REPRODUCTIVE PERIODICITY OF THE SEA URCHIN,TRIPNEUSTES GRATILLA (L.) IN TAIWAN COMPARED WITH OTHER REGIONS

An annual reproductive periodicity of Tripneustes gratilla in northern Taiwan is revealed by both the gonad development stages and the gonad index. The gonads of T. gratilla recovered from spawning in February—March, propagated gametocytes in April—June, came to prematurity in July—August, and matured in September—November. Spawning occurred in October—December. The breeding pattern of T. gratilla over a broad geographical area appears to be related to seasonal changes of sea temperatures.     

Microbial community structure of Arctic multiyear sea ice and surface seawater by 454 sequencing of the 16S RNA gene

Dramatic decreases in the extent of Arctic multiyear ice (MYI) suggest this environment may disappear as early as 2100, replaced by ecologically different first-year ice. To better understand the implications of this loss on microbial biodiversity, we undertook a detailed census of the microbial community in MYI at two sites near the geographic North Pole using parallel tag sequencing of the 16S rRNA gene. Although the composition of the MYI microbial community has been characterized by previous studies, microbial community structure has not been. Although richness was lower in MYI than in underlying surface water, we found diversity to be comparable using the Simpson and Shannon''s indices (for Simpson t=0.65, P=0.56; for Shannon t=0.25, P=0.84 for a Student''s t-test of mean values). Cyanobacteria, comprising 6.8% of reads obtained from MYI, were observed for the first time in Arctic sea ice. In addition, several low-abundance clades not previously reported in sea ice were present, including the phylum TM7 and the classes Spartobacteria and Opitutae. Members of Coraliomargarita, a recently described genus of the class Opitutae, were present in sufficient numbers to suggest niche occupation within MYI.     

Metazoan parasite community structure of sea trout on the west coast of Ireland

A total of 129 sea trout smolts from 10 locations on the west coast of Ireland were examined for metazoan parasites. Of 11 species identified only four had a prevalence >20%. Two species Hysterothylacium aduncum and Hemiuris communis have a confirmed marine origin; Eubothrium crassum has been shown to exist in both the sea and fresh water. The remaining species were fresh water. Overall the parasite community was dominated by autogenic species with only Diphyllobothrium dendriticum having allogenic transmission. Infracommunity values for mean species richness, and Brillouins index of diversity were low, indicating the presence of an impoverished helminth community with little potential for interspecific interaction. The relationship between marine helminths and sea lice was also examined.     

Differences in susceptibility to sea lice infection between a sea run and a freshwater resident population of brown trout

Two experimental groups comprising mixed Norwegian sea run and freshwater resident brown trout Salmo trutta were infected with sea lice Lepeophtheirus salmonis in replicate tanks. Comparison of mean abundance and louse development between the sea run and resident groups revealed highly significant differences in lice abundance. The resident trout had an average abundance ± of 6·3±0·37 and 6·6±0·43 lice whilst the sea trout had an average abundance of 3·5 ±0·25 and 3·3 ±0·28 lice 29 days post infection at 9° C. No differences in development of lice, of either sex, were detected between the groups. As host groups were naive to sea lice at the start of the experiment, this suggests that there was a significant difference in susceptibility to sea lice infection between them, which may be genetically determined.     

Survival and emergence pattern of sea trout fry in substrata of different compositions

The emergence of the sea trout Salmo trutta fry of Gotland, Sweden, was studied in the laboratory. The main limiting factor for survival up to hatching was the interstitial oxygen concentration, which depends on the gravel permeability, therefore on the substratum granulometry. Fry emergence was possible in substrata in which the geometric mean particle diameter ( d _g) was >15 mm and in substrata in which d _g was <6 mm. In the substrata of low d _g, emergence took place earlier than in the other ones. As a consequence the fry were smaller and their yolk sac only partially resorbed. In an unfavourable environment, fry started to emerge as soon as they reacted positively to light, about 2 weeks after hatching.     

