Miyakojima Island Research Articles

Integrating and Utilizing Citizen Biodiversity Data on the Web for Science: An Example of a Rare Triggerfish Hybrid Image Provided by a Sport Fisherman

ABSTRACT Miyazaki, Y.; Murase, A.; Shiina, M.; Masui, R., and Senou, H., 2015. Integrating and utilizing citizen biodiversity data on the Web for science: An example of a rare triggerfish hybrid image provided by a sport fisherman. We report a photograph of the rare triggerfish hybrid, Rhinecanthus aculeatus × R. rectangulus (order Tetraodontiformes; family Balistidae), from Miyako-jima Island, Ryukyu Islands, southern Japan, that was provided by a sport fisherman via WEB sakana-zukan (an online photographic database of fish in Japan). The image was registered in the Fish Image Database of the Kanagawa Prefectural Museum of Natural History to make it available for scientific scrutiny. Here we emphasize the importance of communication between citizens, such as fishermen, scuba divers, and others, and experts via the Internet, to make possible the processing of biodiversity information provided by citizens into museum collections. This communication contributes Global Biodiversity Information Facility data ...

Diagnosis and evaluation of causative factors for the presence of endemic treponemal disease in a Japanese sub-tropical island population from the Tokugawa period

We present a description and differential diagnosis of pathological lesions observed on skeletal elements found during surface surveys of the Nagabaka site on Miyako-jima Island, Japan. The Nagabaka site served as a bone depository during the Early Modern period (c. AD 1600–1870). We evaluated remains via macroscopic inspection to classify infectious lesions according to criteria in Weston (2008). We also obtained CT scans of three bone elements for more extensive lesion analysis and carried out a differential diagnosis utilizing paleopathological literature. Subsequent investigation yielded convincing evidence of treponemal infection on 23 skeletal elements. Based on known geographical spread and morphological comparisons of lesion patterning, we identified yaws as the pathogen most likely responsible, but refrained from calculating site-wide prevalence due to the taphonomical nature of the sample. Lastly, we review treponemal infection rates in other archaeological sites throughout Southeast Asia and Oceania, and assess similar ecological and cultural factors contributing to the observed pathologies. Nagabaka is the northernmost site in the world where yaws has so far been identified. Located between sites between Mainland China and Western Micronesia where this infection has been previously identified, Miyako-jima holds an important geographical position for research into the historical spread of pathogens.

宮古島水道物語序論

宮古島水道物語序論

A model for population dynamics of the mimetic butterfly Papilio polytes in the Sakishima Islands, Japan

We present a mathematical model for population dynamics of the mimetic swallowtail butterfly Papilio polytes in the Sakishima Islands, Japan. The model includes four major variables, that is, population densities of three kinds of butterflies (two female forms f. cyrus, f. polytes and the unpalatable butterfly Pachliopta aristolochiae) and their predator. It is well-known that the non-mimic f. cyrus resembles and attracts the male most, and the mimic f. polytes mimics the model butterfly P. aristolochiae. Based on experimental evidence, we assume that two forms f. cyrus and f. polytes interact under intraspecific competition for resources including the male, and the growth rate of f. cyrus is higher than that of f. polytes. We further assume that both the benefit of mimicry for the mimic f. polytes and the cost for the model are dependent on their relative frequencies, i.e. the motality of the mimic by predation decreases with increase in frequency of the model, while the motality of the model increases as the frequency of the mimic increases. Taking the density-dependent effect through carrying capacity into account, we set up a model system consisting of three ordinary differential equations (ODEs), analyze it mathematically and provide computer simulations that confirm the analytical results. Our results reproduce field records on population dynamics of P. polytes in the Miyako-jima Island. They also explain the positive dependence of the relative abundance (RA) of the mimic on the advantage index (AI) of the mimicry in the Sakishima Islands defined in Section 2.

Correction: Tamura, S. and Fujie, K. Material Cycle of Agriculture in Miyakojima Island: Material Flow Analysis for Sugar Cane, Pasturage and Beef Cattle. Sustainability 2014, 6, 812–835.

We found a typo in our previous published paper [1]. “Okinawa Main Ilsand” and “Kyushu Ilsand” are supposed be “Okinawa Main Island” and “Kyushu Island”. [...]

Development of Miyako-Sone submarine platform, northeastern off Miyako-jima Island, Okinawa

Development of Miyako-Sone submarine platform, northeastern off Miyako-jima Island, Okinawa

Material Cycle of Agriculture on Miyakojima Island: Material Flow Analysis for Sugar Cane, Pasturage and Beef Cattle

Agriculture on Miyakojima Island is highly dependent on imported fertilizer and feed. To reduce this dependence, the present research examines the biomass resources on the island by conducting a material flow analysis of stockbreeding and other related systems. To accurately quantify the amount of available biomass resources, loss ratios of the storage and composting processes are established. Then, a material flow analysis of a composting facility is made. Finally, current material flows between beef cattle, sugar cane and pasturage are shown. Based on this research, two proposals are made: the first is to use urine as liquid fertilizer, which is currently being done in Saga prefecture. The precedent of using urine as fertilizer is now widely accepted in the Saga area; is considered to be readily adoptable in other areas and could be substituted for the imported fertilizers on Miyakojima Island. The second is to use more residues of sugar cane for the beef cattle feed when the pasturage growth is slow in the winter. The present research suggests that the silage feeds for beef cattle.

