This study evaluates the ecological impacts of seawater desalination discharge on coastal marine ecosystems through a sequential analytical framework linking systematic literature synthesis, field-monitoring evidence, spatial analysis, and predictive ecological modeling. The novelty of the study lies in combining multi-regional evidence from Mediterranean coastal zones, Persian Gulf waters, and Pacific coastal environments with threshold-based ecological risk assessment, thereby linking discharge-related environmental stressors with biological responses and ecosystem-function alterations. The systematic review first retained 750 studies published between 2004 and 2024 for qualitative synthesis. On this basis, 59 high-quality references with sufficient numerical information were selected for the main quantitative meta-analysis, while field-monitoring data were used to support the interpretation of distance-based discharge gradients. Spatial interpolation and hierarchical modeling were then applied to evaluate exposure-response patterns and ecological threshold behavior. The results showed that desalination facilities generated measurable ecological impacts mainly within 50-200 m of discharge points, with a critical transition distance of approximately 127 m where hypersaline conditions, typically 1.5-2.0 times ambient seawater levels, were associated with marked changes in marine community structure. Benthic assemblages showed taxon-specific responses, with mollusks and echinoderms exhibiting greater sensitivity than polychaetes and small crustaceans. Marine vegetation declined strongly under combined salinity, thermal, and chemical stress, while phosphonate-based antiscalants accumulated in filter-feeding organisms and produced bioaccumulation factors up to 42.1 times ambient levels. Ecosystem-function indicators, including microbial community composition and sediment organic matter processing, remained altered up to 300 m from discharge points, indicating that functional impacts may extend beyond the primary hypersaline plume. The predictive modeling framework further demonstrated that ecological risk decreased nonlinearly with distance and varied according to discharge intensity, local hydrodynamics, and biological sensitivity. These findings indicate that conventional uniform buffer-based assessment may underestimate the ecological footprint of desalination discharge. Sustainable desalination management should therefore adopt site-specific monitoring, species-sensitive protection thresholds, improved brine-management technologies, and adaptive mitigation strategies based on real-time environmental feedback.

Atrazine (ATZ), a widely used triazine herbicide frequently detected in aquatic environments, poses ecological risks, yet its toxicity mechanisms in estuarine/marine organisms remain unclear. The present study employed juvenile Oryzias melastigma (marine medaka) as the model organism, and the 96-h median lethal concentration (LC50) of ATZ was determined to be 31.65 mg/L. Juvenile marine medaka were exposed to 0, 0.09, 0.36, 1.07, and 3.28 mg/L ATZ for 30 days. Histopathology revealed severe gill alterations (hyperplasia, apical enlargement, disintegration of the lamellae and filament congestion) and hepatic injuries (sinusoidal dilation, cytoplasmic vacuolization, acidophilic body formation and nuclear pyknosis). Biochemically, ATZ altered Na+-K+-ATPase and Ca2+-ATPase activities in the gills, reduced the activity of catalase (CAT) in the liver. ATZ at concentrations of 0.09 and 0.36 mg/L could markedly decrease the activity of total superoxide dismutase (T-SOD), and increase the malondialdehyde (MDA) content in medaka liver. Additionally, ATZ exposure upregulated the expression levels of ucp-2 and decreased the expression levels of cox-2, ccl20, il-1β, cat and sod. Transcriptome results showed 1,078 differentially expressed genes (DEGs) in the liver, with 436 upregulated and 642 downregulated DEGs. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that ATZ exposure disturbed the expression of genes associated with the HIF-1 and PI3K-Akt signaling pathways, suggesting that ATZ may induce hypoxia, oxidative damage and apoptosis. These results corroborate the histological and enzymatic evidence, providing insights into the toxicological impacts and mechanisms of chronic ATZ exposure in estuarine and marine fish.