Impacts of a geotextile container dune core on marine turtle nesting in Juno Beach,Florida, United States

Hard armoring technologies (e.g. rock revetments and seawalls), which are installed to protect homes from beach erosion, can diminish the aesthetics and amenity of the beach. Over time, these structures cause beach narrowing and often prevent marine turtle access to nesting habitat altogether. An alternative armoring technology, known as geotextile dune core systems (or geocores), has been developed and implemented to protect inland infrastructure from beach erosion, yet there remains an absence of research on possible effects on marine turtles. In this study, we examined the impacts of a geocore installed on Juno Beach, Florida, United States in February 2014 on loggerhead (Caretta caretta) and green turtle (Chelonia mydas) nesting success, hatching success, and emergence success. A before‐after‐control‐impact paired series design evaluated the difference in nesting success per week for the impact and control sites 4 years before (2010–2013) and 4 years after (2014–2017) the installation of the geocore. Neither loggerhead nor green turtle nesting success was significantly different after the installation of the geocore; however, when analyzing loggerhead crawls that came to within 5 m of the geotextile bags, nesting success decreased. Neither hatching nor emergence success was significantly different after the installation of the geocore for either species. Our results suggest that geocores may minimally affect loggerhead and green turtles and provide a suitable restoration technique for homeowners facing beach erosion.     

Comparative biometry and isotopy of three dominant pennatulacean corals in the Northwest Atlantic

Spatial and temporal shifts in biometric features were examined in three common deep‐water pennatulacean corals (sea pens) from the Northwest Atlantic: Anthoptilum grandiflorum, Halipteris finmarchica and Pennatula aculeata. These three species show different morphological characters and adaptations to their environment. Analyses of colony length, ratio of peduncle to colony length, weight/length ratio, polyp size and density as well as sclerite shape, location and abundance indicate that their phenotype is modulated by environmental factors (e.g. food availability, currents and sediment type) and antipredator strategies. Moreover, the three species had different carbon and nitrogen stable isotope signatures that could be explain primarily by their different polyp diameters and colony shapes, suggesting that they rely on slightly different food sources (varying proportions of phytodetritus and zooplankton). Finally, sclerites were found only in H. finmarchica and P. aculeata and are not known to occur in A. grandiflorum, except for minute oval bodies inside the peduncle. The Mg/Ca ratio of sclerites differed between the two species and, for P. aculeata, among types of sclerites, evoking different biomineralization pathways related to their functional roles (structural support or defence). Overall, this study provides new information on the ecology of poorly known species, which are ubiquitous and suspected to play an important ecological role in deep‐water ecosystems.     

The rotifer fauna of peat-swamps in southern Thailand

Different taxa have had different degrees of success in invading and proliferating in the deep sea. The reasons for these differences are not well known, and exemplars need to be studied to provide insight as to factors that lead to success in the deep sea. Because the abundance of the deep-sea fauna taken as a whole declines with depth, the absolute abundance of a taxon is not an appropriate metric of its success. Rather, a taxon whose abundance declines as rapidly as or less rapidly than the general trend should be considered successful. In this paper, I used the macrofauna to define the general trend of abundance change with depth. When I compared the trend of abundance of harpacticoids to that for macrofauna, I found that harpacticoid abundance decreased less rapidly. Thus, harpacticoids are unusually successful in the deep sea. The reasons for their success are unknown, but I discuss three possible explanations.     

Heterogeneous and compensatory growth in Melithaea flabellifera (Octocorallia: Melithaeidae) in Japan

Melithaea flabellifera (Kükenthal, 1909) (Octocorallia, Gorgonacea), an endemic and predominant gorgonian in Japanese shallow waters, grows mostly in one plane and ramifies in a dichotomous way. The growth rates of all branches and of the colony were measured from photographs of tagged gorgonian corals for approximately 1 year from June 1995 to May 1996 on the western Pacific coast of Japan (34° 39′ N, 138° 56′ E). The most rapid growth occurred when the water temperature was less than 20 °C. Mean growth ranged from 2.9 to 11.4 mm year⁻¹. Linear growth of individual branches ranged between −30.4 and 24.8 mm year ^-1−1. Both seasonal and non-seasonal variations in growth rate were observed in each colony. When branches were lost, the adjacent branches grew faster, filling the open space in the fan. Heterogeneity in growth rate within a colony was partly caused by this compensatory growth. This indicates that the regular branching pattern of gorgonians is due to irregular and heterogeneous growth. The compensatory growth suggests that M. flabellifera is constrained by some potential optimal size or form.     

