria是Proteobacteria中的优势种群,占54.5％.另外所有原核微生物总共有超过50％的克隆子与硫酸盐的还原以及甲烷的形成相关.[结论]结果表明南海北部XSCS13站位表层沉积物中原核微生物的多样性非常丰富,其中蕴含大量未知的微生物资源;另外古菌和细菌群落结构表明该位点可能处于富含甲烷的冷泉活动区.     

南海北部浮游桡足类对浮游植物的摄食压力

于2004年2月(冬季)和8月(夏季)在南海北部使用肠道色素法研究了浮游桡足类群落对浮游植物现存量的摄食压力。将底到表垂直拖网(网孔径200μm)获得的桡足类分为中型(>500μm)和小型(200~500μm)两个体长组。冬季:中型桡足类的丰度为103~2343(平均633)ind/m3,肠道色素为0.15~2.71(平均1.31)ng/ind,肠道排空率为0.011(A4)~0.019(C1)min-1,个体摄食率为3.13~58.48(平均28.36)ng/(ind.d),群落摄食率为1902~62369(平均18679)ng/(d.m3),对浮游植物生物量的摄食压力为每天0.25%~6.39%(平均3.04%)。小型桡足类的丰度为418~6250(平均1691)ind/m3,肠道色素为0.18~3.44(平均1.19)ng/ind,肠道排空率为0.012(A4)~0.016(C1)min-1,个体摄食率为3.67~70.04(平均24.34)ng/(ind.d),群落摄食率为1540~158561(平均44227)ng/(d.m3),对浮游植物生物量的摄食压力为每天0.44%~15.70%(平均6.59%)。浮游桡足类群体对浮游植物生物量的摄食压力为每天1.02%~20.10%(平均9.63%)。夏季:中型桡足类的丰度为111~1298(平均621)ind/m3,肠道色素分别为0.22~1.58(平均1.03)ng/ind,肠道排空率为0.017min-1,个体摄食率为5.52~39.92(平均25.95)ng/(ind.d),群落摄食率为4411~26667(平均12878)ng/(d.m3),对浮游植物生物量的摄食压力为每天0.23%~6.52%(平均2.52%)。小型桡足类的丰度为756~8804(平均2990)ind/m3,肠道色素含量为0.09~2.92(平均0.87)ng/ind,肠道排空率为0.020min-1,个体摄食率为2.73~87.77(平均26.26)ng/(ind.d),群落摄食率为9309~139817(平均47191)ng/(d.m3),对浮游植物生物量的摄食压力为0.86%~37.79%(平均10.99%)。浮游桡足类群体对浮游植物生物量的摄食压力为1.09%~39.95%(平均13.51%)。数据表明,2月份和8月份桡足类群体对浮游植物现存量的摄食压力较低,桡足类摄食不是南海北部浮游植物死亡的主要原因。     

Spatial structure of eukaryotic ultraplankton community in the northern South China Sea

Spatial distribution, diversity and composition of eukaryotic ultraplankton community of the northern South China Sea (nSCS) surface water and the relationship with the in situ water environment were investigated by the method of polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE). A total of 18 DGGE intensive bands were detected and the sequence analysis of these DGGE bands revealed that Alveolata was the dominant eukaryotic ultraplankton group of surface water in the nSCS (50%). Other species belonged to Bicoecea, Bolidophyceae, Polycystinea and Chlorophyta, which accounted for less proportion of eukaryotic ultraplankton in the study area. Unweighted pair group method with arithmetic averages clustering of the sampling stations indicated that all stations were classified mainly based on geographical proximity. Redundancy analysis (RDA) was employed to further investigate the relationships between DGGE band pattern and the environmental variables. Based on the RDA analysis, temperature, salinity, phosphorus and silicate were the important factors to shape the eukaryotic ultraplankton community composition in the nSCS.     

Spatial and temporal distribution of nanoflagellates in the northern South China Sea

Seasonal variation, horizontal and vertical distribution, and cell size of nanoflagellates, together with physico-chemical and biological factors, were studied in the northern South China Sea (SCS). It was found that nanoflagellate abundance ranged from 0.157 × 10³ to 9.193 × 10³ cells/ml (with a mean of 0.891 × 10³) in winter (February, 2004), while it ranged from 0.107 × 10³ to 5.417 × 10³ cells/ml (with a mean of 0.599 × 10³) in summer (July, 2004). Nanoflagellates were more abundant in winter than summer in offshore regions, showing an unique seasonal pattern in this subtropical marginal sea. The abundance of nanoflagellates decreased from the estuary to the offshore region. Vertical distribution of nanoflagellates coupled well with that of bacteria and Chl a. The small size fraction of less than 5 μm dominated the nanoflagellate populations. Wind-driven mixing, eddies, availability of nutrients as well as Chl a and abundance of picoplankton seemed to be the major controlling factors for the spatial distribution and seasonal variation of nanoflagellates in the study area. Handling editor: P. Tasman     

