We use a 27 year long time series of repeated transient tracer observations (CFCs, SF6) along the Prime Meridian and across the Weddell Sea to investigate changes in ventilation and anthropogenic carbon (Cant) storage in deep and bottom water in the Weddell Sea. Applying the Transit Time Distribution (TTD) method we find that all deep water masses in the Weddell Sea grew older and less ventilated. The decline of the ventilation rate of Weddell Sea Deep and Bottom Water seems to be mainly caused by mixing with Warm Deep Water, which aged even faster As a consequence of the aging, the Cant increase in the deep and bottom water formed in the Weddell Sea slowed down over the period of observations. Part of the observed deep and bottom water warming might also be caused by this process.