Yadong Zhou

Muricauda antarctica sp. nov., a marine member of the Flavobacteriaceae isolated from Antarctic seawater.

A Gram-stain-negative, rod-shaped bacterium with appendages, designated Ar-22(T), was isolated from a seawater sample collected from the western part of Prydz Bay, near Cape Darnley, Antarctica. Strain Ar-22(T) grew optimally at 35 °C, at pH 7.5 and in the presence of 1-3% (w/v) NaCl. The isolate was positive for casein, gelatin and Tween 20 decomposition and negative for H2S production and indole formation. Chemotaxonomic analysis showed that MK-6 was the major isoprenoid quinone and phosphatidylethanolamine was the major polar lipid. The major fatty acids were iso-C(17:0) 3-OH, iso-C(15:1) G, iso-C(15:0) and C(16:1)ω7c/iso-C(15:0) 2OH. The genomic DNA G+C content was 44.8 mol%. Comparative 16S rRNA gene sequence analysis revealed that strain Ar-22(T) is closely related to members of the genus Muricauda, sharing 94.2-97.3% sequence similarity with the type strains of species of the genus Muricauda and being most closely related to the Muricauda aquimarina. Phylogenetic analysis based on the 16S rRNA gene sequence comparison confirmed that strain Ar-22(T) formed a deep lineage with Muricauda flavescens. Sequence similarity between strain Ar-22(T) and Muricauda ruestringensis DSM 13258(T), the type species of the genus Muricauda, was 96.9%. Strain Ar-22(T) exhibited mean DNA-DNA relatedness values of 40.1%, 49.4% and 25.7% to M. aquimarina JCM 11811(T), M. flavescens JCM 11812(T) and Muricauda lutimaris KCTC 22173(T), respectively. On the basis of phenotypic and genotypic data, strain Ar-22(T) represents a novel species of the genus Muricauda, for which the name Muricauda antarctica sp. nov. (type strain Ar-22(T) =CGMCC 1.12174(T) = JCM 18450(T)) is proposed.

Spatial and temporal variability and size fractionation of chlorophyll a in the tropical and subtropical Pacific Ocean

The spatial and temporal variability and size fractionation of chlorophyll a (Chl a) were investigated in the tropical and subtropical Pacific Ocean during four survey cruises from 2005 to 2009. The surface Chl a (S-Chl a) concentration ranged from 0.002 to 0.497 mg/m3 and was obviously higher in the eastern Pacific than in the western and central Pacific. The vertical distribution of Chl a displayed a single peak pattern, and the maximum Chl a layer (MCL) was observed at a shallower depth in the eastern Pacific than in the western Pacific. All three size fractions of Chl a measurements in the surface water showed a similar distribution to total Chl a and were found in higher concentrations in the eastern Pacific than in the western and central Pacific. Picoplankton dominated the phytoplankton in the surveyed tropical and subtropical Pacific Ocean. Furthermore, pico-Chl a (0.2–2 µm) accounted for a larger percentage of the total Chl a in the central Pacific than it did in the western Pacific and eastern Pacific. In the western Pacific, there seemed to be a latitudinal variability in the phytoplankton community composition where small-sized phytoplankton (<2 µm) were more dominant in the tropical than in the subtropical western Pacific. The spatial and temporal variability and size fractionation of Chl a were controlled by hydrological and chemical characteristics and climate events, such as El Niño and La Niña.

A new species of Ophryotrocha (Annelida, Eunicida, Dorvilleidae) from hydrothermal vents on the Southwest Indian Ridge

Abstract Dorvilleids were collected from hydrothermal vents on the Southwest Indian Ridge by manned submersible Jiaolong. These represent a new species of Ophryotrocha that is here described as Ophryotrocha jiaolongi sp. n. This is the first dorvilleid described from vents on the Southwest Indian Ridge. It most closely resembles another vent species, Ophryotrocha akessoni Blake, 1985 from the Galapagos Rift, but can be distinguished by its antennae, palps, jaw structure. The new species has particularly distinctive mandibles, which allow it to be easily identified.

A new species of deep-sea sponge-associated shrimp from the North-West Pacific (Decapoda, Stenopodidea, Spongicolidae)

Abstract A new species of the deep-sea spongicolid genus Spongicoloides Hansen, 1908 is described and illustrated based on material from the northwestern Pacific. Spongicoloides weijiaensis sp. n. was found inside a hexactinellid sponge, Euplectella sp., sampled by the Chinese manned submersible “Jiaolong” at depths of 2279 m near the Weijia Guyot, in the Magellan Seamount Chain. The new species can be distinguished from all congeneric species by several morphological features, involving gill formula, spination of the carapace, antennal scale, third pereiopod, telson and uropod, posteroventral teeth of the pleura, and dactyli of the fourth and fifth pereiopods. An identification key to the Pacific species of Spongicoloides is provided.

