Physiological and biochemical responses of marine invertebrates to changing thermal and nutritional conditions

Abstract

Adaptive physiological responses of marine ectothermic invertebrates to changing thermal and/or nutritional conditions in coastal habitats of Korea were determined by measuring filtration, feces production, ammonium excretion, respiration rates, and scope for growth. A comparison between physiological and proteomic responses was firstly attempted to highlight an interaction between physiological responses and cellular-level molecular processes. Seasonal changes in gross biochemical composition and gametogenic development were applied to monitor biological cycles. The gross biochemical composition and stable isotope ratios of separated organs were also combined to understand the energy-storage allocation strategy in association with reproductive success for survival. A high degree of physiological plasticity allows Ruditapes philippinarum to tolerate the wide range of temperatures and seston concentrations in tidal flats. Modulation of physiological traits and protein expression during semidiurnal thermal fluctuations buffers Haliotis discus hannai from the lethal consequences of extreme temperatures around the tidal front in summer. The gametogenic development of Scapharca subcrenata and Tegillarca granosa has accelerated synchronously with an accumulation of surplus energy as a result of physiological performance to warmer winters and spawning has advanced by at least 1-3 months in the past decade. The newly introduced Argopecten irradians adapted to new environments and keep an intrinsic trait of fast growth and reproductive success through a slight modification of adaptive strategy for survival from the native US populations. Overall, these results suggest that warming of the sea would result in a modification in biological cycles of some species but benefit to others. Furthermore, this change should facilitate settlement of tropical or subtropical species in the temperate coast of Korea, emphasizing the importance of further physiological approaches to better understand biological processes in changing marine ecosystem.