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Impairment of mixed melanin-based pigmentation in parrots

Parrots and allies (Order Psittaciformes) have evolved an exclusive capacity to synthesize polyene pigments called psittacofulvins at feather follicles, which allows them to produce a striking diversity of pigmentation phenotypes. Melanins are polymers constituting the most abundant pigments in animals, and the sulphurated form (pheomelanin) produces colors that are similar to those produced by psittacofulvins. However, the differential contribution of these pigments to psittaciform phenotypic diversity has not been investigated. Given the color redundancy, and physiological limitations associated to pheomelanin synthesis, this study assumed that the latter would be avoided by psittaciform birds. This hypothesis was tested by using Raman spectroscopy to identify pigments in feathers exhibiting colors suspicious of being produced by pheomelanin (i.e., dull red, yellow and grey- and green-brownish) in 26 species from the three main lineages of Psittaciformes. The non-sulphurated melanin form (eumelanin) were detected in black, grey and brown plumage patches, and psittacofulvins in red, yellow and green patches, but no evidence of pheomelanin was found. As natural melanins are assumed to be composed of eumelanin and pheomelanin in varying ratios, these results represent the first report of impairment of mixed melanin-based pigmentation in animals. Given that psittaciforms also avoid the uptake of circulating carotenoid pigments, these birds seem to have evolved a capacity to avoid functional redundancy between pigments, likely by regulating follicular gene expression. The study provides the first vibrational characterization of different psittacofulvin-based colors and thus helps to determine the relative polyene chain length in these pigments, which is related to their antireductant protection activity. informacion[at] Neves et al (2020) Impairment of mixed melanin-based pigmentation in parrots. J Experim Biol. DOI 10.1242/jeb.225912
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Identifying the most threatened areas by human activity in the Mediterranean Sea

Identifying the most threatened areas by human activity in the Mediterranean Sea

A study analysed and distributed the existing information on several impacts that are simultaneously affecting the Mediterranean Sea: from climate impacts like the rise of temperatures in the sea, to the fishing pressure on natural resources or changes in physical and chemical conditions. The result is a map of the places that are most affected by human activity such as the Adriatic Sea, the Aegean Sea, the African coast and the Catalan sea, among others. According to the researchers, this information will enable identifying areas that need local action to minimize the impacts of a global problem such as climate change. The study is framed within the concept of Safe Operating Spaces (SOS), which determines a multidimensional space in which we would find an ecosystem and is delimited by several kinds of impacts such as pollution, fishing, or the temperature of water. In order for this ecosystem to be in the right conditions, magnitude of the impacts should not exceed certain thresholds, therefore, if the magnitude of an impact increases, the thresholds of the others decrease and vice-versa. By delimiting a SOS out of climate and human impacts, when reducing anthropic pressure, the threshold for climate impacts would increase and therefore, the ecosystem's ability to resist environmental impacts related to climate change would increase. To spatially delimit the potential impacts that would affect the Mediterranean Sea, several methodologies and databases such as the largest temporary series of remote sensing –satellite images- that provide data on the temperature of the marine surface were combined. Data on the distribution of the fishing pressure provided by Global Fishing Watch were also used. According to the study, those areas that are affected by human impact would be more potentially vulnerable to climate change. In particular, the results show that there are certain areas that are more vulnerable such as the Adriatic Sea, the Aegean Sea, the African coast and the Catalan sea, where fishing intensity is high. If we add the rise of temperatures in the sea, caused by global warming, the result is that there will be species of commercial interest like the sardine, which will be particularly affected, since they are very sensitive to the rise of temperatures. Knowing how to distribute these threats can help management of several activities like fishing. For instance, it can regulate these activities in affected areas or move fishing to areas that are less affected by other threats. Local administrations cannot fight climate change by themselves, since it requires the consensus and action of all the international community. However, working on other local impacts, the "vulnerability" of certain areas and ecosystems regarding the climate change could be reduced. In addition to fighting global warming, potential measures of mitigation could consist in managing local impacts. informacion[at] Ramírez et al (2018) Spatial congruence between multiple stressors in the Mediterranean Sea may reduce its resilience to climate impacts. Scientific Reports 8:14871 DOI 10.1038/s41598-018-33237-w