Macrobenthic species are effective indicators of marine environmental stress, making them valuable for ecological assessments. This study collected data on macrobenthos and environmental factors in the East China Sea (ECS) during 2019-2020. Through Threshold Indicator Taxa Analysis (TITAN), 21 indicator species were identified, with annelids being the most abundant. A critical dissolved oxygen (DO) threshold (DO <3.71 mg/L) was identified, revealing hypoxic conditions at about 10 % of sites. Depth significantly influenced species distribution, with responses clustering around 50 m. DIN and chlorophyll-a exhibited low thresholds, while TP showed a wider range. The AZTI Marine Biotic Index (AMBI) indicated slightly disturbed ecological conditions, while Multivariate AZTI's Marine Biotic Index (M-AMBI) reflected good overall quality. AMBI provided a broad baseline of ecological health through long-term community responses, while TITAN captured dynamic responses of species to localized environmental pressures. The combination of these three macrobenthic indices complemented each other's limitations, enhancing the comprehensiveness of the assessment, and the findings highlight the importance of integrating these indices to improve marine ecosystem management and provide early warning signals for environmental changes, offering valuable guidance for future conservation and restoration efforts.

As anthropogenic disturbance on deep-sea seamount ecosystems grows, there is an urgent need for a better understanding of the biodiversity and community structure in benthic ecosystems, which can vary at local and regional scales. A survey of the benthic megafauna on two adjacent deep-water seamounts in the northwestern Pacific Ocean was conducted, which are covered by cobalt-rich crusts, to assess the biodiversity patterns and dissimilarity of assemblage composition. Based on a multidisciplinary dataset generated from video recordings, multibeam bathymetry data, and near-bottom currents, environmental and spatial factors impacting the megabenthic communities were explored. Results showed that these two deep-water seamounts were dominated by hexactinellids, crinoids, and octocorals. The seamounts were able to support diverse and moderately abundant megafauna, with a total of 6436 individuals classified into 94 morphospecies. The survey covered a distance of 52.2 km across a depth range of 1421–3335 m, revealing multiple distinct megabenthic assemblages. The megabenthic communities of the two deep-water seamounts, with comparable environmental conditions, exhibited similarities in overall density, richness, and faunal lists, while dissimilarities in the relative abundance of taxa and assemblage composition. No gradual depth-related change in terms of abundance, richness, or species turnover was observed across the two seamounts, despite the statistical significance of depth in structuring the overall communities. The spatial distribution of megabenthic communities displayed a discontinuous and patchy pattern throughout the two deep-water seamounts. This patchiness was driven by the interactive effects of multiple environmental factors. Near-bottom currents and microhabitat features were the primary drivers influencing their dissimilarities in megabenthic community structure. This case study on the megabenthic community structure of two adjacent seamounts with cobalt-rich crusts can serve as an environmental baseline, providing a reference status for the conservation and management of seamount ecosystems, particularly valuable for areas being considered for deep-sea mining.

Deep-water seamount ecosystems are sensitive to human activities and have a slow recovery rate after being disturbed. Bottom trawling and potential deep-sea mineral extraction could severely damage benthic communities on seamounts and seriously impact deep-sea ecosystems. Inadequate knowledge of the distribution of megabenthos on seamounts or their community structure hinders deep-sea conservation and management. In this study, based on a multidisciplinary dataset generated from recordings taken by human-occupied vehicles (HOVs) and remotely operated vehicles (ROVs) along transects and environmental variables, a range of megabenthic morphotaxa were observed on two adjacent deep-water seamounts and predicted using species distribution models (SDMs). Accordingly, based on the predicted distribution of each morphotaxon, five distinct communities were identified through cluster analysis. The results of SDMs showed that environmental variables varyingly impacted the distribution of different morphotaxa, among which the average velocity and eastness direction of near-bottom currents, bathymetric position index (BPI), and backscatter intensity exerted the most significant influence on megabenthic distribution patterns. The distribution of five distinct communities showed a similarity of community composition on the two deep-water seamounts, suggesting a potential connectivity between the two seamounts. The distribution of communities revealed the spatial characteristics of vulnerability of deep-water seamounts at the community level, which could provide a direct basis for marine spatial planning of deep-sea ecosystems.

