Figure 2.

BSi concentration in aboveground Spartina (S. alterniflora and S. patens) as a function of productivity. Using the entire dataset, no relationships were found in the data (R² = 0.05, n = 31). Similarly, no relationships between the variables were found in S. patens (filled circles) (R² = 0.02, n = 9) or non-New England S. alterniflora (R² = 0.21, n = 8) (dashed trend line). However, New England S. alterniflora BSi concentrations showed a significant (p < 0.01, n = 14) positive relationship with productivity (R² = 0.49) (solid trendline). In total these values represent nine marshes: three non-New England marshes (China, France, North Carolina, USA) and six New England marshes. New England data represent average values of triplicate field measurements, with separate points for spring and summer seasons. Individual points representing non-New England marshes either represent distinct seasons (Norris and Hackney, 1999; Hou et al., 2010) or marshes (Querné et al., 2012).