『Abstract
A new mass balance model for the coupled marine cycles of phosphorus
(P) and carbon (C) is used to examine the relationships between
oceanic circulation, primary productivity, and sedimentary burial
of reactive P and particulate organic C (POC), on geological time
scales. The model explicitly represents the exchanges of water
and particulate matter between the continental shelves and the
open ocean, and it accounts for the redox-dependent burial of
POC and the various forms of reactive P (iron(III)-bound P, particulate
organic P (POP), authigenic calcium phosphate, and fish debris).
Steady state and transient simulations indicate that a slowing
down of global ocean circulation decreases primary production
in the open ocean, but increases that in the coastal ocean. The
latter is due to increased transfer of soluble P from deep ocean
water to the shelves, where it fuels primary production and causes
increased reactive P burial. While authigenic calcium phosphate
accounts for most reactive P burial ocean-wide, enhanced preservation
of fish debris may become an important reactive P sink in deep-sea
sediments during periods of ocean anoxia. Slower ocean circulation
globally increases POC burial, because of enhanced POC preservation
under anoxia in deep-sea depositional environments and higher
primary productivity along the continental margins. In accordance
with geological evidence, the model predicts increased accumulation
of reactive P on the continental shelves during and following
periods of ocean anoxia.』
1. Introduction
2. Model description
2.1. Water cycle
2.2. C, O2 and P cycles
2.3. Water column biogeochemical dynamics
2.4. Redox-dependent burial of reactive P and organic C
2.5. Equivalent 1-box ocean model
2.6. Numerical solution
3. Results and discussion
3.1. One-box ocean models
3.2. One- versus four- box ocean models
3.3. Coastal versus oceanic upwelling
3.4. Off-shelf transport of particulate matter
3.5. Redox-dependent P burial
3.6. Transient response to decreased oceanic circulation
4. Conclusions
Acknowledgements
References