The stressful life of red and brown seaweeds on the temperate intertidal zone: effect of abiotic and biotic parameters on the physiology of macroalgae and content variability of particular metabolites

Abstract

Abstract Most marine macroalgae live attached to a substrate in coastal areas characterized by a very variable environment mainly due to the tide cycle which is more or less important depending on the geographical situation. Macroalgae spread over coastal zones according to their resistance to several abiotic and biotic factors. Some species are thus present on intertidal zones and are outside the water for a more or less long time each day; on the other hand, others are always underwater if they are living in the subtidal zone or in pools in which abiotic parameters can be strongly modified during a tide cycle. During these alternating immersion/emersion phases, macroalgae deal then with important modifications of many abiotic parameters, such as light, temperature, salinity, and biotic parameters, such as grazing, fouling, pathogens. To counteract these important variations, intertidal macroalgae develop resistance mechanisms such as the synthesis of special compounds, like photoprotectors, osmolytes, antifouling molecules as examples. In this chapter, after a presentation of the main environmental parameters facing intertidal seaweeds in temperate environment, some adaptation/protection mechanisms of these algae are presented, with an emphasis on brown (structural species whose biomass is very high on intertidal zones) and red seaweeds (whose diversity is very high).