Seaweed Responses to Temperature

Abstract

"Why don't seaweeds spread beyond their present boundaries along an uninterrupted rocky coastline?", asked Breeman in 1988. Two principal aspects play a central role in shaping biogeographical distribution patterns: temperature-dependent effects on performance (e.g., growth, photosynthesis) and temperature tolerance (i.e., survival). The temperature responses of species are often correlated with the local thermal environments, i.e., species are locally adapted, but may vary seasonally or among populations or life stages due to phenotypic plasticity. Accordingly, it is necessary to differentiate three types of temperature responses: (1) genetic adaptation to local conditions, (2) phenotypic acclimation in response to variation of environmental conditions, and (3) short-term physiological regulation. The responses take place over different timescales: seconds to minutes (regulation), hours to days (acclimation), and up to thousands of millions of years (adaptation). This chapter reviews the temperature responses of seaweeds and their biogeographical implications. Local Temperature Adaptation of Growth and PhotosynthesisThe effect of temperature on performance traits, such as growth and photosynthesis, is typically visualized using temperature-response curves. Both growth and photosynthetic rates of seaweeds increase with temperature, plateau at a maximal level, A. Eggert (*)

Temperature tolerance of western Baltic Sea Fucus vesiculosus – growth, photosynthesis and survival

“…Different lowercase letters indicate significantly different means (p b 0.001; one-way ANOVA with post hoc Tukey's test). oxygen species), elaborate repair mechanisms, or damages to membranes and enzymes after prolonged exposure to high temperatures (Davison and Pearson, 1996;Eggert, 2012;Weidner and Ziemens, 1975) which may need longer recovery times than applied here. Furthermore, the time-scale of disruptive stress is relevant as organisms may cope temporarily with strong temperature stress if acting only for hours and subsequently may recover from damage at optimal conditions (Eggert et al, 2003).…”

“…Not only temperature limits but also sub-lethal conditions may cause stress by impairing physiological repair mechanisms or by inducing accumulation of harmful intermediates (Davison and Pearson, 1996;Weidner and Ziemens, 1975). Consequently, if temperature becomes stressful enzymatic functions and membrane structures can be impaired (reviewed in Eggert, 2012), which may cause severe perturbations in organismal physiology and performance.…”

Seasonal variation in floating persistence of detached Durvillaea antarctica (Chamisso) Hariot thalli

“…This allows thalli to quickly recover from stress via adjustment of pigment concentrations, dynamic photoinhibition and/or repair mechanisms (Franklin and Forster 1997, Bischof et al 1998a, 1999, G ó mez et al 2004, Edwards and Kim 2010. Thus, within the tolerance range of algae (e.g., during fall or spring conditions in many temperate regions), physiological acclimation may operate efficiently (Eggert 2012 ), thereby enhancing the persistence of floating algae at the sea surface. Each algal species has a specific temperature range within which the expression of photoprotective mechanisms is most effective ( H ä der andFigueroa 1997 , Eggert 2012 ), thereby enhancing the possibility of persistence for protracted periods at the sea surface.…”

The importance of phenotypic plasticity and local adaptation in driving intraspecific variability in thermal niches of marine macrophytes

“…We found no studies utilising NGS genome scans to identify candidate loci under selection in relation to temperature, or indeed any other environmental gradient. This is surprising as macrophytes are known to form a number of different environmental ecotypes (Eggert 2012, Karsten 2012) and searches for adaptive signatures have been conducted in both seagrass and seaweed research. For example, loci attributed to osmoregulation and desiccation have been identified as candidate genes under selection using pre NGS genome scans along depth and salinity gradients (Oetjen andReusch 2007, Coyer et al 2011a, b).…”