Pastaje (grazing) del microzooplancton en aguas de las Islas Canarias

[EN]The impact of micrograzers upon primary production was measured north of the Canary Islands during 2010 and 2011 using the dilution technique. Grazing was estimated from chlorophyll a but also taking into account the different phototrophic organisms, that is, Synechococcus (Syn), Prochlorococcus (Pro), autotrophic picoeukaryotes (APE) and autotrophic nanoflagellates (ANF). Some experiments showed significant values of grazing upon Syn, Pro or APE although no significant grazing was measured on chlorophyll a. Furthermore, a positive relationship, this means growth instead of grazing, was observed in Syn and Pro in two experiments. Grazing on heterotrophic prokaryotes was also determined and the obtained values were always highly significant. These results showed that the impact of micrograzers upon primary production is a complex process which involves a different grazing pressure upon phytoplankton groups. Therefore, a detailed analysis of the pico, nano and microplanktonic community is essential to really understand the role of micrograzers and the trophic interactions among these groups in subtropical waters.

Changes in species richness and diversity of cryptogrammic communities in páramo ecosystems

Universidad Técnica Particular de Loja

Planktonic potential CO2 emission calculation: preliminary results by applying an adapted enzymatic methodology to marine ecosystems

[EN]Isocitrate Dehydrogenase (IDH) is a key enzyme in the Krebs cycle, being responsible for the production of one of the three CO2 molecules related to cellular respiration. In order to measure the potential CO2 production linked to the marine planktonic community we have adapted an enzymatic methodology. Preliminary results show that different proportions of autotrophs, heterotrophs and mixotrophs and their metabolic pathways, lead to different relationships between potential CO2 emission and potential O2 consumption during cellular respiration. Although more experiments need to be made, this methodology is leading to a better understanding of cellular respiration in marine samples and their impact on the food chain, vertical Carbon flux and the current sequestering capacity for anthropogenic CO2.