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Title: Storage and cycling of organic carbon and nutrients in Holocene coastal sediments
Author: Parkes, Duncan James.
ISNI:       0000 0001 3471 8748
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2003
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Geochemical analyses of Holocene coastal sediments from eastern England were made to better understand the cycling of organic carbon and nutrients in the coastal zone in the past, present and future. Sediments and peat were deposited in freshwater marshes, saltmarshes and intertidal mud- and sand-flat environments that were much more extensive during the Holocene than they are at present. The reduction in these areas, largely through human activities, has decreased the potential annual accumulation and storage of organic carbon, nitrogen and phosphorus associated with sediments. While the carbon and nitrogen contents of modem intertidal environments are similar to Holocene intertidal areas, phosphorus is enriched in modem sediments by up to a factor of two. Budgets of nitrogen and phosphorus cycling in Fenland, eastern England, suggest that the Holocene estuaries in this area were sinks of nutrients from the North Sea despite nitrogen isotopic evidence suggesting that nitrogen buried in freshwater marshes was predominantly terrestrially derived. The present-day estuaries are sources of nutrients to the North Sea as riverine loads and atmospheric deposition are much higher than during the Holocene and sedimentation is also greatly reduced. The southern North Sea is probably autotrophic, in contrast to the coastal zone global average which is heterotrophic. The major differences between these two areas are: 1) the global coastal zone receives much greater loads of riverine particulate matter than the southern North Sea, and 2) sedimentation in the global coastal zone occurs in large river deltas which are absent from the relatively small European estuaries, thus much of the sediment supplied to the North Sea is exported to the shelf edge. Approximately 4x 109 t C, 0.3 x 109 tN and 0.1 x 109 tP are currently stored in fine-grained Holocene sediments in the southern North Sea coastal zone.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available