胶州湾大型底栖动物的丰度、生物量和生产量研究

为了研究胶州湾大型底栖动物的丰度、生物量和生产量,于2002年3月、6月、8月和12月,在胶州湾北部软底区、大沽河口、黄岛养殖区及养殖区邻域选取4个站位进行采样,对大型底栖动物进行了定量研究。共采到大型底栖动物138种,总平均丰度、平均生物量(湿质量)和年生产量(有机碳)分别为1 719个/m2,27 g/m2,2.2 g/(m2.a),初步估算,胶州湾大型底栖动物的总次级生产量为2.8万t/a。与渤海和南黄海大型底栖动物的丰度和生物量比较,丰度和生物量均低于这两个海域,但是胶州湾大型底栖动物的总次级生产量高于渤海。本研究对于了解胶州湾大型底栖动物现状及湾内养殖对大型底栖动物的影响具有重要的意义。     

莱州湾大型底栖动物群落结构及其动态变化特征

本文以莱州湾2009年夏季(8月)、秋季(10月)及2010年春季(5月)、夏季(8月)4个季节大型底栖动物资料为基础,对莱州湾大型底栖动物的种类组成、丰度、生物量、优势种进行了研究,同时与历史资料进行对比,探讨了莱州湾大型底栖动物的群落结构特征及动态变化。4个航次中共鉴定出大型底栖动物272种,其中包括环节动物多毛类122种,软体动物46种,甲壳动物64种,棘皮动物18种,鱼类9种,其他类13种。调查海域平均丰度为(1102.56 ± 216.32) ind./m2, 多毛类在丰度上占绝对优势;平均生物量为(28.16 ± 8.45) g/m2,软体动物占据优势。丰度和生物量空间分布规律具有很强的相似性,低值区位于莱州湾西部黄河口邻近海域,高值区位于渤海中部海域。丰度和生物量季节变化明显,夏季最高,秋季其次,春季最低。多毛类不倒翁虫(Sternaspis sculata)、寡鳃齿吻沙蚕(Nephthys oligobranchia)、紫壳阿文蛤(Alvenius ojianus)等是莱州湾调查海域的优势种。通过与历史资料的对比发现,莱州湾大型底栖动物种类组成及优势种类出现小型化的趋势。     

辽东湾中部海域春季大型底栖生物的群落结构及影响因子

2013年5月对辽东湾中部的大型底栖生物进行了调查,分析了该海域底栖生物的种类组成、丰度、生物量、群落结构及其与环境因子的关系。调查海域共发现大型底栖生物70种,包括多毛类24种,甲壳类18种,软体动物20种,棘皮动物7种,纽虫1种。相对重要性指数大于100的种类有14种,排名前3位的分别是日本游泳水虱、毛蚶、日本长尾虫。底栖动物丰度平均值为244.2个/m~2,生物量为52.52 g/m~2,棘皮动物是生物量的重要贡献者。多样性指数平均值为3.24,丰度生物量比较曲线分析结果认为调查海域大型底栖动物群落未受到干扰,底栖生物群落的结构相似性较低,在20%的相似程度上可分为5个组。底层水中溶解氧含量是影响底栖生物的主要因素,不同底质条件是影响底栖生物生物量和群落结构的重要因素。     

胶州湾春季大型底栖生物多样性及群落结构特征

基于2018年5月胶州湾海域共计20个站位所获取的生物及环境数据，研究胶州湾大型底栖生物多样性以及群落结构特征。调查海域共发现大型底栖生物208种，大型底栖生物总平均丰度和生物量分别为2 654.38 ind./m²和1 024.512 2 g/m²，大型底栖生物物种数、丰度和生物量均呈现北部高、南部低的分布趋势；调查海域优势种以多毛类为主，I_RI值最高的物种为菲律宾蛤仔Ruditapes philippinarum；香农维纳指数与ABC曲线均表明调查海域底栖生态环境整体清洁；在40%相似性水平上，可将调查海域大型底栖生物划分为4个群落；底温和底盐影响调查海域大型底栖生物丰度分布。     

Standing Crops of Planktonic Ciliates and Copepod Nauplii in the Subarctic North Pacific and the Bering Sea in Summer

