C/N mass ratios remain constant throughout MIS 3 and into MIS 2, with values between 6.3 and 8.9, indicating no significant terrestrial input of organic matter (Fig. 3). Low %TOC values during the interstadial increase from 0.4 to 0.7 between 57.8 and 43.7 kyr BP with a concurrent gradual increase in δ13C(organic) amid oscillations between −23.2‰ and −26.1‰ (Fig. 3). %TOC falls to 0.4 between 40.9 and 39.4 kyr BP whereas δ13C(organic) remains high at c. 24‰ with a peak value of −23.6‰ at 39.4 kyr BP. The subsequent two-stage increase in %TOC from 39 to 37.9 kyr BP and between 37.3 and 36.9 kyr BP is marked by a period of δ13C(organic) lowering to c. −26.6‰ before δ13C(organic) increases after 37.9 kyr BP to −24.8‰, values comparable to those prior to the %TOC decline at 40.9 kyr BP.
During 16 months of deployment, 239 g m−2 dry matter settled in the 40-m trap, with an average flux of 14.9 g m−2 month−1 (Table 2 and Fig. 2). The content of organic carbon was 21.9% at that depth and that of total nitrogen 1.6% (Table 2 and Fig. 2). The resulting atomic C/N ratio of 15 indicated that the sedimented material resulted from the autochthonous production by suspended phytoplankton and that terrigenous input is likely to be negligible at that site. The amount of pigments gathered during the 16 months deployment in the 40-m trap was 193.1 μmol m−2 for chlorophyll a and 797 μmol m−2 for chlorophyllide a+pheopigment a. The average flux was hence 61.8 μmol m−2 month−1 settled chlorophyll a+chlorophyllide a+pheopigment a (Table 1). It is worth noting that the replicate samples of the 40-m trap deviated strongly (coefficient of variation: 60.5%), whereas the coefficients of variation for the replicate samples in the traps