A perspective on Plio-Pleistocene hydrosystems of the northern Turkana Depression (East African Rift System) reconstructed from the study of freshwater mollusk communities

<p>The northern Turkana Depression of the East African Rift System in Northern Kenya and Southwestern Ethiopia has one of the most complete and well-documented late Cenozoic continental fossil records worldwide, including remarkable finds of early hominins and associated African Cenozoic vertebrates. Most previous paleoenvironmental reconstructions of the depression were developed using terrestrial vertebrate faunas and paleolandscapes, leaving freshwater ecosystems and associated hydrosystems (lakes, tributaries, river deltas, and wetlands) largely unaddressed. African Cenozoic freshwater mollusks were long considered to be good biostratigraphic indicators, given that their communities are able to represent long phases of morphological stability and at other times rapid morphological changes. However, to what extent changes in freshwater mollusk assemblages match with changes in sedimentary landscapes and lake level fluctuations remains unclear. Here, we address this question through integrative studies on Plio-Pleistocene fossil freshwater mollusks assemblages. Specifically, we are developing a taxonomic framework on fossil freshwater bivalves belonging to the families Unionidae, Iridinidae, Etheriidae and Corbiculidae to create a standardized overview of stratigraphically well-characterized fossil assemblages. Subsequently, we integrate this paleontological dataset with sedimentological characterizations of the depositional environments in which shell beds accumulated at high resolution around faunal turnover events. A detailed reconstruction of environmental changes and how these changes affected freshwater ecosystems in the northern Turkana Depression may allow us to recognize key environmental drivers that triggered faunal turnover events. Such an understanding of drivers from the past perhaps provides our best hope to anticipate how future environmental changes will alter freshwater ecosystems in tropical Africa, and, ultimately, the availability of various freshwater resources on which humanity depends.</p>

Non-destructive Raman Spectroscopic Determination of Freshwater Mollusk Composition, Growth, and Damage Repair

Increased acidification of aquatic habitat due to climate change is damaging mollusks. Non-destructive methods for analysis are necessary to study these endangered species. We analyzed five Unionidae gastropods using Raman...

The Freshwater Mollusk Dreissena polymorpha (Zebra Mussel) - A Review: Living, Prospects and Jeopardies

This review paper aims to address the topic of the living, prospects as well as jeopardies of the invasive Zebra Mussel. Broad literature reviews have been taken place to gather as many facts on this species as possible to summon all the most significant information up in one paper to be available for everyone. To get a better understanding of freshwater mussels in general, a short review of freshwater mussel diversity in America has been written also. The review paper focuses especially on living, prospects, and jeopardies in North America. The review revealed, freshwater mussels to be of practical importance and of great primeness for scientific research due to their unique life cycle. Especially the freshwater mollusk Dreissena polymorpha (Dreissenidae), colloquial known as the zebra mussel draws interest due to the mollusks’ invasive character and their tremendous filtering capacity. Once originated from the Ponto-Caspian region and currently present in 33 European Countries and 33 states of North America the freshwater bivalve draws interest all over the world. Their larval stage allows broad invasions of aquatic systems. Even though they can both harm their habitat as well as other organisms living in it, Dreissena polymorpha enormous filtering capacity can be utilized effectively if managed right. However, a lack of natural enemies and environmentally friendly pesticides makes control of Dreissena polymorpha in open water impossible.

Spatial Variation of Metallic Contamination and Its Ecological Risk in Sediment and Freshwater Mollusk: Melanoides tuberculata (Müller, 1774) (Gastropoda: Thiaridae)

Heavy metal pollution has been on the rise with serious implications for the wellbeing of aquatic ecosystems. Benthic sediments and freshwater mollusk (snail): Mellanoides tuberculata were sampled from five stations for determination of heavy metals concentrations and measurement of antioxidant enzyme activities. The spatial variation was studied using an enrichment factor, potential ecological risk index, and mean probable effect limit quotient (mPELq). From the results, Cu, Zn, Cd, Cr, Pb, Ni, and Co contamination levels were high at stations S3, S4, and S5 with an mPEL quotient of 94.40%. The variation of metal concentration and Enrichment factor were in the order S5 > S3 > S4 > S2 > S1, which was attributed to anthropogenic influences at the catchment due to industrial activities and atmospheric deposition of metals. Station five in this study is downstream and requires the most monitoring and management to prevent several ecological risks of metal pollutants in River Kaduna.

Vestige of The Ancient Estuarine of Cisaar Valley, Sumedang as One of the Pleistocene Fossil Bearing Site in West Jawa

Cisaar Valley is located on the east part of Sumedang Regency, West Jawa Province. It’s close to the boundary of Sumedang-Majalengka Regency. In this location the sandy and clay dominated sedimentary rocks are well exposed along the outcrops in the Cisaar Valley. These sedimentary rocks is inferred from Pliocene-Pleistocene deposits from Kaliwangu and Citalang Formation. Foraminifera microfossil that commonly used for interpretation of depositional environment is rarely found, whereas freshwater mollusk and vertebrate fossils often found in the sediment rocks of this area. This condition raises a question, what is the environment of this valley in the past? Data obtained from measured stratigraphic sections along Cisaar river and its tributary rivers in Cibengkung and Cirendang hamlets, Jembarwangi village. There are at least three depositional paleoenvironments which from old to young are: shallow marine, estuarine and fluviatil braided channel depositional paleoenvironment. Characteristics of the lower, middle and upper of the estuarine environment were found in this Cisaar Valley as the evidences of the oceanic regression processes was happened in the past in this area.