Diel patterns in a Posidonia meadow: measuring molecules to macrophytes

Posidonia oceanica is an important habitat forming seagrass in European waters. Understanding how P. oceanica copes with environmental change provides an important baseline for future management of these meadows. Of the... [ view full abstract ]

Posidonia oceanica is an important habitat forming seagrass in European waters. Understanding how P. oceanica copes with environmental change provides an important baseline for future management of these meadows. Of the natural environmental variables, diel changes in light intensity plays a major role in meadow photosynthetic or respiratory performance. Similarly, seasonal changes also strongly influencing net productivity or respiration. The attenuation of light with depth also plays an important role on Posidonia performance. Seagrasses more suited to low light environments are potentially better able to achieve net photosynthesis even when daylength is short. We examined a range of protein and genetic attributes of Posidonia oceanica samples collected at various times of day and different depths with accompanying physiological measurements including gas exchange and fluorescence-based measurements. Direct comparisons of genes representing specific physiological processes such as photosynthesis and respiration provided clear patterns where some genes were switched on under high light environments and others only at night. The direct comparison of molecular and traditional physiology methods provides an important link between these two approaches, enabling researchers to infer likely patterns in one area of measurement to indicate the other.