Stress Tolerance in Intertidal Seaweeds

Abstract

Intertidal seaweeds are periodically exposed to air where they experience a variety of potentially stressful environmental conditions, including nutrient limitation, high light, high and low temperature, desiccation, and osmotic stress. This paper considers the current understanding of stress tolerance in intertidal seaweeds and discusses ways in which future research could increase our understanding of the role of environmental factors in the ecology and physiology of these algae. We believe research is required in at least three areas. 1) Laboratory physiological studies have established that correlations exist between stress tolerance and the vertical distribution of species. However, little information is available on the importance of stress in determining community structure in nature. Field experiments are essential to relate the impact of single or multiple stresses on the survival, growth, and reproductive output of macroalgae. In paticular, it is necessary to clarify the role of sublethal stress in determining the outcome of competitive interactions. 2) With the exception of obvious lethal effects or damage associated with extreme environmental conditions, such as unusually hot and dry weather, it is difficult to evaluate the occurrence and severity of stress in natural populations of seaweeds. There is a need to develop molecular and biochemical markers specific for individual stresses or groups of stresses to allow the unambiguous and direct determination of stress in situ. 3) Despite the apparent importance of stress in intertidal seaweeds, we are largely ignorant of the mechanistic basis of tolerance. The application of currently available tools of molecular and cell biology to the investigation of stress‐induced transcriptional and translational changes could enormously increase our understanding of both the sites of, and pathways involved in, stress tolerance. In summary, there are numerous unanswered fundamental questions about the stress tolerance of intertidal seaweeds, providing opportunities for research ranging from field ecology to molecular biology and biochemistry.

Understanding the intertidal zonation of two estuarine red macroalgae fromex situphotoacclimative responses

“…7), its greater independence from external nutrient supply and higher uptake rates for NH 4 + , the major N source in the estuary (Sánchez de Pedro et al, 2013). This would support the hypothesis proposed by Davison & Pearson (1996), that abiotic stress can affect macroalgal distribution by modifying interspecific relationships. In our study both species would directly compete for the available substrate in the intermediate zone, where light conditions are optimal for the growth of both species (Fig.…”

Evolution and diversification within the intertidal brown macroalgae Fucus spiralis/F. vesiculosus species complex in the North Atlantic

“…One of the commonly occurring intertidal fucoids, and usually confined to the upper intertidal of rocky shores, is the desiccation-resistant (Davidson and Pearson, 1996), hermaphroditic and mainly self-fertilizing F. spiralis Perrin et al, 2007). Along eastern Atlantic shores in the northern hemisphere, F. spiralis (sensu lato) ranges from northern Norway to the Azores and Canary Islands, the latter being the southern-most record for the genus (Lüning, 1990;Haroun et al, 2002).…”

Fucus vesiculosus and spiralis species complex: a nested model of local adaptation at the shore level

“…In Fucus species co-occurring along intertidal gradients, upper-shore F. spiralis recovers better from desiccation (Dring & Brown 1982) and from exposure to more extreme high and low temperatures (Chapman 1995, Davison & Pearson 1996 vesiculosus recovers better from temperature stress than lower-shore F. serratus, although in the latter the recovery capacity is even further diminished at the warmer edge of the distributional range (Pearson et al 2009). Species from the upper shore also tend to have greater physiological performance at low tide while still hydrated (Skene 2004).…”