SURVIVAL AND GROWTH OF THE NONINDIGENOUS AMPHIPOD MELITA PALMATA (MONTAGU, 1804) IN A FUTURE SCENARIO OF OCEAN ACIDIFICATION

MARÍA CIELO BAZTERRICA; FERNANDO JOSÉ HIDALGO; MARTINEZ, LORENA E.; ROBLES, RUBÉN A.

Congreso; XVIII Congreso Latinoamericano de Ciencias del Mar. COLACMAR 2019; 2019

Ocean acidification (OA) is consequence of the increment of atmospheric dissolvedCO2 via anthropogenic activities that affects biological systems having importantecological, evolutionary and management implications. On the other hand, invasivespecies also represent an anthropic problem for conservation of biodiversity sincebiological invasion processes modify natural macrofaunal assemblages. Consideringthat OA might changes population dynamic of invasive species, current knowingpathways of biological invasion processes could change, therefore understand the jointeffects of both processes became relevant for the development of conservationstrategies and management of natural ecosystems. In this context, our objective herewas 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 Ficopomatusenigmaticus (Fauvel, 1923). To that, incubation aquariums of adults M. palmataindividuals were established (range = 20-25 individuals per aquarium under controlledconditions) and new juveniles during a week were collected and separated in cohorts(10 - 18 individuals). Cohorts were randomly assigned to aquariums with brackishwater 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 thatan 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). Meangrowth 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 mortalityand lower mean growth. For NIS species such as M. palmata, with shows plasticityand ability to perceive the environment, the effect of OA could be negative, affecting itsinvasive potential (e.g., the ability to colonize new environments). Our result suggeststhat invasive traits of currently identified as NIS species could be subject to significantchanges under OA predicted future scenario