In this study, changes in the photosynthetic characteristics, pigment content, leaf light absorption, growth and survival of the seagrass Cymodocea nodosa were examined across a range of simulated hypersaline conditions.
Climate-induced changes in air temperature, precipitation and other stressors affect the physical, chemical and biological characteristics of freshwater ecosystems (; ; ). The changes in the characteristics of water affect the growth, productivity and survival of aquatic plant species. The species composition gets altered because of impacts such as habitat loss/transition, shifting ranges and phenological alterations. Aquatic vegetation especially macrophytes are vulnerable to changes in climate. Since, macrophytes represent the keystone species of aquatic ecosystems, hence it becomes essential to study and discuss the effects of on their growth patterns with its possible implications.
Effects of temperature on photosynthesis and ..
Seagrasses grow in salty and brackish (semi-salty) waters around the world, typically along gently sloping, protected coastlines. Because they depend on light for photosynthesis, they are most commonly found in shallow depths where light levels are high. Many seagrass species live in depths of 3 to 9 feet (1 to 3 meters), but the deepest growing seagrass () has been found at depths of 190 feet (58 meters). While most coastal regions are dominated by one or a few seagrass species, regions in the tropical waters of the Indian and western Pacific oceans have the highest seagrass diversity with . Antarctica is the only continent without seagrasses.
Mediterranean Seagrass Growth and Demography …
While previous work has identified effects of PSII herbicides on the photophysiology, biochemistry and growth of seagrass (), there is little reliable quantitative toxicity data for seagrass. Here we applied standard ecotoxicology protocols to quantify the concentrations of four priority PSII herbicides that inhibit photochemistry by 10, 20 and 50% (IC10, IC20 and IC50) over 72 h in two common seagrass species from the GBR lagoon. The time to reach maximum inhibition of photosynthesis by herbicides was also tested using an additional two seagrass species. These data will enable improved assessment of the risks posed by PSII herbicides to tropical seagrass for both regulatory purposes and for comparison with other taxa.
Effects of CO2 enrichment on photosynthesis, growth, …
Terrados, J. and J.D. Ross. 1995. Temperature effects on photosynthesis and depth distribution of the seagrass Cymodocea nodosa (Ucria) Ascherson in a Mediterranean coastal lagoon: the Mar Menor (SE Spain). PSZNI Mar. Ecol. 16: 133-144.
The effects of CO 2 enrichment on seagrasses have ..
Coastal ecosystems exhibit naturally high variability in pH and seawater chemistry due to biological activity, freshwater input, upwelling, atmospheric deposition, and other factors. They are also subject to a diversity of stresses caused by human activities, such as organic matter and nutrient inputs, pollution by toxic organic compounds and metals, acid rain, sea level rise and other climate change effects, and overfishing. The effects of ocean acidification on coastal ecosystems may be small relative to the effects of these natural and human-induced stresses. But in some instances, acidification may act synergistically with other factors (). For example, coastal upwelling is a natural phenomenon that brings deep water to the surface; this water is often undersaturated with respect to calcium carbonate. However, further acidification of these upwelled waters by anthropogenic CO2 uptake may be increasing the intensity and areal extent of these “corrosive” events (Feely et al., 2008). Increased temperature due to climate change is another stressor that is likely to interact with acidification; for example, temperature has been shown to act synergistically with acidification in the development of the Sydney rock oyster (Parker et al., 2009). Another likely interaction is that of increased nutrients and acidification. For example, in kelp forests, it is predicted that local nutrient pollution and increased CO2 will enhance the growth of filamentous algae species while simultaneously decreasing calcifying macroalgae that serve as the understory of kelp forests, thus allowing for a shift from kelp forests to filamentous turf mats (Russell et al., 2009).