资源一号02D高光谱数据红树林地上生物量反演

红树林生态系统是地球上生产力最高的生态系统之一,它也是海岸带“蓝碳”生态系统的重要组成部分。地上生物量作为红树林蓝碳的重要组成部分,如何准确快速地获取红树林地上生物量已成为红树林生态系统研究的热门问题。分析北部湾茅尾海红树林地上生物量(AGB)空间分布格局及其量级,可为该区域红树林生态环境保护及“南红北柳”生态修复提供科学依据。资源一号数据作为我国自主研发的民用国产高光谱卫星,其高光谱数据为红树林地上生物量的研究提供了新的机遇。机器学习算法因其高性能、高效率的优势被越来越多的应用于红树林相关研究,目前已经成为获取红树林参数信息的重要手段。高光谱数据在红树林地上生物量的反演精度如何?国产高光谱卫星数据和机器学习算法在红树林地上生物量的估算中能否应用?这些问题仍需进一步验证。基于国产资源一号02D高光谱数据,采用极端梯度提升(XGBoost)、随机森林回归(RFR)以及K近邻回归(KNNR)三种不同的机器学习算法对茅尾海的红树林地上生物量进行估算,在此基础上对比了不同的机器学习算法的性能。结果显示:(1)无瓣海桑红树林地上生物量的平均值最高(90.93 Mg·ha^(-1)),桐花树次之(52.63 Mg·ha^(-1)),而秋茄最小(20.27 Mg·ha^(-1))。(2)采用XGBoost、 RF以及KNN三种机器学习算法进行红树林地上生物量和红树林光谱变量建模后发现,基于对数倒数1阶变换的XGBoost模型精度最高,为最佳的机器学习模型。其模型在测试阶段R^(2)=0.751 5, RMSE=27.494 8 Mg·ha^(-2)。(3)基于资源一号02D高光谱数据,采用XGBoost算法反演茅尾海的红树林地上生物量介于4.58~208.35 Mg·ha^(-2)之间,平均值为88.98 Mg·hm^(-2),地上生物量在空间上呈现出中部低,两边高的空间分布格局。总之,该研究论证了国产高光谱卫星数据和XGBoost机器学习算法的组合在红树林生物量的估算方面具有良好的应用前景,可为茅尾海红树林的生态修复和保护提供科学依据和技术支撑。

广西红树林生态系统的常见物种

红树林湿地是链接陆地与海洋的重要枢纽,地貌特征独特,内部构造复杂多样,集海洋与陆地的普遍性与特殊性于一体,具有强大的包容性,为数以千计的海洋生物提供了生存、觅食、繁衍的环境。本文主要从食用红树林生物、广西红树林鸟类和昆虫3个方面重点介绍广西红树林生态系统中的常见物种。

一株红树林来源稀有放线菌的鉴定和抑菌活性物质的初步研究

对分离自香港米埔红树林放线菌XY-R10进行鉴定并研究其抑菌活性。采用R2A和ISP-2培养基分离和纯化菌株。通过PCR扩增和测序获得菌株16S rRNA序列,利用邻接法构建系统发育树并结合形态学分析,初步鉴定该菌可能为拟孢囊菌属的Kibdelosporangium phytohabitans。通过纸片扩散法和微量稀释法研究发酵粗提物的抑菌活性,发现其具有广谱抗革兰氏阳性菌作用。初步分离发现粗提物中可能存在多个活性成分,结合液相-串联高分辨质谱分析,鉴定出活性成分Maipomycin A,它对表皮葡萄球菌、单增李斯特菌和副溶血弧菌有抑菌活性。该文为挖掘红树林微生物资源、抗菌药物的开发,以及食品工业寻找新的抑菌防腐物质提供了研究基础。

Study on Sonneratia apetala productivity in restored forests in Leizhou Peninsula, China

