Vertical Changes of Recent Ostracode Assemblages and Environment in the Inner Part of Jakarta Bay, Indonesia

A short sediment core from the inner part of Jakarta Bay, Indonesia, was quantitatively analysed for ostracods (minute Crustacea), total organic carbon (TOC) and total nitrogen (TN) contents, and the vertical distributions were recorded. A total of 53 ostracod species were obtained from 80 continuous core samples. The dominant species were Keijella carriei and Loxoconcha wrighti, which are common in areas with high TOC and TN contents. Based on an analysis of ostracod assemblages and carbon/nitrogen ratio, the study site began to be influenced by organic contamination from around 1950. Although the population of Jakarta City has increased rapidly since then, TOC and TN contents which were low, have gradually increased (0.7%–0.9% and 0.10%–0.12%, respectively), probably due to addition of nutrients from river sedimentation. The increased sedimentation rate after 1950 resulted in an increasing TOC ratio. The observed correlation between TOC and dominant species shows that Phlyctenophora orientalis may be a good indicator for monitoring increases in the narrow TOC content range of 0.7%–1.1%

Is the meiofauna a good indicator for climate change and anthropogenic impacts?

Our planet is changing, and one of the most pressing challenges facing the scientific community revolves around understanding how ecological communities respond to global changes. From coastal to deep-sea ecosystems, ecologists are exploring new areas of research to find model organisms that help predict the future of life on our planet. Among the different categories of organisms, meiofauna offer several advantages for the study of marine benthic ecosystems. This paper reviews the advances in the study of meiofauna with regard to climate change and anthropogenic impacts. Four taxonomic groups are valuable for predicting global changes: foraminifers (especially calcareous forms), nematodes, copepods and ostracods. Environmental variables are fundamental in the interpretation of meiofaunal patterns and multistressor experiments are more informative than single stressor ones, revealing complex ecological and biological interactions. Global change has a general negative effect on meiofauna, with important consequences on benthic food webs. However, some meiofaunal species can be favoured by the extreme conditions induced by global change, as they can exhibit remarkable physiological adaptations. This review highlights the need to incorporate studies on taxonomy, genetics and function of meiofaunal taxa into global change impact research

Occurrence of a rare puncioid ostracod, Promanawa konishii (Nohara, 1976), in Recent sediments of the East China Sea

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Playing the detective in Ostracoda taxonomy: on types of the family Trachyleberididae

Session 1: Taxonomy: abstract no. 1.6The class Ostracoda possesses one of the most extensive fossil records among all animals. One of the most diverse and abundant ostracod families, the Trachyleberididae Sylvester-Bradley, 1948, inhabits marine environments since the Jurassic and has left an impressive stratigraphic record. Therefore, its fossil records have outstanding utilities for macroevolutionary research to better understand evolutionary history of marine life and to test the evolutionary theories in longer time-scales beyond those available for the most biological studies. However, the morphological characters defining the Trachyleberididae remain controvertial, in part because there is considerable taxonomic confusion regarding the Trachyleberididae’s type genus Trachyleberis Brady, 1898, and its type species Trachyleberis scabrocuneata (Brady, 1880). Here we resolve this confusion to develop robust taxonomic framework of this important ostracod family. We discuss in detail the taxonomic history of all taxa involved in this confusion, and validly fix Trachyleberis scabrocuneata (Brady, 1880) (sensu lectotype and paralectotypes from the Challenger Expedition) as the type species of Trachyleberis. Previous attempts to fix the type species of Trachyleberis either involved mixing of distinct species or decisions contrary to the International Code of Zoological Nomenclature. Additionally, we provide: (1) new diagnoses and discriptions of Trachyleberis and Trachyleberis scabrocuneata (Brady, 1880); (2) SEM photos of Trachyleberis scabrocuneata (Brady, 1880), Trachyleberis sp. nov. 1 (previously confused with Trachyleberis scabrocuneata (Brady, 1880)), Trachyleberis lytteltonensis Harding and Sylvester-Bradley, 1953 (previously mistakenly considered the type species of Trachyleberis) and Trachyleberis raynerae Neale, 1975 (the oldest species of Trachyleberis, which lived during the Cretaceous).link_to_OA_fulltex

Changes in holocene ostracode faunas and depositional environments in the Kitan Strait, southwestern Japan

At least 106 species were identified from 36 samples obtained from two cores (T1 and T2), which were recovered from the Kitan Strait off Wakayama City, southwestern Japan. Q-mode cluster analysis of cores T1 and T2 revealed three biofacies (PL, PT and LS). Changes in depositional environments based on the observed distribution of ostracodes were analysed, and the following sequence is proposed. Before ca. 7,000 cal yr BP, the T1 site was a sandy coast, ranging from an outer bay to the open sea, close to a river mouth, at water depths of more than 15-20 m, while the T2 site ranged from a bay coast to an outer bay, close to a river mouth, at water depths of less than 15-20 m. During ca. 7,000-2,000 cal yr BP, the position of the sites fell within ranging an outer bay to the open sea at water depths of 30-40 m influenced by residual and/or tidal currents from the straits. After ca. 2,000 cal yr BP, the sites were situated on a sandy coast, ranging from an outer bay to the open sea, close to a river mouth, at water depths of more than 15-20 m. Two new species, Trachyleberis ishizakii and Cytheropteron kumaii, are also described.link_to_subscribed_fulltex

Temporal changes of ostracode assemblages and anthropogenic pollution during the last 100 years, in sediment cores from Hiroshima Bay, Japan

Temporal changes of ostracodes during the last 100 years observed in three sediment cores from Hiroshima Bay, the Seto Inland Sea, Japan, provide valuable information about influences on ostracodes caused by anthropogenic pollution. This is the first detailed report of historical records of the relationship between ostracodes and pollution established from core samples drilled in the polluted inner bay. At least 38 ostracode species were identified from 40 samples. Based on biofacies, the density of ostracodes and the faunal structure, it is elucidated that industrialization combined with the effects of the second world war caused a decrease in the density and a increase in the equitability of ostracodes, and that anthropogenic pollution caused a simplification of ostracode assemblages in Hiroshima Bay. The response of two particular ostracode species to anthropogenic pollution is also demonstrated. Callistocythere alata was sensitive and Bicornucythere bisanensis has a strong resistance for anthorogenic pollution in ostracode species. Thus, the relative frequencies of these two ostracodes can be used as an indication of such pollution. We discuss the limitations of using recent ostracode assemblages in the analysis of the palaeoenvironment, resulting from the changes induced by anthropogenic pollution during the last 100 years.link_to_subscribed_fulltex