The mitochondrial genome of a sea anemone Bolocera sp. exhibits novel genetic structures potentially involved in adaptation to the deep‐sea environment

The deep sea is one of the most extensive ecosystems on earth. Organisms living there survive in an extremely harsh environment, and their mitochondrial energy metabolism might be a result of evolution. As one of the most important organelles, mitochondria generate energy through energy metabolism and play an important role in almost all biological activities. In this study, the mitogenome of a deep‐sea sea anemone (Bolocera sp.) was sequenced and characterized. Like other metazoans, it contained 13 energy pathway protein‐coding genes and two ribosomal RNAs. However, it also exhibited some unique features: just two transfer RNA genes, two group I introns, two transposon‐like noncanonical open reading frames (ORFs), and a control region‐like (CR‐like) element. All of the mitochondrial genes were coded by the same strand (the H‐strand). The genetic order and orientation were identical to those of most sequenced actiniarians. Phylogenetic analyses showed that this species was closely related to Bolocera tuediae. Positive selection analysis showed that three residues (31 L and 42 N in ATP6, 570 S in ND5) of Bolocera sp. were positively selected sites. By comparing these features with those of shallow sea anemone species, we deduced that these novel gene features may influence the activity of mitochondrial genes. This study may provide some clues regarding the adaptation of Bolocera sp. to the deep‐sea environment.     

Early juvenile development of deep-sea asteroids of the NE Atlantic Ocean, with notes on juvenile bathymetric distributions

The postmetamorphic ontogenesis of 11 deep‐sea asteroid species is described. Juvenile bathymetric distributions are compared to adults. The deep‐sea juvenile asteroids of the NE Atlantic could be distinguished to species level from a very early stage of development. In all species, except Porcellanaster ceruleus and Plinthaster dentatus, the arms grow faster than the body. In Porcellanaster ceruleus and Plinthaster dentatus, early growth is nearly isometric. In the appearance of the epiproctal cone, the change in form of the furrow and apical spines, the early development of the cribriform organ adjacent to the madreporite and the appearance of sediment in the stomach indicate that Porcellanaster ceruleus is likely to undergo a shift in habitat and diet during the juvenile phase. Porcellanaster ceruleus is probably a predator on meiofauna and small macrofauna during the early stages of life, changing to a burrowing lifestyle ingesting sediment particles. Juvenile sea stars showed wider bathymetric distributions than their adult counterparts, suggesting that events occurring during the early stages of life are important for the maintenance of the local population structure and diversity in the deep NE Atlantic.     

Residence time of the sea louse, Lepeophtheirus salmonis K., on Atlantic salmon, Salmo salar L., after immersion in fresh water

Returning adult salmon caught at the mouth of the River Dee, Aberdeenshire, were transferred to tanks in the laboratory. For fish placed in fresh water, sea lice remained attached for up to 6 days, though most lice were lost in the first 48 hours. Few lice were lost from salmon maintained in sea water. The experiments were conducted in water within a temperature range of 12·8 to 16° C, equivalent to summer river temperatures in the Aberdeenshire Dee.     

