Diversity and diet preferences of Artemia from hypersaline lakes at Rottnest Island (WA): a metabarcoding-based survey

Dr Mattia Saccò¹, Dr Matthew A. Campbell¹, Dr Nicole E. White¹, Dr William F. Humphreys^2,3, Prof Morten E. Allentoft^1,4

¹Curtin University, Perth, Australia, ²Western Asutralian Museum, Perth, Australia, ³University of Wstern Australia, Perth, Australia, ⁴University of Copenhagen, Copenhagen, Denmark

Abstract:

Hypersaline lakes, water bodies where the concentration of salt exceeds that of seawater, represent ecosystems hosting unique biodiversity and extraordinary levels of endemism. These habitats are often buzzing with populations of the brine shrimp Artemia, a micro-crustacean that display a vast suite of adaptations to cope with these extreme conditions. However, despite being defined as “the most resistant of all animal life history stages to environmental stress”, our knowledge of their diversity and food web interactions is still incomplete. This is particularly the case for remote and overlooked hypersaline lakes which are continuously and increasingly threatened by both anthropic and climate change-related impacts. This study makes use of DNA metabarcoding techniques –environmental DNA from water samples, and metabarcoding analysis from gut contents – to investigate the species diversity and dietaries of Artemia populations from five hypersaline lakes at Rottnest Islands in Western Australia. Our results provide strong indication that the brine shrimp community at Rottnest Island, previously ascribed to Artemia Partenogenetica (Bowen and Sterling, 1978), is largely composed by Artemia urmiana (Günther, 1890), suggesting that wading birds from Asia act as drivers of Artemia colonisation processes. Assessment of diet habits revealed a preference for planktonic algae (i.e. diatoms), however bacterial content compatible with marginal filter feeding of microbial mats was also detected. Our molecularly-based findings expand the ecological characterisation of the biotic communities of hypersaline lakes at Rottnest Island. Combination of biogeochemical data will help improve understanding of food webs of some of the most important but underrated ecosystems worldwide.

Biography:

I am a postdoctoral researcher interested in freshwater environments – both superficial and subterranean – and the incorporation of multidisciplinary designs into the study of functional ecology. My current main project focuses on monitoring biodiversity and characterising ecosystem functioning of hypersaline lakes within the Chilean precordillera. Other satellite projects include studies on subterranean trophic dynamics, stygofaunal species identification and urban pond ecology.