scholarly journals Palaeolithic voyage for invisible islands beyond the horizon

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Yousuke Kaifu ◽  
Tien-Hsia Kuo ◽  
Yoshimi Kubota ◽  
Sen Jan
Keyword(s):  
Maritime Transportation ◽  
Western Pacific ◽  
Ryukyu Islands ◽  
Technological Advancement ◽  
The Ryukyu Islands ◽  
Show Evidence ◽  
Ocean Flows ◽  
The Kuroshio ◽  
The Western Pacific ◽  
Key Questions

AbstractHow Palaeolithic maritime transportation originated and developed is one of the key questions to understand the world-wide dispersal of modern humans that began 70,000–50,000 years ago. However, although the earliest evidence of maritime migration to Sahul (Australia and New Guinea) has been intensively studied, succeeding development of Paleolithic maritime activity is poorly understood. Here, we show evidence of deliberate crossing of challenging ocean that occurred 35,000–30,000 years ago in another region of the western Pacific, the Ryukyu Islands of southwestern Japan. Our analysis of satellite-tracked buoys drifting in the actual ocean demonstrated that accidental drift does not explain maritime migration to this 1200 km-long chain of islands, where the local ocean flows have kept the same since the late Pleistocene. Migration to the Ryukyus is difficult because it requires navigation across one of the world’s strongest current, the Kuroshio, toward an island that lay invisible beyond the horizon. This suggests that the Palaeolithic island colonization occurred in a wide area of the western Pacific was a result of human’s active and continued exploration, backed up by technological advancement.

scholarly journals Pre-Bomb Marine Reservoir Ages in the Western Pacific

Radiocarbon ◽  
2010 ◽  
Vol 52 (3) ◽  
pp. 1197-1206 ◽  
Author(s):  
Kunio Yoshida ◽  
Tatsuaki Hara ◽  
Dai Kunikita ◽  
Yumiko Miyazaki ◽  
Takenori Sasaki ◽  
...  
Keyword(s):  
Western Pacific ◽  
Ryukyu Islands ◽  
Japanese Archipelago ◽  
The Ryukyu Islands ◽  
The Mean ◽  
The Japanese Archipelago ◽  
University Museum ◽  
The University ◽  
Specific Correction ◽  
The Western Pacific

In this study, molluscan shells housed at the University Museum, the University of Tokyo, provided a new set of region-specific correction values (ΔR) for the western Pacific, in particular for the central part of the main islands in the Japanese Archipelago and the southwest islands of Japan. The values of 40 total samples were calculated from 11 regions. North of the main islands and in the Ryukyu Islands, the mean ΔR values showed comparatively small values, 5–40 14C yr; in the central part of the main islands, these values were 60–90 14C yr.

scholarly journals A review of some common Indo-Malayan and western Pacific species of Chthamalus barnacles (Crustacea: Cirripedia)

2003 ◽  
Vol 83 (4) ◽  
pp. 797-812 ◽  
Author(s):  
A.J. Southward ◽  
W.A. Newman
Keyword(s):  
Indian Ocean ◽  
Southern China ◽  
The Philippines ◽  
Western Pacific ◽  
Ryukyu Islands ◽  
Mariana Islands ◽  
Type Specimens ◽  
The Ryukyu Islands ◽  
The Indian Ocean ◽  
The Western Pacific

The type specimens of the common tropical intertidal barnacles Chthamalus malayensis and C. moro, were re-investigated and compared with other specimens of Chthamalus from the Indian Ocean, Indo-Malaya, northern Australia, Vietnam, China and the western Pacific, using ‘arthropodal’ as well as shell characters.  Chthamalus malayensis occurs widely in Indo-Malayan and tropical Australian waters. It ranges westwards in the Indian Ocean to East Africa and northwards in the Pacific to Vietnam, China and the Ryukyu Islands. Chthamalus malayensis has the arthropodal characters attributed to it by Pope (1965); conical spines on cirrus 1 and serrate setae with basal guards on cirrus 2.  Chthamalus moro is currently fully validated only for the Philippines, Indonesia, Taiwan, the Xisha (Paracel) Islands, the Ryukyu Islands, the Mariana Islands, the Caroline Islands, Fiji and Samoa. It is a small species of the ‘challengeri’ subgroup, lacking conical spines on cirrus 1 and bearing pectinate setae without basal guards on cirrus 2. It may be a ‘relict’ insular species.  Chthamalus challengeri also lacks conical spines on cirrus 1 and has pectinate setae without basal guards on cirrus 2. Records of C. challengeri south of Japan are probably erroneous. However, there is an undescribed species of the ‘challengeri’ subgroup in the Indian Ocean, Indo-Malaya, Vietnam and southern China and yet more may occur in the western Pacific. The subgroups ‘malayensis’ and ‘challengeri’ require genetic investigation.  Some comments are included on the arthropodal characters and geographical distributions of Chthamalus antennatus, C. dalli and C. stellatus.

