Occurrence of two types of El Nin?o events and the subsurface ocean temperature anomalies in the equatorial Pacific

The relationships between the evolution of two types of El Ni?o events and the subsurface ocean temperature anomaly(SOTA) in the equatorial Pacific are compared in this study. The results show that both types of El Ni?o are negatively correlated to the SOTA in the equatorial western Pacific, but relationships are different in different phases of El Ni?o. Furthermore, the occurrence of different types of El Ni?o is related to different features of the equatorial thermocline, e.g. its zonal gradient, significant variation area, amplitude and duration of thermocline oscillation. The propagation of SOTA in the equator plays an important role during the evolution of both types of El Ni?o, but shows dramatic differences in intensity, duration and phase reverse of warm SOTA. Moreover, the pathways of SOTA signal are different between these two types of El Ni?o. The dominant pathway in the life cycle of Eastern Pacific(EP)-El Ni?o lies on the equator and to its north, but there is no loop to the south of the equator. In contrast, the dominant pathway in Central Pacific(CP)-El Ni?o is located on the equator and to its south, and the propagation signal of SOTA to the north of the equator is very weak.The relationships between the zonal wind anomalies and the two types of El Ni?o are also preliminarily discussed. It is shown that EP-El Ni?o is more likely to respond to the westerly anomalies over the equatorial central and western Pacific, while CP-El Ni?o is more likely to respond to the westerly anomalies over the equatorial western Pacific and need the cooperation of easterly anomalies over the equatorial eastern Pacific to certain extent.     

The terraced thermal contrast among the Tibetan Plateau, the East Asian plain, and the western North Pacific and its impacts on the seasonal transition of East Asian climate

The heating sources over the Tibetan Plateau （TP）, the East Asian plain, and the western North Pacific （WNP） form a terraced thermal contrast in the west-east direction. Over East Asia and the WNP, this zonal thermal contrast contributes as high as 45 % to the seasonal variance based on the EOF analysis and exerts a significant impact on the seasonal transition of the East Asian climate through the enhancement of the year-round southerly to the southeast of the TP in late March and early April. This effect is investigated in this study using a high-resolution regional atmospheric model by doubling the surface sen- sible heat flux, respectively, over the TP, the East Asian plain, and the WNP in three sensitivity experiments. Comparisons among the experiments reveal that doubling the surface sensible heat flux over the WNP has little upstream response over East Asia. The increased zonal thermal contrast between the TP and the East Asian plain due to doubled heat flux over the TP would induce anomalous northerly over the region with year-round southerly to the southeast of the TP and weaken its seasonal enhancement. Doubling the surface sensible heat flux over the East Asian plain decreases the zonal thermal contrast and leads to southerly anomaly over the region with year-round southerly to the southeast of the TP and South China, which is favorable for the enhancement of the year-round southerly and its eastward extension.     

热带印度洋-太平洋夏季OLR变化的时空特征及其与我国夏季降水的关系

利用美国NOAA卫星观测1979-2007年OLR(Outing Longwave Radiation)资料和中国气象局国家气候中心的我国160站月降水资料,分析了热带印度洋-太平洋地区(22.5°S-22.5°N,40°E-80°W)OLR的时空变化特征及和我国夏季降水的关系。结果表明:近29年来热带太平洋南部地区OLR值有增加趋势,而热带印度洋和热带太平洋北部呈减少趋势。EOF分析表明热带印度洋一太平洋地区夏季OLR场具有东西反位相和南北反位相的变化特点,小波分析表明,这种变化主要存在着准5 a和准12 a左右的周期振荡。SVD分析表明,热带印度洋-太平洋夏季OLR场与我国夏季降水密切相关。     

Sediment dynamic responses of coastal salt marsh to typhoon “KAEMI” in Quanzhou Bay, Fujian Province, China

