In this study, we examined and compared the WBR processes of B. jacksonianum, B. affinis anceps (hereafter referred to as B. anceps here), and B. diegensis. B. anceps displayed twin-body regeneration, whereas B. jacksonianum and B. diegensis regenerated only one zooid each. Histological examination confirmed the presence of multiple vesicles formed from hemoblast aggregates during WBR, a phenomenon observed in other Botrylloides spp. The investigated species exhibited strong similarities in their WBR, with some variations in the overall process, indicating the presence of similar mechanisms underlying WBR. Understanding the intricacies of tunicate WBR contributes to our knowledge of regenerative biology and may offer valuable insights for regenerative medicine research in vertebrates.
The increased illegal fishing to supply swim bladders is the current threat to the Totoaba macdonaldi, due to the high commercial value of swim bladders. Species identification is the foundation of the endangered animal protection. Limited by the sophisticated thermal cycling, specialized machine, and sequencing costs, DNA barcoding might not better satisfy the needs of on‐site inspection to the efficiency, convenience, and low cost, although it has reliable results and has been widely used. It is necessary to establish a convenient, rapid, sensitive, and accurate method for customs to inspect the swim bladders in legal or illegal trade on site. In this study, we introduce real‐time fluorescence‐based recombinase‐aided amplification (RF‐RAA) into species identification of swim bladders. Specific primers and probes targeted to Totoaba macdonaldi were designed and the reaction temperature and time were screened. It was applied to the forensic identification of swim bladders confiscated by custom after its sensitivity and specificity were verified. The results showed that (1) the primers of TMcytB F1 and TMcytB R3 targeted to the Cytb had a good amplification at 39°C, 30 cycles (15 min) with good repeatability and stability; (2) the method had good specificity and no cross‐reaction with other 22 swim bladder originated species; (3) the lowest detectable limit (LDL) of this method was 3.7 × 101 copies/μL; (4) about 1.836 kg of all the swim bladders confiscated by Shenzhen customs on 2022 were identified to be Totoaba macdonaldi by using this method. This study provides an effective species identification alternative for competent authorities to tackle the illegal import and market regulation of totoaba swim bladders.
As Fujairah comprises extremely diverse natural landscapes which enforce us to protect and understand possible risks and challenges faced by the coastal waters of Fujairah, it is critical to mitigate, reduce, and eliminate the risks. The aim of this study is to assess and evaluate the effect of such anthropogenic activities on the offshore waters of Fujairah. Accordingly, two buoys were deployed after conducting a baseline survey for 30 locations targeting areas affected by the anthropogenic activities. Furthermore, two sites were chosen for the buoy deployment, nearshore which is across the desalination plant (Qidfa) and offshore which is across the oil and gas facility port (Skamkam). After analyzing the water quality measurements taken for 1 year from both deployed buoys and compared it with the baseline survey measurements, an indication of water quality deterioration in nearshore and offshore buoys was evinced, and the nearshore site which located in Qidfa has a higher deterioration in water quality measurements compared to the offshore site located in Skamkam. A long-term monitoring program needs to be conducted to gather additional data on water quality over several years to help identify the seasonal variations, trends, and long-term changes in water quality.
Sea urchin population demographics can respond to changes in keystone species abundances, with the magnitude of these responses varying depending on environmental influences. In this study, sea urchin populations were surveyed across 15 Aleutian archipelago islands over a 30-year period to understand how patterns of sea urchin demography (density, biomass, and size structure) varied through different ecological regimes that were caused by changes in the abundance of sea otters, a keystone species in this system. To examine long-term changes in sea urchin demographics, four time periods across the recent decline of sea otters were examined: during sea otter presence (1987-1994), nearing absence at the end of the decline (1997-2000), 10 years postdecline (2008-2010), and 15-20 years following the loss of sea otters from the ecosystem (2014-2017). Our results show that when sea otters were broadly present, sea urchin demographics were generally similar across the archipelago, with few urchins that had large-sized bodies. During this time, bottom-up environmental controls were muted relative to top-down forces from keystone predation. However, as sea otters declined and remained absent from the system, abiotic factors became more influential on sea urchin biomass, density, and size structure. In particular, differences among island groups during these periods were correlated with variation in ocean temperature, bathymetric complexity, and habitat availability. Sea urchin recruitment also varied among island groups, corresponding to ecoregions delineated by oceanic passes across the archipelago. The functional extinction of sea otters revealed an increasing influence of abiotic forcing in the absence of top-down control. This study further highlights the importance of understanding how keystone predators regulate herbivore demographics.
