Survival and growth of the nonindigenous amphipod Melita palmata (Montagu, 1804) in a future scenario of ocean acidification.

FERNANDO HIDALGO; BAZTERRICA, M CIELO; ROBLES, RUBÉN; LORENA MARTINEZ

Mar del Plata

Congreso; XVIII Congreso Latinoamericano de Ciencias del Mar; 2019

Universidad Nacional de Mar del Plata, INIDEP

Ocean acidification (OA) is consequence of the increment of atmospheric dissolved CO2 via anthropogenic activities that affects biological systems having important ecological, evolutionary and management implications. On the other hand, invasive species also represent an anthropic problem for conservation of biodiversity since biological invasion processes modify natural macrofaunal assemblages. Considering that OA might changes population dynamic of invasive species, current knowing pathways of biological invasion processes could change, therefore understand the joint effects of both processes became relevant for the development of conservation strategies and management of natural ecosystems. In this context, our objective here was to assess potential direct effects of OA on cohorts of the nonindigenous species (NIS) amphipod Melita palmata from Mar Chiquita coastal lagoon (37°37′29″S, 57°18′16″O) associated with the invader reef building polychaete Ficopomatus enigmaticus (Fauvel, 1923). To that, incubation aquariums of adults M. palmata individuals were established (range = 20-25 individuals per aquarium under controlled conditions) and new juveniles during a week were collected and separated in cohorts (10 - 18 individuals). Cohorts were randomly assigned to aquariums with brackish water with ?current? pH values (ph ~ 8.10; n = 4) and ?predicted? (pH ~ 7.5; n = 4). Mortality and mean growth were assessed weekly during a month. Results show that an increase in the pH of the water increases the mortality of juveniles (mean ?current? mortality: 28.75%, ES = 8.05; mean ?predicted? mortality: 64.85%, ES = 17.15). Mean growth tend to be lower in individuals in water with predicted PH value (mean ?current? size increment: 1.68 mm, ES = 0.07; mean ?predicted? size increment: 1.63, ES = 0.09). Our results showed that an increase in pH resulted in elevated juvenile mortality and lower mean growth. For NIS species such as M. palmata, with shows plasticity and ability to perceive the environment, the effect of OA could be negative, affecting its invasive potential (e.g., the ability to colonize new environments). Our result suggests that invasive traits of currently identified as NIS species could be subject to significant changes under OA predicted future scenario.