黄渤海海草分布区日本鳗草根际微生物群落结构特征及其功能分析

日本鳗草(Zostera japonica)是亚洲特有的海草种类,具有重要生态价值。近年来,黄渤海海草分布区中的日本鳗草海草床持续退化,引起了研究人员的广泛关注。【目的】基于根际微生物的分布与日本鳗草的健康生长密切相关的设想,本文旨在探究黄渤海海草分布区日本鳗草根际细菌群落结构多样性并分析其与海草健康生长的内在联系。【方法】选取黄渤海海草分布区中东营、威海、大连3个地点的日本鳗草根际与非草区表层沉积物,采用高通量测序技术(Illumina HiSeq PE300)解析根际微生物群落特征,并结合相关环境参数分析其环境功能。【结果】日本鳗草根际表层沉积物中主要存在的细菌类群有:变形菌门(Proteobacteria)所占比例为41.1%,蓝细菌门(Cyanobacteria)占15.4%,拟杆菌门(Bacteroidetes)占12.6%,放线菌门(Actinobacteria)占9.3%。不同地点之间以及样品类型(海草床根际与非根际)之间的微生物群落存在显著差异,主要表现为根际富含硫酸盐还原菌和固氮菌。环境因素:TN (total nitrogen)、TC (total carbon)、TOC (total organic carbon)、黏土(Clay)、砷(As)与根际群落组成与分布显著相关。【结论】从功能的角度来看,不同地点、不同样品类型之间的差异物种多与硫、氮代谢相关,硫酸盐还原菌对维持日本鳗草的生态健康起关键作用;日本鳗草根际微生物群落分布与环境因子、空间分布有一定相关性。     

Development of a microtitre plate indirect ELISA for measuring cortisol in teleosts, and evaluation of stress responses in rainbow trout and gilthead sea bream

A microtitre plate indirect enzyme‐linked immunoassay (ELISA) was developed for measuring plasma cortisol levels in rainbow trout Oncorhynchus mykiss, gilthead sea bream Sparus auratus sea bass Dicentrarchus labrax and Senegalese sole Solea senegalensis. Covalink microplates pretreated with disuccinimidyl suberate were coated with bovine serum albumin (BSA) conjugated to cortisol‐3‐carboxymethyl oxime. After blocking with BSA, competition was started by addition of plasma samples and anti‐cortisol antibody raised in rabbit. Goat anti‐rabbit IgG conjugated‐peroxidase was added as second antibody and then incubated with orthophenylenediamine as substrate. Reaction was stopped with 0·1 M HCl and absorbance was read at 450 nm in an automatic plate reader. The standard curve was linear from the lower limit of sensitivity of the assay (c. 0·3 ng ml^?1) to c. 3000 ng ml^?1. Dose‐response inhibition curves using serially diluted plasma samples of four species consistently showed parallelism with the standard curve using cortisol. The ELISA satisfied the strictest criteria of specificity (cross‐reactivity of anti‐cortisol antibody with testosterone, progesterone and 17ß‐oestradiol was negligible, cross‐reactivity with cortisone, corticosterone and 11‐deoxycortisol, was 1·5, 1 and 0·1%, respectively), reproducibility (interassay CV <6%), precision (intra‐assay CV <4%), and accuracy (average recovery >98%). Plasma cortisol concentration in rested fishes was in the range of 5–30 ng ml^?1. To physiologically validate the technique, changes in plasma cortisol concentrations were also measured in plasma of rainbow trout and gilthead sea bream following an acute 15 min chasing or 3 min air‐exposure stress, respectively. In both species plasma concentrations of cortisol, glucose and lactate rose significantly with respect to controls, showing concentrations similar to those reported previously for these species under similar stress conditions. Furthermore, gilthead sea bream chronically stressed by maintaining for 14 days under increased stocking density conditions also showed increased concentrations of plasma cortisol and glucose. These results validate the indirect ELISA technique developed for use in the evaluation of plasma cortisol concentration of at least four fish species.     

