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Physiological performance of three calcifying green macroalgae Halimeda species in response to altered seawater temperatures
Zhangliang Wei, Jiahao Mo, Ruiping Huang, Qunju Hu, Chao Long, Dewen Ding, Fangfang Yang, Lijuan Long
doi: 10.1007/s13131-019-1471-3
The effects of seawater temperature on the physiological performance of three Halimeda species were studied for a period of 28 d. Five treatments were established for Halimeda cylindracea, Halimeda opuntia and Halimeda lacunalis, in triplicate aquaria representing a factorial temperature with 24°C, 28°C, 32°C, 34°C and 36°C, respectively. The average Fv/Fm of these species ranged from 0.732 to 0.756 between 24°C and 32°C but declined sharply between 34°C (0.457±0.035) and 36°C (0.122±0.014). Calcification was highest at 28°C, with net calcification rates (Gnet) of 20.082±2.482 mg/(g·d), (12.825±1.623) mg/(g·d) and (6.411±1.029) mg/(g·d) for H. cylindracea, H. opuntia and H. lacunalis, respectively. Between 24°C and 32°C, the specific growth rate (SGR) of H. lacunalis (0.079–0.110%/d) was lower than that of H. cylindracea (0.652–1.644%/d) and H. opuntia (0.360–1.527%/d). Three Halimeda species gradually bleached at 36°C during the study period. Malondialdehyde (MDA) and proline levels in tissues of the three Halimeda were higher in 34–36°C than those in 24–32°C. The results indicate that seawater temperature with range of 24–32°C could benefit the growth and calcification of these Halimeda species, however, extreme temperatures above 34°C have negative impacts. The measured physiological parameters also revealed that H. cylindracea and H. opuntia displayed broader temperature tolerance than H. lacunalis.
key words: calcifying macroalgae, climate change, seawater temperature, physiological performance, photosynthesis, calcification
The long-term prediction of the oil-contaminated water from the Sanchi collision in the East China Sea
Liping YIN, Min ZHANG, Yuanling ZHANG, Fangli QIAO
doi: 10.1007/s13131-018-1193-5
The condensate and bunker oil leaked from the Sanchi collision would cause a persistent impact on marine ecosystems in the surrounding areas. The long-term prediction for the distribution of the oil-polluted water and the information for the most affected regions would provide valuable information for the oceanic environment protection and pollution assessment. Based on the operational forecast system developed by the First Institute of Oceanography, State Oceanic Administration, we precisely predicted the drifting path of the oil tanker Sanchi after its collision. Trajectories of virtual oil particles show that the oil leaked from the Sanchi after it sank is mainly transported to the northeastern part of the sink location, and quickly goes to the open ocean along with the Kuroshio. Risk probability analysis based on the outcomes from the operational forecast system for years 2009 to 2017 shows that the most affected area is at the northeast of the sink location.
key words: Sanchi collision, long-term prediction, oil spill
Paleoenvironmental implications of Holocene long-chain n-alkanes on the northern Bering Sea Slope
Haifeng ZHANG, Rujian WANG, Wenshen XIAO
doi: 10.1007/s13131-017-1032-0
The records of high-resolution terrestrial biological markers (biomarkers) from Core B2-9 from the northern Bering Sea Slope over the last 9.6 ka BP were presented in the study. Variations in input of terrestrial long-chain n-alkanes (referred to as n-alkanes) and vegetation structure in their source regions were investigated. The results show that the nC27 is the main carbon peak and has the greatest contribution rate of the total n-alkane content; this might be related to the abundance of woody plants and their spatial distribution in the source region. nC23 is another n-alkane having a relatively high content; this was mainly derived from submerged plants widespread along the coastal areas in the northern hemisphere. Total n-alkane content dropped quickly at ca. 7.8 ka BP, ca. 6.7 ka BP and ca. 5.4 ka BP, and was followed by four relatively stable stages mostly controlled by sea-level rise, climate change and vegetation distribution in the source region. Variation in carbon preference index (CPI) indicates that the n-alkanes primarily originated from higher land plants, and the average chain length (ACL) and nC31/nC27 ratio reveal the relatively stable presence of woody/herbaceous plants during the Holocene, and dominate woody plants in most of the time. Simultaneous variation in total n-alkane content, nC27 content and its contribution, CPI, ACL and nC31/nC27 ratio over several short periods suggest that the growth rate of the woody plant n-alkane contribution was lower than that of herbaceous plants and fossil n-alkanes under the particular climatic conditions of the source region.