Arsenic, a toxic metalloid widely distributed in nature, stands as one of the most hazardous environmental pollutants in estuarine and coastal ecosystems. The biotoxicity of arsenic is highly dependent on its chemical speciation and environmental conditions, where salinity acts as a critical factor that markedly influences its toxicological effects on aquatic organisms. To date, few studies have reported the combined effects of arsenic and salinity on fish, and the mechanisms of arsenic-induced toxicity on early fish development under varying salinity conditions remain poorly understood. In our study, the toxic effects of arsenic at different concentrations (0, 0.1, 1, and 10 mg/L) on the embryonic development of marine medaka (Oryzias melastigma) under three salinities (10, 20, and 30 ppt) were investigated. Our research results showed that arsenic exposure reduced the hatching rate of medaka embryos. At salinities of 10 and 20 ppt, the exposure to arsenic induced additional developmental toxicities, including decreased heart rate, shortened hatching time, increased malformation rate, and reduced body length of newly hatched larvae. Additionally, arsenic exposure altered the expression levels of cardiac development-related genes and immune-related genes, with varying expression changes observed across different salinity levels. These findings, taken together, demonstrate that salinity influences the arsenic-induced toxicity (cardiotoxicity, oxidative damage) on the embryonic development of medaka. Our study provides additional data support for the toxicity research and ecological risk assessment of arsenic in estuarine and coastal ecosystems.

Abstract Glutathione S-transferases (GSTs) play critical roles in cellular detoxification and antioxidant defense, yet their molecular characteristics remain poorly understood in brown macroalgae. In this study, three GST genes (designated as StGST1 , StGST2 , and StGST3 ) were identified from Sargassum thunbergii based on transcriptomic data and were systematically characterized at the molecular level. Conserved domain analysis revealed that StGST1 and StGST3 share structural features typical of Sigma-type GSTs, with N-terminal thioredoxin-like domains and C-terminal GST_C domains, whereas StGST2 belongs to the dehydroascorbate reductase (DHAR)-type family containing a GstA superfamily domain. Phylogenetic analysis demonstrated that StGST1 and StGST3 clustered with Sigma-class GSTs from Ectocarpus siliculosus and Laminaria digitata , while StGST2 grouped with DHAR-type GSTs from higher plants. To examine cadmium responsiveness, a time-matched transcriptomic comparison was performed between cadmium-exposed (5 mg l −1 ) and non-exposed control thalli cultured in parallel for three days. Among the three genes, StGST1 was significantly upregulated under cadmium exposure, identifying it as the principal cadmium-responsive GST isoform in S. thunbergii . These results provide the first molecular characterization of GST genes in S. thunbergii and identify StGST1 as a cadmium-responsive GST, contributing to our understanding of heavy-metal detoxification mechanisms in brown algae.

Annual large-scale green tides in the Yellow Sea initially appeared in the Subei Shoal, Jiangsu Province, with Ulva prolifera identified as the dominant species. Molecular identification of Ulva species has been a key focus during green tide monitoring. In this study, we used the chloroplast gene tufA (encoding elongation factor Tu) as a molecular marker to assess species composition and frequency across 11 Ulva populations. These were sampled from three coastal sites in Jiangsu and Shandong Provinces at six time points, totaling 420 biologically identified Ulva individuals. Additionally, the sporulation features of Ulva spp., which are directly linked to biomass variation, were examined to understand why U. prolifera dominates these blooms. (1) TufA proved to be a highly accurate and unambiguous molecular marker for Ulva species identification. We found that propagules in the coastal waters of Yancheng, Jiangsu, consisted mainly of Ulva aragoensis and U. prolifera, whereas floating biomass sampled during green tides in Shandong was predominantly U. prolifera. (2) A lower sporulation ratio in U. prolifera compared to U. aragoensis affects their relative proportions in floating biomass. This contributes to U. prolifera becoming the dominant floating species during the annual large-scale green tides in the Yellow Sea.