Tissue regeneration and wound healing remain extremely understudied in elasmobranchs as many wounds are recorded through one-off opportunistic observations with an inability for long-term monitoring of individuals. This study demonstrates partial fin regeneration of a silky shark (Carcharhinus falciformis) almost one year after a traumatic injury that resulted in a 20.8% loss of the first dorsal fin. The shark was photographed 332 days after the recorded injury with a newly shaped dorsal fin that had healed to 87% of the original size. Photographs provided by divers allowed for accurate measurements of fin growth, confirming an approximate 10.7% increase in fin area, indicative of tissue regeneration. Wound healing rate was calculated to conclude that the initial wound reached complete closure by day 42, which is analogous with other elasmobranch healing rates. Prior to this study, only one other record of dorsal fin regeneration had been documented in a whale shark. This provides the first evidence of dorsal fin regeneration in a silky shark and contributes to the limited studies of wound healing rates in sharks. This newfound insight into tissue regeneration and wound healing underscores the importance of further research to understand how they respond to traumatic injury in the face of mounting environmental challenges, both natural and anthropogenic. Additionally, this study exemplifies the power of collaboration between researchers and the public, including photographers and divers, to expand the scope of research studies and bridge the gap between science and society.
Skipjack tuna (Katsuwonus pelamis) is the most dominating tuna species caught in the Indian Ocean. However, tuna fishermen in the Indian Ocean still face difficulties determining potential skipjack tuna fishing grounds due to limited geographic information. An attempt to improve information regarding potential skipjack tuna fishing grounds is through modeling the SST, SSC, SSH, and SSS oceanographic parameters with skipjack tuna distribution using GIS. The characteristics of the skipjack tuna habitat can be found through the generalized additive model (GAM) statistical analysis using data of skipjack tuna catch and oceanographic parameters from satellite imagery. The integrated GIS and GAM methods can improve the study of the habitat of skipjack tuna species. Therefore, this research is aimed at analyzing the condition and SST, SSC, SSH, and SSS variations in 2016-2021 in the South Java Sea; at predicting the correlation of SST, SSC, SSH, and SSS towards skipjack tuna catch in 2016-2021 in the South Java Sea using GAM; and at creating a map of skipjack tuna seasonal migration zones. The data included skipjack tuna catches, number of trips, and skipjack tuna fishing coordinates in 2016-2021 from PPS Cilacap and PPP Pondokdadap. The oceanographic parameter data in 2016-2021 was derived from Aqua MODIS level 3 (SST and SSC) and CMEMS (SSH and SSS) satellite imagery. The results showed that the average values of oceanographic parameters at skipjack tuna fishing ground coordinates in the South Java Sea (2016-2021) were SST (26.050-30.816°C), SSC (0.094-0.564 mg/m3), SSH (0.268-0.639 m), and SSS (33.075-34.514 psu). The best GAM modeling was the combination of four oceanographic parameter variables with an AIC value of 45357.92. Skipjack tuna in the South Java Sea migrates southeast during the west monsoon season to the first transitional season and tends to migrate northwest during the east monsoon season to the second transitional season.
Peru’s industrial fishery centers on the Peruvian anchoveta (Engraulis ringens), which is highly productive due to the marine conditions of the Humboldt Current. However, like elsewhere, the country’s marine fishing industry is linked to climate change. The objective of this study is to analyze the relationship between industrial marine fishing and climate change in Peru. Correlation and linear regression methods were used. A key variable of climate change is the sea surface temperature (SST). The study found that in Peru during 1997-2020, the higher the SST, the lower the industrial fishing catch ( α = 5 % ). There is also evidence of an inverse correlation between sea level and industrial catch; i.e., sea level rise would alter marine ecosystems. A positive correlation between landings of industrial marine fishing and exports for nonfood purposes was corroborated, especially fishmeal. The study concludes that the industrial Peruvian anchoveta catch is negatively affected by SST, fishing effort (search time in hours), and catch per unit of effort (CPUE). For the sustainability of Peru’s industrial fishery, climate change adaptation measures, such as a reduction of fishing effort and research on alternative production of fishmeal with unmodified natural inputs without or in combination with anchoveta, should be implemented. For the future, a change in fishing policies is required that replaces anchoveta for fishmeal with a warm-water marine species during strong El Niño events.