深海多毛类环节动物的多样性与地理分布格局是深海生物多样性研究关注的焦点问题之一.基于海洋生物地理信息系统(Ocean Biogeographic Information System,OBIS)数据库中的公开数据分析了西太平洋深海底栖多毛类动物的多样性与地理分布格局.多毛类数据多分布于靠近临海国的海沟、海山等显著地貌区,共记录到51个科318个物种,其中,多鳞虫科是物种多样性最高的科,且具有最大的深度分布范围.深海底栖多毛类物种数量随着水深增加而下降,但在2500～3000m水深处以及4 000～4 500 m水深处略增多.分析显示深海底栖多毛类的特有性水平较高,在热液口环境,形成了以热液口特有种为特征的底栖多毛类动物区系.西太平洋深海底栖多毛类动物分布可划分为4类生物地理区:日本海生物地理区域、以相模湾为代表的靠近大陆的生物地理区域、以深海热液口为典型特征的生物地理区域(冲绳海槽、马努斯盆地、斐济海盆区)以及以深海海沟、平原(日本海槽-千岛-堪察加海沟区、澳大利亚东侧区、新西兰区)为特征的生物地理区域.

It is widely acknowledged that the distribution of macrobenthos is affected by salinity,but the degree of influence varies in different areas.To explore the distribution pattern of macrobenthic assemblages in the Hangzhou Bay,12 stations were sampled to collect macrobenthos and the corresponding bottom water.Changes in the general characteristics of macrobenthos along the salinity gradient in the Hangzhou Bay and its adjacent waters were considered.Three dominant species were identified,including the polychaetes Sternaspis chinensis,the crustacea Oratosquilla oratoria and the echinoderm Ophiuroglypha kinbergi.And the macrobenthic assemblages showed a zonal distribution along with the salinity change.The correlation analyses showed that salinity,depth,temperature,suspended solids and dissolved oxygen had concurrent significant correlations with carnivorous group,Margalef species richness(d),Brillouin index(H)and Shannon-Wiener diversity index(H').In light of the strong correlation between salinity and Changjiang River diluted water,which produces considerable disturbances by freshwater inflows,the deposition of suspended solids and the resuspension of seabed sediments,the combined environmental disturbances,instead of salinity alone,should be adopted to explain the zonation distribution pattern of macrobenthic assemblages.

The northern East China Sea is currently subjected to anthropogenic disturbances during the past few decades. Using data collected in July 2019 and July 2020, the AZTI's Marine Biotic Index (AMBI), multivariate-AMBI (M-AMBI), Shannon-Wiener diversity index (H & PRIME;), and BENTIX index were adopted to assess their applicability and evaluate the benthic ecological quality of the northern East China Sea. The results of the Pearson correlation between biotic indices and eutrophication environmental factors showed that H & PRIME; and M-AMBI were suitable biotic indices for evaluating the benthic ecological quality in the northern East China Sea rather than AMBI and BENTIX. The overall benthic ecological quality in the northern East China Sea was moderate to good during 2019-2020. Ecological quality showed a positive correlation with distance to mainland. However, a slow declining trend was detected for the benthic ecological quality of the northern East China Sea, especially the nearshore areas.

Based on macrobenthos collected from intertidal seagrass bed in Guangrao, Shandong Province in May 2013, the macrobenthic structure and diversity were analyzed. A total of 41 macrobenthic species were identified, among which crustaceans were the most speciose macrobenthic taxa (16 species), followed by polychaetes (15 species) and mollusks (10 species). Seven dominant macrobenthic species were identified, including 3 species of polychaetes, 2 species of crustaceans and 2 species of mollusks. The total abundance across the whole sampling area was 661.33 ind/m2. Total abundance and the abundance of Potamocorbula laevis and Heteromastus filiformis showed significant spatial variation, and the macrobenthic abundance distributed in seagrass meadows was higher than that in other areas. The results of cluster, nMDS ordination, SIMPER and IMS analyses all showed no linear correlation along the distance gradient from the seagrass meadow. Therefore, degraded seagrass can still provide detectable but limited ecological services. However, the rehabilitation of seagrass bed is essential and urgent to regain their full ecological function.

