Human-induced stresses on mangrove swamps along the Kenyan coast

Cultural use of spring-fed wetlands in Death Valley National Park, California has reduced populations of endemic macroinvertebrates. Studies were conducted during the spring and late autumn of 1994 to assess demography and habitat use by the Badwater snail (Assiminea infima), which is endemic to low-elevation, spring-fed habitats in Death Valley where its abundance is believed to be adversely affected by municipal diversions and habitat trampling by Park visitors. Effects on demography and habitat were examined at sites highly, lightly, and unaffected by these activities. Field experiments examined the response of its habitat and abundance to trampling.Snail density ranged from 0 to 19000 m^–2 along the banks of seven springs sampled at Badwater and Cottonball Marsh. Springbrooks with high, steep, and overhanging banks were preferred A. infima habitat. Mean distance of snails from water ranged from 1 mm at Badwater to 39 mm at Cottonball Marsh, and distance from water was greater in autumn than spring. Frequency distributions of shell height showed each population was comprised of several cohorts during spring and autumn, suggesting that reproduction occurs several times a year.Field experiments demonstrated that trampling reduces bank heights, angles and overhangs, and A. infima population density. Actions are required to manage public use at Badwater to arrest declines in abundance and distribution of A. infima, and to allow for recovery. Historical diversion of springs for irrigation and municipal uses have reduced and dried many aquatic and riparian habitats in the Funeral Mountains, causing current distribution in these springs to be approximately 15% of historical levels.     

Genetic and morphological variation of Rhizophora mangle (red mangrove) along the northern Pacific coast of Nicaragua

Red mangrove (Rhizophora mangle) dominates in tidally active areas of neotropical mangrove forests. Despite the ecological and economic importance of this species, we still know little about the genetic structure and diversity of its natural populations. In particular, Nicaraguan populations have not yet been investigated although they could be important for a better understanding of the evolutionary history of R. mangle in Mesoamerica. The aim of this study was to estimate the genetic and morphological variability of 4 populations sampled along the northwestern coast of Nicaragua. Microsatellite analysis showed higher levels of allelic diversity (30 alleles and a mean number of allele per locus per population = 6.42) than reported for the same species in other sites of tropical America. This variability could be attributed to the existence of a glacial refugium in the studied area and/or to repeated introgression among closely related species. Analysis of molecular variance (AMOVA) revealed that there was little but significant variation among the sampled sites suggesting that the studied populations cannot be considered as a single panmictic group, although they are closely related. This result was confirmed by the Bayesian analysis and UPGMA dendrogram showing three genetically distinct clusters. Bayesian analysis of migration rates showed that propagule dispersion associated with marine currents is an important factor shaping the observed genetic structure. The scatterplot from discriminant analysis indicated significant phenotypic differences between two groups, mainly related to specific leaf area variation. The morphological similarity between PR and PO was consistent with the results of molecular analysis, supporting the common origin of these two populations. Nevertheless, we did not find a significant statistical correlation between microsatellite and morphological data. In conclusion, the results reported here contribute to a better understanding of R. mangle genetic structure and would provide baseline information to guide land managers in implementing conservation initiatives in Nicaragua.     

Microsporidians in penaeid shrimp along the west coast of Madagascar

Three species of penaeid shrimp, Fenneropenaeus indicus, Penaeus monodon and P. semisulcatus, found in trawler catches off the west coast of Madagascar were infected with microsporidian parasites. The infections were evident as muscular lesions with a cottony appearance when abundant. Spore size (2.6 x 1.6 microm) and morphology (ovoid) for the parasites infecting both F. indicus and P. semisulcatus were not significantly different, suggesting that they might be the same microsporidian species. Spore size (1.4 x 1.1 microm) and morphology (sub-globose to ovoid) in P. monodon infections were significantly different from those in the other 2 shrimp species, suggesting that it was a different parasite. The presence of microsporidians in this biogeographical zone means that there is a potential risk of infections of cultured shrimp in farms situated in the vicinity. This must be assessed by increasing current knowledge of the parasites.     