key words: Bering Sea, terrestrial input, long-chain n-alkanes, vegetation structure, Holocene
Long duplication of 18S ribosomal DNA in Cynoglossus lineolatus (Pleuronectiformes: Cynoglossidae): novel molecular evidence for unequal crossing over model
Li GONG, Wei SHI, Min YANG, Lizhen SI, Xiaoyu KONG
doi: 10.1007/s13131-016-0957-z
Although 18S rDNA sequence is extremely conservative, the polymorphism still has been found in few species. In the present study, three types (Type A, B and C) of 18S rDNA sequence coexisted inCynoglossus lineolatus genome, suggesting a non-concerted evolution process, rather than a strictly concerted evolution fashion. Based on the differences of sequence variation, GC content, secondary structure and minimum free energy, Types A and B were speculated as the potential pseudogenes. Additionally, a fascinating finding was a 189-bp duplication of 18S rDNA in Type A sequence. To our knowledge, this is the first report on such a long duplication in teleostean ribosomal DNA. Compared with several theories accounting for the formation of tandem repeats, the unequal crossing over model was thought to be the most likely mechanism to generate the 189-bp duplication of 18S rDNA. These results not only provide a novel molecular evidence for the unequal crossing over model, but also benefit for the further study on 18S rDNA in fishes.
key words: nrDNA, Cynoglossus lineolatus, tandem repeat, pseudogene, polymorphism, non-concerted evolution
Roles of fishing and climate change in long-term fish species succession and population dynamics in the outer Beibu Gulf, South China Sea
Xuehui Wang, Yongsong Qiu, Feiyan Du, Weida Liu, Dianrong Sun, Xiao Chen, Weiwen Yuan, Yong Chen
doi: 10.1007/s13131-019-1484-5
A prevailing, controversial hypothesis is that fishing pressure has played a greater role than climatic and environmental drivers, in changing fish species succession and biomass fluctuation in the South China Sea (SCS). Based on otter trawl survey data from 1959 to 2010 in the outer Beibu Gulf (OBG), northern SCS, large seasonal and interannual variation is reported for fish species composition, the proportional abundances of dominant taxa, and fish biomass. Generalized additive models are developed to quantify relationships between fish biomass and the external factors of fishing pressure and climate change. Fishing pressure proved to be the main driver of sharp declines in demersal fish stocks, with high-value species being replaced by low-value ones over time. Abrupt decreases in fish biomass during the years of 1993 and 1998 correspond to El Niño events, with climate change possibly the main driver of proportional representation of pelagic species in fisheries trawl catch. The need to differentiate impacts of fishing and environmental drivers on fish species with different life history strategies is stressed to better understand fish community dynamics.
key words: fish species succession, biomass fluctuation, fishing effect, climate influence, Beibu Gulf, northern South China Sea
Two new free-living nematode species (Comesomatidae) from the mangrove wetlands in Fujian Province, China
Yuqing GUO, Yu CHANG, Peipei YANG
doi: 10.1007/s13131-018-1320-3
Two new free-living marine nematode species from the mangrove wetlands of Fujian Province, China are identified and illustrated. Sabatieria conicoseta sp. nov. is characterized by its short conical somatic setae. There are 12–15 tubular pre-cloacal supplements and 12–15 μm long straight gubernacular apophyses. Dorylaimopsis papilla sp. nov. is characterized by spicules which are 1.5–1.8 a. b. d. long with media cuticularized strip along entire spicules, and have a cephalated proximal end with small hooked. There are 16–18 small papillate pre-cloacal supplements and 37–40 μm long dorso-caudal gubernacular apophyses.