Abundances and biomasses of planktonic ciliates and copepod nauplii, major components of the microzooplankton community, were investigated in the subarctic North Pacific and the Bering Sea in summer of 1997. Their regional variation was illustrated by demarcating the entire area into five regions. Ciliates always predominated both in abundance (>94%) and biomass (>78%) over nauplii. Regional means of ciliates in the water column were higher in the Alaskan Gyre (120 × 10⁶ cells/m²) and the Western Subarctic Gyre (110 × 10⁶ cells/m²) in terms of abundance, and rich in the Bering Sea Gyre (360 mgC/m²) and the Western Subarctic Gyre (340 mgC/m²) in terms of biomass. By contrast, standing crops of ciliates were poor in the Oyashio Region (67 × 10⁶ cells/m²; 170 mgC/m²) and the Transition Region (64 × 10⁶ cells/m²; 160 mgC/m²). The values of biomass reported here are generally in agreement with the values reported previously from the Bering Sea Gyre and the Alaskan Gyre but are considerably higher than the previous value found in the Western Subarctic Gyre. No significant correlations could be found between chlorophyll a crop and standing crops of ciliates and copepod nauplii over the entire subarctic North Pacific and the Bering Sea during this summer.     

浙江舟山海域大型底栖动物群落组成及主要影响因子分析

为了解舟山附近海域大型底栖动物群落组成特点及其与环境因子的内在关联,在2019~2020年对舟山附近海域12个站位的大型底栖动物及环境因子进行了调查研究。采用丰度、生物量、相对重要性指数(IRI)、Cluster聚类以及PCoA分析和Pearson相关性分析等方法对该海域的大型底栖动物群落组成、主要影响环境因子进行了分析。结果表明,两个航次共在舟山海域采集到大型底栖动物56种,其中多毛类动物28种,甲壳动物8种,软体动物7种,棘皮动物6种,刺胞动物3种、纽形动物2种,星虫动物和脊索动物各1种;两年平均丰度和生物量分别为36.32ind./m²和5.59g/m²,纽虫(Nemertea)是丰度的最大贡献者,而星虫爱氏海葵(Edwardsia sipunculoides)和棘刺锚参(Protankyra bidentata)则是生物量的最大贡献者;2020年大型底栖动物的总物种数、丰富度指数和多样性指数高于2019年,且两年舟山海域大型底栖动物的总物种数、丰富度指数和多样性指数均高于舟山邻近海域。与舟山海域大型底栖动物群落最相关的环境因子是水深、底层水盐度和硝态氮(NO₃),这三个环境因子彼此相关性显著,随着盐度的增加,水深逐渐增加而硝酸氮含量则显著降低,群落物种数、丰度和丰富度则显著增加。通过对舟山附近海域大型底栖动物群落组成特点及其与环境因子的内在关联的研究,有望为东海近岸海域大型底栖动物群落的演替规律研究提供基础数据和科学依据。     

辽东湾西部倾废区临近海域大型底栖动物群落结构

2012年9月对辽东湾西部倾倒区海域的大型底栖动物进行了调查。调查海域共发现底栖动物54种,包括多毛类35种,甲壳类10种,软体动物6种,棘皮动物1种,其他2种。底栖动物丰度平均为1 140.8个/m2,生物量为11.02 g/m2,多样性指数平均为3.39。丰度、生物量比较结果显示,调查海域大型底栖动物群落受到中度干扰,调查海域底栖动物群落可分为以对照组为主的群落和倾倒区群落。海洋倾倒导致倾倒区内大型底栖动物的种类数量、丰度、生物量和多样性水平下降,群落特征种受倾倒的影响较明显。底栖动物与重金属含量之间无显著相关关系,掩埋是辽东湾西部倾倒活动主要的影响方式。     

东营河口浅海贝类生态国家级海洋特别保护区大型底栖动物的群落结构特征

为了解东营河口浅海贝类生态国家级海洋特别保护区中大型底栖动物的群落结构及分布特征,于2019年对保护区内大型底栖动物进行了春、夏、秋、冬4个季度的详细调查,研究结果为:共采集大型底栖动物73种,优势种类为:彩虹明樱蛤(Moerella iridescens)、四角蛤蜊(Mactra veneriformis)、寡节甘吻...     

