Fig. 4

Spider diagrams of arithmetic mean log10 concentrations in July (excluding KA-10) and May shrimp ponds. Slight seasonality is apparent between July and May shrimp ponds irrigated with tidal channels (A), albeit with overlap within 1σ error bars. Concentrations in shrimp ponds normalized to seawater (B), with log10(geometric mean/seawater) instead of arithmetic mean of log10 concentrations, with points above 0 showing relative enrichment and points below 0 showing relative depletion compared to seawater. Two Si values are omitted from the July shrimp pond data because of anomalous negative values