Population dynamics of Cymodocea nodosa under future ocean scenarios.

Abstract

Rising carbon dioxide (CO 2 ) concentrations in the atmosphere will increase the average pCO 2 level in the world oceans, which will have a knock-on effect on the marine ecosystem.Coastal seagrass communities are predicted to benefit from the increase in CO 2 levels, but long-term effects of elevated CO 2 on seagrass communities are less understood. Population reconstruction techniques were used to investigate the population dynamics of Cymodocea nodosa meadows, exposed to long term elevated CO 2 at volcanic seeps off Greece and Italy.Effect of elevated CO 2 was noticed on the growth, morphometry, density, biomass and age structure at CO 2 seeps than reference sites. Above to below ground biomass ratio of C. nodosa were higher at CO 2 seeps. The shoot age and shoot longevity of plants were lower at seeps. The present recruitment (sampled year) of the seagrass were higher than long-term average recruitment of the communities near the seeps. Carbon to nitrogen ratios (%DW) and annual leaf production of C. nodosa were higher in leaves at seeps. This study suggests under long-term CO 2 enrichment C. nodosa production increases, but the plant survival rate decreases because of other co-factors such as nutrient availability and trace metal toxicity.Therefore, along with high CO 2 other factors must be taken into consideration while predicting effects of future CO 2 concentrations.

Instability and Stasis Among the Microbiome of Seagrass Leaves, Roots and Rhizomes, and Nearby Sediments Within a Natural pH Gradient

“…It should be noted that our study, however, differed from Ettinger et al (2017) in number of samples, sample processing (extraction kit and vortex period), primer selection ("universal" 515F and 806R), and sequencing depth. Mishra (2018) found an increase in the above to below-ground biomass ratio with increased pCO 2 levels for C. nodosa at volcanic seeps in Greece and Italy, suggesting a greater impact of environmental factors on the below-ground ecology for this species of seagrass. The altered below-ground ecology in Mishra (2018) was also associated with a decline in C. nodosa survivability with increasing pCO 2 due to reduced nutrient availability and soil toxicity [62].…”

“…Mishra (2018) found an increase in the above to below-ground biomass ratio with increased pCO 2 levels for C. nodosa at volcanic seeps in Greece and Italy, suggesting a greater impact of environmental factors on the below-ground ecology for this species of seagrass. The altered below-ground ecology in Mishra (2018) was also associated with a decline in C. nodosa survivability with increasing pCO 2 due to reduced nutrient availability and soil toxicity [62]. However, differences in microbial communities among sites may not always be detrimental and may simply be a result of local adaptation to environmental conditions.…”