Physiological performance of intertidal coralline algae during a simulated tidal cycle

Abstract

Intertidal macroalgae endure light, desiccation, and temperature variation associated with sub-merged and emerged conditions on a daily basis. Physiological stresses exist over the course of the entire tidal cycle, and physiological differences in response to these stresses likely contribute to spatial separation of species along the shore. For example, marine species that have a high stress tolerance can live higher on the shore and are able to recover when the tide returns, whereas species with a lower stress tolerance may be relegated to living lower on the shore or in tidepools, where low tide stresses are buffered. In this study, we monitored the physiological responses of the tidepool coralline Calliarthron tuberculosum (Postels and Ruprecht) E.Y. Dawson and the nontidepool coralline Corallina vancouveriensis Yendo during simulated tidal conditions to identify differences in physiology that might underlie differences in habitat. During high tide, Corallina was more photosynthetically active than Calliarthron as light levels increased. During low tide, Corallina continued to out-perform Calliarthron when submerged in warming tidepools, but photosynthesis abruptly halted for both species when emerged in air. Surprisingly, pigment composition did not differ, suggesting that light harvesting does not account for this difference. Additionally, Corallina was more effective at resisting desiccation by retaining water in its branches. When the tide returned, only Corallina recovered from combined temperature and desiccation stresses associated with emergence. This study broadens our understanding of intertidal algal physiology and provides a new perspective on the physiological and morphological underpinnings of habitat partitioning.

The regulation of coralline algal physiology, an in situ study of <i>Corallina officinalis</i> (Corallinales, Rhodophyta)

“…Our findings indicate that Corallina species are highly tolerant of environmental stress and are well adapted to intertidal habitats, in agreement with previous studies (Williamson et al, 2014;Guenther and Martone, 2014). Photosynthesis, respiration and calcification varied significantly with abiotic stressors and strongly interacted with one another to produce predominantly beneficial outcomes at the level of the organism.…”

Thermal plasticity is independent of environmental history in an intertidal seaweed

“…Much evidence for intertidal stress or reduced physiological performance is derived more from aerial exposure during low tide than from temperature or nutrient excursions in tidal pools (Ji & Tanaka, 2002;Martone, Alyono, & Stites, 2010;McCoy, Pfister, Olack, & Colman, 2016;Mueller, Fischer, Bolch, & Wright, 2015). Within the articulated coralline algae, comparison between a subtidal species and an intertidal species found submerged in tide pools revealed that only the intertidal pool-dwelling species was able to recover from both thermal and desiccation stress (Guenther & Martone, 2014). Additionally, the tide pool-dwelling alga photosynthetically outperformed the subtidal alga under both high-and low-tide conditions, which simulated warming water in pools during low tide (Guenther & Martone, 2014).…”

“…Within the articulated coralline algae, comparison between a subtidal species and an intertidal species found submerged in tide pools revealed that only the intertidal pool-dwelling species was able to recover from both thermal and desiccation stress (Guenther & Martone, 2014). Additionally, the tide pool-dwelling alga photosynthetically outperformed the subtidal alga under both high-and low-tide conditions, which simulated warming water in pools during low tide (Guenther & Martone, 2014). Intertidal algae are generally more productive than subtidal algae during favorable environmental conditions, exhibiting greater photosynthetic activity despite having similar concentrations of photosynthetic pigments (Guenther & Martone, 2014), continuing to calcify at night and when aerially exposed (Egilsdottir et al, 2015;McCoy et al, 2016), and having greater activity of carbon concentrating mechanisms (Murru & Sandgren, 2004;Raven & Osmond, 1992;Stepien, 2015).…”

Interaction of Photoprotective and Acclimation Mechanisms in Ulva rigida (Chlorophyta) in Response to Diurnal Changes in Solar Radiation in Southern Chile

“…Many of these mechanisms involve complex interactions related with different environmental thresholds and it has been recently reported that they operate in cascade along the day (Guenther and Martone , Guajardo et al. ).…”