Benjamin Eickmann

Se colectan muestras de diferentes microorganismos de las chimeneas de cerro Machin. A partir de lo anterior, se hará un estudio de las características físicas de los lípidos de los diferentes microorganismos recolectados. 

Se colectan muestras de diferentes microorganismos de las chimeneas de cerro Machin. A partir de lo anterior, se hará un estudio de las características físicas de los lípidos de los diferentes microorganismos recolectados. 

Se colectan muestras de diferentes microorganismos de las chimeneas de cerro Machin. A partir de lo anterior, se hará un estudio de las características físicas de los lípidos de los diferentes microorganismos recolectados. 

Se colectan muestras de diferentes microorganismos de las chimeneas de cerro Machin. A partir de lo anterior, se hará un estudio de las características físicas de los lípidos de los diferentes microorganismos recolectados. 

In order to obtain a more refined understanding of Earth’s oxygenation and the link between the co-evolution of life and the ocean-atmosphere system through time, this project focusses on the following work packages (WP):  WP-1 aims to identify potential Se-based microbial activity in Archean stromatolites that, in analogy to sulfate, can be linked to the presence of oxidized Se species in the aqueous environments. Here, the PI selected Paleoarchean stromatolites from, the 3.48 Ga Dresser Formation, the 3.4 Ga Strelley Pool Formation and from the 2.7 Ga Tumbiana Formation (all Pilbara Craton, Western Australia). The three sample sets were selected because they represent different geological settings, including a caldera (10), a shallow-marine setting (8) and a lake (9). Consequently, this WP aims to compare the isotopic signatures in all three settings and tests whether Se-based microbes already evolved in the Paleoarchean and if such organisms were probably restricted to certain environments.  WP-2 focusses on the transient oxygen fluctuations prior to the GOE by combining Se and multiple S isotopes on the 2.7 Ga Carajás Formation. The black shales yield heavy Mo isotope values that would indeed result from a transient “whiff of oxygen”, similar to other Neoarchean sediments, but could also result from hydrothermal overprinting (14). Combined Se and multiple S isotope studies will help to distinguish between both scenarios. Moreover, the results of WP-2 will also help to interpret the Se and multiple S isotope data of Tumbiana stromatolites of WP-1 and to discriminate between different abiogenic and biogenic processes.      WP-3 investigates the Se and multiple S isotopic composition of carbonaceous and pyrite-bearing shales of the Serra do Garrote Formation (Vazante Group) in the San Francisco Craton (central Brasil). The age of this formation is highly debated and ranges from upper-Mesoproterozoic to Cryogenian, but has been mostly likely deposited during the early Neoproterozoic (15). This time period is characterized by a second oxygenation step during the Neoproterozoic Oxidation Event (GOE), records major climatic changes and marks the time before the Cambrian Explosion (16).  WP-4 aims to reconstruct the paleoenvironmental conditions of the poorly studied Lower Cretaceous Paja Formation, which is a key sedimentary succession in Colombia and records two subsequently following oceanic anoxic events (OAE 1a and OAE 1b, 17). Such OAEs are related to enhanced volcanic activity, characterized by increasing temperatures that enhanced continental weathering rates, the deposition of organic-rich black shales, and the deoxygenation of the oceans during transient cooling episodes (18). Such intense climatic fluctuations are thought to result in fluctuations in the marine primary productivity and combined Se and multiple S isotope systematics of the Paja sediments will help to resolve the environmental conditions during the Lower Cretaceous.