The Development and Inheritance of Agricultural Water Facilities in Miyako-jima Island

The Development and Inheritance of Agricultural Water Facilities in Miyako-jima Island

Contributions of C3/C4 organic materials and carbonate rock to dissolved inorganic carbon in a karst groundwater system on Miyakojima Island, southwestern Japan

Summary Groundwater δ 13 C values and chemical compositions were employed to quantitatively evaluate the controlling processes and sources of dissolved inorganic carbon in a karst aquifer system on Miyakojima Island (MI), southwestern Japan. Most MI groundwater is Ca–HCO 3 type water, but some Na–Cl, Ca–Cl, or Na–HCO 3 type groundwaters occur, formed mainly by seawater intrusion and partly by cation exchange reactions. Calculations using the WATEQ4F and PHREEQC programs revealed that all MI groundwater, not just the Ca–HCO 3 type, was strongly influenced by calcite dissolution in a karst aquifer system open with respect to soil CO 2 , initially derived from organic materials with mainly around 10–50 matm as pCO 2 , and that most groundwater was saturated with respect to calcite. Moreover, oxidation of ammonium sulfate (applied as fertilizer) added H + to the MI groundwater, resulting in surplus calcite dissolution. These processes sufficiently explained contents of alkalinity, DIC, and Ca 2+ in the groundwater, and were evaluated by model calculation using the PHREEQC program with measured groundwater δ 13 C and pH values. The results showed that the average mass fractions of dissolved inorganic carbon (DIC) initially from calcite dissolution and C3 and C4 organic materials in the groundwater were 46.4%, 18.5%, and 35.1%, respectively. The model results regarding the origins of DIC in the groundwater agreed fairly well with land use distributions on MI, in particular, with the spatial distribution of forest and sugarcane fields, and gave us some constrains of groundwater recharge areas and flowpaths.

宮古島近海における固有地震活動

We found eight M 5.1 characteristic earthquakes regularly occurring since 1966 on the plate boundary between the Eurasian plate and the Philippine Sea plate near Miyakojima Island, the Ryukyu Arc, Japan. The quake recurrence interval was 5.89 years in average, and the standard deviation was only 0.73 years. The accumulating stress presumably ruptured the same asperity enclosed by the creeping zone repeatedly. Also, we found three other groups of small repeating earthquakes of M 4, which occurred close to the hypocenters of the M 5 events. Those groups also occurred regularly and we can consider them to be ‘characteristic’ earthquake sequences. Now, we called those groups A, B, and C. It is not clear whether groups A and B had an intrinsic recurrence interval or if they influenced each other. However, two events of group C occurred within one week after the M 5 quakes, indicating that the M 5 events triggered the group C events whose asperity had suffcient strain energy. No earthquake exceeding M 7, which could change the recurrence intervals, has been observed on the subduction zone around the Ryukyu Islands. Therefore, there should be numerous characteristic earthquake sequences in other areas of the Ryukyu district. We expect that the next M 5 earthquake at 50 km depth on the plate boundary near Miyakojima Island will occur between September 2012 and July 2014 with 70% probability, using the small-sample theory with a log-normal distribution model. Moreover, the M 5 event may be accompanied by an M 4 quake that could rupture the asperity of group C within one week.

DNA Barcoding in Photosymbiotic Species ofDiplosoma(Ascidiacea: Didemnidae), with the Description of a New Species from the Southern Ryukyus, Japan

Partial sequences of the cytochrome c oxidase subunit I (COI) gene were determined for six species of the genus Diplosoma (Ascidiacea, Didemnidae) to develop tools for species identification. Because each Diplosoma species has distinctly different COI haplotype(s), the gene sequence seems to be usable for species discrimination in this ascidian genus. The phylogenetic hypothesis supported by the COI data is congruent with the distribution of character states of the retractor muscle. in this paper, we describe a new Diplosoma species harboring symbiotic cyanophytes, found on Miyakojima Island, Ryukyu Archipelago, Japan. Diplosoma aggregatum sp. nov. forms mosaic-like aggregates of small colonies. Although the zooids of D. aggregatum are similar to those of D. virens, these species are differentiated by colony form and COI sequences.

