responses to sedimentation due climate change of one key Antarctic species.

ALURRALDE, G.; RUIZ MICAELA; SAHADE, RICARDO; SERVETTO NATALIA; CHRISTOPH HELD

Congreso; Congreso Latinoamericano de Ciencias del Mar; 2019

The Antarctic Peninsula has been experienced one of the highest climate change rates of the planet on the last decades. This heating has produced a massive loss of ice-sheet and glaciers retreat. With this, sediment runoff is produced on the water column. This ?sedimentation? process is an important stressor, primary for filter feeders animals (Thrush et al., 2004). In this context, changes have been registered at community scale in the Antarctic benthos, where a shift from a ?filter feeders?ascidian domination? to a ?mixed assemblage? was observed (Sahade et al., 2015). The ascidian Cnemidocarpa verrucosa, is a conspicuous and key species in the Antarctic benthos, being one of the most affected species by a reduction on its abundance over the last 20 years. Using Next Generation sequencing is possible to investigate a wide range of cellular processes, and to identify the early responses to environmental changes. Gene expression analyses can characterize the cellular changes that underlie physiological responses, and find molecular mechanisms that might explain physiological plasticity (Gracey, 2007). The aim of this work is to analyze the response of C. verrucosa to sedimentation through its transcriptome. Animals were exposed to 200 mg/L of sediment. The gene expression profile showed a strong effect of sedimentation on the C. verrucosa response. We found 167 up-regulated and 245 down-regulated differential expressed transcripts (Fold Change ≥ 2; p-value ≤ 0,05). In particular, apoptosis and nucleic acid metabolic process were up-regulated; while response to stress, immune system process and lipid, carbohydrate and protein metabolic process were down-regulated. This is a first approach on the understanding of the molecular response to short-term sedimentation of C. verrucosa, and thus to identify the early responses to Antarctic environmental changes in this benthic assemblage.