In the Sandha river of Bangladesh, we investigated the temporal and geographical fluctuation in species of fish composition and diversity. The extent of our understanding of the fish variety in this river varies greatly on both a temporal and a geographical scale. From July 2021 to June 2022, fish specimens were gathered from five stations using various conventional fishing methods. During the study period, 5118 individuals from 67 species were collected which include 8 orders, 24 families, and 54 genera. Cypriniformes made up the majority of the order (32.84%), whereas Beloniformes and Tetraodontiformes made up the least number of species (1.49% each). Six species were listed as endangered (8.96%), seven as vulnerable (10.45%), nine as near threatened (13.43%), forty-three as least concern (64.18%), one with data deficient (1.49%), and one as not evaluated (1.49%) in Bangladesh. In order to quantify the temporal and geographical changes in community composition, diversity indices were calculated and put to use. Three (temperature, humidity, and rainfall) out of the four environmental factors (temperature, humidity, rainfall, and photoperiod) had a big impact on how species were distributed. At a similarity level of 79% and 75.5% separation, 2 substantial clusters were seen in the case of stations and 2 large clusters were detected in the case of months, respectively. However, at a similarity threshold of 20% separation, three different groups of fish species were found. Our research offers the most recent status data on fish distribution in the Sandha river. The knowledge acquired from this research is crucial for creating protection and management plans that will promote the long-term viability of fishery resources in the Sandha river and its nearby coastal tributaries.
为评估绿色石化项目运营前后的环境变化,于2018-2021 年连续4 年对项目所在地鱼山岛邻近海域的表层沉积物多环芳烃(PAHs)进行了调查.结果表明,PAHs含量为16.9～178.0 μg·kg-1,平均值为75.9±24.0～102.6±41.4 μg·kg-1,4 年来整体呈下降趋势,与国内其他海区相比,总体含量较低;各组分平均值为4 环PAHs>5 环PAHs>3 环PAHs>6 环PAHs>2 环PAHs.调查海域表层沉积物以粉砂为主,PAHs的空间分布受到多种因素的综合影响.调查海域PAHs来源相对稳定,年际差异较小,主要来源于石油、木柴、煤炭等燃烧产物的远距离迁移.依据沉积物质量基准法评价,调查海域沉积物PAHs生态风险水平较低.绿色石化项目在建设期及投产期未引起邻近海域沉积物PAHs的增加,但随着项目持续运营,其对周边生态环境的影响需持续关注.
利用海-气界面浮标观测得到的高频数据,分析了春季青岛近岸海域海表二氧化碳分压(p CO2)的变化规律及驱动因素,并对海-气CO2 通量进行了估算.观测期间该海域由大气的碳汇转变为碳源,主要是由海表 p CO2 的不断增长所致.对海表 p CO2 控制因素进行分析,发现温度升高是p CO2 增长的主要驱动因素,生物过程起到一定的抑制作用.海表p CO2 呈现出日变化特征,温度和生物因素对海表p CO2 日变化的作用均与太阳辐射相关,但两者的作用相反.此外,分析发现浮标的不同采样频率会对海-气CO2 通量估算产生影响,缩短采样间隔能有效降低海-气CO2 通量估算的偏差,提高估算的准确性.
《海洋学研究》是由中国海洋学会、自然资源部第二海洋研究所和浙江省海洋学会联合主办的海洋科学综合性学术期刊,创刊于 1983 年(前身为《东海海洋》),于 2005 年第 2期起正式更名为现刊名,季刊,大 16 开本(A4),国内外公开发行.
利用浙江苍南近岸海域一年实测波浪资料,统计分析了波参数特征,采用最小二乘法拟合分析了波参数之间的相关关系,研究波浪平均持续时间和波高的关系,对波浪能进行估算,并分析了台风"利奇马"期间典型台风浪特征.结果表明:研究海域以谱峰周期 5～9s的轻浪为主,年平均有效波高为1.25 m,年最大波高为10.80 m,常浪向为E,强浪向为ENE.特征波高之间具有显著的线性关系,符合典型的瑞利分布.有效波高 2.7m以下的非台风、非寒潮期和 4.1m以上的台风期,波浪平均持续时间随波高的增大呈指数衰减,且有效波高在4.1m以上的台风期的波浪衰减速率高于有效波高在2.7m以下的非台风、非寒潮期.台风"利奇马"影响期间,最大波高、谱峰周期、谱峰密度呈现基本同步的先增大后减小的过程,最大谱峰密度为55.10 m2∕Hz;台风影响前、后的波浪谱型均呈双峰谱,台风影响最显著期间的波浪谱型呈单峰谱.