Distribution of polycystine radiolarians in the northern South China Sea in September 2005

We studied the distribution of polycystine radiolarians in the northern South China Sea (SCS) in September 2005 in order to document the relation between radiolarian assemblages and environmental parameters. Vertical plankton tows were collected at depth-intervals from 0 to 250 m at thirteen stations, using a closing net (62 µm mesh). The highest abundance of polycystine radiolarians generally occurred at depths of 0–75 m, i.e., above the chlorophyll-a maximum and thermocline. In contrast, the maximum polycystine abundance occurred below the chlorophyll-a maximum at station E105 (75–150 m), possibly as a result of down-welling of warm waters, and the maximum fell within the chlorophyll-a maximum at station E702, as a result of upwelling of intermediate cold waters.During our sampling period, the southwestern monsoon caused upwelling in the northern SCS (the Taiwan Bank region), as shown by the high abundance of Tetrapyle octacantha, Acanthodesmia vinculata, Cladococcus cervicoris, Octopyle octospinosa, Spongaster tetras, Streblacantha circumtexta and Spongotrochus glacialis. The patterns of distribution and the abundances of the species Botryocyrtis scutum, Pterocorys hertwigii, Collosphaera tuberosa and Didymocyrtis tetrathalamus tetrathalamus suggested that western Equatorial Pacific waters did not yet influence the region at the time of sampling; the first two species were dominant in the northern SCS during our sampling. The species Cornutella profunda and Cyrtopera laguncula were rare at depths of 150–250 m in the tropical region of the SCS, and assemblages in northern and southern SCS were very similar. The relative abundance of B. scutum and P. hertwigii is an indicator for seasonal changes in monsoonal circulation.     

南海北部浮游植物生长对营养盐的响应

2004年夏季作者在南海北部海域研究了浮游植物生长的营养动力学,结合物理-化学过程对浮游植物生物量分布的影响与机制进行了研究,阐明了水平对流和中尺度涡对营养盐分布的影响及浮游植物生长和现存生物量对其的响应。受西南季风和东向沿岸流作用所形成的Ekman输送的影响,南海北部海岸带表层海水作离岸运动,使深层富含营养盐的冷水爬坡涌升到表层来补充,激发浮游植物生物量迅速增长。海区反气旋涡使海水辐聚下沉,造成水体具高温、低盐、高溶解氧浓度、低营养盐浓度和低浮游植物生物量。同时通过现场营养盐加富试验,发现该海域营养盐是浮游植物生长的主要限制因子,而且是多种营养元素共同限制了浮游植物的生长,添加单一的营养盐并不能促进浮游植物的生长。在生物量出现增长的试验组中,营养盐添加不仅促使浮游植物生物量的增长,而且也改变了浮游植物的粒级结构和群落结构。例如,在站S1008,培养前叶绿素a浓度为0.28 mg.m-3,加富培养60 h后浮游植物生物量在NP和NPSi的试验组中有显著的增加,叶绿素a浓度分别达1.07 mg.m-3和1.19 mg.m-3;培养前粒度分级叶绿素a主要以Pico级份占优势,而加富试验结束后,在NP和NPSi的试验组以Nano级份占优势,其它试验组仍以Pico级份占优势;同时,在培养后生物量出现增长的试验组,浮游植物群落的优势类群从甲藻向硅藻演替。     

2007年10月南海北部浮游纤毛虫的丰度和生物量

报道2007年10月南海北部海域(21°25.47′N 17°24.95′N,109°28.86′E 113°13.01′E)纤毛虫丰度和生物量的水平分布及砂壳纤毛虫的种丰富度。包括了13个断面的82个站位,Rosette采水器采水,水深低于15 m的站位采0,5 m和10 m;小于30 m站位,采0,10 m和底层;大于30 m的站位,采0,10,30 m和底层。纤毛虫丰度为0 5757 ind./L,平均(848±776)ind./L。无壳纤毛虫占绝对优势,其丰度占纤毛虫总丰度的比例平均为(91.9±9)%;纤毛虫生物量为0 12.09μg C/L,平均是(1.2±1.54)μg C/L,无壳纤毛虫的生物量平均为(0.94±1.27)μg C/L,占纤毛虫总生物量的78.6%。共发现砂壳纤毛虫16个属,49种,拟铃虫最多,具有一定的季节性。纤毛虫水体(40 m到表层)丰度为6.4×1069.1×107ind./m2,平均是(3.6×106±1.4×106)ind./m2;水体生物量3.6 195.8 mg C/m2,平均(48.1±33.7)mg C/m2。纤毛虫多分布于近岸浅水区(高温低盐,高Chl a),最大丰度要高于我国其他海区,不是Chl a最高的地方纤毛虫的丰度也最大,纤毛虫丰度最大时Chl a偏低。     

