Cyanobacterial biodiversity and associated ecosystem services: introduction to the special issue
Cyanobacteria, one of the oldest groups of known organisms, are photosynthetic prokaryotes. They have existed for about 3.5 billion years, from Pre-cambrian times, and played a significant role in oxygen accumulation in the Earth’s early atmosphere making it fit for the survival of aerobic life-forms. Their unique ability, the ability to fix nitrogen and carry out oxygen-evolving photosynthesis and oxygen-labile nitrogen fixation within the same organisms, has always fascinated researchers (Mitsui et al. 1986). During their long evolutionary history, cyanobacteria have been able to adapt to geochemical and climate changes as well as anthropogenic disturbances (Paerl and Otten 2013). They probably exhibit the widest range of diversity in growth habitats of all photosynthetic organisms, and have developed CO2 concentrating mechanisms which adapt them to various environmental limitations (Badger et al. 2006). With an estimated global biomass of 3 9 10 g C, or 10 g wet biomass (Garcia-Pichel et al. 2003), quantitatively they are also some of the world’s most important organisms (Whitton 2012). Many of the species, however, remain to be discovered (Nabout et al. 2013), and cyanobacteria remain a neglected component of biodiversity research (Rejmankova et al. 2004). Global warming will have a profound impact on cyanobacterial biodiversity, probably favouring them over other phytoplankton (Carey et al. 2012), increasing cyanobacterial blooms formation (Wagner and Adrian 2009), and also favour toxin producing species or elevated toxin concentration by extant species with severe consequences for associated ecosystem services (Kleinteich et al. 2012). Lake warming with reduced water turnover and a changed nutrient ratio too will also favour the growth of harmful filamentous cyanobacteria (Posch et al. 2012) and their dominance will affect ecosystem functioning and community turnover in nutrient-enriched lakes (Filstrup et al. 2014). As cyanobacteria have significant ecological roles, their biodiversity need to be fully explored and conserved