The exotic Sonneratia apetala in Leizhou Peninsula, has shown outstanding fast-growing ability in restored mangrove forests, at the middle and high tide intertidal zone, with year-round fresh water input from drainage. By setting plot and selecting standard tree, investigation and measurement on height growth, diameter growth, biomass, productivity, and so on, were made in a S. apetala plantation at age of six at Lanbei, Fucheng, Leizhou Peninsula in May 2001. The investigating results showed that the mean annual height growth of plantation was 2.03 m and mean annual growth of diameter at breast height (DBH) was 2.35 cm. There exists a significant correlation between the diameter at ground surface (DGS) and DBH. The average biomass of a single standard tree in dry weight was 95.647 kg/m2. A ratio of above-ground biomass to under-ground biomass was 1.60. The stand biomass of unit area was 22.955 kg/m2, singletree wood volume was 88.23 dm3, and the annual wood volume productivity (PA) of the same year was 0.407. The forest energy accumulation was 424.851 MJ/m2, with annual solar energy fixing rate of 40.68 ×10-7%. It is concluded that S. apetala species had characteristics of outstanding high biomass accumulation and could be used as coastal planting tree species in southern China.

First report of an endophyte (Diaporthe phaseolorum var. sojae) from Kandelia candel

Mangrove endophytic fungus 1893 was isolated from Kandelia candel from an estuarine mangrove on the South China Sea Coast Two new lactones 1893A and 1893B, together with other known compounds, have been isolated from its fermentation broth. To classify the endophyte correctly for further industrial application, a combination of morphological and molecular techniques was used to approach its identity. The endophyte was compared with similar species having trichogynes or trichogyne-like hyphae which apparently fused with an- theridium-like hyphae, and perithecia initials developing from an ascogonial coil surrounded by enveloping hyphae in early developmental stages on pure culture. Further morphological characteristics on host and non-host were used for comparison with similar species when the endophyte was cultivated on leaves ofKandelia candel and Mangifera indica, respectively, which resulted in classifying the endophyte as a Phomopsis specics. The ITS sequence of rDNA was used to infer its phylogenetic relationships with Phomopsis species that resembled the strain in morphology or ecology. Finally, the endophyte was identified as Diaporthe phaseolorum var. sojae based on morphological and molecular evidence. Our study is a first report ofDiaporthephaseolorum var. sojae isolated from mangrove Kandelia candel.

Biodiversity and biotechnological potential of mangrove-associated fungi

This review describes the present hot research areas of mangrove-associated fungi, including its biodiversity, ecological roles, novel metabolites productions and biotechnological potential. Mangrove-associated fungi were divided into saprophytic, parasitic and true symbiotic fungi based on its ecological roles. Saprophytic fungi are fundamental to decomposition and energy flow of mangrove, additionally, their potential toxicity also exists. Pathogenic fungi have significant effects on mangrove survival, growth, and fitness. Endophytic fungi, the most prolific source of diverse bioactive compounds found among that of mangrove-associated fungi, are found in most species of mangroves. Although a significant number of reports focused on the antimicrobial, insecticidal and other bioactive metabolites as well as many novel enzymes isolatcd from mangrove-associated fungi, and many of those metabolites from endophytic fungi are suspected to be of significant to mangrove, only few studies have provided convincing evidence for symbiotic producers in mangrove. Hence, this paper discusses the present progress of molecular methods used to correlate the ecological roles of endophytic fungi with their bioactive metabolites;, meanwhile, the potential of using metabolic engineering and post-genomic approaches to isolate more novel enzymes and bioactive compounds and to make their possible commercial application was also discussed.

