Search results for "Biota"

Toxic Effects of Organometallic Compounds towards Marine Biota

2002

Organometallic derivatives are compounds containing a direct σ or π carbon metal linkage. Furthermore, the concept of the metallic atom must be extended to all the elements that are less negative than the carbon atom. As a consequence, taking into account all elements that are less negative than carbon and the number of existing organic compounds, it is possible to synthesize millions of organometallic derivatives. Several of these are extensively used in organic syntheses; others may find application in agriculture and in many other fields as pesticides, fire retardants, wood preservatives, antifouling agents, etc. In general, the organic derivatives of the metals are more toxic than the p…

Polychlorinated Dibenzothiophenes (PCDTs), Thianthrenes (PCTAs) and Their Alkylated Derivatives

2000

Polychlorinated dibenzothiophenes (PCDTs) and polychlorinated thianthrenes (PCTAs) are interesting compounds due to their structural similarity with polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzo-p-dioxins (PCDDs). PCDTs are sulfur analogues of PCDFs and PCTAs are sulfur analogues of PCDDs. PCDTs and PCTAs are probably formed by processes similar to the formation of PCDFs and PCDDs. PCDTs were first detected in the environment in 1986. Since then PCDTs have been analyzed in samples from combustion and metallurgy, sediments, pulp mill effluents, and in aquatic biota. Combustion and metallurgy seem to be the major sources of PCDTs in the environment. PCDTs and PCTAs are ana…

A multivariate approach of changes in filamentous, nitrifying and protist communities and nitrogen removal efficiencies during ozone dosage in a full…

2019

[EN] The application of low ozone dosage to minimize the problems caused by filamentous foaming was evaluated in two bioreactors of an urban wastewater treatment plant. Filamentous and nitrifying bacteria, as well as protist and metazoa, were monitored throughout a one-year period by FISH and conventional microscopy to examine the effects of ozone application on these specific groups of microorganisms. Multivariate data analysis was used to determine if the ozone dosage was a key factor determining the low carbon and nitrogen removal efficiencies observed throughout the study period, as well as to evaluate its impact on the biological communities monitored. The results of this study suggest…

150 years of the discovery of the Cambrian Lagerstätte of Murero (Cadenas Ibéricas, NE Spain)

2013

El yacimiento paleontológico del Cámbrico inferior-medio de Murero (Cadenas Ibéricas, NE de España) es una localidad clásica del Cámbrico europeo. Fue dado a conocer a la ciencia por Edouard de Verneuil en 1862, celebrándose en 2012 el 150 aniversario de su descubrimiento. Es un siglo y medio de trabajos geológicos y de logros puestos al servicio del conocimiento del Período Cámbrico. Murero es un Lagerstätte excepcional porque coexisten en él grupos esqueléticos y de cuerpo blando a lo largo de un registro estratigráfico continuo que abarca unos 8 millones de años, dividido en 14 zonas de trilobites. En 1997, este yacimiento paleontológico fue el primero de España en obtener de la Administ…

Eckfeld Maar: Window into an Eocene Terrestrial Habitat in Central Europe

2010

: To mark the occasion of the 175th anniversary of the Rheinische Naturforschende Gesellschaft in 2009 and of the centennial of the Mainz Natural History Museum in 2010, we present a short account of our present knowledge of the Eckfeld Maar after 20 years of continuous research. This paper does not attempt to include all of the detailed results on the geology of the Eckfeld site or its biota. To date, nearly 250 papers and books have been published since the start of our project An up-to-date list of these publications can be found at http://www.eckfeldermaar.de.

A Middle Cambrian edrioasteroid from the Murero biota (NE Spain) with Australian affinities

2007

Abstract A Middle Cambrian edrioasteroid belonging to the genus Cambraster is described from the Middle Cambrian Murero biota (Cadenas Ibericas, NE Spain). Up to now, this genus was known only from Australia and France. This represents the first record of the class Edrioasteroidea in the Cambrian of Spain. Moreover, preliminary results on the diversity and biostratigraphic position of Cincta, Eocrinoidea and Edrioasteroidea from this area are reported.

Characterization of the microbiota from coelomic fluid of the sea urchin Paracentrotus lividus

2016

The study of the microbiota is a subject of considerable and growing interest since it is drawing new important perspectives in the life sciences concerning the functional relationships between metazoans and microbial cells. In fact, it has already shown that the endogenous microbial community affects various physiological activities of multicellular organisms. The coelomic cavity of echinoderms contains a fluid in which coelomocytes are reported to exert immune functions like phagocytosis, opsonization and production of antimicrobial agents against marine bacteria [1, 2]. However, up to day nothing is known about the endogenous bacterial population of coelomic fluid. We focused on this iss…

New articulated protospongiid sponges from the early Cambrian Chengjiang biota

2015

Sponges are among the earliest diverging crown-group animals and widely regarded as the earliest biomineralizing animals. Indeed, unambiguous hexactine sponge spicules first occur in the lowermost Cambrian strata of the Fortunian Stage. Articulated sponge skeletons interpreted as hexactinellids and demosponges have been reported from Cambrian Stage 2–3 strata at multiple localities. Articulated sponge skeletons in the Chengjiang biota (Cambrian Stage 3), however, are dominated by forms interpreted as demosponges, despite the exceptional preservation in this biota. Here, we report new articulated sponge skeletons from the Chengjiang biota, including Paradiagoniella magna n. gen. n. sp. and P…

Ģeogrāfija. Ģeoloģija. Vides zinātne: referātu tēzes

2008

Abundant and diverse arsenic‐metabolizing microorganisms in peatlands treating arsenic‐contaminated mining wastewaters

2020

Mining operations produce large quantities of wastewater. At a mine site in Northern Finland, two natural peatlands are used for the treatment of mining‐influenced waters with high concentrations of sulfate and potentially toxic arsenic (As). In the present study, As removal and the involved microbial processes in those treatment peatlands (TPs) were assessed. Arsenic‐metabolizing microorganisms were abundant in peat soil from both TPs (up to 108 cells gdw‐1), with arsenate respirers being about 100 times more abundant than arsenite oxidizers. In uninhibited microcosm incubations, supplemented arsenite was oxidized under oxic conditions and supplemented arsenate was reduced under anoxic con…