Biodiversity and community structural characteristics of macrobenthos in the Chukchi Sea

Field sampling of the macrobenthos from 23 stations in the Chukchi Sea was conducted during the 4th CHINARE(Chinese National Arctic Research Expeditions, July–August, 2010). We identified a total of 140 species of macrozoobenthos belonging to nine phyla, which were dominated by polychaetes(66), crustaceans(30), and mollusks(25), followed by echinoderms(9) and others(ten others, including four cnidarians, one oligochaete, one sipuncula, one priapulida, two bryozoans, and one urochordata). The dominant species were Aphelochaeta pacifica, Heteromastus filiformis, Nephtys ciliata, Nephtys caeca, Scoletoma fragilis, Golfingia margaritacea, Nuculana pernula, Macoma calcarea, Ennucula tenuis, Macoma inquinata, Musculus discors, Echinarachnius parma, and Ophiura sarsii, so there were more cold-eurythermal boreal immigrants than truly Arctic species(endemics). The average density and biomass(mean ± SD across all stations) of the total macrozoobenthos were(916 ± 907) ind/m2 and(902.9 ± 1 227.7) g/m2(wet weight), respectively. Relatively high density and biomass were observed in the samples from the northeastern and southern Chukchi Sea. The spatial variation of benthic communities in the study sea area was relatively large; this spatial heterogeneity has led to high diversity and a patchy distribution pattern in the community structure. Compared to the 1st CHINARE( July–August, 1999), this investigation revealed different degrees of decreases in the average taxa numbers and the average density, abundance, and biodiversity in the area over the recent decade, which might be associated with global warming, human activities, and sea ice variations.     

Impact of a new invasive ctenophore (Mnemiopsis leidyi) on the zooplankton community of the Southern Caspian sea

The invasive ctenophore Mnemiopsis leidyi (Agassiz), which was transported from the Black Sea into the Caspian Sea at the end of the 1990s, has negatively affected the ecosystem of the Caspian Sea. Zooplankton abundance, biomass and species composition were evaluated on the Iranian coast of the Caspian Sea during 2001–2006. A total of 18 merozooplankton (13 species composed of larvae of benthic animals) and holozooplankton (four Copepoda and one Cladocera) species were identified. The total number of zooplankton species found here was 50% less than in a previous investigation performed in the same region in 1996 before the introduction of Mnemiopsis leidyi into the Caspian Sea. Cladocera species seemed to be highly affected by the invasion of Mnemiopsis leidyi; only one species, Podon polyphemoides, remained in the study area, whereas 24 Cladocera species were found in the study carried out in 1996. Whereas among the Copepoda Eurytemora minor, Eurytemora grimmi, Calanipeda aquae dulcis and Acartia tonsa that were abundant before the Mnemiopsis leidyi invasion, only A. tonsa (copepodites and adults) dominated the inshore and offshore waters after the invasion. The maximum in zooplankton abundance (22,088 ± 24,840 ind·m^?3) and biomass (64.1 ± 56.8 mg·m^?3) were recorded in December 2001 and August 2004, respectively. The annual mean zooplankton abundance during 2001–2006 was in the range of 3361–8940 ind·m^?3; this was two‐ to five‐fold less than the zooplankton abundance in 1996. During 2001–2006, the highest abundance and biomass of Mnemiopsis leidyi were observed during summer‐autumn months coincident with warm temperatures and generally when the abundance of other zooplankton organisms was low.     

东南极普里兹湾陆架区大型底栖动物群落结构

To explore the spatial pattern of macrobenthic communities and their response to environmental factors in the Prydz Bay,samples were collected using a 0.25-m2 box corer at 10 stations from November 2012 to April 2013.A total of 50 species of macrobenthos belonging to 8 phyla and 33 families were identified,of which polychaetes(e.g.,Maldane sarsi)and sponges(e.g.,Halichondria sp.and Leucosolenia sp.)were the most prominent groups.The macrobenthos in study area were categorized into five functional groups based on the feeding type,and the detritivorous group represented by polychaetes showed the highest average abundance,while the planktophagous group represented by sponges showed the highest average biomass.Macrobenthos abundance(0–592 ind./m2)and biomass(0–1155.5 g/m2)in the Prydz Bay were relatively lower than those of other Antarctic shelf soft-bottom waters,although the compositions of the dominant species and functional feeding groups were similar.The results of the Spearman rank correlation analysis indicated that the average biomass of the macrobenthos and the biomass of the planktophagous group in the study area were negatively correlated with the water depth,sediment grain size and silt percentage.However,these variables were clearly not strong determinants of macrobenthos assemblage structure.Many factors not measured in the study,e.g.,sediment organic matter and iceberg interference,have probably influenced the spatial distribution of macrobenthic community structure in the Prydz Bay.     

