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Coastal saltmarshes are key ecosystems with important ecological functions. Yet, they have experienced a widespread decline. Due to their importance, the conservation and restoration of saltmarshes ... are globally shared objectives, including China. Despite multiple local studies, nationwide information about saltmarshes in China is scarce. Thus, we used remote sensing to delineate the spatial distribution and areal extent of saltmarshes along coastal China and resolve their species composition. By interpreting 10 m spatial resolution Sentinel-2 images on Google Earth Engine, assisted with field survey and literature search, a total of 118 010 ha of saltmarshes were delineated in coastal China in 2019. Seven typical saltmarsh species were identified, with Phragmites australis , Spartina alterniflora, and Scirpus mariquater as dominant species, accounting for 95.5% of total saltmarsh extent, while Suaeda salsa , Tamarix chinensis , Cyperus malaccensis, and Sesuvium portulacastrum were present in limited abundance. The P. australis and exotic species S. alterniflora grow along almost all coastal provinces, but P. australis dominates in the north while S. alterniflora dominates in the middle part of coastal China. Suaeda salsa occurs mainly in the north and has suffered large losses. Tamarix chinensis is abundant in Shandong province, S. mariquater in the Yangtze River delta, C. malaccensis in Guangdong and Guangxi provinces, and S. portulacastrum in Taiwan. The exotic species S. alterniflora expanded extensively along the coast and its expansion rate continues to increase. The results provided conform a much-needed baseline for future monitoring efforts and the assessment of progress in the conservation and restoration projects toward recovering saltmarshes in China. more

This study mapped the areal extent, identified the species composition, and analyzed the changes of salt marshes in the intertidal zone of China during the period 1985–2019. With the aid of the cloud ... platform of the Google Earth Engine, we selected Landsat 5/8 and Sentinel-2 images and used the support vector machine classification method to extract salt marsh information for the years of 1985, 1990, 1995, 2000, 2005, 2010, 2015, and 2019. Seven major species of salt marshes: Phragmites australis , Suaeda spp., Spartina alterniflora , Scirpus mariqueter , Tamarix chinensis , Cyperus malaccensis , and Sesuvium portulacastrum were identified. Our results showed that salt marshes are mainly distributed in Liaoning, Shandong, Jiangsu, Shanghai, and Zhejiang, with varying patterns of shrinking, expansion, or wavering in different places. The distribution of salt marshes has declined considerably from 151,324 ha in 1985 to 115,397 ha in 2019, a drop of 23.7%. During the same period, the area of native species has dropped 95.4% from 77,741 ha to 3,563 ha for Suaeda spp. and 45.1% from 60,511 ha to 33,193 ha for P. australis ; on the contrary, the area of exotic species, S. alterniflora , has exhibited a sharp rise from just 99 ha to 67,527 ha. For the past 35 years, the driving factors causing salt marsh changes are mainly land reclamation, variations in water and sand fluxes, and interspecific competition and succession of salt marsh vegetation. These results provide fundamental reference information and could form the scientific basis for formulating policies for the conservation and utilization of salt marsh resources in China. more

Seaweed aquaculture is vital in protecting the marine eco-environment and mitigating climate change. China generates more than half of the world's total seaweed production. However, despite multiple ... local studies, accurate and reliable information on broad-scale seaweed farms is still scarce. Using an object-based method to classify 3 m spatial resolution Planet Scope images along offshore China, a total of 129,494 ha of cultured seaweed was identified and delineated with an overall accuracy of 95.70% and a KAPPA index of 0.912, respectively. Then, a seaweed map in offshore China in 2018-2019 was developed. The results provided basic information about seaweed farms in China. The approach reported in this work is accurate and efficient, which can be used to replace the conventional method to obtain the culture seaweed information. This study can be of reference for mapping seaweed on a broader or global scale. more

