Quantitative reconstruction of primary productivity in low latitudes during the last glacial maximum and the mid-to-late Holocene from a global Florisphaera profunda calibration dataset. (1st February 2019)

• Record Type: Journal Article
• Authors: Hernández-Almeida, I.; Ausín, B.; Saavedra-Pellitero, M.; Baumann, K.-H.; Stoll, H.M.
• Is Part Of: Quaternary science reviews. Volume 205(2019)
• Page Start: 166
• Page End: 181
• Publication Date: 2019-02-01
• Subjects: Global calibration -- Paleoceanography -- Holocene -- Last Glacial Maximum -- Carbon cycle -- Biogeography -- Paleoecology -- Coccolithophores -- Ocean net primary productivity -- Quantitative reconstruction; Geology, Stratigraphic -- Quaternary -- Periodicals; Stratigraphie -- Quaternaire -- Périodiques; 551.79
• DOI: 10.1016/j.quascirev.2018.12.016
• Languages: English
• ISSNs: 0277-3791

Abstract

Abstract: Ocean net primary productivity (Npp) is a key component of the marine carbon cycle. Multi-model Npp projections based on a few decades of satellite data show large uncertainties, in particular at low latitudes (30°N−30°S). Calibration of sedimentary proxies with satellite-based Npp estimates allows for the quantitative reconstruction of this variable at longer time-scales. Relative abundance of deep-photic zone coccolithophore species Florisphaera profunda in the fossil record can potentially be used as a quantitative proxy for Npp. However, the robustness of this proxy calibration has been tested in very specific oceanographic settings using surface sediment samples. Here, we use a global dataset of surface sediment (n = 1258) and sediment trap (n = 26) samples with relative abundance data of F. profunda (%) to test the robustness of this proxy as a quantitative indicator of Npp. We study the modern and paleo-ecology of this species and the main factors affecting its latitudinal distribution. Results show that F. profunda % is a strong indicator of Npp at latitudes between 30°N and 30°S, while at higher latitudes temperature-related variables are more important. We develop a global calibration model between satellite Npp estimates and F. profunda for the latitudinal range between 30°N and 30°S, and we apply it to several low-latitude sediment cores with available F. profunda counts covering the Late Glacial Maximum (LGM; 24–19 ka) and the Mid-to-Late Holocene period (MLH; <6 ka). Reconstructed Npp during the LGM is 15% higher than during the MLHdue to the intensification of trade winds that enhanced oceanic upwelling at low latitudes. Highlights: An extensive new modern and fossil global dataset of Florisphaera profunda relative abundances. F. profunda % show strong correlation to net primary productivity (Npp) only at low latitudes. Temperature control of F. profunda at high latitudes does not warrant its use as Npp indicator. F. profunda -Npp calibration allows quantitative reconstruction of past ocean productivity. Reconstructed Npp at low latitudes is 15% higher during the LGM than the MLH.