サンゴ増殖礁の開発を目的としたタカセガイ中間育成礁による検証実験

We confirmed that high coral community cover in top-shell snail (Tectus niloticus) aquaculture structure installed in the northern part of Miyako-jima Island, Okinawa prefecture. The purpose of this study is to grasp the reason why the structure has been functioning recruitment and growth of coral. As the results, it was suggested that the lattice structure in top-shell snail aquaculture structure functioned effectively recruitment of a coral larva. In addition, it was suggested that the measure-shaped structure functioned as to damp current speed at the time of the high surge and it has contributed to the growth of coral.

Estimating groundwater recharge using the SMAR conceptual model calibrated by genetic algorithm

Proper groundwater management of a contaminated aquifer requires the accurate estimation of groundwater recharge, which carries the contaminated load. There are many direct and indirect methods and sophisticated models for estimating recharge. However, most of them require many field data or model parameters, which limit their actual field application. To overcome this limitation, the Soil Moisture Accounting and Routing (SMAR), a conceptual rainfall-runoff model, is employed. The SMAR model has the potential for estimating recharge using only rainfall, evaporation and groundwater level data. However, for an aquifer having prominent horizontal groundwater flow, this model cannot be used directly. For this reason a horizontal flow component is added to this model. Model parameters are calibrated by the Genetic Algorithm (GA) optimization technique. Sensitivity of calibrated parameters to model efficiency and estimated recharge, and parameter interdependence are investigated. This model is applied to 11 observation locations in four catchment areas of Miyakojima Island, Japan, where groundwater nitrate contamination is a threat. The effectiveness of the model is evaluated using the model efficiency ( R 2), the mean of the sum of square errors (MSE), plots of observed versus estimated groundwater levels, scatter plots of observed versus estimated groundwater levels, measure of timing of the peaks, and the correlation between monthly rainfall and monthly estimated recharge. All show that this technique is very efficient for estimation of recharge. Model efficiency ( R 2) up to 92%, minimum MSE 0.32 m 2/day, average relative error of timing of the peaks 4.13%, and coefficient of determination ( r 2) up to 0.92 are obtained for the study area. The estimated recharge is 45% of the mean annual rainfall and agrees with other finding. It is thus concluded that the SMAR model could be a viable alternative since it can estimate dependable recharge with a minimum of input data.

The War Epics from the Miyako-jima Island : The Birth of a Hero(<Special Issue>Representations of War

The War Epics from the Miyako-jima Island : The Birth of a Hero(<Special Issue>Representations of War

Cytogeography of Ixeris nakazonei (Asteraceae, Lactuceae) in the Ryukyu Archipelago of Japan and Taiwan.

The cytogeographical structures of Ixeris nakazonei, a putative hybrid between I. debilis (6x) and I. repens (2x), were investigated in the Ryukyu Archipelago and Taiwan. In the Ryukyus, I. debilis occurs on Miyakojima Island of the southern Ryukyus and northward, while I. repens occurs on all islands except for Iriomotejima and Yonagunijima Islands. I. nakazonei, comprises six polyploid cytotypes, 3x, 4x, 5x, 6x, 7x and 8x, based on x=8. Four cytotypes from 3x to 6x occur in the central Ryukyus, while four cytotypes from 5x to 8x occur in the southern Ryukyus. The higher polyploids of I. nakazonei tend to be distributed in the more southerly area. Tetraploids of I. nakazonei always co-occur with I. debilis and I. repens, supporting the hybrid origin of this cytotype. Considering the chromosome number, octoploids, which predominate in the southern Ryukyus and Taiwan, may have derived directly from hybridization between I. debilis and I. repens. Odd-numbered polyploids of I. nakazonei, 3x, 5x and 7x, are relatively rare. Their chromosome numbers indicate that triploids and heptaploids are hybrids between the tetraploid of I. nakazonei and I. repens, and between the octoploid of I. nakazonei and I. debilis, respectively. Pentaploids of I. nakazonei in the central and southern Ryukyus are, respectively, hybrids between the tetraploid of I. nakazonei and I. debilis and between the octoploid of I. nakazonei and I. repens, indicating that pentaploids of I. nakazonei have at least two independent origins.

Development of Water Resources by the Large Scale Subsurface Dams on Miyako-jima Island, Okinawa Prefecture

Development of Water Resources by the Large Scale Subsurface Dams on Miyako-jima Island, Okinawa Prefecture

宮古島砂川地下ダム流域に分布する琉球石灰岩の水文地質学的検討

宮古島砂川地下ダム流域に分布する琉球石灰岩の水文地質学的検討

Government-operated Irrigation Project with Underground Dams in Miyako-jima Island, Okinawa, Japan

Government-operated Irrigation Project with Underground Dams in Miyako-jima Island, Okinawa, Japan

小笠原平島, 宮古島のビーチロック (板干瀬)

小笠原平島, 宮古島のビーチロック (板干瀬)