−In order to understand the mechanisms of coastal protection by salt marshes during typhoon events, in situ measurements of water level, tidal current speed and direction, and suspended sediment concentration (SSC) were carried out using Electromagnetic Current Meter (EMCM, AEM HR), miniature pressure sensor (MkV/D) and Seapoint Turbidity Meter (STM) sensor on a tidal flat in Quanzhou Bay, during the period when the typhoon “KAEMI” was passing through the region. The analysis of the data obtained shows that the near-bed current speed within the Spartina alterniflora marsh was generally below 5 cm s⁻¹, which was apparently smaller than on the adjacent bare flat (i.e. 5―30 cm s⁻¹). The change in the near-bed current speed in response to the typhoon event was not significant within the S. alterniflora marsh, but the current direction was influenced by the typhoon. The effect of the typhoon on the SSC was highly significant, with the SSC reaching 13 to 19 times the values on the bare flat or within the marsh under fair weather conditions; the near-bed SSC within the marsh was higher than on the bare flat, after the typhoon landed. The near-bed suspended sediment fluxes within the marsh and on the bare flat during the typhoon event were both enhanced, i.e., 4 times larger than under fair weather conditions. During the ebb, the bottom shear stress on the bare flat exceeded the critical shear stress for sediment motion for most of the ebb duration of the tide and, therefore, the bed sediment was eroding, with the erosion flux after the typhoon landed being around 2 to 3 times the value associated with fair weather conditions. In contrast, within the S. alterniflora marsh, the bottom shear stress was mostly lower than the critical shear stress for sediment motion, or lower than the critical shear stress for the maintenance of suspension; hence, the marsh surface was dominated by settling processes, with a settling flux during the typhoon being 3 to 6 times compared with the fair weather situations. The settling flux during the ebb was up to twice the magnitude for the flood. The comparison of sediment dynamic processes between the S. alterniflora marsh and the bare flat demonstrates that during the typhoon event the bare flat was dominated by erosion, whilst the presence of S. alterniflora favored the accretion of suspended sediment.     

The pathway of the interdecadal variability in the Pacific Ocean

Cases of the interdecadal variability in the Pacific Ocean and their evolution were examined in the paper with the statistic methods (CEOF and composite analysis) over the period of 1950–1993. Observations of oceanic temperatures in the upper 400 m revealed an obvious region of the interdecadal signals in the central North Pacific. Such signals propagated southwestward, then subducted to the subtropics. The hypothesized link for interdecadal oceanic variability between the subtropics and the tropics, especially with the western tropical Pacific was unraveled in order to detect the cause of decadal signals in the tropics. The thermal anomalies subducted in the central North Pacific east to the dateline only reach 18°N. There has been no further southward propagation since then due to a certain barrier. The origin of the interdecadal signals in the western tropical Pacific was traced to the southern tropical Pacific. There is a meridional pathway around the dateline where the signals were loaded. These variabilities were in the nature of the thermocline circulation.     

Diversity and biogeography of the little known deep-sea barnacles of the genus Waikalasma Buckeridge, 1983 (Balanomorpha: Chionelasmatoidea) in the Southwest Pacific,with description of a new species

Due to the extreme scarcity of specimens, little is known about the biodiversity and biogeography of the barnacles of the genus Waikalasma Buckeridge, 1983 (Thoracica: Waikalasmatidae Ross and Newman, 2001), which inhabit the deep sea of the Southwest Pacific. Previous studies reported only a single living species, W. boucheti Buckeridge, 1996, from Vanuatu. In the present study, the collections by French deep-sea expeditions off New Caledonia (NORFOLK 1 & 2, EBISCO, SMIB 2, SMIB 4, SMIB 8, BIOCAL, MUSORSTOM 6, MUSORSTOM 4, MUSORSTOM 5, BATHUS 2), the Solomon Islands (SALOMON 1), Vanuatu (BOA1) and Papua New Guinea (BIOPAPUA) yielded specimens of Waikalasma species from 500 to 800 m depth. From molecular (DNA barcode region cytochrome c oxidase subunit I (COI) and 12S gene) and morphological analysis, a new species Waikalasma dianajonesae sp. nov., and W. boucheti were identified. From molecular phylogenetic analysis, sequence divergence in the DNA barcode region between W. dianajonesae sp nov. and W. boucheti reached > 10%. Waikalasma dianajonesae sp. nov. differs from W. boucheti in the number and size of imbricating plates on the shell and the shape of the tergum. Waikalasma dianajonesae sp. nov. and W. boucheti exhibit sympatric biogeographical distributions in the Southwest Pacific. Waikalasma dianajonesae was found in the waters of Papua New Guinea and Solomon Island, whilst W. boucheti was collected from Papua New Guinea, Vanuatu and New Caledonia waters.

http://zoobank.org/urn:lsid:zoobank.org:pub:713013C7-677A-478F-B5DF-FD4690A7C6A9     

Marine biodiversity on the Algerian Continental Shelf (Mediterranean Sea)