海南岛西海岸红树林软体动物多样性

为了掌握海南岛西海岸红树林软体动物多样性状况, 本文于2015-2016年对海南岛西海岸6个主要红树林分布区软体动物的种类组成、物种多样性和群落结构的时空变化进行了研究。共采集到软体动物57科201种, 主要优势种有珠带拟蟹守螺(Cerithidea cingulata)、绯拟沼螺(Assiminea latericea)、圆胖樱蛤(Pinguitellina cycladiformis)和斜肋齿蜷(Sermyla riqueti)等。年平均密度与平均生物量分别为324.13 ind./m²和142.88 g/m², 物种数、密度和生物量均高于北部湾沿岸的其他红树林。海南岛西海岸各红树林软体动物的密度和生物量均未呈现明显的季节变化, 软体动物密度存在空间上的显著差异。聚类分析结果显示, 在盐度、土壤结构和红树林群落存在差异的不同红树林, 软体动物种类组成相似度低。多因子AZTI海洋生物指数(M-AMBI)结果表明海南岛西海岸红树林软体动物群落未受明显扰动, 生态环境质量介于一般和优良之间, 但仍受到人类活动与外来植物入侵威胁, 因其在候鸟迁徙中的重要作用, 亟需加强管理与保护。     

广西西端海岸四种红树植物天然种群生境高程

在广西防城港市东湾渔洲坪、石角、交东3个样地平行海面方向共设置18条剖面对4种红树植物白骨壤(Avicenniamarina)、桐花树(Aegiceras corniculatum)、秋茄(Kandelia obovata)、木榄(Bruguiera gymnorhiza)在沿海滩涂生长带高程测量和群落调查。调查结果表明:由于人类活动造成东湾渔洲坪和交东两个样地的坡度变化较大,分别从-0.37变化为-0.05和-0.72变化为-0.10,而地处北仑河口保护区内的石角样地受到保护,没有人为因素的影响,坡度从-0.23变化为-0.10变化不大。石角和交东两个样地中的桐花树集中出现在高程15至40 cm和33至36 cm范围内;秋茄集中出现在高程43至60 cm和37至51cm范围内;木榄集中出现在高程94至106 cm和111至119 cm范围内。所有样地中的白骨壤在高程60至80 cm范围内,树高最高达到220 cm,且分布密集;桐花树在高程20至40 cm范围内,树高最高达到200 cm,且分布密集;秋茄在高程40至80 cm范围内,树高最高达到200 cm,且分布密集;木榄在高程60至100 cm范围内,且分布密集,树高最高达280 cm。通过对各样地剖面上红树植物种类出现频度的分析和林木高度的测量,4种红树植物天然林临界滩涂高程分别为:桐花树为-7 cm;秋茄为+33 cm;白骨壤为+23和+26 cm;木榄为+44 cm。对应的浸淹时间分别为8.5、7.0、7.0、6.0h。在石角和交东分别有30.0%和56.7%的桐花树分布于平均海平面以下,秋茄也能分布在此高程下,平均株高也达1.75 m。根据现场实际调查结果,桐花树、秋茄可以大量生存在平均海平面以下的滩涂上。     

Anemia and childhood mortality: latitudinal patterning along the coast of pre-Columbian Peru

Hrdlicka ([1914] Smithson. Inst. Misc. Collect. 61:1-69) reported that pre-Columbian skeletal material from the coastal lowland Andean region exhibited a high frequency of porotic hyperostosis, a pathological condition of bone that generally is thought to indicate childhood anemia. While subsequent studies tended to reinforce this conclusion, factors implicated in the condition have yet to be fully explored in the region as a whole. This study explores regional and intravalley variation as one step in establishing biocultural variables that increase the apparent risk of childhood anemia. The study sample includes 1,465 individuals: 512 from Peruvian collections housed at the Field Museum of Natural History, and 953 from systematically excavated contexts from Moquegua, Peru. Environmental stressors, such as parasites and disease, rather than specific dietary practices were found to be more likely associated with childhood anemia in these coastal Andean samples. The study supports cribra orbitalia as an earlier expression of porotic hyperostosis and suggests that porotic hyperostosis, as recorded here, cannot be easily dismissed as a result of cranial shape modification. No clear temporal patterns were observed. Finally, the study establishes that comparing data for children and adults can reveal the relative association between childhood anemia and mortality. Childhood mortality associated with anemia was elevated where the presence of tuberculosis or tuberculosis-like conditions was more common and the presence of water-borne pathogens was negligible. In contrast, those buried at lower altitudes, closer to the coast, and consuming mainly marine resources were less likely to die in childhood with anemia than in the other contexts studied.     

