Composition Of Entire Communities Research Articles

Addressing the "Paradox of the Plankton": Using Metabarcoding to Explore Zooplankton Diversity Patterns Across Chemical Conditions in the Salish Sea

Traditional taxonomic analysis of zooplankton is time consuming, expensive, and unable to resolve the true species diversity of a community due to a lack of diagnostic morphological characters for many taxa. This is especially true for early life stages, undescribed, and cryptic species. This limitation has led to a dramatic under-estimation of the incredible diversity of life that inhabits the ocean, hindering our understanding of the environmental conditions that structure communities. Multi-gene metabarcode high-throughput sequencing (HTS) analyses entailing field sampling and bioinformatics offer new means to rapidly and accurately characterize the species identities, diversity, and composition of entire communities. We use multiple diagnostic Illumina MiSeq HTS metabarcode assays (for mitochondrial COI, 16SRNA, and 12SRNA gene regions) and a custom bioinformatics pipeline to analyze communities of invertebrates and fishes from zooplankton net tows collected concurrently with environmental chemistry data across Puget Sound in the southern Salish Sea. We compare results among sites for spring and autumn seasons, as a prelude to multi-year analyses. Findings show considerable divergence in species composition and diversity among sites and season, reflecting differences in salinity, pH, and proximity to the ocean. This approach has great potential for wide-spread use in monitoring programs to assess the diversity of marine plankton communities in conjunction with changing conditions, including ocean acidification, hypoxia, and global temperature rise.

Effects of climate-driven temperature changes on the diversity of freshwater macroinvertebrates

Increasing temperatures due to climate change were found to influence abundance and timing of species in numerous ways. Whereas many studies have investigated climate-induced effects on the phenology and abundance of single species, less is known about climate-driven shifts in the diversity and composition of entire communities. Analyses of long-term data sets provide the potential to reveal such relationships. We analysed time series of entire communities of macrozoobenthos in lakes and streams in Northern Europe. There were no direct linear effects of temperature and climate indices (North Atlantic Oscillation index) on species composition and diversity, but using multivariate statistics we were able to show that trends in average temperature have already had profound impacts on species composition in lakes. These significant temperature signals on species composition were evident even though we analysed comparatively short time periods of 10-15 years. Future climate shifts may thus induce strong variance in community composition.