The complete mitochondrial genome of a yeti crab Kiwa tyleri Thatje, 2015 (Crustacea: Decapod: Anomura: Kiwaidae) from deep-sea hydrothermal vent

Abstract The complete mitochondrial genome of Kiwa tyleri (Anomura, Chirostyloidea, Kiwaidae) was recovered by next generation sequencing. The mitogenome is 16,865 bp in length and contains 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), two ribosomal RNAs (rRNAs) and a 1525bp non-coding AT-rich region. This is the first mitogenome for the family Kiwaidae and the superfamily Chirostyloidea. The inversion of three consecutive genes (16S rRNA, tRNA-Val, 12S rRNA) was first reported for the Anomura. The phylogenetic tree indicated that Kiwaidae was close to Paguroidea and Lithodoidea rather than Galatheoidea.

Aquaticitalea lipolytica gen. nov., sp. nov., isolated from Antarctic seawater

A Gram-stain-negative, rod-shaped bacterium, designated Ar-125T, was isolated from Antarctic seawater. It produced carotenoid-like pigments and did not produce Bchl a. Ar-125T was positive for hydrolysis of DNA, aesculin, gelatin, starch, Tween 40 and Tween 60. The sole respiratory quinone was MK-6. The major polar lipids were phosphatidylethanolamine, one unidentified aminolipid, one unidentified glycolipid and two unidentified lipids. The principal fatty acids were branched-chain fatty acids, including iso-C15 : 0, iso-C15 : 1 G, summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c), iso-C16 : 0, iso-C17 : 0 3-OH, iso-C16 : 0 3-OH and iso-C15 : 0 3-OH, as well as C15 : 0. The genomic DNA G+C content was 31.8 mol%. On the basis of 16S rRNA gene sequence analysis, Ar-125T is closely related to the species of the genera Bizionia(with 16S rRNA gene pairwise sequence similarity of 93.7-96.5 %), Formosa(94.3-95.8 %), Gaetbulibacter(94.2-95.7 %), Geojedonia(95.5 %), Gelidibacter (93.3-95.4 %), Meridianimaribacter(95.3 %) and Psychroserpens (94.8-95.3 %), of the family Flavobacteriaceae. Phylogenetic analysis indicated that it represented an independent lineage and that the closest relatives were members of the genus Gelidibacter. Differential phenotypic properties and chemotaxonomic differences, together with phylogenetic distinctiveness, revealed that Ar-125T could be differentiated from members of closely related genera. Therefore, it is proposed that Ar-125T represents a novel species in a new genus, for which the name Aquaticitalea lipolytica gen. nov., sp. nov. (type strain Ar-125T =CGMCC 1.15295T =JCM 30876T) is proposed.

Branchinotogluma bipapillata n. sp., a new branchiate scale worm (Annelida: Polynoidae) from two hydrothermal fields on the Southwest Indian Ridge

A new species of Branchinotogluma, found at two hydrothermal vent fields on Southwest Indian Ocean Ridge, is described herein. It can be distinguished from its congeners by the small acicular lobe on the tentacular segment, the stout smooth notochaetae, 5 pairs of dorsal and ventral papillae surrounding the pharynx, 2 pairs of long ventral papillae and 4 pairs of ventral lamellae on males, and modified parapodia on posterior segments. Sexual dimorphism is also reported in the new species, as male and female individuals display differences in characters on the ventral papillae and posterior segments.

The distribution of chlorophyll a in the tropical eastern Indian Ocean in austral summer

To study the effect of hydrographic factors on the spatial distributions of chlorophyll a (Chl a), an investigation was carried out in the tropical eastern Indian Ocean (80°-100°E along 7°S, and 7°-18°S along 80°E) in December 2010. The fluorescent method was used to obtain total Chl a and size-fractioned Chl a at the 26 stations. The results show that surface Chl a concentration averaged at (0.168±0.095) mg/m3 s.d. (range: 0.034–0.475 mg/m3), concentrations appeared to be higher in the west for longitudinal variations, and higher in the north for latitudinal variations. Furthermore, the surface Chl a concentration was lower (0.034–0.066 mg/m3) in the region to the south of 16°S. There was a strong subsurface Chl a maximum layer at all stations and the depth of the Chl a maximum increased towards to the east and south along with the respective nitracline. The spatial variation of Chl a was significant: correlation and regression analysis suggests that it was primarily affected by PO43−, N(NO3-N+NO2-N) and temperature. Size-fractionated Chl a concentration clearly showed that the study area was a typical oligotrophic open ocean, in which picophytoplankton dominated, accounting for approximately 67.8% of total Chl a, followed by nanophytoplankton (24.5%) and microphytoplankton (7.6%). The two larger fractions were sensitive to the limitation of P, while picophytoplankton was primarily affected by temperature.