Diversity of endophytic fungi in the roots of mangrove species on the west coast of India

Because mangrove plant species are a valuable source of useful metabolites, their endophytes have gained more importance. Randomly sampled surface-sterilized whole root segments of four mangrove plant species, Acanthus ilicifolius, Avicennia officinalis, Rhizophora mucronata, and Sonneratia caseolaris from the mangroves of Udyavara (Karnataka) on the west coast of India, were characterized for fungal communities by direct plating, damp chamber, and bubbling chamber incubation methods. The richness of endophytic fungal species from whole root segments after direct plating and damp chamber incubation was greatest for R. mucronata than for other plants (18 vs. 8-13). Incubation of whole root segments in bubbling chambers yielded conidia of two freshwater hyphomycetes: Mycocentrospora acerina (in Avicennia officinalis) and Triscelophorus acuminatus (in R. mucronata and in S. caseolaris). Surface-sterilized whole root and root bark segments of R. mucronata sampled from the mid-tide level on direct plating yielded more fungi than that of the root segments sampled from low-tide and high-tide levels. The greatest number of isolates, species richness, and diversity of fungi were shown by the whole root segments of R. mucronata from the mid-tide level. Rarefaction indices also revealed the highest expected number of species out of 150 random isolations from the mid-tide level samples of whole root and root bark segments of R. mucronata. The present study showed that fungi in mangrove roots are composed of a consortium of soil, marine, and freshwater fungi.     

Salinity stratified benthic macrofaunal communities and long-term monitoring along the west coast of Sweden

Benthic macrofauna was quantitatively sampled in 12 coastal areas along the west coast of Sweden in 1971–1976. The Baltic Current creates a halocline at ≈15m depth which acts as a barrier between two differently structured benthic communities, one of which has a wide extension along the coast below the halocline and the other above the halocline. Physical and chemical factors, e.g., variations in salinity and temperature, have a great influence on the faunal structure above the halocline, whereas biological processes are the main determinating factors of the faunal composition in the comparatively more stable environment below the halocline. The sub-halocline community contains significantly more species (60%), a significantly higher mean abundance (4200 compared with 2000 ind. m^?2) and a significantly greater mean biomass (146 compared with 71 g m^?2 wet wt) than that above the halocline. Diversity measured by the Shannon-Wiener formula and its evenness had approximately the same means in both these habitats, 3.3–3.7 and 0.62, respectively.Four of the areas investigated in 1976 were also studied in the 1920's by approximately the same methods. The number of species, abundance, and biomass were significantly greater in the recent samples than in those taken half a century ago. and the community structures differed between the two periods. These differences are attributed to seasonal and natural long-term changes and different methods in processing the samples obtained. It is concluded that the halocline is a habitat divider and creates a vertical discontinuity for benthic communities on the west coast of Sweden.     

Survey of imposex in prosobranchs mollusks along the northern Mediterranean coast of Morocco

Imposex, i.e., the superimposition of male sex organs on female gonochoristic neogastropods has been observed in more than 140 species worldwide and suggested as a suitable biomarker of tributyltin pollution in the marine environment. In this study, an imposex survey for three neogastropod species: Murex trunculus, Murex brandaris and Thaïs haemastoma was conducted for the first time at five sites along the northern Mediterranean coasts of Morocco. The imposex phenomenon was observed in the all surveyed sites. Nevertheless, rates of occurrence and degree of imposex were more important in both harbours sites (Tangier and Mdiq) characterized with heaving shipping activity than in the three seaside stations (Martil, Azla and Amsa) where only sporadic and small boats are used in traditional fishing activities.     

