The increase in temperature modifies the relationships between algae and non-photosynthetic organisms, such as bacteria and zooplankton, and this may alter balances in food webs.
Ultraviolet radiation is detrimental to algae, as it reduces their photosynthetic capacity and hampers their growth. Nevertheless, some algae are adapted to this detrimental radiation and to nutrient scarcity through a mixed feeding system known as “mixotrophy”. Some mixotrophic species, such as Chromulina nevadensis, do their photosynthesis and additionally feed on bacteria. This helps them make up for the harmful effects of ultraviolet radiation and nutrient scarcity.
Nevertheless, the increases in temperature and in the frequency and intensity of the haze episodes from the Sahara currently pose a threat to mixotrophic species. Saharan dust provides nutrients that certain species of green fast-growing algae, such as Dictyosphaerium chlorelloides, may take advantage of. Consequently, mixotrophic algae are displaced by the massive growth of green algae, which reduces the taxonomic and functional biodiversity of ecosystems.
Mountain ponds are not immune to plastic contamination either. We have detected higher concentrations of microplastics in ponds that are surrounded by meadows called borreguiles (areas with small lakes and peat bogs), which usually receive a larger number of visitors.