夏、冬季南海北部浮游植物群落特征

对2009年7月19日—8月16日和2010年1月6—30日南海北部(18°—23.5°N、109°—120°E)两个航次的浮游植物样品应用Utermhl方法进行了分析鉴定。结果如下:夏季样品鉴定浮游植物4门72属150种,浮游植物细胞丰度范围为(0.16—6001.78)×103个/L,平均细胞丰度为26.49×103个/L,硅藻的平均细胞丰度为25.81×103个/L,主要优势种属有铁氏束毛藻(Trichodesmium thiebautii)、菱形海线藻(Thalassionema nitzschioides)、柔弱伪菱形藻(Pseudo-nitzschia delicatissima)及裸甲藻(Gymnodinium spp.)等;冬季样品鉴定浮游植物4门58属168种,浮游植物细胞丰度范围为(0.08—37.52)×103个/L,浮游植物平均细胞丰度为2.69×103个/L,硅藻的平均细胞丰度为2.49×103个/L,主要优势物种为菱形海线藻、伏氏海线藻(Thalassionema frauenfeldii)及短刺角毛藻(Chaetoceros messanensis)等;夏季调查区5m层浮游植物细胞丰度的平面分布由近岸到外海迅速减少,高值区主要在广东东部近岸及海南东部近岸;冬季则在珠江口近岸和海盆区出现较高值。两次调查中,浮游植物细胞丰度在浅水站位(200m)远高于深水站位(200m);较冬季相比,夏季浮游植物平均细胞丰度偏高,但物种丰富度却略偏低。夏、冬季浮游植物的香农-威纳多样性指数平均值分别为2.12和2.36,Pielou均匀度指数平均值分别为0.79和0.81。两个航次调查中,浮游植物细胞丰度均与盐度表现出显著性负相关性;在冬季还与磷酸盐浓度表现出显著性负相关性。     

夏季南海北部纤毛虫群落组成及其水平分布

在2007年中国科学院南海海洋研究所南海北部开放航次期间,设计了两条纤毛虫采样断面(X断面、Y断面),共13个站位,涵盖了珠江冲淡水区、粤东上升流区和陆坡开阔海区,旨在对纤毛虫的种类组成和空间分布及其影响因素进行探讨。共检出4纲8目22属38种纤毛虫,其中种类数最多的属是砂壳目拟铃虫属(9种),其次是急游目急游属(5种)。本航次中纤毛虫主要是砂壳目纤毛虫(27种),共鉴定出砂壳虫15属27种。纤毛虫优势种为蚤状中缢虫Mesodinium pulex(18.1%),其次是丁丁急游虫Strombidium tintinnodes(9.7%),盾形拟铃虫Tintinnopsis urula(5.8%)。纤毛虫种类数和丰度从近岸向外海逐渐减少,纤毛虫种类数与温度(R2=0.53,P0.05)和盐度(R2=0.43,P0.05)呈负相关,随着温度的升高,纤毛虫种类数逐渐降低。纤毛虫丰度与温度和盐度相关性并不明显,这可能由于受上升流的影响,近岸上升流高盐区存在着纤毛虫丰度较为丰富的情况。叶绿素a浓度与纤毛虫种类数(R2=0.36,P0.05)和纤毛虫丰度(R2=0.36,P0.05)呈正相关,近岸浮游植物生物量高,纤毛虫种类丰富,丰度大,叶绿素a沿纵断面降低,纤毛虫种类数和丰度也降低。     

