ProjectBIOCAN-2 Tübingen – Winter particle fluxes from the oxygen-minimum zone OMZ area off Pakistan: description and…

Basic data

BIOCAN-2 Tübingen
Winter particle fluxes from the oxygen-minimum zone OMZ area off Pakistan: description and correlation of water column and sediment results
15/09/2023 to 15/10/2026
Abstract / short description:
Due to the lack of bioturbation, the varve-laminated muds from the oxygen-minimum zone OMZ (Oxygen Minimum Zone = SMZ Sauerstoff Minimum Zone) off Pakistan provide a unique opportunity to precisely determine the vertical and lateral sediment fluxes in the nearshore part of the northeastern Arabian Sea. The high flux of biogenic matter originates from enhanced primary productivity in monsoonal upwelling areas and from the preservational effects from lateral southern to western inflow of oxygen depleted water masses. The role of suspended matter eventually mobilized along the steep eastern and northern slopes of Pakistan during winter, adding to the high vertical flux directly or indirectly (through ballasting effects), however, is hardly known and difficult to estimate. In addition, we face the variable lateral input of the Indus River.
Our present understanding of the winter processes are mainly based on only four sediment trap observations providing longer periods of in-situ observations from the OMZ: the traps off the steep Makran continental slope document exceptionally high, pulsed winter fluxes of up to 5000 mg m−2 d−1, when compared to the summer fluxes in the water column. Based on sediment core results, sedimentary flux at the seafloor amounts to the same magnitude, pointing to the importance of these winter events.
Teilprojekt (TP 5 e.g. Hauptantrag Gaye) of cruise SONNE303 (20.01.2024-16.02.24) is entirely dedicated to these winter OMZ conditions and processes. For the first time, the winter water column (+the underlying sediments) will be sampled extensively by vertical plankton tows, CTD-casts, fluorescence probes, in-situ pumps filtrates, and (ultra-)filtration of bottle waters from within, above and below the OMZ. An intense geochemical, granulometric and (electron)microscopic program (ultra-sieving, FlowCAM, BET) in combination with advanced microanalytical techniques (SEM/EDX, TEM, CRYO FIB-SEM) is proposed. The aim of the TP sampling is to investigate the shape, mass and chemistry of the biogenic and lithogenic settling and sedimentary particles, and their (OMZ-)modifications. The unique laminated sediments deposited in the OMZ on the continental slope will be sampled and analyzed similarly in order to better understand sediment varve formation and to better reconstruct Holocene climate in high resolution, comparable to that of terrestrial archive and climate data sets. The Tübingen group also contributes with sediment core storage and with the main instrumentation for sediment sampling by gravity coring and multi-coring, that are essential running the geological programme on board SO303.
OMZ, Partcle Flux, Monsun, Arabian Sea

Involved staff


Department of Geoscience
Faculty of Science

Other staff

Department of Geoscience
Faculty of Science
Department of Geoscience
Faculty of Science

Local organizational units

Department of Geoscience
Faculty of Science
University of Tübingen


Bonn, Nordrhein-Westfalen, Germany

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