CPPB-aE (132,173-cyclopheophorbide-a enol) in sediments - A potential proxy of oxygen deficiency in near-bottom water

The labile degradation product of chlorophyll-a - 132,173-cyclopheophorbide-a enol (CPPB-aE) - has been found in considerable amounts (up to 380 nmol/g d.w.) in marine sediments from the Gdańsk Deep (southern Baltic Sea) and in hypoxic/anoxic sediments from the Oslofjord/Drammensfjord (up to 371 nmol/g d.w.). A modified version of HPLC-DAD analysis with a lower column temperature (10 °C) significantly improved separation of this compound. The results of this work show that the presence of CPPB-aE in sediments, owing to its instability under oxic conditions, may be a biomarker of oxygen deficiency in near-bottom water.