Chemical constituents of marine mangrove-derived endophytic fungus Alternaria tenuissima EN-192

A chemical investigation of the ethyl acetate extract of the fermentation broth of Alternaria tenuissima EN- 192, an endophytic fungus obtained from the stems of the marine mangrove plant Rhizophora stylosa, resulted in the isolation of nine known secondary metabolites, including four indole-diterpenoids： penijanthine A （1）, paspaline （2）, paspalinine （3）, and penitrem A （4）; three tricycloalternarene derivatives： tricycloalternarene 3a （5）, tricycloalternarene lb （6）, and tricycloalternarene 2b （7）; and two alternariol congeners： djalonensone （8） and alternariol （9）. The chemical structures of these metabolites were characterized through a combination of detailed spectroscopic analyses and their comparison with reports from the literature. The inhibitory activities of each isolated compound against four bacteria were evaluated and compounds 5 and 8 displayed moderate activity against the aquaculture pathogenic bacterium Vibrio anguillarum, with inhibition zone diameters of 8 and 9 mm, respectively, at 100 gg/disk. To the best of our knowledge, this is the first report on the secondary metabolites of mangrove-derived Alternaria tenuissima and also the first report of the isolation ofindole-diterpenoids from fungal genus Alternaria.

Secondary Production of Macrobenthos in Mangrove Area of Tong'an Bay,China

Studies on secondary production lead to a better understanding of the functions of the macrobenthic ecosystem.Basedon the macrobenthic data obtained at 6 sampling stations from April 2006 to January 2007,Brey's(1990)empirical formula wasapplied to calculate the secondary production of macrobenthos in the mangrove area of Tong'an Bay.The results showed that themean annual secondary production of macrobenthos was 13.24 gAFDWm-2-a-1.The mean secondary production in the mangrovehabitat was 12.22 gAFDWm-2-a-1,lower than that in the non-mangrove habitat,which was 15.29 gAFDWm-2-a-1.Two possible rea-sons existed for this difference.First,mollusk and crustacean,which contribute more to the secondary production,probably benefitfrom longer inundation period in the non-mangrove habitat.Second,the higher organic matter in the mangrove habitat results in hy-poxia in the bottom sediment,which may decrease the secondary production.The annual mean production-to-biomass(P/B)ratio inTong'an Bay was 1.17,with a ratio of 1.27 in the mangrove habitat and 0.96 in the non-mangrove habitat,which was coincident withthe much higher density of Limnodriloides sp.and Corophium sp.in the mangrove habitat than in the non-mangrove habitat.Themaximum secondary production and P/B ratio of macrobenthos both appeared at sampling station FL2 in April,2006(namelyApril-FL2)with values of 31.38 gAFDWm-2-a-1and 2.20,respectively.The macrobenthic secondary production in Tong'an Bay islower than those in other intertidal studies except that in Haitan Strait,the reason being the different sediment properties.The P/Bratio in Tong'an Bay was the lowest due to the high proportion of crustaceans in the macrobenthic community.

DEPOSITS OF THE MANGROVE TIDAL FLATSAND MANGROVE PEATS IN HAINAN ISLAND

In this paper, the environment characteristics, micro-environment division and evolution of the mangrove tidal flats, peats and their genetic markers are discussed. It proves that the mangrove tidal flat is a kind of tidal flats and the peat flats are developed in a specific evolution stage of mangrove tidal flats; the mangrove peats are the products of a specific evolution stage of the mangrove tidal flats.

Isolation of Marine Actinomycetes from the Mangrove Swamps for Biotechnological Exploration

The mangroves are specialized marine environments widely distributed along the coast lines, which support biologically diverse groups of organisms including microbes. The microorganisms present in this ecosystem contribute significantly in the food web of the tropical marine ecosystem. In the present investigation, Actinomycete isolates obtained from mangrove sediments have been studied for diversity as well as for their bioactive potential. Seven different Actinomycete isolates （MS 1-MS7） were obtained from the sediments collected from the mangrove swamps. The phylogenetic analysis of these isolates showed that out or seven isolates, 3 isolates belong to Streptomyces sp., which has bioactive potential as several bioactive metabolites have been isolated from this group. One bacterium showed genetic similarity with Corynebacterium sp.. The microbes from this group are used for very important industrial applications. Three Actinomycete isolates showed very low similarity with the reported strains from the gene bank. In suggests that, these cultures could be novel and further research work is warranted to prove this speculation. In antagonistic studies, three Actinomycete isolates showed promising results. This investigation highlights the importance of mangrove ecosystem as a rich source of diverse Actinomycete strains for biotechnological applications.