The Mediterranean Sea is known as a biodiversity hot spot, with 16,848 species reported. Biodiversity is higher in coastal areas and decreases with depth. However, knowledge about the southwestern sector remains scarce. For the last three decades, sampling of soft-bottom communities along the 1180 km of the shallow Algerian coast (0–136 m) has recorded 1642 macrobenthic species. There is a decreasing west–east species-richness gradient, especially for the total species richness and the amphipods. In addition, quantitative sampling in Bou Ismail Bay in summer 1988 (98 sampling sites for a total of 841 species) shows that diversity indices (i.e. species richness, >100 species for 0.2 m^?2; Shannon diversity, >6.0; and ES₅₀, >34) are among the highest for similar sand and muddy-fine sand communities in the Mediterranean Sea and the northeastern Atlantic Ocean. Bou Ismail Bay appears to have the highest species richness among Algerian bays, probably because of its variety of benthic habitats and the absence of significant pollution in this area. Monitoring must be undertaken to survey this high biodiversity, and a national strategy should be proposed to preserve high diversity zones.     

Life cycle and geographic distribution of the gymnophallid Bartolius pierrei (Digenea) on the Patagonian coast,Argentina

The life cycle of the gymnophallid Bartolius pierrei Cremonte, 2001 Cremonte, F. 2001. Bartolius pierrei n. g. n. sp. (Digenea: Gymnophallidae) from Península Valdés, Argentina. Systematic Parasitology, 49: 139–147. [Crossref], [PubMed], [Web of Science ®] , [Google Scholar] (Digenea) at Fracasso Beach (the type locality) (42°25′S, 64°07′W), Península Valdés, Argentina, was elucidated. This digenean uses the clam Darina solenoides (Mactridae) as both first and second intermediate host. The Kelp Gull, Larus dominicanus, and the Red Knot, Calidris canutus rufa, a Neotropical migratory bird, act as definitive hosts. A prevalence of infection of 92% was found in the Red Knot. The cercariae of B. pierrei did not parasitize other invertebrates, not even the tellinid clam Tellina petitiana, which shares the intertidal habitat with D. solenoides. This fact could be explained by the behaviour of the cercaria and its strategy for penetration. The cercariae enter directly in the extrapallial space of the clam by piercing the exposed mantle border. Tellina petitiana could not be invaded by B. pierrei cercariae because it does not expose the mantle border when feeding. Because the Red Knot does not feed on T. petitiana, this behaviour may constitute an adaptive strategy of the parasite. Under laboratory conditions, cercariae lived up to 2 days, metacercariae became infective in 50 days, and the adult life is considerd to be shorter than 3 days. The short adult life span in gymnophallids could be a result of adaptation to migratory birds. This fact would ensure parasite dispersion (i.e. by covering long distances in a short time) and inter-breeding with other Darina-infesting populations located far apart. Bartolius pierrei is an endemic parasite of the Magellan Region, distributed where its intermediate clam host is present, from San José Gulf in Península Valdés to the southern tip of South America.     

Review of the southern temperate fish family Aplodactylidae (Pisces: Perciformes)

The southern temperate perciform fish family Aplodactylidae is reviewed. The monotypic genus Crinodus is relegated to the synonymy of the genus Aplodactylus, which is recognized as containing five species: A. arctidens Richardson from New Zealand and Australia (Victoria, South Australia and Tasmania); A. lophodon (Günther) restricted to south-eastern Australia (New South Wales and Victoria); A. westralis Russell restricted to south Western Australia; A. etheridgii (Ogilby) from the south-west Pacific (north-eastern New Zealand, Kermadec Islands, Lord Howe Island and Norfolk Island); and A. punctatus Valenciennes from the west coast of South America (Peru and Chile). A key to the species is given.     

Factors linked to temporal and spatial variation in the metazoan parasite communities of green jack Caranx caballus (Günther 1868) (Pisces: Carangidae) from the Pacific coast of Mexico

ABSTRACT

Biotic or abiotic factors responsible for temporal or spatial variation in metazoan parasite communities of the green jack Caranx caballus were studied over a nine-year period using samples collected at locations along the south-central Pacific coast of Mexico. A total of 708 fish were collected from six locations between December 2009 and October 2017. Thirty-two parasite species were identified: three Monogenea, nine Digenea, two Cestoda, five Nematoda, eight Copepoda, and three Isopoda. At the component community level, parasite species richness varied significantly from seven (Zihuatanejo 2016) to 18 (Acapulco Bay 2011). The component communities and infracommunities of C. caballus exhibited a similar pattern: low species numbers, low diversity, and dominance by a single species (mainly the monogenean Pseudomazocraes selene or the digenean Bucephalus varicus). Parasite community structure and species composition varied between locations and/or sampling years. The main factors responsible for these variations were host traits such as feeding behaviour and body size, the occurrence of a set of distinctive parasite species, and possible variations in the availability of infected prey between locations.