Sedimentation flux from mariculture of oyster C

Authors: Hayakawa Y Kobayashi M Izawa M

Publish Date: 2001/01/01

Volume: 58, Issue: 2, Pages: 435-444

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Abstract

Seasonal patterns of Chl a in water samples sedimentation rates total dry weight per area per day and content of total carbon total nitrogen and total phosphorus in sediment trap samples as well as in sediment samples were measured at several stations in Ofunato estuary Japan High rates of sedimentation to the bottom were observed in March and September corresponding to elevated concentrations of Chl a In the middle part of the estuary the peaks of sedimentation rate and fluxes of chemical elements through the 20m deep layer in September amounted to 23 g m −2 d −1 2200 mg C m −2 d −1 290 mg N m −2 d −1 and 28 mg P m −2 d −1 coinciding with oxygen depletion in deeper layers Seasonal changes in sedimentation can be explained by marked increases in biodeposits from oysters cultured in the surface layers However no marked seasonal changes in chemical elements were found within the sediment suggesting high degradation rates of biodeposits at the sedimentwater interface Biodeposits from culture rafts were estimated using a population dynamic model for the Japanese oyster This model gave predictions in agreement with observed seasonal changes in biodeposition fluxes through the 20m layer in September with a minimum estimation of 51 g m −2 d −1 with uniform seawater dispersion and a maximum estimation of 390 g m −2 d −1 without dispersion

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