Coastal bays serve as undeniable dissolved organic matter (DOM) reactors and the role of prevalent mariculture in DOM cycling deserves investigation. This study, based on four seasonal field ... samplings and a laboratory incubation experiment, examined the source and seasonal dynamics of DOM and fluorescent dissolved organic matter (FDOM) in the seawater of fish (Larimichthys crocea, LC), seaweed (Gracilaria lemaneiformis, GL) and abalone (Haliotis sp., HA) culturing zones in Sansha Bay, China. Using three-dimensional fluorescence spectroscopy coupled with parallel factor analysis (EEMs-PARAFAC), three fluorescent components were identified, i.e. protein-like C1, protein-like C2, and humic-like C3. Our results showed that mariculture activities dominated the DOM pool by seasonal generating abundant DOM with lower aromaticity and humification degrees. Accounting for 40–95 % of total fluorescent components, C1 (Ex/Em = 300/340 nm) was regarded the same as D1 (Ex/Em = 300/335 nm) identified in a 180-day degradation experiments of G. lemaneiformis detritus, indicating that the cultured seaweed modulated DOM through the seasonal production of C1. In addition, the incubation experiment revealed that 0.7 % of the total carbon content of seaweed detritus could be preserved as recalcitrant dissolved organic carbon (RDOC). However, fish culture appeared to contribute to liable DOC and protein-like C2, exerting a substantial impact on DOM during winter but making a negligible contribution to carbon sequestration, while abalone culture might promote the potential export and sequestration of seaweed-derived carbon to the ocean. Our results highlight the influences of mariculture activities, especially seaweed culture, in shaping DOM pool in coastal bays. These findings can provide reference for future studies on the carbon accounting of mariculture. Display omitted •Mariculture activities dominated the dynamics of dissolved organic matter (DOM).•Mariculture resulted in lower degrees of DOM humification and aromaticity.•Seaweed culture modulated DOM by the seasonal production of protein-like C1.•Fish culture contributed to seasonal variations in liable DOC and protein-like C2.•Abalone culture might promote the export of recalcitrant carbon from seaweed. more

Various marine aquaculture systems have different impacts on the environment, but few assessments were focused on the environmental impact by different systems in the same region. To study the ... effects of various aquaculture systems on phytoplankton community structure and water properties, 5 surveys were carried out in seaweed (Gracilaria lemaneiformis, GL), shellfish (Mytilus coruscus, MC) and cage fish (Larimichthys crocea, LC) mariculture areas in Dongji island, Zhejiang, China from June to September 2020. Significant differences were observed in some environmental parameters and phytoplankton communities among three aquaculture systems. The dissolved oxygen concentrations and Secchi depth in the surface waters in GL area were relatively higher than in the blank and other areas. As for nutrients concentration, LC and MC areas had higher concentrations than blank area, while GL area was the lowest. Though Chlorophyll-a concentration displayed fluctuations, relatively lower concentrations were found in GL area. Shannon diversity index was found to be relatively constant and higher in GL area. The Non-metric multidimensional scaling results revealed that phytoplankton composition had a distinct pattern among sampling times. The correlations and Redundancy analysis showed that total nitrogen, salinity and transparency were primary environmental factors associated with phytoplankton composition. Our study confirmed that different marine aquaculture systems can cause environmental fluctuations. Among the three systems, seaweed cultivation can bring multiple positive effects by improving surrounding water quality and increasing the phytoplankton composition. G. lemaneiformis culture in summer has great positive impact on seawater environment as it can maintain the ecological balance and reduce the risk of harmful algal blooms (HABs), and therefore, it is strongly recommended more G. lemaneiformis cultivation in this region in summer. Display omitted •Seaweed, shellfish and cage fish culturing areas in the same coast were sampled.•Diversity indices were found to be constant and higher in seaweed culturing area.•Though species composition was similar, the abundance varied among culturing areas.•Different systems were affected by different environmental factors.•Seaweed cultivation can maintain the ecological balance in the culturing area. more

Seagrass meadows are virtual blue carbon ecosystems facing a dramatic decline on a global scale. Tracking the status and trends of seagrass meadows, which is still pending on large scales, is an ... emerging priority for their conservation and restoration. Here, we develop a semi-automatic procedure to identify and map seagrass meadows. Using Sentinel-2 data in Google Earth Engine (GEE) platform, a map is generated, showing a total of 11113.4 ha of seagrass meadows in coastal China in 2020. There exists the largest extent (6450.3 ha) in the coast of the South China Sea, while the second area (3909.5 ha) is in the Yellow Sea-Bohai Sea, and the seagrass meadows in the East China Sea cover about 753.6 ha. Our results provide the baseline data of seagrass meadows distribution in coastal China, and this study can be of reference for mapping seagrass meadows on a broader or even global scale. more

