The Vertical Flux of Organic Matter in the Öresund Estimated by Two Different Methods Using Oxygen Measurements

The vertical flux of organic matter out of the euphotic zone, the net or export production, is computed using two independent methods which both make use of repeated standard hydrographical measurements. The first method utilizes the close relationship between the vertical flux of organic matter into the water mass beneath the euphoric zone and the rate of oxygen consumption in this water mass. The oxygen consumption is computed from repeated hydrographical observations. The second method is based on an oxygen budget for the euphotic zone. From this the net production may be computed. The two methods are applied to the Öresund and it is found that they give quite similar estimates of the annual mean flux of organic matter out of the euphotic zone.