0000000000019409
AUTHOR
M. Rosa Miracle
Photoautotrophic community changes in Lagunillo del Tejo (Spain) in response to lake level fluctuation: Two centuries of sedimentary pigment records
Lagunillo del Tejo is a small doline lake in a karstic region of the Iberian Ranges (central-eastern Spain) that undergoes significant lake level fluctuation in response to changing aquifer influxes. In order to assess changes in the primary producer community in the lake over the last two centuries and to elucidate whether these were conditioned by climatic variability, photosynthetic pigments and their derivatives were extracted from the sediments and the data analysed using multivariate statistical techniques. Quantitative variations in total pigment concentrations through the sedimentary sequence are considered a result of changes in sedimentation rate, largely due to lake level fluctua…
Relationships between oxygen concentration and patterns of energy metabolism in the rotifer Brachionus plicatilis
Abstract 1. 1. Activities of 10 enzymes and accumulation of two metabolites under experimental hypoxia were investigated in the rotifer Brachionus plicatilis . 2. 2. Pyruvate kinase (PK), lactate dehydrogenase (LDH), malic enzyme (ME), phosphoenolpyruvate carboxykinase (PEPCK), malate dehydrogenase (MDH) and fumarase (FUM) activities showed great increase at low oxygen levels. Alcohol dehydrogenase (ADH) activity was not detected. 3. 3. Alanine concentration showed an increase with low oxygen concentrations, while alanine aminotransferase (GTP) showed a slight activity increase with oxygen levels. The high alanine concentration was interpreted as enhanced proteolysis. 4. 4. Our results show…