Arbuszewski Jennifer

No Thumbnail Available
Last Name
Arbuszewski
First Name
Jennifer
ORCID

Filters

2013 - 2019 1 2020 - 2023 1
1 1
2
Reset filters

Settings

Search Results

Now showing 1 - 2 of 2
  • Preprint
    The influence of salinity on Mg/Ca in planktic foraminifers - evidence from cultures, core-top sediments and complementary δ18O
    ( 2013-06) Honisch, Barbel ; Allen, Katherine A. ; Lea, David W. ; Spero, Howard J. ; Eggins, Stephen M. ; Arbuszewski, Jennifer ; deMenocal, Peter B. ; Rosenthal, Yair ; Russell, Ann D. ; Elderfield, Henry
    The Mg/Ca ratio in foraminiferal calcite is one of the principal proxies used for paleoceanographic temperature reconstructions, but recent core-top sediment observations suggest that salinity may exert a significant secondary control on planktic foraminifers. This study compiles new and published laboratory culture experiment data from the planktic foraminifers Orbulina universa, Globigerinoides sacculifer and Globigerinoides ruber, in which salinity was varied but temperature, pH and light were held constant. Combining new data with results from previous culture studies yields a Mg/Ca-sensitivity to salinity of 4.4±2.3%, 4.7±1.2%, and 3.3±1.7% per salinity unit (95% confidence), respectively, for the three foraminifer species studied here. Comparison of these sensitivities with core-top data suggests that the much larger sensitivity (27±4% per salinity unit) derived from Atlantic core-top sediments in previous studies is not a direct effect of salinity. Rather, we suggest that the dissolution correction often applied to Mg/Ca data can lead to significant overestimation of temperatures. We are able to reconcile culture calibrations with core-top observations by combining evidence for seasonal occurrence and latitude-specific habitat depth preferences with corresponding variations in physico-chemical environmental parameters. Although both Mg/Ca and δ18O yield temperature estimates that fall within the bounds of hydrographic observations, discrepancies between the two proxies highlight unresolved challenges with the use of paired Mg/Ca and δ18O analyses to reconstruct paleo-salinity patterns across ocean basins. The first step towards resolving these challenges requires a better spatially and seasonally resolved δ18Osw archive than is currently available. Nonetheless, site-specific reconstructions of salinity change through time may be valid.
  • Article
    North Atlantic cooling triggered a zonal mode over the Indian Ocean during Heinrich Stadial 1
    (American Association for the Advancement of Science, 2023-01-04) Du, Xiaojing ; Russell, James M. ; Liu, Zhengyu ; Otto-Bliesner, Bette L. ; Oppo, Delia W. ; Mohtadi, Mahyar ; Zhu, Chenyu ; Galy, Valier V. ; Schefuß, Enno ; Yan, Yan ; Rosenthal, Yair ; Dubois, Nathalie ; Arbuszewski, Jennifer ; Gao, Yu
    Abrupt changes in the Atlantic meridional overturning circulation (AMOC) are thought to affect tropical hydroclimate through adjustment of the latitudinal position of the intertropical convergence zone (ITCZ). Heinrich Stadial 1 (HS1) involves the largest AMOC reduction in recent geological time; however, over the tropical Indian Ocean (IO), proxy records suggest zonal anomalies featuring intense, widespread drought in tropical East Africa versus generally wet but heterogeneous conditions in the Maritime Continent. Here, we synthesize proxy data and an isotope-enabled transient deglacial simulation and show that the southward ITCZ shift over the eastern IO during HS1 strengthens IO Walker circulation, triggering an east-west precipitation dipole across the basin. This dipole reverses the zonal precipitation anomalies caused by the exposed Sunda and Sahul shelves due to glacial lower sea level. Our study illustrates how zonal modes of atmosphere-ocean circulation can amplify or reverse global climate anomalies, highlighting their importance for future climate change.