Sargassum muticum is one of the dominant species in the coastal algal communities of China, and investigating its response to high-temperature stress is crucial for algal resource conservation and utilization. This study assessed the effects of exogenous salicylic acid (SA: 10.0 mu g & sdot;mL-1) on the heat tolerance of S. muticum under high light (160 mu mol photons & sdot;m-2 & sdot;s-1) and low light (80 mu mol photons & sdot;m-2 & sdot;s-1) at 15 degrees C and 30 degrees C, respectively. The results indicate that at 15 degrees C, growth rate, activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD), and the expression of the hsp70 gene in S. muticum were significantly higher under high light than under low light conditions, with non-significant effect of SA. At the elevated temperature of 30 degrees C, S. muticum was able to maintain a daily growth rate exceeding 9 % within 3 days, and the maximum photochemical efficiency (Fv/Fm) showed no significant changes. However, under low light conditions, the content of photosynthetic pigments and the actual quantum yield of PS II (Y(II)) decreased significantly, while malondialdehyde (MDA) content increased markedly; conversely, little change was observed in the high light group. Additionally, the addition of SA significantly enhanced the growth of S. muticum in both high and low light conditions, regulated photosynthetic characteristics, increased the expression of the rbcL gene, enhanced peroxidase activity, and further promoted the expression of the hsp70 gene induced by high temperature. These findings provide insights for the artificial cultivation of S. muticum under challenging environmental conditions.

Heterotrimeric G proteins are key components of signal transduction mediating growth, development, and stress responses in eukaryotes. Here, we identified and characterized a G protein α subunit gene (SjGPA1) from the economically important brown alga Saccharina japonica using genomic databases, molecular techniques, and bioinformatic analyses. SjGPA1, encoded by the nuclear genome, contains a 1,065 bp open reading frame encoding 354 amino acids. The predicted protein has a molecular weight of 39.84 kDa and an isoelectric point of 4.90, and exhibits the features of a stable, hydrophilic protein lacking signal peptides and transmembrane domains. SjGPA1 possesses the conserved functional domains typical of Gα proteins and is predicted to localize primarily to the cytoplasm and nucleus. Phylogenetic analysis shows that SjGPA1 clusters within a monophyletic clade of brown algae (Phaeophyceae), is most closely related to its ortholog from Sargassum thunbergii and forms a sister group with Gα proteins from Undaria pinnatifida and the model brown alga Ectocarpus siliculosus. Promoter analysis identified 22 cis-acting elements, including 9 growth-responsive, 2 hormone-responsive, 6 light-responsive, and 5 stress-responsive elements. Real-time quantitative PCR indicated that low salinity significantly upregulated SjGPA1 expression (3.52-fold), whereas high temperature caused no significant change, and no transcript was detected under high light, drought, or darkness. By contrast, Western blotting showed significantly reduced SjGPA1 protein levels under drought and darkness, and markedly suppressed accumulation under high temperature, low salinity, and high light. The purified recombinant SjGPA1 bound GTP but showed no detectable GTPase activity. Together, these results indicate complex post-transcriptional regulation and suggest that SjGPA1 contributes to the adaptation of S. japonica to marine environmental stresses, providing a basis for further functional analyses and molecular breeding for stress resistance.

The YanTai HY-Nuclear Power Plant (HYNPP) is a newly constructed nuclear power plant that entered operation after 2021. To establish a preoperational ecological baseline for the HYNPP, this study examined macrobenthic community structure and its relationships with multiple environmental variables using year-round field surveys conducted from 2016 to 2017. Eighty-five species from eight phyla were recorded in total, with winter showing the highest species number and spring exhibiting peak biomass. Species composition displayed pronounced seasonal turnover, with replacement rates exceeding 93% between adjacent seasons. Principal coordinates analysis (PCoA) and hierarchical clustering confirmed significant seasonal variation and the localized aggregation of species near the HYNPP. Diversity indices (S, H′, D′, and J′) varied across seasons and spatial gradients, strongly influenced by sea bottom temperature (SBT), salinity, dissolved oxygen (DO), and nutrient concentrations. Spearman correlation analysis and random forest (RF) modeling revealed SBT, DO, phosphate, and phytoplankton cell as dominant factors shaping macrobenthic diversity. RF models provided key insights into nonlinear interactions and variable importance across seasons. Leveraging the dependence-preserving power of copulas, Copula-Based Random Forest (CBRF) models were further developed under a +4°C warming scenario to simulate post-operational thermal-discharge effects; the CBRF framework captured complex spatial responses, predicting localized biomass increases in sheltered muddy areas and biomass reductions in the outer bay. Mollusk biomass was projected to peak in spring near mixed-substrate habitats, while annelids and arthropods showed variable responses linked to sediment type and nutrient availability. These findings highlight strong spatiotemporal coupling between environmental parameters and macrobenthic assemblages, emphasizing the roles of SBT and phytoplankton-driven organic inputs in modulating community structure. The predictive framework built here supports long-term ecological risk assessments and management strategies for mitigating thermal discharge impacts in the Yellow Sea region.

