Seasonality of foraminiferal flux in sediment traps at Chatham Rise, SW Pacific: implications for paleotemperature estimates

Analysis of sediment traps located either side of the Subtropical Front eas t of New Zealand reveals a strong association between water masses and fora miniferal assemblages, The composition and timing of foraminiferal producti vity is distinct between waters north and south of the front; and these dif ferences are also reflected in the assemblages of nearby care-tops, The sed iment trap data indicate highly seasonal flux patterns in this region, so s edimentary records may represent flux during a particular season, rather th an throughout the annual cycle, This pronounced seasonality has implication s for our estimates of the annual temperature range based on faunal assembl ages, This study shows that despite strong flux seasonality the annual sea- surface temperature (SST) range is reliably estimated from the sediment tra p foraminiferal assemblages by the modern analog technique, The successful estimation of the annual SST range also indicates that the annual flux obta ined from these sediment traps is representative of the longer term flux pr eserved in surface sediments, Care-top assemblages from this region can the refore be directly related to modern sea-surface conditions, providing an a nalogue for interpreting past environmental change from fossil assemblages. (C) 2001 Elsevier Science Ltd, All rights reserved.