Oil bioremediation in salt marsh mesocosms as influenced by nitrogen, phosphorus, and bacterial seeding

Due to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to digital@library.tamu.edu, referencing the URI of the item.Includes bibliographical references.Issued also on microfiche from Lange Micrographics.Glasshouse experiments were conducted to determine the effects of N and P fertilization and bacterial seeding on crude oil degradation in salt marsh mesocosms containing marsh soil and Spartina alterniflora. Fertilization with urea, NH4, and N03 applied at 75 or 150 kg N ha-1 did not enhance oil degradation during 82 d of experimentation in continuously flooded mesocosms during winter (temperature range of 17-30'C). Phosphorus applied at 40 kg P ha-' with or without N significantly enhanced oil degradation during winter. Phosphorus applied alone led to 46% of the applied total petroleum hydrocarbons (TPH) remaining in mesocosms while 57% of the applied TPH remained in the treatment not receiving P. Two slow-release fertilizers containing N and P, Max Bac and Inipol, enhanced oil degradation more than other N fertilizers applied with P. During summer (temperature range of 27-42'C), Max Bac and P applied at 100 kg N ha-' and 40 kg P ha-' did not enhance oil degradation in continuously or alternately flooded mesocosms during the 40 d of experimentation. Continuously flooded mesocosms averaged 28% TPH remaining while alternately flooded mesocosms averaged 49%. Bacterial seeding proved ineffective in enhancing oil degradation. Five commercial bioremediation products did not enhance oil degradation compared to uninoculated controls in continuously flooded mesocosms during 33 d of experimentation during spring (temperature range of 27 42'C) or in alternately flooded mesocosms during 41 d of experimentation during summer. Max Bac and P applied at 100 kg N ha-] and 40 kg P ha-I enhanced oil degradation during spring but not during summer. The use of 15 N techniques during winter revealed that approximately 23% of the applied urea-N and NH4-N was taken up by S. alterniflora compared to 8% of the applied N03-N. Further studies may be needed to assess the effectiveness of N and P fertilization in natural field conditions