Mangroves Restoration and Observation in Kaohsiung Jhong-Dou Wetland

The ecosystems of Kaohsiung are rich and diverse. Examples of ecosystems include the tropical rainforest ecology, marine ecology of the coastal forests, and the estuary type ecology of mangrove forests. The Jhong-Dou Wetland Park is situated in the Jhong-Dou Redevelopment Zone, 2.5km from the Lover River Estuary. This area is defined by brackish aquatic environments--a mixture of fresh and salt water, and fulfills the criteria for mangrove restoration. It is expected that the current restoration project will recreate an epitome of the once-diverse, co-existing mangrove species of Kaohsiung＇s past, and improves upon the functions of environmental education. The initial mangrove species planned for restoration are the existing Kandelia obovata, Rhizophora stylosa, Avicennia marina and the Lumnitzera racemosa populations of the Kaohsiung area. These plants will be placed in experimental habitats that correspond to the unique micro-climates required for the growth of each species, and the mangrove-associated plants will also be restored concurrently in the terrestrial environments behind the mangrove forests. The process of restoration will be monitored by academia, as well as providing reference for subsequent mangrove environment restoration efforts. The main purpose of this research in these four mangrove species of this wetland park is to understand their adaptation to the rehabilitating environment, and be able to feedback these information to the design and maintenance team of the park. The research method is to observe and record their growing status, also execute a survey on the nearby mangrove habitation. The observation has started on December 1 st of 2010, and still has been continued carry on since then. From the research result, it shows that the A vicennia marina （Forsk.） Vierh. and Lumnitzera racemosa Willd. are the two species that had been well adapted to this wetland park. It was recommended to the Kaohsiung City Government that the restoration of the extinct Ceriops tagal and Bruguiera gymnorrhiza can be achieved through foreign species exchanges （the species must be identified before introduction）, and that plans for monitoring the flora and fauna in the park should be drafted to record the ecological alterations of the Jhong-Dou Wetlands. This will pronounce the ecological importance of Kaohsiung on a global, geographical scale. Lastly, the Government should draw up plans of mangrove forest maintenance in order to sustain the ecological and landscape recreational functions of the Jhong-Dou Wetland Park.

Geographical Variation in Oligochaete Density and Biomass in Subtropical Mangrove Wetlands of China

Oligochaetes play an important role in nutrient cycling and energy flow in benthic food webs as well as in mangrove wetlands. However, they have not been as extensively studied as other macrofaunal groups such as polychaetes, gastropods, bivalves, and crustaceans. Under the assumption that oligochaete density and biomass obey specific geographical distribution patterns in subtropical mangrove wetlands of China, we investigated these two parameters in the Luoyang Estuary of Quanzhou Bay, Zhangjiang Estuary and Gaoqiao mangrove wetlands. A geographical gradient in oligochaete density was present in Aegiceras corniculatum and Kandelia obovata habitats, whereby it decreased from lower latitudes to higher latitudes. Further, ANOVA tests on oligochaete distribution revealed that both oligochaete density and biomass were significantly influenced by region, season and region × season at the A. corniculatum and K. obovata habitats. The annual average oligochaete density and biomass at the A. corniculatum habitat were higher than that at the K. obovata habitat, in both the Luoyang and Zhangjiang estuaries. There were significant correlations between oligochaete density and biomass and sediment particle size parameters, confirming that sand, silt, and clay contents were the key environmental factors affecting oligochaete distribution.