The costs of migration: Injuries in migratory waterbirds along the west coast of India

The long distant, transcontinental migration of shorebirds entails many well identified costs in terms of time, energy, and direct mortality risk. Injuries from debris or from human structures and activities were observed as the major reasons for the direct mortality of shorebirds during migration worldwide. We recorded injured birds in major coastal wetlands of Kerala, for a period of 15 years from 2005 to 2019. The injured birds were observed in 9 different sites in various districts of Kerala. The highest instances of injuries were observed in Kadalundi-Vallikunnu Community Reserve, the major wintering and stop over site of migrant shorebirds in the west coast of India. During the study period, fifty-eight individuals of shorebirds belonging to four families were found to be injured. The highest proportion of injuries was recorded among the families Scolopacidae and Charadriidae comprising long distance migrant shorebird species and the lowest among Laridae and Ardeidae. We recommend that environmental authorities pay special attention to minimize anthropogenic debris along the flyways used by migratory birds thereby reducing the risk of injuries to some of these species. Proactive measures such as removal of discarded fishing gear or plastic debris from wintering areas as well as stopover areas could greatly reduce injuries in migratory birds arising from anthropogenic sources.     

海南西海岸真红树内生细菌多样性及其延缓衰老活性研究

该文设计9种分离培养基,采用稀释涂布法从14份真红树植物的46份组织样品中分离纯化内生细菌。并基于菌株形态学特征和16S rRNA基因序列确定分离菌株的种属及分析其物种多样性,采用秀丽隐杆线虫模型筛选菌株延缓衰老活性。结果表明:(1)通过基因序列去重复后从46份真红树植物组织样品中获得32株海洋细菌,基于菌株16S rRNA基因序列信息分析,覆盖12科17属,其中芽孢杆菌属(Bacillus)为优势菌属,并获得1株疑似橙单胞菌属(Aurantimonas)新种,16S rRNA基因序列相似性低于97%;(2)经过秀丽隐杆线虫粗筛发现3株海洋细菌具有显著延缓线虫衰老的活性(P<0.05)。以上结果表明海南西海岸真红树内生细菌具有物种多样性,部分菌株具有延缓线虫衰老活性。     

Patterns of macroalgal diversity, community composition and long-term changes along the Swedish west coast

This study analyses the complicated patterns of vertical distribution of the macroalgal vegetation in an area where brackish and marine waters meet and mix. Variables used to record vegetation characteristics are algal cover, species composition and diversity. The data set includes 64 diving profiles, all from sites exposed to wave action, along a ca. 260 km long coastline. The profiles belong to four categories: coastal sites in the Skagerrak (more marine), coastal sites in the Kattegat (more brackish), coastal sites in the Kattegat after a toxic phytoplankton bloom, and submerged offshore stone reefs in the Kattegat. The highest species diversity was found at the reefs, which are not affected directly by land runoff. At the reefs the 18 most common perennial species penetrate 2–11 m (on average 5.5 m) deeper than at the coastal sites. The virtual absence of sedimentation, and thus the availability of substratum, at the reefs may explain the differences so that the lower limit for the algae is determined by light penetration or by recruitment problems caused by strong currents at the reefs, whereas sedimentation limits the settlement of algae in coastal sites. Ordination analysis based on species composition reveals that the major environmental gradients structuring the algal vegetation in the Kattegat and the Skagerrak are salinity and water depth. The large data set of this study made it possible to quantify the downward dislocation of Atlantic intertidal species to the sublittoral along the Swedish west coast. For example, the mean upper limit of Corallina officinalis is 2 m in the Skagerrak but 12.5 m in the Kattegat and the mean occurrence interval of Fucus serratus is 0.9–2.7 m in the Skagerrak, but 1.1–6.3 m in the Kattegat. This downward dislocation is suggested to be the result of decreased competition when species successively disappear with lower salinity. Comparisons of the present study's results with those of previous investigations show that eight common red algal species have moved upwards compared to the situation before the large-scale eutrophication started in the 1960s, e.g. Cystoclonium purpureum and Polysiphonia elongata by ca. 8 m, Phycodrys rubens and Delesseria sanguinea by ca. 5 m. A toxic phytoplankton bloom affected macroalgal community composition on the whole only slightly, but it had a negative effect on algal cover and species richness below a water depth of ca. 5 m, the algae were visibly damaged and the lower vegetation limit temporarily moved upwards.     