Saccharina japonica is a commercially important species in the seaweed industry, with a long history of cultivation. Understanding the differences in the integrated quality of S. japonica across major production regions is necessary for achieving high-quality output and maximizing resource utilization efficiency. However, to date, comprehensive analyses and evaluations of S. japonica have received limited attention. In this study, we analyzed variations and characteristics of 17 physical and chemical indices of S. japonica from nine cultivated populations across the three primary producing provinces in China, namely Fujian, Liaoning and Shandong. Correlation and path analysis were used to explore the interrelationships among the indices, while hierarchical cluster analysis was used to further identify similarities and differences among populations. We employed two comprehensive analysis methods: grey correlation degree analysis (GCDA) and dynamic technique for order preference by similarity to ideal solution (DTOPSIS) to evaluate the integrated quality of S. japonica. The results showed that coefficients of variation for all physical and chemical indices were 9.4 %-54.6 %, with the color index b * exhibiting the greatest variability. Significant correlations were observed among the physical and chemical indices, and blade length and width were identified as key determinants of fresh weight. Moreover, physical and chemical indices showed significant differences among populations and producing provinces. S. japonica from Liaoning exhibited superior morphological traits, while samples from Shandong displayed better appearance color and higher mannitol content. According to the ranking from the two comprehensive analysis methods, S. japonica from Liaoning had the best overall integrated quality. These findings provide a foundation for the scientific evaluation of the integrated quality of cultivated S. japonica, offering insights for breeding and cultivation strategies, and promoting the high-value utilization of S. japonica.

Antibiotic selective pressure in aquaculture systems often results in the antibiotic resistance genes (ARGs) proliferation. Nonetheless, a paucity of data exists concerning the mechanisms of ARGs development in aquaculture systems without the influences of antibiotics. This study utilized metagenomic approaches to elucidate the dynamics and transfer mechanisms of ARGs throughout the aquaculture of Pacific white shrimp. A marked change in the resistome was observed throughout the aquaculture without antibiotics. The total ARGs relative abundance increased from 0.05 to 0.33 by day 90 of cultivation, with even higher in mixed wastewater (0.44). Both bacterial communities and mobile genetic elements play pivotal roles in the development of ARGs. Metagenome-assembled genomes showed enrichment of environmentally intrinsic ARGs on chromosomes including macB and mdtK. The plasmid-mediated horizontal transfer was recognized as a principal factor contributing to the rise of ARGs, particularly for tetG and floR, and this led to an escalation of resistance risk, peaking at a risks core of 35.43 on day 90. This study demonstrates that horizontal gene transfer plays a crucial role in ARGs development without antibiotic pressure, which can provide a theoretical foundation for controlling ARGs proliferation in aquaculture systems.

