14
diminishment, increased expression of desiccation-associated proteins, hormone
accumulation, ROS scavenging by antioxidant enzymes and compounds, and osmolyte and protein synthesis. These mechanisms explain the permanence of tolerant
algae species in the upper intertidal zone in comparison with lower intertidal species.
Therefore, this chapter focuses on identifying tolerant algal species, and explaining
the mechanisms underlying the high capacity of these species to cope with desiccation-induced oxidative stress.
Keywords Desiccation • Seaweeds • Tolerance pathways • Ecophysiology • Intertidal
distribution
Contents
2.1 Desiccation Stress Tolerance in Seaweeds: Ecological and Physiological Aspects .......... 14
2.1.1 Early Studies Relating Desiccation Stress to Intertidal Zonation Patterns ............ 15
2.1.2 Differential Buffering Capacities of Seaweeds Against the Overproduction
of ROS and Cellular Damage During Desiccation Stress ...................................... 17
2.1.3 Species of the Bangiales Order as Models for Studying Desiccation
Stress Tolerance and Seaweed Distribution in the Intertidal Zone ........................ 18
2.1.4 Differential Tolerances to Emersion Stressors and the Geographic
Distribution of Seaweeds Across Intertidal Shores ................................................ 19
2.1.5 Perspectives ............................................................................................................ 20
2.2 Molecular Mechanisms of Desiccation Tolerance in Seaweeds ........................................ 21
2.2.1 Decrease of Photosynthetic Activity ...................................................................... 22
2.2.2 Morphological Changes and the Accumulation of Compatible Solutes ................ 23
2.2.3 Increased Expression of Desiccation-Associated Proteins .................................... 24
2.2.4 Increased Antioxidant Activity .............................................................................. 25
2.2.5 Perspectives ............................................................................................................ 26
References ................................................................................................................................... 28
2.1 Desiccation Stress Tolerance in Seaweeds: Ecological
and Physiological Aspects
Macro- and microalgae are the main primary producers in coastal benthic ecosystems, with other organisms in the food web directly or indirectly reliant on algae
(Hurd et al. 2014). Macroalgae provide habitats, refuges against predators or other
physical threats, and recruitment sites, particularly in stressful environments for the
juvenile stages of other algae, fish, and invertebrates (e.g., Wright et al. 2006; Hay
2009; Watt and Scrosati 2013). Therefore, fluctuations in seaweed abundances and
distributions by natural or anthropogenic events can impact higher trophic levels,
affecting the equilibrium and persistence of whole communities. In this context,
understanding the physiological and biochemical mechanisms underlying the local
and regional distribution and abundances of seaweeds in rocky intertidal communities is of great relevance. Furthermore, such information could provide significant
contributions toward the sustainable economic exploitation of algae, in addition to
expanding upon existing scientific knowledge.
L. Contreras-Porcia et al.
diminishment, increased expression of desiccation-associated proteins, hormone
accumulation, ROS scavenging by antioxidant enzymes and compounds, and osmolyte and protein synthesis. These mechanisms explain the permanence of tolerant
algae species in the upper intertidal zone in comparison with lower intertidal species.
Therefore, this chapter focuses on identifying tolerant algal species, and explaining
the mechanisms underlying the high capacity of these species to cope with desiccation-induced oxidative stress.
Keywords Desiccation • Seaweeds • Tolerance pathways • Ecophysiology • Intertidal
distribution
Contents
2.1 Desiccation Stress Tolerance in Seaweeds: Ecological and Physiological Aspects .......... 14
2.1.1 Early Studies Relating Desiccation Stress to Intertidal Zonation Patterns ............ 15
2.1.2 Differential Buffering Capacities of Seaweeds Against the Overproduction
of ROS and Cellular Damage During Desiccation Stress ...................................... 17
2.1.3 Species of the Bangiales Order as Models for Studying Desiccation
Stress Tolerance and Seaweed Distribution in the Intertidal Zone ........................ 18
2.1.4 Differential Tolerances to Emersion Stressors and the Geographic
Distribution of Seaweeds Across Intertidal Shores ................................................ 19
2.1.5 Perspectives ............................................................................................................ 20
2.2 Molecular Mechanisms of Desiccation Tolerance in Seaweeds ........................................ 21
2.2.1 Decrease of Photosynthetic Activity ...................................................................... 22
2.2.2 Morphological Changes and the Accumulation of Compatible Solutes ................ 23
2.2.3 Increased Expression of Desiccation-Associated Proteins .................................... 24
2.2.4 Increased Antioxidant Activity .............................................................................. 25
2.2.5 Perspectives ............................................................................................................ 26
References ................................................................................................................................... 28
2.1 Desiccation Stress Tolerance in Seaweeds: Ecological
and Physiological Aspects
Macro- and microalgae are the main primary producers in coastal benthic ecosystems, with other organisms in the food web directly or indirectly reliant on algae
(Hurd et al. 2014). Macroalgae provide habitats, refuges against predators or other
physical threats, and recruitment sites, particularly in stressful environments for the
juvenile stages of other algae, fish, and invertebrates (e.g., Wright et al. 2006; Hay
2009; Watt and Scrosati 2013). Therefore, fluctuations in seaweed abundances and
distributions by natural or anthropogenic events can impact higher trophic levels,
affecting the equilibrium and persistence of whole communities. In this context,
understanding the physiological and biochemical mechanisms underlying the local
and regional distribution and abundances of seaweeds in rocky intertidal communities is of great relevance. Furthermore, such information could provide significant
contributions toward the sustainable economic exploitation of algae, in addition to
expanding upon existing scientific knowledge.
L. Contreras-Porcia et al.