极值样本的选取和分布模型的确定是设计波高推算中的两个关键环节.使用阈值法选取波高过阈样本作为极值样本时,常用标准风暴长度法对超出量序列进行"去聚类"处理,以使样本符合独立性标准.然而标准风暴长度法中的标准风暴长度需要人为选择,增加了取样结果的不确定性.本文提出了一种自动的标准风暴长度估计方法,并基于该方法选取了粤西海域的波高过阈样本.波高过阈样本具有尖峰、厚尾的统计特征,为了更准确地拟合该样本,本文基于组合模型原理构建了一种新的分布模型——Gumbel-Pareto分布模型,并用该模型进行了粤西海域的设计波高推算,结果表明Gumbel-Pareto分布对波高过阈样本的拟合优度比Gumbel分布和广义Pareto分布更高,可以为大型海洋工程设计波高的确定提供参考.
深海沉积物中的黏土矿物组合特征能反映物源区古气候与古环境的变化.前人已有较多关于马里亚纳海沟以西太平洋沉积物黏土矿物组合特征方面的研究,但对马里亚纳海沟以东黏土矿物组合特征的研究较少,从而限制了对亚洲大陆风尘输入与太平洋深海沉积环境之间关系的深入认识.本文以2019 年大洋54 航次在西太平洋马尔库斯-威克海山区采集到的31 个表层样和1 个柱状样为研究对象,结合收集到的西太平洋海域及附近地区的数据,开展了黏土矿物组成与分布特征、物质来源等研究.结果表明,研究区表层沉积物中的黏土矿物类型以伊利石为主,含量平均值为69%;绿泥石和高岭石次之,含量平均值分别为16%与11%;蒙脱石最少,含量平均值为 3%.柱状样黏土矿物组合与表层沉积物基本一致,但在 250 cm深度以下,蒙脱石含量明显增高,伊利石含量相对减少.物源分析表明,亚洲风尘是研究区伊利石的主要物源,高岭石和绿泥石的主要物源可能也是亚洲风尘,东亚冬季风是这些风尘物质的主要搬运营力.沉积物中的蒙脱石则主要由海底火山物质风化形成.P04 柱上部伊利石含量增加而蒙脱石含量降低的变化响应了中更新世以来亚洲风尘输入量增加的过程.
基于 1993-2019 年海面高度异常数据分析了南澳大利亚海盆表层涡动能的时空变化特征.结果表明,表层涡动能在空间上存在两个高值区,分别位于海盆的西部和东部;在季节尺度上表现为南半球的冬季强,秋季弱,最大值出现在7 月(57±9 cm2∕s2),最小值出现在3 月(40±5 cm2∕s2).涡动能在年际尺度上与ENSO呈显著负相关关系,即在厄尔尼诺(拉尼娜)衰退年,涡动能显著减弱(增强),滞后Niño3.4 指数9 个月;与SAM呈显著正相关关系,滞后SAM指数 14 个月,即在SAM正(负)位相的次年,涡动能显著增强(减弱).
南太平洋岛国大多四面环海且国土面积狭小,多为生态环境脆弱区.基于此,本文利用多源卫星数据,对瑙鲁、帕劳、图瓦卢、马绍尔群岛四国的海洋生态环境进行监测,基于长时间序列遥感结果的回溯,分析了其时空变化,并对比分析了汤加火山爆发前后,各国生态环境是否发生显著变化.结果显示:1)在气候态时空分布上,南太平洋岛屿国家周边海域海表温度和透明度一直维持在较高水平,叶绿素和净初级生产力则随离岸距离增加快速下降;2)升温、酸化和海平面升高是四个岛屿国家周边海域面临的共同问题;3)汤加火山的爆发对于南太平洋四岛国的沿岸悬浮物质量浓度、海表温度等无明显影响;4)火山爆发前半个月海岛地表温度以及周边海域悬浮物质量浓度异常升高的现象对利用遥感手段进行灾害预警预报具有启示作用.