为研究山东沿海不同地理群体中国蛤蜊(Mactra chinensis)形态差异和地理分化特点,运用多变量形态度量学方法,通过方差分析、主成分分析、聚类分析和判别分析对日照东港(DG)、烟台海阳(HY)、青岛黄岛(HD)、威海文登(WD)和东营垦利(KL)5个中国蛤蜊野生群体形态数据进行比较分析.生长指标指数显示,文登群体贝壳最厚,黄岛群体贝壳最薄、肥满度最低,海阳群体软体部最肥;5个群体间最大差异系数为0.515～1.245,均小于1.28,尚未达到亚种水平;主成分分析共提取3个主成分,主成分1贡献率为33.71％,主成分2贡献率为27.16％,主成分3贡献率为14.42％,累计贡献率达75.29％;聚类分析结果表明,5个中国蛤蜊群体聚为2类,海阳群体、文登群体和垦利群体聚为一类,东港群体和黄岛群体分别聚为一类;通过判别分析,共建立了4个判别函数,判别准确率为70.0％～94.0％,综合判别率为80.0％.研究结果可为中国蛤蜊的地理群体识别、种质资源保护与利用提供重要依据.

In this study, the total phenolic and flavonoid contents, antioxidant activity and volatile components of brown seaweed Sargassum muticum were investigated after treated with charcoal suspensions at concentrations of 5%, 10%, and 15% (w/v) for 6, 12, 18 and 24 h, respectively. Results revealed that the total phenolic content was reduced by 71.90%, 74.1% and 76.5% respectively compared to the non-charcoal treated control after 6 h of 5%~15% charcoal treatment, while extending treatment time had little impact on it. The total flavonoid content did not differ significantly from the control at 6 h with 5% charcoal treatment (P>0.05) and decreased slightly with longer treatment time, whereas it decreased significantly with both 10% and 15% charcoal treatment to 68.2% and 60.0% of the control after 24 h, respectively (P<0.05). For antioxidant capacity, the scavenging activities of ABTS+· and DPPH· were both reduced after charcoal treatment, moreover the differences between different charcoal concentrations were not significant at first 6 h (P>0.05), whereas decreased gradually with charcoal concentration elevated after 12 h. A total of 25 volatile components were identified from S. muticum, of which the content and types of hydrocarbons dominated. The relative content of volatile components decreased significantly after charcoal treatment (P<0.05), especially the key odor compounds (aldehydes) decreased by 58.8% of 15% charcoal treatment for 24 h, indicating that deodorization using charcoal could effectively reduce the fishy flavor of S. muticum samples. These results provide reference and basis on development of S. muticum for functional food products.

近年来,莱州湾作为我国北方重要海水养殖区,养殖产量及规模迅速增长,贝类增长尤为迅速.大规模集约养殖下,养殖污染问题已不可忽视.本文基于近10年(2008-2017)莱州湾海水养殖产量等数据,通过排污系数法估算莱州湾海水养殖总氮(TN)、总磷(TP)及化学需氧量(COD)入海通量的年际变化,同时进行组间差异显著性比较.结果表明:近十年莱州湾海水养殖总TN、TP入海通量均为负值且呈"不断减小"趋势,平均值分别为-5 868.30(±1 364.03)t和-320.54(士82.96)t;COD通量呈"持续增大"趋势,平均值为6 446.06(士 1 382.67)t;鱼类TN、TP年通量与甲壳和海参间有显著性差异(P＜0.05),甲壳、海参间无显著性差异(P＞0.05);甲壳和海参、贝类、鱼类三者COD年通量间有显著性差异(P＜0.05),甲壳、海参间无显著性差异(P＞0.05).本文结果显示莱州湾养殖排放水氮磷比(N/P)约为2.91,较低的N/P对于平衡局部海区营养盐组成有积极作用.排污系数法无法体现排污季节性差异,因此在精准计算月通量时,需结合其他方法同时进行.在今后,应加强养殖污染通量及养殖容量的相关研究,只有实现养殖生产与生态环境的协调统一,才能实现海水养殖的可持续发展.

