Phosphorus flux from sediment reporting

Would it be possible to check your code on the EFDC Explorer reporting of sediment fluxes? I’m getting some odd results. I would expect that SOD would generally be a positive number, and that during periods of water column anoxia I would see positive numbers for fluxes of ammonia and phosphate from sediments, with smaller or negative fluxes (to sediments) during oxygenated periods. In my model, EFDC Explorer reports negative SODs, and, typically, small but negative phosphate fluxes (from water column into the sediment?), with the flux becoming larger and more negative during anoxic periods. Organic phosphorus flux, which I would expect to be usually negative (settling to sediments) is in fact almost always positive. On the other hand, ammonia flux is generally positive and exhibits the expected inverse relationship with DO in the bottom layer. I am using EFDC+ with EFDC Explorer 8.2.5, and the full diagenesis model. Thanks

Hi Kirk, For SOD values, the sign convention is + into the water column and - out (i.e., to the bed). Technically, SOD is actually the O2 flux, so the signs are the same as the other fluxes. That said, SOD definition is already the “from the water column to the bed”. We keep it that way to eliminate confusion when manually specifying fluxes. Please let us know if this sign convention helps you understanding to interpret what’s going in your model.Best, Janesh Devkota