To analyze the distribution pattern of macrobenthic feeding guilds, 26 stations in Hangzhou Bay and its adjacent areas were investigated from 2012 to 2016. Twelve feeding guilds were determined, and predator (Pr) was the most speciose group. Deposit feeder (De) and Pr were the major contributors to abundance across the whole study area, and macrobenthos labeled with multiple feeding modes were quite rare. The abundance and biomass of different feeding guilds showed significant interannual and spatial variations. According to the result of hierarchical cluster analysis, Hangzhou Bay and its adjacent areas could be divided into three subareas. The offshore subarea had the highest feeding guilds diversity, abundance and biomass. The environmental factors in the study area had different effects on different macrobenthic feeding guilds. Results of canonical correspondence analysis (CCA) showed that the depth and nitrogen were the most important driving factors in structuring the feeding guilds composition.

根据2017年9月和2018年9月对韭山列岛岩礁潮间带大型底栖生物的调查资料,分析了韭山列岛岩礁潮间带大型底栖动物的群落组成和结构特征,包括群落种类组成、丰度、生物量、优势种和功能性状等,并对大型底栖动物群落进行聚类和排序.本次调查共鉴定出大型底栖动物25种,其中软体动物18种,甲壳动物6种,刺胞动物1种.韭山列岛潮间带底栖生物平均生物量为1228.40 g·m-2,平均丰度676.00 ind·m-2,其中鳞笠藤壶(Tetraclita squamosa)为生物量的主要贡献种,其生物量占总生物量的42.39％;厚壳贻贝(Mytilus unguiculatus)、短滨螺(Littorina brevicula)、条纹隔贻贝(Mytilisepta virgata)和鳞笠藤壶是丰度的主要贡献者,占总丰度的59.96％.群落分析结果显示,不同站位的空间差异要远大于不同年份之间的时间差异.研究区域的大型底栖动物呈现明显的生物分带现象,可分为滨螺带和贻贝藤壶鼠尾藻带.与浙江其他岩礁潮间带相比,本研究的物种数量、丰度和生物量均处于较低水平.本研究可为保护区岛屿潮间带生态环境评估、海洋生物资源保护和进一步的科学研究提供基础数据.

本研究根据2017年8月和2018年8月在东海北部杭州湾和三门湾大型底栖动物的拖网采集资料,对这两个海域的大型底栖动物群落结构和多样性进行了研究.杭州湾的10个站位和三门湾的6个站位共获得61种大型底栖动物,其中甲壳动物最多(22种),其次是鱼类(20种)、软体动物(14种)、棘皮动物(2种)、刺胞动物(2种),多毛类最少(1种).杭州湾大型底栖动物优势种出现3种,三门湾出现8种,脊尾白虾Palaemon carinicauda是两个海域唯一的共同优势种.相比2017年,杭州湾和三门湾在2018年鱼类的种类和数量都有明显的增长.根据大型底栖群落的多样性指数,杭州湾不同区域的生物多样性差异较大,而三门湾则较为平均.对杭州湾和三门湾大型底栖动物进行聚类分析和nMDS排序分析,结果表明,杭州湾不同站位大型底栖动物相似度低,Q8、Q9、Q10站位群落结构与三门湾的站位更为接近,三门湾的底栖群落在2017年和2018年存在较大差异.杭州湾和三门湾大型底栖动物群落的变化可能与环境因子、人类活动、厄尔尼诺事件等的变化相关.

本研究根据2012-2016年8月浙江北部海域大型底栖动物的调查资料,对浙江北部海域4个区域(杭州湾、舟山海域、象山海域和近海区域)的大型底栖动物优势种的时空变化进行了研究.结果 表明,5个航次大型底栖动物优势种有29种(优势度＞0.02),其中多毛类动物13种,软体动物7种,甲壳动物2种,鱼类2种,纽形动物2种,棘皮动物2种以及刺胞动物1种.对浙江北部海域大型底栖动物优势种的时空分布进行分析,结果表明:杭州湾优势种种类最少,时空分布变化明显;近海优势种组成较复杂,包含甲壳动物、软体动物、多毛类动物、鱼类、棘皮动物和纽形动物;象山海域的优势种组成较简单,优势种以多毛类动物为主;舟山海域的优势种中多毛类动物种类数逐年增加.对研究区域大型底栖动物优势种的变化趋势进行分析,浙江北部海域大型底栖动物优势种中多毛类动物明显增加,取代该海域软体动物优势地位.大型底栖动物优势种的时空分布变化与有机质积累、底质环境改变以及食物网变化密切相关,浙江北部海域的生态环境状况在不断恶化.