Manganese (Mn) is an essential metal for organisms, but high levels can induce serious toxicity. To date, the toxic mechanism of Mn to marine fish is still poorly understood. In the present study, Oryzias melastigma embryos were exposed to different concentrations of MnCl2 (0-152.00 mg/L) to investigate its effect on early development. The results showed that exposure to MnCl2 caused developmental toxicity to embryos, including increased heart rate, delayed hatching time, decreased hatching rate and increased malformation rate. MnCl2 exposure could induce oxidative stress in O. melastigma embryos, as indicated by increased the contents of malondialdehyde (MDA) and the activities of the antioxidant enzymes (superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT)). The heart might be an important target organ for MnCl2 because of cardiac malformations and disruption in the expression of cardiac development-related genes (ATPase, epo, fg8g, cox1, cox2, bmp4 and gata4). In addition, the expression levels of stress- (omTERT and p53) and inflammation-related genes (TNFα and il1β) were significantly up-regulated, suggesting that MnCl2 can trigger stress and inflammatory response in O. melastigma embryos. In conclusion, this study demonstrated that MnCl2 exposure can induce developmental toxicity, oxidative stress and inflammatory response in O. melastigma embryos, providing insights into the toxic mechanism of Mn to the early development of marine fish.

Zooplankton community is ecological important because of its high sensitivity to environmental changes especially in estuarine areas. The Yellow River estuary (YRE) in China is the fifth biggest estuary in the world with significant seasonal characteristics and anthropogenic influence of Water-Sediment Regulation (WSR). This study investigated the spatio-temporal patterns of zooplankton in the YRE to explore the response of zooplankton to seasonal variation and WSR. Results suggested that the temporal patterns of zooplankton were mainly characterized by seasonal shift of dominant species. Hierarchical cluster analysis and non-metric multidimensional scaling determined summer, summer-autumn and winter-spring three zooplankton assemblages. Zooplankton spatial distributions represented seasonal consistency, in which the abundance generally showed a decreasing gradient from the river mouth to sea. WSR caused a high species replacement rate in July-August (80.36%) and a dramatic abundance decline from 4224.60 ind./m3 to 1541.10 ind./m3 with persistency and hysteresis effect. The high zooplankton abundance moved seaward in spatial distribution after WSR. Summer spatial pattern was determined with two and three zooplankton station assemblages, which was more clear after WSR. Redundancy analysis identified SSS, SST and transparency as important factors structuring zooplankton spatio-temporal patterns, in which SSS was the key one. The results provide a necessary reference for understanding the response of zooplankton community in estuarine areas to spontaneous changes and anthropogenic factors, and can help the protection of estuarine ecosystems and the formulation of hydrological regulatory policies.

目的:海带具有微小配子体世代和大型孢子体世代,可利用营养生长的配子体克隆长期保存海带种质,但配子体克隆肉眼较难分辨雌雄,本研究以 901 海带品系(Saccharina 901)、DF海带品系(S.DF)、早厚成海带品系(S.zaohoucheng)、长海带(S.longissima)和真海带(S.japonica)的雌雄配子体为研究对象,分析它们的超微结构差异,为种质雌雄鉴定提供细胞学研究参考.方法:海带配子体克隆保存在低温弱光条件,取 5 种海带共 10 份配子体克隆,打碎后,固定包埋,在电子显微镜下观察细胞的超微结构.结果:5 种海带雌雄配子体的区别在于雌配子体的质体在细胞内各个部位均有分布,雄配子体的质体靠近细胞壁分布,而且雄配子细胞有较小的质体与细胞体积比值,研究结果可作为长期保存的海带种质性别鉴定的指标.

为调查山东某水蛭养殖场病情暴发原因,从该场患病水蛭中分离得到优势菌株SZ-1,对其进行生理生化特性及分子生物学分析.形态学、生理生化分析显示,菌株SZ-1为革兰氏阴性菌,杆状,两端钝圆,有鞭毛;Biolog GenIII分析表明,该菌株生长代谢利用情况与假单胞菌属吻合,与荧光假单胞菌B特征相似.基于16S rRNA基因序列分析同源性,该菌株16S rRNA基因序列与荧光假单胞菌(Pseudomonas f luorescens)相聚类,聚合置信度可达99％.综合生物学及分子特征,判定SZ-1为荧光假单胞菌.

