Sea ice diatom contributions to Holocene nutrient utilization in East Antarctica
Panizzo, V; Crespin, J; Crosta, X; Shemesh, A; Masse, G; Yam, R; Mattielli, N.; Cardinal, D. (2014). Sea ice diatom contributions to Holocene nutrient utilization in East Antarctica. Paleoceanography 29(4): 328-342. dx.doi.org/10.1002/2014PA002609 In: Paleoceanography. American Geophysical Union: Washington, DC. ISSN 0883-8305; e-ISSN 1944-9186, more |  |
| Keywords | Bacillariophyceae [WoRMS]; Fragilariopsis curta (Van Heurck) Hustedt, 1958 [WoRMS]; Fragilariopsis cylindrus (Grunow) Krieger, 1954 [WoRMS]; Fragilariopsis kerguelensis (O'Meara) Hustedt, 1952 [WoRMS]
Marine/Coastal | | Author keywords | diatoms; silicon isotopes; diatom bound carbon isotopes; seasonal icezone; Holocene; Southern Ocean |
| Authors | | Top | - Panizzo, V
- Crespin, J
- Crosta, X.
- Shemesh, A
| - Masse, G
- Yam, R
- Mattielli, N., more
- Cardinal, D., more
| |
| Abstract | Combined high-resolution Holocene d30Sidiat and d13Cdiat paleorecords are presented from the Seasonal Ice Zone, East Antarctica. Both data sets reflect periods of increased nutrient utilization by diatoms during the Hypsithermal period (circa 7800 to 3500?calendar years (cal years) B.P.), coincident with a higher abundance of open water diatom species (Fragilariopsis kerguelensis), increased biogenic silica productivity (%BSi), and higher regional summer temperatures. The Neoglacial period (after circa 3500?cal years B.P.) is reflected by an increase in sea ice indicative species (Fragilariopsis curta and Fragilariopsis cylindrus, up to 50%) along with a decrease in %BSi and d13Cdiat (< -18‰ to -23‰). However, over this period, d30Sidiat data show an increasing trend, to some of the highest values in the Holocene record (average of +0.43‰). Competing hypotheses are discussed to account for the decoupling trend in utilization proxies including iron fertilization, species-dependent fractionation effects, and diatom habitats. Based on mass balance calculations, we highlight that diatom species derived from the semi-enclosed sea ice environment may have a confounding effect upon d30Sidowncore compositions of the seasonal sea ice zone. A diatom composition, with approximately 28% of biogenic silica derived from the sea ice environment (diat-SI) can account for the increased average composition of d30Sidiat during the Neoglacial. These data highlight the significant role sea ice diatoms can play with relation to their export in sediment records, which has implications on productivity reconstructions from the seasonal ice zone. |
|