为探究苗种规格对虎斑乌贼(Sepia pharaonis)养殖效果的影响,进行了放养3种不同规格乌贼苗种(胴长分别为(4.09±0.15)、(5.25±0.48)和(6.16±0.19)cm)的养殖实验.结果表明:不同规格乌贼苗种的摄食量均波动上升,饵料系数随养殖时间逐渐降低,由8.00±1.01降至3.74±0.35.乌贼苗种的特定生长率先增加,在胴长6cm左右时达到峰值,后减少并稳定至4％左右.3种规格乌贼苗种养殖30d后的存活率分别为(88.50±0.88)％、(92.00±0.60)％、(93.83±0.34)％.大规格乌贼苗种的日均增重量、存活率显著(P<0.05)高于小规格乌贼苗种.综上所述,在虎斑乌贼养殖中苗种放养规格以胴长6 cm左右为宜.

2013年2月、5月和8月对黄河入海口附近潮间带的大型底栖动物进行了调查,调查工作涵盖3个季节2条断面的样品,分析了黄河口潮间带大型底栖动物的群落结构特征,包括群落种类组成、丰度和生物量、优势种、多样性,采用CLUSTER聚类分析了大型底栖动物的群落结构,并用AMBI和m-AMBI对底栖群落和环境质量进行了评估.本次调查共鉴定出大型底栖动物52种,其中,多毛纲动物24种,软体动物14种,甲壳动物12种,鱼类1种,纽虫1种.多毛纲动物为该海域底栖群落的主要成分,占据了群落总种数的46.15％.从季节来看,物种数春季最高(38种),夏季则处于最低水平(16种).群落丰度和生物量均具有明显的季节变化,丰度在春季达到最高,为3 549.33 ind/m2,远高于冬季的256.67 ind/m2和夏季的100.67 ind/m2,其中扁玉螺(Neverita didyma)是丰度的主要贡献者,贡献了全年群落总丰度的75.44％.生物量春季最高,夏季次之,冬季最低.在全年尺度上,甲壳动物的日本大眼蟹(Macrophthalmus japonicus)是生物量的主要贡献者,占据总生物量的49.86％.群落的季节变化也得到了群落CLUSTER分析与SIMPER分析结果的验证.这与黄河入海口附近底质不稳定,易受侵蚀、环境条件如盐度等具有明显季节差异,以及一定程度的人为扰动密切相关.AMBI和m-AMBI的分析结果显示,该区域环境质量状况较好,仅受到了轻微扰动影响.

Several marine mollusks, including cephalopods (cuttlefish, squid, and octopus) and gastropods (e.g., sea hares), can release a colored ink secretion when chased by predators or stimulated. Ink release is part of a defensive response, but the threshold for the biochemical responses caused by stimulation is unknown. The present study aimed to reveal antipredator responses of cuttlefish, such as escaping via inking and/or jetting, and to investigate its biological and biochemical responses to continuous ink release. Results showed that the behavioral responses to continuous ink release mainly manifested as blazing body pattern changes. Cuttlefish escaped from predators covered by jetting/inking and warned the potential threats by displaying a unique body pattern. Moreover, persistent inking in the presence of an overt stimulus caused uncontrollable ink release from the ink duct/anal canal (loss of control). This study first verified the characteristics of the cuttlefish ink solution, prepared a standard curve of ink solution concentrations, and fitted the relationship function between the release frequency and the released ink weight. Biological statistics indicated that cuttlefish has the ability to continuously release ink (releasing ∼90% of the ink from the ink sac) and that the individuals adapted well during the recovery period. However, re-releasing ink would result in “overexploitation” and high mortality. Hexokinase (HK), pyruvate kinase (PK), and superoxide dismutase (SOD) activities, as well as malondialdehyde (MDA) concentration increased or remained stable in different tissues after releasing ink. The expression of heat shock protein 90 and arginine kinase (AK) were upregulated by stimuli in all tissues. Biochemical changes indicated that continuous inking not only consumed considerable energy but also damaged the tissues. In summary, cuttlefish released almost 90% of their ink for active defense against predators, and it took ∼30 days for the ink sac to be refilled, but “overexploitation” resulted in serious physiological damage. These findings will be helpful to further study the defense and ink release mechanisms and to consider animal health and welfare when using cephalopods as experimental animals and for aquaculture practices.