We have reconstructed temperature and salinity in a Holocene marine sediment record (8000-1600 cal yr B.P) from the high-latitude Malangenfjord, northern Norway. These results are based on 32 Mg/Ca ratios and 178 oxygen isotope measurements. Sediment samples from almost every 1 cm were picked for stable isotope measurements and thus sample resolution varies between 1 and 198 years with an average of 39 years. Mg/Ca content was measured on the benthic foraminifera Cassidulina neoteretis where values ranged from 1.08 to 1.63 mmol/mol. We transformed these data to paleotemperatures using a monospecific exponential equation. Results imply that temperatures of bottom water in Malangenfjord (Atlantic water) have varied by at least 3ºC during the Holocene with a gradual cooling throughout the whole period. Corresponding benthic foraminiferal oxygen isotope measurements indicate the same trend. Using these Mg/Ca-temperature estimates and benthic 18O-temperature estimates records of bottom water 18O and salinity have been calculated.

Temperature reconstructions from 7600-5000 cal. yr BP show high bottom water temperatures (5-7ºC), however temperatures do decline in this period showing a continuing cooling and superimposed on this trend are four visible cooling periods. Bottom water temperatures were evidently similar to modern instrumental values. Other proxies in JM98-1PC show that the Malangenfjord was dominated by water masses with similar characters as today ((Hald et al., 2003; Husum, 2004). For instance the benthic foraminifera species from this period are found in the fjord today and the dominating dinocyst (Operculodinium centrocarpum) reflecting AW shows a marked maximum appearance at 6000 cal yr BP (Hald et al., 2003). The events of colder conditions that interrupted this warm period show that temperature drop as much as 1ºC within 100 years. Reconstructed salinity values (34-35‰) are in good agreement with present day values.

A temperature and salinity decline at ~5000 cal yr BP is interpreted as a possible oceanographic regime shift with decreased inflow of warm AW and increased inflow of Norwegian Coastal water into the Malangenfjorden. This increase in NCW is synchronized with a decline in the dinocyst Operculodinium centrocarpum (Hald et al. 2003) often associated with AW and shifts in hydrography and is also reflected in the benthic foraminiferal fauna with an increase in the Arctic Elphidium excavatum f. clavata towards 2100 cal. yr BP (Hald et al., 2003; Husum and Hald, 2004). Another cooling event is recorded at 4400-4200 cal yr B.P. which previously has been recorded from other proxies ((Bond, 1997; Hall et al., 2004; Oppo et al., 2003). At 3700-3600 and 3500-3300 cal yr B.P. decreases in temperature are observed. The Late Holocene JM98-1 PC record shows a clear cooling trend from ~2800-2100 cal yr B.P with distinct events at 2850-2750, 2650-2550 and 2300-2100 cal yr B.P