Response of the Calanoid Copepod Clausocalanus furcatus, to Atmospheric Deposition Events: Outcomes from a Mesocosm Study

Atmospheric deposition is assumed to stimulate heterotrophic processes in highly oligotrophic marine systems, controlling the dynamics and trophic efficiency of planktonic food webs, and is expected to be influenced by climate change. In the course of an 8-day mesocosm experiment, we examined the channeling, of the Saharan dust (SD) and mixed aerosols (A) effects on microplankton up to the copepod trophic level, in the highly oligotrophic Eastern Mediterranean Sea. Based on mesocosms with SD and A treatments, we evaluated the feeding response of the dominant copepod Clausocalanus furcatus every other day. We hypothesized that increased food availability under atmospheric deposition would result in increased copepod ingestion rates, selectivity and production. Overall, no robust pattern of food selection was documented, and daily rations on the prey assemblage of all mesocosms were very low indicating severe food limitation of C. furcatus. Although increased food availability was not true, after few days ingestion of ciliates was maximized, followed by egg production, in both the SD and A treatments, indicating their importance in the diet of this copepod as well as a response of C. furcatus feeding performance. Our results help in understanding the trophic efficiency of marine food webs in ultra-oligotrophic environments under atmospheric deposition. We suggest that future mesocosm research in oligotrophic waters should consider more than one copepod speciesVersión del edito

Chelated mineral supplements for Nelore: quality and early embryonic development

ABSTRACT. Pasa C., Hatamoto-Zervoudakis L.K., Zervoudakis J.T. & Soares L. [Chelated mineral supplements for Nelore: quality and early embryonic development.] Suplementos minerais quelatados para vacas Nelore: qualidade e desenvolvimento embrionário inicial. Revista Brasileira de Medicina Veterinária, 36(1):29-34, 2014. Programa de Pós-Graduação em Ciência Animal, Faculdade de Agronomia e Medicina Veterinária, Universidade Federal do Mato Grosso, Av. Fernando Corrêa da Costa, 2367, Bairro Boa Esperança, Cuiabá, MT 78060-900, Brasil. E-mail: [email protected] The objective of this study was to evaluate the quality and early development of embryos produced with oocytes of cows supplemented with copper, zinc and selenium in a non-chelated and chelated. The experiment was conducted in Cuiabá-MT during the months April to July 2009. We used 24 adult Nellore multiparous, aged, average weights of the initial 36 months, 395 kg and mean body condition score 4.8, respectively randomly divided into 2 groups: control group (CG, supplemented with conventional mineral) and Supplemented Group (GS, animals supplemented with zinc, copper and selenium chelated. Each group was kept in a paddock of Brachiaria brizantha cv Marandu received 1 kg of animal per day. chelated mineral supplementation (GS) and conventional mineral (GC ) delivered via the protein supplement was given during a period of 99 days with daily average 1kg/cabeça. During the experimental period were two follicular aspirations, one to 59 days and another at 99 days of supplementation. Every two weeks the animals were weighed and ECC evaluated. oocytes viable (grades I, II and III) were used for in vitro production of embryos. The experiment was completely randomized and data were analyzed by ANOVA and a significance level of 10%. There was no effect (p> 0.10) of supplementation with chelated minerals on the percentage of cleaved oocytes, total embryos produced, percentage of produced embryos, cells in the morula stage, embryos in blastocyst stage embryos and expanded blastocyst stage assessed on day six of culture. Moreover, there was no effect of supplementation in the collection for a number of in vitro matured oocytes (IVM) (p = 0.0981, 24.9166 ± 4.2878 GC and GS 16.2500 ± 2.6057) , number of cleaved oocytes (p = 0.0902 for the GC animals and animals 13.9166 ± 2.4103; 9.0833 ± 1.2759 GS) and number of embryos to the blastocyst stage assessed in the initial 06 days (p = 0.0091, 2.7500 ± 0.4909 GC and GS 5.2857 ± 0.9184). Oral supplementation with minerals zinc, copper and selenium chelate via protein supplements at the levels and conditions for nutrient management in this experiment did not influence the parameters of percentage of cleaved oocytes, total number of embryos, percentage of embryos, cells in the morula stage, embryos in the blastocyst stage and expanded blastocyst evaluated on day 06 of cultivation, however had a significant effect for in vitro matured oocytes, cleavage and blastocyst stage embryos in the initial young Nelore cows

Copepod response to ocean acidification in a low nutrient-low chlorophyll environment in the NW Mediterranean Sea

In order to identify how ocean acidification will influence biological interactions and fluxes among planktonic organisms and across trophic levels, a large-scale mesocosm experiment was performed in the oligotrophic Northwestern Mediterranean Sea in the framework of the European MedSeA project. Nine mesocosms were deployed in the Bay of Calvi (Corsica, France) in summer 2012. Six mesocosms were subjected to different levels of CO2 partial pressures (pCO2; 550, 650, 750, 850, 1000 and 1250 μatm) covering the range of atmospheric pCO2 anticipated for the end of this century depending on future emission scenarios, and the last three mesocosms were unaltered (ambient pCO2 of ∼450 μatm). During this 21-day experiment, we monitored copepod egg and naupliar stocks, estimated copepod (Acartia clausi and Centropages typicus) feeding rates and determined the abundance and taxonomic composition of the mesozooplankton community at the start and at the completion of the experiment. This community was clearly dominated by copepods and its final composition slightly varied between mesocosms most likely due to natural and experimental variability that cannot be related to CO2 conditions. The abundances of eggs and nauplii as well as feeding rates of A. clausi and C. typicus on diatoms, dinoflagellates and ciliates showed no significant differences among CO2 levels. The above findings suggest that the experimental set-up especially for the specific trophic conditions and the short duration of the experiment did not provide the information on the effect of acidification that was expected. The acidification might have an effect on planktonic communities and even worsen the problems imposed by food limitation, therefore on this short time scale experiment and under the extreme ologotrophic conditions the signal that dominates was the food limitation. © 2016 Elsevier Lt

Copepod response to ocean acidification in a low nutrient-low chlorophyll environment in the NW Mediterranean Sea

International audienc

ARCANOBACTERIUM-HAEMOLYTICUM IN CHILDREN WITH PRESUMED STREPTOCOCCAL PHARYNGOTONSILLITIS OR SCARLET FEVER

Arcanobacterium haemolyticum was cultured from pharyngeal specimens obtained from 12 of 129 children with pharyngotonsillitis, some of whom had a scarlatiniform rash. This organism should be considered to be a cause of infections that are clinically similar to those caused by beta-hemolytic streptococci