山东长岛潮间带大型底栖动物生态特征研究

2015年11月(秋季)、2016年2月(冬季)、2016年6月(春季)、2016年9月(夏季)大潮期间对山东长岛列岛中南长山岛和北长山岛的3个不同底质类型的潮间带采样点进行了系统的大型底栖动物调查,研究了其数量特征和季节变化,包括群落种类组成、密度和生物量、优势种、物种多样性等,结果表明:本次调查共鉴定出大型底栖动物隶属7个门,共81种。其中环节动物门多毛类动物25种,软体动物门25种,节肢动物门22种,棘皮动物门6种,其他类群共3种(包括纽虫、腔肠动物和鱼类各1种)。潮间带大型底栖动物平均密度为118.97 ind./m~2,软体动物和甲壳动物占据了研究区域底栖群落的密度主要成分,两者分别占比为39.58%和36.68%。各采样点平均密度为北长山岛(BCS)(141.17 ind./m~2)避险角(NCS1)(122.33ind./m~2)明珠广场东(NCS2)(93.42ind./m~2);各采样点平均生物量为128.03g/m~2,软体动物和甲壳动物占据了研究区域底栖群落的生物量主要成分,两者分别占比为58.56%和35.32%。平均生物量北长山岛(BCS)(234.95g/m~2)避险角(NCS1)(99.99g/m~2)明珠广场东(NCS2)(49.13g/m~2)。从季节来看,各站点的物种数、平均密度和生物量季节变化的规律性不明显,总体为秋、春季较多,夏、冬季较少。3个站点物种多样性指数(H′)、丰富度指数(D)和均匀度指数(J′)平均值分别为2.30、1.99和0.79,各潮区中,均为中潮带低潮带高潮带,各季节变化不明显。优势种受底质类型和季节变化的影响明显,没有在各站点和季节均为优势种的种类,主要的优势种有平背蜞(Gaetice depressus)、绒螯近方蟹(Hemigrapsus penicillatus)、短滨螺(Littorina brevicula)等。与以往历史资料相比,长岛潮间带生物出现了一定变化,种类和数量减少,与烟台近岸潮间带大型底栖动物种类组成差别很大。     

胶州湾中部海域大型底栖生物生态学初步研究

2006年8月～2007年10月分4个航次对胶州湾中部海域进行大型底栖生物调查。调查结果表明,大型底栖生物总平均丰度和总平均生物量为1507个/m~2和35.88g/m~2。与历史资料做了对比,并初步分析了与以往调查结果不同的原因。调查海域大型底栖生物多样性指数和丰度生物量比较曲线显示,胶州湾中部海域底栖生物处于轻微扰动状态。     

山东半岛镆铘岛潮间带大型底栖动物群落特征

于2007年1月至2007年10月间冬、春、夏、秋4个季度月,对位于山东荣成的镆铘岛潮间带的高潮带、中潮带和低潮带进行大型底栖动物生态调查,根据所获得的样品,对该潮间带不同潮区大型底栖动物的种类组成、平均密度、平均生物量及物种多样性进行了分析.本次调查共采到大型底栖动物92种,其中多毛类环节动物11科22种,软体动物17科28种,甲壳动物18科33种,棘皮动物2科2种,扁形动物1种,腔肠动物2种,鱼类3种;平均栖息密度为329.67个/m2,软体动物贡献最大,其次为甲壳动物;平均生物量为81.74 g/m2,软体动物贡献最大,其次为多毛类环节动物.镆铘岛潮间带多样性指数H'垂直变化规律为高潮带>中潮带>低潮带,季节变化规律为秋季>春季>冬季>夏季.     