琼东海域橙黄滨珊瑚骨骼生长特性及其主要影响因素

基于珊瑚骨骼X射线照片,使用CoralXDS软件,对海南岛(琼)东部海域的橙黄滨珊瑚生长特性进行研究,获取了百年来的年生长率(ER)、骨骼密度(D)和钙化速率(CR) 3种生长参数.结果表明: 该橙黄滨珊瑚ER的变化范围为0.49～1.10 cm·a^-1,年均值0.76 cm·a^-1;D的变化范围1.11～1.35 g·cm^-3,年均值1.22 g·cm^-3;CR的变化范围为0.55～1.41 g·cm^-2·a^-1,年均值0.94 g·cm^-2·a^-1.统计分析表明,研究海区表层水温(SST)是橙黄滨珊瑚骨骼生长参数变化的主要环境影响因素,对ER和CR的控制较强,对D的影响较弱,但总体上3项生长参数都随SST升高而增大.光照、盐度和水动力条件等是次要影响因素.台风和强热带风暴对琼东海域橙黄滨珊瑚骨骼密度条带分布的影响也较为显著.复杂的气候环境,赋予了橙黄滨珊瑚骨骼多变的生长模式.过去一个世纪以来,琼东海域年平均表层水温显著上升,气候倾向率为0.15 ℃·(10 a)^-1,SST上升分为两个阶段,20世纪40年代初和80年代初,人类活动加剧和全球气候变暖是导致琼东海域SST显著上升的原因.     

Mechanical defensive adaptations of three Mediterranean sea urchin species

In the Mediterranean, Paracentrotus lividus and Sphaerechinus granularis are important drivers of benthic ecosystems, often coexisting in sublittoral communities. However, the introduction of the invasive diadematoid Diadema setosum, which utilizes venomous spines, may affect these communities. To describe the mechanical properties of the test and spines of these three species, specimens were collected in winter of 2019 from the sublittoral zone of the Dodecanese island complex, southeastern Aegean Sea. This region serves as a gateway for invasive species to the Mediterranean Sea. Crushing test was conducted on live individuals, while 3‐point bending test was used to estimate spine stiffness. Porosity and mineralogy of the test and spine, thickness of the test, and breaking length of the spine were measured and compared, while the microstructural architecture was also determined. The test of S. granularis was the most robust (194.35 ± 59.59 N), while the spines of D. setosum (4.76 ± 2.13 GPa) exhibited highest flexibility. Increased porosity and thickness of the test were related to increased robustness, whereas increased flexibility of the spine was attributed to high porosity, indicating that porosity in the skeleton plays a key role in preventing fracture. The spines of S. granularis exhibited highest length after fracture % (71.54 ± 5.5%). D. setosum exhibited higher values of Mg concentration in the test (10%) compared with the spines (4%). For the first time, the mineralogy of an invasive species is compared with its native counterpart, while a comparison of the mechanical properties of different species of the same ecosystem also takes place. This study highlights different ways, in which sea urchins utilize their skeleton and showcases the ecological significance of these adaptations, one of which is the different ways of utilization of the skeleton for defensive purposes, while the other is the ability of D. setosum to decrease the Mg % of its skeleton degrading its mechanical properties, without compromising its defense, by depending on venomous bearing spines. This enables this species to occupy not only tropical habitats, where it is indigenous, but also temperate like the eastern Mediterranean, which it has recently invaded.     

RANGE-WIDE SURVEY AND ESTIMATION OF TOTAL NUMBER OF STELLER SEA LIONS IN 1989

Abstract: The first range-wide survey of Steller (northern) sea lions ( Eumetopias jubatus ) was completed in 1989 with a total of 68,094 adult and juvenile (nonpup) Steller sea lions counted. This total count includes 10,000 in Russia (15% of the range-wide count), 47,960 in Alaska (70%), 6,109 in British Columbia (9%), 2,261 in Oregon (3%), and 1,764 in California (3%). A range-wide pup count was not obtained. We estimated the 1989 world population based on a calculation for total pups and obtained a range-wide estimate of 116,000 total animals, or about 39–48% of the 240,000-300,000 estimated 30 yr ago.     

厦门杏林湾红树林根际真菌分离及活性分析

[背景]海洋微生物是天然药物资源宝库,海洋环境中的微生物能够产生很多区别于陆生微生物的天然产物.红树林生长于陆地与海洋交界带的滩涂浅滩,是陆地向海洋过渡的特殊生态系统,可能蕴含着丰富的微生物资源和潜在的大量结构新颖的代谢产物.[目的]以厦门杏林湾红树林根际海泥和海水为研究对象,探索其中可培养海洋真菌的多样性及其发酵提取...