scholarly journals Distribution, abundance, and feeding ecology of baleen whales in Icelandic waters: have recent environmental changes had an effect?

Author(s):  
Gísli A. Víkingsson ◽  
Daniel G. Pike ◽  
Héðinn Valdimarsson ◽  
Anna Schleimer ◽  
Thorvaldur Gunnlaugsson ◽  
...  
2015 ◽  
Vol 12 (1) ◽  
pp. 16-29 ◽  
Author(s):  
Guðmundur J. Óskarsson ◽  
Asta Gudmundsdottir ◽  
Sveinn Sveinbjörnsson ◽  
Þorsteinn Sigurðsson

2021 ◽  
pp. 102690
Author(s):  
Raquel García-Vernet ◽  
Asunción Borrell ◽  
Gisli Víkingsson ◽  
Sverrir D. Halldórsson ◽  
Alex Aguilar

2010 ◽  
Vol 70 (3) ◽  
pp. 569-574 ◽  
Author(s):  
R. Mazzoni ◽  
CF. Rezende ◽  
LR. Manna

In the present study we aimed to compare the feeding ecology of Hypostomus punctatus from a coastal stream from Southeast Brazil with data previously published for the same study site before environmental changes. Feeding preferences were assessed through a sample of 138 specimens (67 from the dry and 71 from the rainy season) using the Index of Alimentary Importance (IAi). We registered five different food items (detritus, plant fragments, Diatoms, Chloroficeae and Cianobacteries) composing the species diet. Detritus was the most abundant one both during the rainy and dry seasons (IAirainny = 90.34 and IAidry = 96.30). No significant differences were registered for the volume of food items consumed during the rainy and dry seasons. The Frequency of Occurrence analysis showed that four (detritus, plant fragments, Diatoms and Chloroficeae) among the five all other consumed ones, were always frequent. Comparing our own results with those available for the study site, we suggest that the feeding habit of H. punctatus has changed according to environmental changes and that the species diet is strongly dependent upon environmental conditions.


2010 ◽  
Vol 70 (3) ◽  
pp. 503-509 ◽  
Author(s):  
DO. Lima ◽  
ER. Behr

Knowledge of the feeding ecology of fish is essential for understanding the functioning of freshwater communities. Here we report on an analysis of the diet of Pachyurus bonariensis Steindachner, 1879, a freshwater sciaenid. Fish were collected bimonthly from December 1999 to January 2002 at three locations along the Ibicuí River in the Rio Grande do Sul State, Brazil. At each location, the specimens were collected in both lentic and lotic environments. The stomachs of 324 fish were analysed for contents and fullness. The main items were Ephemeroptera, Diptera (larvae), Trichoptera and Odonata. Annelida, plant matter, Decapoda, Diptera (pupae), Coleoptera and Mollusca were present in small amounts. The fish consumed smaller amounts of food in winter than in other seasons. The most important source of dietary variation for P. bonariensis was the ontogenetic, related to intrinsic biological characters. However, spatial variation was also found, suggesting that this species can adapt its diet to environmental changes. Although P. bonariensis showed ontogenetic and spatial variations in the main items consumed, the main items were always insects, characterising P. bonariensis as a fish with an insectivorous feeding habit in the Ibicuí River.


2020 ◽  
Vol 477 (16) ◽  
pp. 3091-3104 ◽  
Author(s):  
Luciana E. Giono ◽  
Alberto R. Kornblihtt

Gene expression is an intricately regulated process that is at the basis of cell differentiation, the maintenance of cell identity and the cellular responses to environmental changes. Alternative splicing, the process by which multiple functionally distinct transcripts are generated from a single gene, is one of the main mechanisms that contribute to expand the coding capacity of genomes and help explain the level of complexity achieved by higher organisms. Eukaryotic transcription is subject to multiple layers of regulation both intrinsic — such as promoter structure — and dynamic, allowing the cell to respond to internal and external signals. Similarly, alternative splicing choices are affected by all of these aspects, mainly through the regulation of transcription elongation, making it a regulatory knob on a par with the regulation of gene expression levels. This review aims to recapitulate some of the history and stepping-stones that led to the paradigms held today about transcription and splicing regulation, with major focus on transcription elongation and its effect on alternative splicing.


2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.


Author(s):  
JG Calado ◽  
SN Veríssimo ◽  
VH Paiva ◽  
R Ramos ◽  
PT Vaz ◽  
...  

Author(s):  
Ksenya V. Poleshchuk ◽  
Zinaida V. Pushina ◽  
Sergey R. Verkulich

The diatom analysis results of sediment samples from Dunderbukta area (Wedel Jarlsberg Land, West Svalbard) are presented in this paper. The diatom flora consists of four ecological groups, which ratio indicates three ecological zones. These zones show environmental changes of the area in early–middle Holocene that is demonstrating periods of regression and temperature trends.


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