Eviota fallax, a New Dwarfgoby from the Western Pacific (Teleostei: Gobiidae)

Zootaxa ◽  
2012 ◽  
Vol 3522 (1) ◽  
pp. 42 ◽  
Author(s):  
DAVID W. GREENFIELD ◽  
GERALD R. ALLEN
Keyword(s):  
Solomon Islands ◽  
Western Pacific ◽  
Ryukyu Islands ◽  
Pore System ◽  
Group I ◽  
The Ryukyu Islands ◽  
West Papua ◽  
New Britain ◽  
The Western Pacific ◽  
Pelvic Fin

Eviota fallax is described from West Papua, Indonesia and also is known from Bali, Banda, and Sangihe Island, Indonesia,New Britain, Solomon Islands, Yap, Ngulu Atoll, and the Ryukyu Islands, Japan. The species has an occipital spot (moreobvious in males and preserved specimens), a complete cephalic sensory-pore system (Group I), and a dorsal/anal formulaof 9/8, characters shared with E. karaspila, E. melasma, and E. smaragdus. It differs from these species in coloration, measurements and pelvic-fin structure.

scholarly journals <i>Trichodesmium</i> and nitrogen fixation in the Kuroshio

2015 ◽  
Vol 12 (14) ◽  
pp. 11061-11087
Author(s):  
T. Shiozaki ◽  
S. Takeda ◽  
S. Itoh ◽  
T. Kodama ◽  
X. Liu ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
North Pacific Ocean ◽  
Ryukyu Islands ◽  
Material Transport ◽  
Nutrient Distribution ◽  
Marginal Seas ◽  
Dissolved Iron ◽  
The North ◽  
The Ryukyu Islands ◽  
The Kuroshio

Abstract. Nitrogen fixation in the Kuroshio influences nitrogen balance in the North Pacific Ocean. The genus Trichodesmium is recognized as a major diazotroph in the Kuroshio. Although its abundance is higher in the Kuroshio than in adjacent waters, the reason for this difference remains unclear. The present study investigated the abundance of Trichodesmium spp. and nitrogen fixation together with concentrations of dissolved iron and phosphate, whose availabilities potentially control diazotrophy, in the Kuroshio and its marginal seas. We performed the observations near the Miyako Islands, which form part of the Ryukyu Islands, situated along the Kuroshio, since satellite analysis suggested that material transport could occur from the islands to the Kuroshio. Trichodesmium spp. bloomed (> 20 000 filaments L−1) near the Miyako Islands, and the abundance was high in the Kuroshio and the Kuroshio bifurcation region of the East China Sea, but was low in the Philippine Sea. The abundance of Trichodesmium spp. was significantly correlated with the total nitrogen fixation activity. The surface concentrations of dissolved iron (0.19–0.89 nM) and phosphate (< 3–36 nM) were similar for all of the study areas, indicating that the nutrient distribution could not explain the spatial differences in Trichodesmium spp. abundance and nitrogen fixation. We used a numerical model to simulate the transportation of water around the Ryukyu Islands to the Kuroshio. Our results indicate that Trichodesmium growing around the islands situated along the Kuroshio is potentially important for determining diazotrophy in this region.

scholarly journals Why is <i>Trichodesmium</i> abundant in the Kuroshio?

2015 ◽  
Vol 12 (23) ◽  
pp. 6931-6943 ◽  
Author(s):  
T. Shiozaki ◽  
S. Takeda ◽  
S. Itoh ◽  
T. Kodama ◽  
X. Liu ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Ryukyu Islands ◽  
Material Transport ◽  
Nutrient Distribution ◽  
Marginal Seas ◽  
Dissolved Iron ◽  
Nitrogen Fixation Activity ◽  
The Ryukyu Islands ◽  
Spatial Differences ◽  
The Kuroshio