The influence of three mangrove species on the distribution of inorganic nitrogen and phosphorus in the Quanzhou Bay estuarine wetland soils

This study aims to investigate the effects of region and three regional dominated mangrove species(Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus. Measurement of the inorganic nitrogen and phosphorus and enzymatic activities was carried out in soils covered by three mangrove species in the Quanzhou Bay estuarine wetlands, a typical coastal wetland in China.Species with a higher biomass in upstream and midstream absorb more nitrogen from soils, and the retention of the available phosphorus in the soils of different regions causes the regional variation of phosphorus. In areas dominated by A. marina, nitrate nitrogen is lower while available phosphorus is higher. Meanwhile, nitrate nitrogen and available phosphorus are higher in the soils covered by K. candel.Moreover, all three species affect the elemental and enzymic stoichiometry. The mangrove species influences the diversity of the elemental and enzymic stoichiometric relationship through differential microenvironments, which induce the biodiversity of wetland ecosystems. Thus, this study may facilitate a better understanding of the transformation ability of mangroves to nitrogen and phosphorus and will therefore be beneficial for providing a basis for the ecological restoration of estuarine wetlands.

Water Quality and Loading of Pollutants from Shrimp Ponds during Harvesting

Shrimp aquaculture is an important source of revenue for the state of Sarawak, Malaysia. However, there were concerns on the impact of shrimp farming on the mangrove ecosystem due to the discharge of shrimp pond water to the surrounding environment and potential self-pollution through the intake of surrounding water for the shrimp ponds. Therefore, the objectives of this study were to determine the water quality of the harvesting pond water and quantify the pollutants loadings. Samplings were conducted in three ponds and three channels near the pond outflow in a commercial shrimp farm during complete draining of water at harvest. Results indicated that TSS and Chl-a were high in both the ponds and channels. Total ammonia-nitrogen was the predominant form of the inorganic nitrogen and the mean values in both the ponds and channels were more than 1 mg/L which exceeded the maximum recommended for fish. Therefore, the water quality of the ponds and channel indicate that pond effluent should not be discharged directly into the surrounding environment but treated and nutrients recovered. Loads of total suspended solids, BODs, inorganic nitrogen, ammonia nitrogen, soluble reactive phosphorus and Chl-a of the effluent were quantified.

Characteristics and Carbon Storage of a Typical Mangrove Island Ecosystem in Beibu Gulf,South China Sea

By studying the structural characteristics and carbon storage of the mangrove island ecosystem in the Beibu Gulf,this study provides a scientific basis for mangrove ecological compensation in the coastal areas of Guangxi,South China Sea.On the basis of the unmanned aerial vehicle remote sensing images and a sample plot survey,the object-oriented multi-scale segmentation algorithm is used to extract the mangrove community type information,and one-way analysis of variance is conducted to analyse the structural characteristics of the mangrove community.The carbon storage and carbon density of different mangrove ecosystems were obtained based on the allometric growth equation of mangrove plants.The analysis yielded four main results.(1)The island group covers about 27.10 ha,41.32%(11.20 ha)of which represents mangrove areas.The mangrove forest is widely distributed in the tidal flats around the islands.(2)The main mangrove types were Aegiceras corniculatum,Kandelia obovata+Aegiceras corniculatum,Avicennia marina+Aegiceras corniculatum and Avicennia marina communities.(3)Amongst the mangrove plants,Avicennia marina had the highest biomass(18.52 kg plant^(–1)),followed by Kandelia obovata(7.84 kg plant^(–1))and Aegiceras corniculatum(3.85 kg plant^(–1)).(4)The mangrove carbon density difference was significant.Kandelia obovata had the highest carbon density(148.03 t ha^(–1)),followed by Avicennia marina(104.79 t ha^(–1))and Aegiceras corniculatum(99.24 t ha^(–1)).The carbon storage of the mangrove island ecosystem was 1194.70 t,which was higher than in other areas with the same latitude.The carbon sequestration capacity of the mangrove was relatively strong.