Study on the maltooligosaccharide composition of mucilage samples collected along the northern Adriatic coast

The mucilage phenomenon, a sporadic but massive accumulation of gelatinous material, can cause serious damage to the tourism and fishing industries along the Adriatic coast. Mucilage is presently thought to be the result of the aggregation of dissolved organic matter (DOM) into particulate organic matter (POM). Three principal classes of compounds have been identified in organic matter by spectrometric determination: carbohydrates, proteins and lipids. Carbohydrates are suspected to play a role in the first steps of DOM aggregation. Despite its importance in understanding the processes leading to mucilage formation, our present knowledge of the composition of the mucilage carbohydrate fraction is incomplete. Due to its high sensitivity and specificity, liquid chromatography coupled with electrospray-ionization tandem mass spectrometry (LC-ESIMS/MS) is gaining an increasing importance as a powerful technique for carbohydrate purification and characterization in complex samples. In this work, LC-ESIMS/MS is proposed as a useful method for the investigation of the oligosaccharide content in mucilage samples. The approach was applied using 3-7 unit maltooligosaccharides as reference compounds. The composition of the investigated mucilage sample was further investigated combining LC-ESIMS/MS with classic approaches, such as spectroscopic techniques and liquid chromatography coupled with the refractory index LC-RI.     

海南西海岸真红树内生放线菌多样性及其延缓衰老活性初筛

为了发掘红树林内生放线菌资源和进行新型海洋药物研究,该文选择海南西海岸14种真红树的根、茎、叶、花、胚轴为研究对象,采用9种不同分离培养基[改良的高氏培养基(AGG)、海藻糖-天冬酰胺培养基(M4)、海藻糖-脯氨酸培养基(M5)、改良ISP5培养基(M7)、精氨酸-天冬酰胺培养基(M9)、改良淀粉-水解酪素培养基(M10)、酪氨酸-天冬酰胺培养基(P7)、燕麦培养基(P3)、棉籽糖-组氨酸培养基(M11)],结合稀释涂布法和三线划线法从真红树组织中分离菌株,基于菌株16S rRNA基因序列信息等分子生物学鉴定方法对获得的海洋放线菌进行多样性分析,并使用模式生物秀丽隐杆线虫对所得内生放线菌的延缓衰老活性进行研究。结果表明:(1)从46份真红树组织中共获得24株放线菌,隶属于7科11属,其中9株菌株为链霉菌属(Streptomyces),且IMDGX 6270、IMDGX 6137和IMDGX 6173为3株疑似潜在新菌株。(2)秀丽隐杆线虫模型筛选发现4株放线菌(IMDGX 6157、IMDGX 6182、IMDGX 6248、IMDGX 6360)具有延缓衰老的活性,与空白组比较,生存时间分别延长17.16%、28.11%、29.05%、27.10%。综上结果说明海南西海岸区域真红树植物中可能含有较丰富的放线菌资源,能够为延缓衰老药物的研发提供新来源。     

Shifting N and P limitation along a north-south gradient of mangrove estuaries in South Florida