通过对山东省威海市荣成俚岛、荣成靖海卫、文登泽库近岸海域潮间带大型海藻资源调查发现,底质对海藻的种数及分布均有影响.荣成俚岛潮间带为岩礁底质,海藻的种数较多,有3门31属37种,荣成靖海卫与文登泽库潮间带以砂质底为主,海藻的种数较少,分别为3门8属11种与3门7属9种.岩礁底质的形状、布局影响海藻的生长与分布,分析了九种不同岩礁类型的海藻分布规律以及适宜生长的海藻种类多数海藻不易在岩礁迎浪面附着,在低潮带,易在有一定沉积效应处生长,在高潮带,易在有一定的存水量的地方生长.研究结果对潮间带海藻资源增殖与恢复中藻礁材质、形状等的选用与设计有指导意义.

Environmental condition is a significant factor that directly affects the growth, metabolism and productivity of marine algae. This study examined the influences of diluted seawater on the growth, antioxidation capacity and accumulation of bioactive compounds of the marine macroalga, Sargassum muticum. Compared to the natural seawater (30 ppt, parts per thousand) control, the specific growth rate was clearly elevated at diluted seawater with 15 and 20 ppt during the initial 3 days, and was not statistically different at diluted seawater from 15 to 30 ppt at 15 days, while it decreased significantly at a low seawater concentration of 10 ppt. Chlorophyll a, carotenoids and total protein content fluctuated slightly under the different seawater solutions, suggesting that the algal cells underwent metabolic regulation during the period of adaptation to culture media changes. Changes in seawater concentration altered antioxidant enzyme activity, for instance, total superoxide dismutase, catalase and peroxidase, especially at low seawater solutions with 10 and 15 ppt. The malondialdehyde content also increased substantially, indicating that oxidative damage occurred in diluted seawater below 15 ppt. Moreover, the alginate content increased with decreasing seawater concentration, the alginate productivity was significantly increased by 22.32%-54.79% in all dilutions at 3 days and this promotion continued only at 15 and 20 ppt salinities after 7 days. The fucoxanthin content reduced significantly in the 10 and 15 ppt dilutions at 15 days, however, its productivity increased slightly at 10 and 15 ppt salinities in the first 3 days. The phlorotannin content increased slightly in the seawater dilutions with 20 ppt at 3 and 7 days, meanwhile, its productivity was significantly elevated during the initial 3 days at all seawater dilutions and the highest value was found at 20 ppt treatment. These results provide valuable data for the development and management of the aquaculture of S. muticum.

为探究山东长岛养殖坛紫菜(Pyropia haitanensis)的最适营养盐条件,对不同氮、磷浓度下坛紫菜的生长、光合色素含量、营养成分(粗蛋白、粗脂肪、灰分)和氨基酸组成进行测定分析,并评价其营养价值.结果显示:山东长岛养殖的坛紫菜在氮、磷加富浓度分别为50μmol·L-1、3.13μmol·L-1时生长速率最快,叶绿素a、类胡萝卜素、藻红蛋白及藻蓝蛋白含量均显著升高,但在氮、磷浓度分别高于200μmol·L-1、12.5μmol·L-1时其生长减缓.坛紫菜对氮、磷的吸收速率受营养盐浓度的显著影响,在氮、磷浓度分别高于200μmol·L-1、12.5μmol·L-1时,其对NH+4-N的吸收速率显著高于NO-3-N.氮、磷加富培养使坛紫菜营养成分的含量呈显著变化,其中粗蛋白和灰分含量显著增加,而粗脂肪的含量则显著降低;氨基酸总量以及呈味氨基酸占总氨基酸的比值(DAA/TAA)均有不同程度的升高,而必需氨基酸占总氨基酸的比值(EAA/TAA)、必需氨基酸和非必需氨基酸的比值(EAA/NEAA)则略有下降.以氨基酸评分和化学评分为标准所计算的几种必需氨基酸评分结果表明,氮、磷加富培养对坛紫菜蛋白质的构成产生显著影响.