Gracilibacillus marinus sp. nov., isolated from the northern South China Sea

Two gram-positive, aerobic, spore-forming, rod-shaped bacteria, designated HB09003^T and HB12160, were isolated from seawater and sediment in the northern South China Sea, respectively. Cells were found to be motile by means of peritrichous flagella. The strains were found to grow with 0–15 % (w/v) NaCl, at 10–45 °C and pH 5.0–10.7, with an optimum of 3 % NaCl, 28 °C and pH 8.5, respectively. The predominant isoprenoid quinone of strain HB09003^T, selected as the representative strain, was identified as MK-7. This strain was found to possess anteiso-C15:0, iso-C15:0, anteiso-C17:0 and C16:0 as the major fatty acids. The G+C contents of strain HB09003^T and HB12160 were determined to be 34.1 and 34.3 mol%, respectively. Analysis of the 16S rRNA gene sequences of the two strains showed an affiliation with the genus Gracilibacillus, with Gracilibacillus kekensis CGMCC 1.10681^T (similarity of 97.4, 98.0 %, respectively) and Gracilibacillus ureilyticus CGMCC 1.7727^T (similarity of 97.1, 97.8 %, respectively) as their closest relatives. The DNA–DNA hybridization values between strain HB09003^T and the two type strains were 42.2 and 54.1 %, respectively. On the basis of phenotypic and genotypic data, strain HB09003^T and HB12160 are proposed to represent a novel species of the genus Gracilibacillus, for which the name Gracilibacillus marinus sp. nov. is proposed. The type strain is HB09003^T (=CGMCC 1.10343^T = DSM 23372^T).     

南海西北部陆架区鱼类的种类组成与群落格局

根据2006-2007年在南海西北部陆架区海域进行的4航次底拖网调查数据,对该海域鱼类的种类组成和群落格局进行分析.调查共采获鱼类262种,隶属于20目102科.以冬季出现种类数最多,为166种;夏季和秋季次之,分别为161种和155种;春季最少,为135种.运用聚类分析和非度量多维标度(NMDS)方法分析了南海西北部陆架区鱼类群落结构的空间分布.研究表明,该海域鱼类可划分为5个群落,分别为粤西沿岸群落(群落Ⅰ)、海南岛东南沿岸群落(群落Ⅱ)、海南岛东部深海群落(群落Ⅲ)、过渡群落(群落Ⅳ)和混合群落(群落Ⅴ).ANOSIM检验表明,各群落间鱼类组成的差异极为显著(R=0.847-0.939,P＜0.001).鱼类群落格局的变化与海流和水深关系密切,有较明显的沿水深梯度分布的规律.咸淡水鱼类在雷州半岛东部的冷涡区域,形成群落Ⅰ;南海暖流控制区域内的深海鱼类,形成群落Ⅲ;在南海暖流最为强劲的冬季,研究区域内大部分鱼类集结为混合性群落Ⅴ;琼东南沿岸的上升流区内形成群落Ⅱ;沿岸流强劲的夏、秋季,在沿岸流和上升流交汇处,形成过渡性群落Ⅳ.     

中国南海北部陆坡沉积物古菌多样性及丰度分析

【目的】海洋沉积物中的古菌在全球生物地球化学循环中充当重要的角色,深入了解沉积物中古菌群落的结构及功能特征是探究海洋沉积物中古菌参与生物地球化学循环和生态学功能的基础。【方法】采用高通量测序技术,分别对南海北部陆坡不同海域(东部,西部和神狐海域的7个站位)沉积物中古菌16SrRNA基因进行Illumina Mi Seq测序。【结果】中国南海北部陆坡沉积物中古菌的主要门类是Bathyarchaeota、Thermoplasmata、Woesearchaeota(DHVEG-6)、Thaumarchaeota(Marine Group I)、Lokiarchaeota和Marine Hydrothermal Vent Group(MHVG),还存在少量的AK8、Marine Benthic Group A和Terrestrial Hot Spring Crenarchaeota Group(THSCG)等。在潜在水合物区沉积物中还发现了甲烷代谢相关古菌(Anaerobic methanotrophic archaea,ANME)类群,主要为ANME-1、ANME-2ab和ANME-2c等。甲烷代谢古菌的分布特征也从甲烷代谢保守功能基因mcr A(Methyl coenzyme-Mreductase A)的扩增中得到了验证。利用定量PCR对南海沉积物中的细菌、古菌的16SrRNA基因和mcrA基因进行了定量,发现细菌16SrRNA基因拷贝数为10~5-10~7 copies/g(湿重),古菌16SrRNA基因拷贝数为10~5-10~6 copies/g(湿重),潜在水合物区mcrA基因拷贝数为10~3-10~5 copies/g(湿重)。【结论】揭示了中国南海北部陆坡沉积物中具有丰富的微生物资源,其中古菌种类多样且丰度较高,同时发现冷泉特征古菌群落,为深入认识和理解南海沉积物中微生物丰度和古菌多样性,以及解析古菌地球化学功能奠定基础。     