key words: free-living marine nematode, new species, Sabatieria, Dorylaimopsis, mangrove
Two new species of the genus Wieseria (Nematoda: Enoplaida: Oxystominidae) from the Jiaozhou Bay
Mian HUANG, Jing SUN, Yong HUANG
doi: 10.1007/s13131-018-1319-9
Two new species of free-living marine nematodes of the genus Wieseria are described from the sublittoral sediment of the Jiaozhou Bay in Qingdao. Wieseria sinica sp. nov. is characterized by having short labial and cephalic setae in a backward direction; oblong amphidial foveas with double contour; arcuate spicules with alea; ring-like guberculum; and clavated tail. Wieseria tenuisa sp. nov. is characterized by its very large " a” value (133.6), long labial setae in a forward direction; spicules with alea and hooked proximal end; rodlike gubernaculums; and relatively longer clavated tail (7.9 a.b.d. long). It differs from Wieseria sinica sp. nov. mainly by the longer labial setae, slightly straight spicules with hooked proximal end, and its thinner body. Amended dichotomous key to male species of Wieseria is provided.
key words: Wieseria sinica sp. nov., Wieseria tenuisa sp. nov., free-living marine nematode, taxonomy
A new record of Auchenoplax Ehlers, 1887 (Polychaeta: Ampharetidae) from the East China Sea
Jixing SUI, Xinzheng LI
doi: 10.1007/s13131-018-1312-3
A new record of the ampharetid genus Auchenoplax, A. worsfoldi Jirkov and Leontovich, 2013, is reported and described from the East China Sea. The specimens agree well with the original description of Auchenoplax worsfoldi with two pairs of branchiae, two thoracic uncinigers with enlarged neuropodia and 12 abdominal uncinigerous segments. The present specimens have long and filiform branchiae extending to thoracic chaetiger 9, which was not included in the original description. This is the first record of this species in Chinese waters.
key words: polychaete, Auchenoplax, taxonomy, East China Sea
The first report of the genus Willenstenhelia (Copepoda: Harpacticoida: Miraciidae) from the China seas, with description of a new species
Lin MA, Xinzheng LI
doi: 10.1007/s13131-018-1306-1
A new species Willenstenhelia mirabilipes sp. nov. (Copepoda: Harpacticoida: Miraciiidae) is described based on specimens collected from the South China Sea. This is also the first report of the genus Willenstenhelia from the China seas. The new species differs from congeners by the combined characters: all somites without spinules on surface except anal somite; third segment of female P4 exopod with two inner setae; female P5 baseoendopodal lobe with four elements and P5 exopod with sharp apical spine; caudal ramus about six times as long as broad.
key words: Crustacea, new species, taxonomy
China Argo project: progress in China Argo ocean observations and data applications
Zenghong LIU, Xiaofen WU, Jianping XU, Hong LI, Shaolei LU, Chaohui SUN, Minjie CAO
doi: 10.1007/s13131-017-1035-x
This paper reviews the current achievements of the China Argo project. It considers aspects of both the construction of the Argo observing array, float technology, and the quality control and sharing of its data. The developments of associated data products and data applications for use in the fields of ocean, atmosphere, and climate research are discussed, particularly those related to tropical cyclones (typhoons), ocean circulation, mesoscale eddies, turbulence, oceanic heat/salt storage and transportation, water masses, and operational oceanic/atmospheric/climatic forecasts and predictions. Finally, the challenges and opportunities involved in the long-term maintenance and sustained development of the China Argo ocean observation network are outlined. Discussion also focuses on the necessity for increasing the number of floats in the Indian Ocean and for expanding the regional Argo observation network in the South China Sea, together with the importance of promoting the use of Argo data by the maritime countries of Southeast Asia and India.
key words: China Argo, ocean observation, float development, Argo data, data application

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