In this study, the full-length GIH cDNA sequence from Litopenaeus vannamei was cloned from the eyestalk by reverse transcriptase polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ... ends. The fulllength GIH cDNA was 865 bp with a 288 bp open-reading frame, which encoded a 96 amino acid prepro-GIH with 17 amino acid signal peptide. L. vannamei GIH (LvGIH) can be classified as a member of type-II crustacean hyperglycemic hormone polypeptide family. LvGIH shares 93.8 and 66.7 % amino acid sequence identity with GIH from Penaeus monodon, and the molt-inhibiting hormone from Marsupenaeus japonicas, respectively. By quantitative real-time PCR (qPCR), LvGIH mRNA transcripts were detected in fertilized eggs, nauplius, zoea, mysis and juveniles of 25, 35 and 40 days old. LvGIH transcript levels increased significantly with the development from fertilized eggs to juveniles. LvGIH transcript levels were highest in juveniles at 35 days old. By RT-PCR, LvGIH mRNA transcripts were detected only in the eyestalks and brains but not in the muscles, intestines, gills, heart, hepatopancreas, ovaries and testes of adults, and there was no difference in the expression level of LvGIH between males and females. Using the P. monodon anti-GIH antibody, we showed that LvGIH was located mainly in the XO-SG and slightly in axon, with similar fluorescence intensity found in XO and SG. To summarize, we have cloned and characterized the GIH of the shrimp L. vannamei. In addition to the GIH properties described in other crustaceans, a peak of LvGIH expression was identified at the time of sexual differentiation (i.e., day 35 larvae) suggesting that LvGIH may also be involved in the control of this process. more

评价杂交水稻的光温特性，为高产优质杂交水稻品种的选育和生产中品种的合理布局提供参考。用因子分析方法，对52个杂交水稻营养生长期、抽穗开花期和灌浆成熟期的光温因子指标进行分析，评价杂交水稻的光温特性。3个公因子对变异的方差累计贡献率达91.74%，公因子1，2和3的贡献率分别为49.44%，23.20%和19.10%，其能真实反映12个光温指标及其相互关系；在杂交水稻的全生育期中，光温因子对杂交水稻生长发育影响最大的生育期是营养生长期，其次是灌浆成熟期。光温敏感型的杂交水稻组合主要有BⅡA×1-22、Ⅱ-32A×YB6、S420×T411、Q-A×1-11、BⅡA×NC、YS3550、N2×3550、YS122和BⅡA×1-10；光温钝感型的杂交水稻组合主要有YⅡA×T411、N2×R122、N22×R122、N2×2006、N2×T411、N22×2006和N22×T411。杂交水稻主要性状的表现型优劣与杂交组合的光温型没有必然关系。因子分析可以用于研究杂交水稻的光温特性，其研究结果与杂交水稻育种实际情况较为吻合。 The study was to evaluate the characteristics of the light and temperature in hybrid rice, and to provide theoretical basis for selecting high-yield and quality of hybrid rice breeding and species distribution. Factor analysis was performed for light and temperature indicators of 52 varieties (combination) during nutritive growing stage, heading flowering stage and filling-mature stage in hybrid rice, and for evaluation of light and temperature characteristics. The contributive rate of the first three factors to total variation of population studied acc

Genetic variations of three species from primary parent（OI Q，SIS Q，Kona Bay Q）and their first filial generation（OI Z，SIS Z，Kona Bay Z）of Litopenaeus vannamei were detected using microsatellite marker ... technique. The amplified products of genomic DNA with 8 microsatellite makers indicated 8 loci presents polymorphism，the number of total alleles were 28 in 6 species；the number of allele every loci was 2 to 6；mean allele number（Na）was 3.5；expected heterozygosity value（He）were higher than observed heterozygosity value（Ho）；mean polymorphism information content（PIC）ranged from 0.479 4 to 0.769 9，which showed these 8 loci posses relatively high information content. Through analysis of genetic structure in primary parent and their first filial，allele and effective allele number，observed heterozygosity and expected heterozygosity values and mean polymorphism information content（PIC）in filial generation were little lower than their primary parents. However，genetic diversity of filial generation is not influenced，and sti more