The heterotrophic utilization of organic substrates by diatoms is likely an important survival strategy when light levels are too low for photosynthesis. The objectives of this study were: (1) to determine if heterotrophic utilization of a large array of organic compounds by eight common freshwater benthic diatom taxa was light-dependent, and (2) to determine if organic substrate utilization patterns differed between dark-grown diatoms and bacteria as a possible means of reducing competition by niche separation. Eight light- and dark-grown diatom taxa and five bacterial species were incubated in 96-well Biolog^® Microtiter plates with each well containing 1 of 95 different organic substrates. Oxidation rates of each organic substrate were measured through time. There was a substantial increase in the number of organic substrates oxidized by diatoms grown in the dark compared to their light-grown counterparts, indicating that the transport systems for these molecules may be light activated. Therefore, diatoms likely only utilize these metabolically expensive uptake mechanisms when they are necessary for survival, or when substrates are plentiful. A principal components analysis indicated discernible differences in the types of organic-C substrates utilized by dark-grown diatoms and bacteria. Although bacteria were able to oxidize a more diverse array of organic substrates including carboxylic acids and large polymers, diatoms appeared to more readily utilize the complex carbohydrates. By oxidizing different organic substrates than bacteria, heterotrophically metabolizing diatoms may be reducing direct competition and enhancing coexistence with bacteria.     

Short term spatio-temporal variabilities of microphytobenthic assemblages in the mangrove ecosystems along the southwest coast of India

Wetlands Ecology and Management - Microphytobenthos (MPB) or benthic microalgae are recognized as the dominant flora in shallow neritic ecosystems such as mangroves. The diversity, biomass and...     

海南西海岸红树林伴生植物内生放线菌多样性及其延缓衰老活性初筛

为寻找新型抗衰老药物,该文以海南西海岸红树林伴生植物为研究对象,采用9种不同培养基从7种伴生植物21份样品中分离纯化放线菌,通过PCR扩增,16S rRNA基因序列分析已纯化放线菌的多样性,利用秀丽隐杆线虫(Caenorhabditis elegans)模型筛选菌株来进行延缓衰老活性研究。结果表明:(1)从7种伴生植物21份样品中共分离到26株海洋放线菌,隶属于9科15属,分别为拟诺卡菌属、短状杆菌属、短小杆菌属、Demequina、戈登氏菌属、类诺卡氏菌属、Lysinimicrobium、细杆菌属、假诺卡氏菌属、微球菌属、原小单孢菌属、拟无枝酸菌属、Yimella、北里孢菌属和链霉菌属,其中链霉菌属为优势菌属。(2)经秀丽隐杆线虫模型筛选,发现有2株海洋放线菌的发酵粗提物具有延缓秀丽隐杆线虫衰老的作用。综上结果说明海南西海岸红树林伴生植物中含有丰富多样的药用放线菌资源,为海洋放线菌抗衰老研究奠定了基础。     

海南西海岸四种真红树根系土壤放线菌物种多样性及其延缓衰老活性初筛

为更好地开发利用海洋微生物资源积累丰富的放线菌菌种,该文以海南西海岸潮间带区域四种真红树根系土壤为研究对象,分析了红树林根系放线菌物种多样性组成及其代谢产物活性。该研究以9种不同培养基为分离介质,采用纯培养方法和三区划线法分离纯化菌株,结合放线菌形态学特征及其16S rRNA基因序列结果开展多样性分析。放线菌发酵液经乙酸乙酯萃取,利用秀丽隐杆线虫(Caenorhabditis elegans)测试其延缓衰老活性。结果表明:(1)共分离获得22株放线菌,隶属于4目7科9属,其中链霉菌属(Streptomyces)为优势菌群,并初步确认IMDGX 6012、IMDGX 6028、IMDGX 6118、IMDGX 6326、IMDGX 6119 5株放线菌可能为潜在的新物种。(2)发酵产物延缓衰老研究结果表明,8株放线菌的代谢产物可显著延长线虫寿命(P0.05);其中,IMDGX 6028和IMDGX 6118作为拟无枝酸菌属(Amycolatopsis)和短小杆菌属(Curtobacterium)的潜在新物种,具有极显著延缓衰老活性(P 0. 01),与空白组比较,可分别延长线虫寿命的22.2%和26.6%。综上结果表明海南西海岸真红树根系土壤具有丰富的可培养放线菌资源,具有发现放线菌新物种和延缓衰老活性菌株的潜力。