Multi-decadal synthesis of benthic–pelagic coupling in the western arctic: Role of cross-shelf advective processes

Using geographic information systems (GIS) software and geostatistical techniques, we utilized three decades of water-column chlorophyll a data to examine the relative importance of autochthonous versus allochthonous sources of reduced carbon to benthic communities that occur from the northern Bering to the eastern Beaufort Sea shelf. Spatial trend analyses revealed areas of high benthic biomass (>300 g m⁻²) and chlorophyll (>150 mg m⁻²) on both the southern and northern Chukchi shelf; both areas are known as depositional centers for reduced organic matter that originates on the Bering Sea shelf and is advected northward in Anadyr and Bering shelf water masses. We found a significant correlation between biomass and chlorophyll a in the Chukchi Sea, reflective of the strong benthic–pelagic coupling in a system that is utilized heavily by benthic-feeding marine mammals. In contrast, there was no significant correlation between biomass and chlorophyll in the Beaufort Sea, which by comparison, is considerably less productive (biomass and chlorophyll, <75 g m⁻² and <50 mg m⁻², respectively). One notable exception is an area of relatively high biomass (50–100 g m⁻²) and chlorophyll (80 mg m⁻²) near Barter Island in the eastern Beaufort Sea. Compared to other adjacent areas in the Beaufort Sea, the chlorophyll values in the vicinity of Barter Island were considerably higher and likely reflect a long-hypothesized upwelling in that area and close coupling between the benthos and autochthonous production. In the Bering Sea, a drop in benthic biomass in 1994 compared with previous measurements (1974–1993) may support earlier observations that document a decline in biomass that began between the 1980s and 1990s in the Chirikov Basin and south of St. Lawrence Island. The results of this study indicate that the benthos is an excellent long-term indicator of both local and physical advective processes. In addition, this work provides further evidence that secondary production on arctic shelves can be significantly augmented by reduced carbon advected from highly productive adjacent shelves.     

Spatial Variability of Living Coccolithophore Distribution in the Western Subarctic Pacific and Western Bering Sea

Vertical distributions of coccolithophores were observed in the depth range 0–50 m in the western subarctic Pacific and western Bering Sea in summer, 1997. Thirty-five species of coccolithophores were collected. Overall, Emiliania huxleyi var. huxleyi was the most abundant taxon, accounting for 82.8% of all coccolithophores, although it was less abundant in the western Bering Sea. Maximum abundance of this species was found in an area south of 41°N and east of 175°E (Transition Zone) reaching >10,000 cells L⁻¹ in the water column. In addition to this species, Coccolithus pelagicus f. pelagicus, which accounted for 4.2% of the assemblage, was representative of the coccolithophore standing crop in the western part of the subarctic Pacific. Coccolithus pelagicus f. hyalinus was relatively abundant in the Bering Sea, accounting for 2.6% of the assemblage. Coccolithophore standing crops in the top 50 m were high south of 41°N (>241 × 10⁶ cells m⁻²) and east of 170°E (542 × 10⁶ cells m⁻²) where temperatures were higher than 12°C and salinities were greater than 34.2. The lowest standing crop was observed in the Bering Sea and Oyashio areas where temperatures were lower than 6–10°C and salinities were less than 33.0. From the coccolithophore volumes, the calcite stocks in the Transition, Subarctic, and the Bering Sea regions were estimated to be 73.0, 9.7, and 6.9 mg m⁻², respectively, corresponding to calcite fluxes of 3.6, 0.5, and 0.3 mg m⁻²d⁻¹ using Stoke's Law. This revised version was published online in July 2006 with corrections to the Cover Date.     

白令海夏季浮游植物的群落结构与时空变化

通过1999年和2010年夏季同期7月在白令海(169°E~166°W,50°N~67°N)获取的94份浮游植物样品分析,获得了近十年的始末两个时间节点的浮游植物群落结构与时空变化,探讨了浮游植物群落动态及其与环境因素的关联。研究结果显示,共鉴定浮游植物(>10μm)5门58属153种,分为3个生态类群。硅藻是浮游植物的主体,种类多丰度高,占总种类数目的66.7%,占总丰度的95.2%。鉴于样品属性和空间范围的不同,物种组成有细微差别,丰度有较大差异且空间分布明显不同,高丰度区受控于上层营养盐供给和表层环流系统。优势种从北方温带大洋性硅藻演变为广温广盐性与冷水性硅藻,1999年以西氏新细齿状藻为第一优势种,柔弱伪菱形藻次之;2010年以丹麦细柱藻为第一优势种,冷水性的诺登海链藻次之并在陆架和陆坡占优。浮游植物群落结构较为稳定,由深水群落和浅水群落组成。深水群落分布于太平洋西北部和白令海盆,种类组成以温带大洋性的西氏新细齿状藻、长海毛藻、大西洋角毛藻和广布性的菱形海线藻、扁面角毛藻、笔尖根管藻为主,丰度低,种间丰度分配均匀,优势种多元化,物种多样性高;浅水群落分布于白令海陆坡和陆架,主要由冷水性的诺登海链藻、叉尖角毛藻、聚生角毛藻和广布性的丹麦细柱藻、旋链角毛藻组成,丰度高,种间丰度分配不均匀,优势种突出,物种多样性低。白令海夏季浮游植物种类组成及丰度变化直接受控于表层环流、营养盐、春季冰缘线等环境因素。     