Abstract. The genus Trichodesmium is recognized as an abundant and major diazotroph in the Kuroshio, but the reason for this remains unclear. The present study investigated the abundance of Trichodesmium spp. and nitrogen fixation together with concentrations of dissolved iron and phosphate in the Kuroshio and its marginal seas. We performed the observations near the Miyako Islands, which form part of the Ryukyu Islands, situated along the Kuroshio, since our satellite analysis suggested that material transport could occur from the islands to the Kuroshio. Trichodesmium spp. bloomed (> 20 000 filaments L−1) near the Miyako Islands, abundance was high in the Kuroshio and the Kuroshio bifurcation region of the East China Sea, but was low in the Philippine Sea. The abundance of Trichodesmium spp. was significantly correlated with the total nitrogen fixation activity. The surface concentrations of dissolved iron (0.19–0.89 nM) and phosphate (< 3–36 nM) were similar for all of the study areas, indicating that the nutrient distribution could not explain the spatial differences in Trichodesmium spp. abundance and nitrogen fixation. Numerical particle-tracking experiments simulated the transportation of water around the Ryukyu Islands to the Kuroshio. Our results indicate that Trichodesmium growing around the Ryukyu Islands could be advected into the Kuroshio.

scholarly journals First record of Australatya obscura Han & Klotz, 2015 (Decapoda, Atyidae) from the Ryukyu Islands, Japan

2019 ◽  
Vol 7 ◽  
Author(s):  
Naoto Inui ◽  
Tomoaki Maruyama ◽  
Ken Okamoto
Keyword(s):  
First Record ◽  
Kuroshio Current ◽  
Ryukyu Islands ◽  
Freshwater Shrimp ◽  
Ishigaki Island ◽  
The Ryukyu Islands ◽  
The Kuroshio

The freshwater shrimp, Australatyaobscura Han &amp; Klotz, has been known only from Taiwan and Panay Island, Philippines. An adult A.obscura was collected from a river on Ishigaki Island, Ryukyu Islands, Japan. This is the first record of the species in Japan and the northernmost specimen-supported record to date. The species is suggested as having been transported northwards by the Kuroshio Current.

Palaeogeographic reconstruction of the 1.55 Ma synchronous isolation of the Ryukyu Islands, Japan, and Taiwan and inflow of the Kuroshio warm current

2011 ◽  
Vol 54 (12) ◽  
pp. 1369-1388 ◽  
Author(s):  
Soichi Osozawa ◽  
Ryuichi Shinjo ◽  
Alroem Armid ◽  
Yasushi Watanabe ◽  
Toshiaki Horiguchi ◽  
...  
Keyword(s):  
Ryukyu Islands ◽  
Warm Current ◽  
The Ryukyu Islands ◽  
The Kuroshio

scholarly journals Environmental influences on sinking rates and distributions of transparent exopolymer particles after a typhoon surge at the Western Pacific

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Shahanul Islam ◽  
Jun Sun ◽  
Guicheng Zhang ◽  
Zhuo Chen ◽  
Hui Zhou
Keyword(s):  
Water Layer ◽  
Kuroshio Current ◽  
Western Pacific ◽  
Transparent Exopolymer Particles ◽  
Chl A ◽  
Bottom Water Layer ◽  
Regression Curves ◽  
The Impact ◽  
The Kuroshio ◽  
The Western Pacific

AbstractA multidisciplinary approach was used to investigate the causes of the distributions and sinking rates of transparent exopolymer particles (TEPs) during the period of September–October (2017) in the Western Pacific Ocean (WPO); the study period was closely dated to a northwest typhoon surge. The present study discussed the impact of biogeophysical features on TEPs and their sinking rates (sTEP) at depths of 0–150 m. During the study, the concentration of TEPs was found to be higher in areas adjacent to the Kuroshio current and in the bottom water layer of the Mindanao upwelling zone due to the widespread distribution of cyanobacteria, i.e., Trichodesmium hildebrandti and T. theibauti. The positive significant regressions of TEP concentrations with Chl-a contents in eddy-driven areas (R2 = 0.73, especially at 100 m (R2 = 0.75)) support this hypothesis. However, low TEP concentrations and TEPs were observed at mixed layer depths (MLDs) in the upwelling zone (Mindanao). Conversely, high TEP concentrations and high sTEP were found at the bottom of the downwelling zone (Halmahera). The geophysical directions of eddies may have caused these conditions. In demonstrating these relations, the average interpretation showed the negative linearity of TEP concentrations with TEPs (R2 = 0.41 ~ 0.65) at such eddies. Additionally, regression curves (R2 = 0.78) indicated that atmospheric pressure played a key role in the changes in TEPs throughout the study area. Diatoms and cyanobacteria also curved the TEPs significantly (R2 = 0.5, P < 0.05) at the surface of the WPO. This study also revealed that TEP concentration contributes less to the average particulate organic carbon in this oligotrophic WPO.

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