本研究以西太平洋表层海水为基质,制备了浓度为 0.5～4.0 μmol∕L的海水活性磷酸盐系列标准物质.通过对所研制的4 批次样品进行均匀性、稳定性评估,确定样品性能良好.对基于磷钼蓝分光光度法的气泡间隔连续流动分析系统的反应和操作条件进行优化,优化后的方法检出限低至0.03 μmol∕L.不同浓度样品的相对标准偏差为0.37%～2.45%(n =9);通过与国际已有有证标准物质比对,本研究方法测量误差小于0.05 μmol∕L.经6 家具有中国计量认证资质且具备海水磷酸盐检测能力的实验室联合定值,确定了该系列标准物质的标准值,并对定值结果的不确定度进行了分析评价,相对扩展不确定度为2%～10%.
潮流能是指潮水水平运动中携带的动能,开发前景巨大.对区域潮流的精准模拟及特征分析有助于准确评估潮流能的时空分布状况,是潮流能资源开发利用的关键.本文选取潮流能蕴藏丰富的舟山海域,应用FVCOM海洋模式构建了高分辨率的潮汐潮流数值模型,经潮位、潮流验证,该模型可靠.根据模拟结果中流速的大小确定了潮流能资源密集的6 处水道进行评估,其中西堠门水道、册子水道、桃花港水道平均能流密度超过2.0 kW∕m2,最大能流密度超过20 kW∕m2,流速大于1.0 m∕s时长超过80%,潮流涨落期间以往复流为主,潮流不对称性及旋转性低,潮流稳定系数大于 0.98,较其他3 处水道更适合潮流能的开发利用.通过有效发电小时数及可利用小时数确定了这 3 处水道内潮流能开发的最佳位置,并应用 Farm 法计算了相应的潮流能资源可开发量,分别为 27.53、39.96 和130.26 MW.
硝酸盐是海洋中浮游植物生命活动可利用的主要氮形态,其跃层深度(ZN)会直接影响硝酸盐垂向输送、海洋初级生产力以及海洋碳循环.随着海洋观测技术的不断发展,硝酸盐剖面数据的采集呈现多样化,包括船基CTD观测和生物地球化学浮标BGC-Argo自动观测等,且垂向采样分辨率差异较大(CTD较低,BGC-Argo较高).针对不同采样数据,亟需对硝酸盐跃层深度计算方法进行系统且定量化的对比分析研究.本文利用西北太平洋历史船测CTD数据和BGC-Argo浮标数据,采用差值法、梯度法和阈值法分别计算对应硝酸盐跃层深度.研究结果表明:就单一硝酸盐剖面,基于BGC-Argo数据,差值法计算的ZN 与目视解译的ZN 相差仅为0.2 m,阈值法次之为20.0 m,梯度法相差最大为202.8 m;基于CTD数据,差值法计算的ZN与目视解译的ZN相差2.0 m,阈值法相差49.0 m,梯度法相差155.0 m.相较于梯度法和阈值法,差值法计算的ZN与目视解译的ZN相差最小.根据误差统计分析结果发现,基于BGC-Argo数据,三种方法计算得到的ZN 与目视解译的ZN 均呈现良好相关性,其中差值法计算结果误差最小(R2 为0.77,RMSE为28.48 m),阈值法的R2 为0.64,RMSE为34.85 m,梯度法的R2 为0.52,RMSE为53.80 m;对于CTD数据,由于其垂向采样分辨率较低,三种方法计算得到的ZN 与目视解译的ZN相差较大,但相比于梯度法和阈值法,差值法的误差仍最小(R2 为0.81,RMSE为16.13 m),阈值法的R2 为0.47,RMSE为27.65 m,梯度法的R2 为0.42,RMSE为36.41 m.通过对比分析各方法的特点和差异性,初步探究了各方法的适用性,可为深入研究硝酸盐垂向分布特征和向上输运过程提供科学参考.
《海洋学研究》国内刊号为CN 33-1330/P,国际刊号为ISSN 1001-909X,季刊,16 开,目前为自办发行,每册定价为9. 00 元,全年定价为40 元(含邮寄费). 请读者将书款通过邮局直接寄往如下地址:"浙江省杭州市保俶北路36 号《海洋学研究》编辑部" ,邮编:310012.