南海北部白姑鱼生长和死亡参数的估算

将南海北部白姑鱼分成南海北部大陆架和北部湾两个不同海域群体,根据20世纪60年代和90年代在南海北部底拖网渔业资源调查资料,利用ELEFAN技术估算了南海北部白姑鱼的生长和死亡参数.结果表明,北部湾和陆架区的生长参数L_∞、K、t₀分别为382mm、0.42、-0.16龄和315mm、0.35、-0.23龄.体重生长拐点年龄t_r分别为244和287龄;瞬时总死亡率(Z)、自然死亡率(MF)分别为3.55、0.93、2.62和3.12、0.85、2.27;当前开发率为074和073,资源处于过度利用状态.根据BevertonHolt动态综合模型,建议北部湾和陆架区白姑鱼的最适开捕年龄应大于190和195龄,相应的开捕体长大于2.11和168mm.     

南海北部近海渔业资源密度概率分布特征

根据2014-2017年南海北部近海8个调查航次渔获量数据,结合统计方法分析该海域渔业资源密度分布特征并探索其适宜概率分布类型,进而估算区域平均资源密度.结果表明:各时期资源密度变异系数(CV)在0.67~1.03,说明该海域渔业资源密度呈较高程度的不均匀空间分布,且渔获资源密度频率分布呈现明显的右偏特征,总体以0~1000 kg·km-2资源密度为主导;单样本Kolmogorov-Smirnov检验结果表明,对数正态、伽玛和韦伯分布是该区域资源密度的适宜分布类型;在海域平均资源密度估算方面,对数正态所得结果与另两个分布类型在统计学上无显著差异,而伽玛和韦伯分布的估计值有显著差异.与1960-1970年代相比,该海域渔业资源密度适宜概率分布型已从单一类型转变为多类型,这主要归于渔业资源结构、捕捞强度以及气候变化等引起的低渔获量比例变化.     

Reproductive parameters of rhinobatid and urolophid batoids taken as by‐catch in the Queensland (Australia) east coast otter‐trawl fishery

Reproductive variables are provided for batoids regularly taken as by‐catch in the east coast otter‐trawl fishery on the inner‐mid continental shelf off the south‐east and central coasts of Queensland, Australia. Total length at maturity (L_T50 and 95% c.i .) for the eastern shovelnose ray Aptychotrema rostrata was 639·5 mm (617·6–663·4 mm) for females and 597·3 mm (551·4–648·6 mm) for males. Litter size (n = 9) ranged from nine to 20 (mean ± s.e. = 15·1 ± 1·2). This species exhibited a positive litter size–maternal size relationship. Disc width at maturity (W_D50 and 95% c.i .) for the common stingaree Trygonoptera testacea was 162·7 mm (155·8–168·5 mm) for females and 145·9 mm (140·2–150·2 mm) for males. Gravid T. testacea (n = 6) each carried a single egg in the one functional (left) uterus. Disc width at maturity (W_D50 and 95% c.i .) for the Kapala stingaree Urolophus kapalensis was 153·7 mm (145·1–160·4 mm) for females and 155·2 mm (149·1–159·1 mm) for males. Gravid U. kapalensis (n = 16) each carried a single egg or embryo in the one functional (left) uterus. A single female yellowback stingaree Urolophus sufflavus carried an embryo in each uterus. A global review of the litter sizes of shovelnose rays (Rhinobatidae) and stingarees (Urolophidae) is provided.     

2006年冬季南海北部浮游植物生物量和初级生产力及其环境调控

通过2006年2月在南海北部现场调查所获得的数据分析研究了海域的浮游植物现存量和生产力,结果表明冬季浮游植物的分布特征与东北季风引起的环流场的变化关系密切。调查海域水柱平均Chla浓度的变化范围为0.03～1.21mg·m-3（平均（0.33±0.33）mg·m^-3）,高值区出现在广东沿岸及海南岛东部附近海域;初级生产力的分布范围为41.3～1040.0mgC·m^-2d^-1。由于东北季风引起近岸水体混合剧烈,不利于浮游植物生长,因此虽然沿岸带Chla浓度（（0.53±0.50）mg·m^-3）较高,但初级生产力却是最低的,只有41.3mgC·m^-2d^-1,同时冬季反气旋涡强度下降和底层富营养水的涌升,营养盐充足,因此开阔海的Chla浓度（（0.31±0.30）mg·m^-3）和初级生产力（（631.3±578.0）mgC·m^-·2d^-1）均高。浮游植物粒度级份测定表明,Pico级份对冬季南海北部浮游植物现存量和生产力的贡献很大,特别是在开阔海区,分别占47%和66%。