Features of the soft-bottom subtidal macrobenthos in Nha Trang Bay (Vietnam, South China Sea)

General characteristics of macrobenthos of the muddy sediments of the subtidal (19–24 m) zone in Nha Trang Bay (South Vietnam) were described based on the survey performed in April–May 2002. The mean abundance of organisms was 637 ind/m² and the mean biomass was 2.3 g/m². Sixty-seven macrobenthic species were found during the study. The main structural features of the macrobenthos were high species diversity, low species recurrence, and high eveness of the species structure with the absence of clearly manifested dominants. The number of species encountered regularly increased with the increase in the total area sampled from 210 to 5000 cm², though the relation did not reach saturation. The similarities and differences between the macrobenthos structures in Nha Trang Bay and those in some tropical and boreal soft-bottom communities are discussed.     

Seasonal variability of the zooplankton community in the southwest of the Huanghai Sea (Yellow Sea) Cold Water Mass

Samples were collected with a plankton net in the four seasonal cruises during 2006-2007 to study the seasonal variability of the zooplankton community in the southwest part of Huanghai Sea Cold Water Mass (HSCWM, Yellow Sea Cold Water Mass). The spatial and temporal variations of zooplankton species composition, biomass, abundance and biodiversity were examined. A total of 122 zooplankton species and 30 pelagic larvae were identified in the four cruises. Calanus sinicus and Aidanosagitta crassa were the most dominant species, and Themisto gaudichaudi and Euphausia pacifica were widely distributed in the HSCWM area. The spatial patterns of non-gelatinous zooplankton (removing the high water content groups) were similar to those of the total zooplankton biomass in autumn, but different significantly in the other three seasons. The seasonal means of zooplankton biomass in spring and summer were much higher than that in autumn and winter. The total zooplankton abundance averaged 283.5 ind./m~3 in spring (highest), 192.5 ind./m~3 in summer, 165.5 ind./m~3 in autumn and 65.9 ind./m~3 in winter (lowest), and the non-gelatinous groups contributed the most total abundance. Correlation analysis suggests that the non-gelatinous zooplankton biomass and abundance had a significant positive correlation in the whole year, but the relationship was insignificant between the total zooplankton biomass and abundance in spring and summer. The diversity index H of zooplankton community averaged 1.88 in this study, which was somewhat higher than historical results. Relatively low diversity in summer was related to the high dominance of Calanus sinicus, probably due to the strongest effect of the HSCWM in this season.     

2008年初冷事件对南海北部夏季浮游动物的影响

2008年初,我国南方出现了罕见的低温冰冻极端天气过程。通过对2007年8月和2008年8月南海北部现场调查所获得的数据分析研究了浮游动物种类组成。结果表明,与2007年8月相比2008年8月浮游动物丰度和生物量有很大的下降。聚类分析结果表明浮游动物群落被分为近岸和远海两大类群。浮游动物近岸类群和远岸类群的分界点在不同的时间有所不同,这是由于外海水向近岸的入侵所致。与2007年8月相比,2008年8月浮游动物优势种发生了很大的演替,主要是因为四种浮游动物优势种亚强真哲水蚤、异尾宽水蚤、锥形宽水蚤和小哲水蚤丰度急剧下降所致。相反,水母类和海樽类丰富有很大的升高,其原因可能是2008年春季极端低温导致的鱼类大量死亡所致。与远岸浮游动物群落相比,近岸浮游动物群落变化更剧烈,这说明近岸浮游动物群落结构不稳定。南海北部浮游动物群落结构的变化与2008年初的冷事件有很大关系。