Water as a thermodynamic parameter of biosphere evolution

Water has a profound influence on the evolution of the biosphere and can be regarded as a thermodynamic parameter. The priorities and objectives in this research include determining the hydrological features of rivers and lakes in the region as indicators of the thermodynamic activity of water in the evolutionary processes; hydrology and ecology of the cryptobiosphere; the effects of water on the evolutionary adaptations and strategies in living organisms in biogeochemical systems of different origins; and the hydrology of possible alternative stable states of biogeochemical systems.

The emergence of subaerial crust and onset of weathering 3.7 billion years ago

<p>Reconstructing the emergence and weathering of continental crust in the Archean is crucial for our understanding of early ocean chemistry, biosphere evolution and the onset of plate tectonics. However, considerable disagreement exists between the various elemental and isotopic proxies that have been used to trace crustal input into marine sediments, and data are scarce prior to 3 billion years ago. Here we show that chemical weathering modified the Sr isotopic composition of Archean seawater as recorded in 3.52 to 3.20 Ga stratiform marine-hydrothermal barite deposits from three different cratons. We use a combination of barite crystal morphology, oxygen, multiple sulfur and strontium isotope data to select barite samples with the most seawater-like isotopic compositions, and subsequently use these in a hydrothermal mixing model to calculate a plausible seawater Sr isotope evolution trend from measured <sup>87</sup>Sr/<sup>86</sup>Sr data. From modeled mixing ratios between seawater and hydrothermal fluids required for barite precipitation and comparison of <sup>87</sup>Sr/<sup>86</sup>Sr in theoretical seawater-hydrothermal fluid mixtures with those recorded in the barite, we obtain a novel seawater Sr isotope evolution trend for Paleoarchean seawater that is much more radiogenic than the curve previously determined from carbonate rocks. Our findings require the presence and weathering of subaerial and evolved (high Rb/Sr) crust from 3.7 ± 0.1 Ga onwards, and demonstrate that crustal weathering affected the chemistry of the oceans 500 million years earlier than previously thought.</p>

Sizes of Genomes of Paleoproterozoic Microfossil Eukaryotes

We studied siliceous rocks (microquartzites) enriched with light isotope 12С of biogenic origin (δ13С up to –29.5‰), found within the volcanogenic-sedimentary strata of the Paleoproterozoic (1640 Ma) of Hogland Island in the Gulf of Finland (Baltic Sea). In these siliceous rocks we found silificated and ferruginizated microfossils of planktonic eukaryotes: amoebas, diatoms,foraminifers, flagellates, virus-like and multicellular organisms. In mineralized cytoplasm and nuclei of microfossils we found grains of apatite, which could be crystallized from phosphoric acid residue of decayed nucleotides. This allowed as to estimate the size of genomes of ancient eukaryotes and virus-like structures, which were tens of thousands of times greater than those of genomes of modern single-cell organisms. Additionally, we estimated the weights of genomes of ancient eukaryotes using the principle of genomic-nuclear proportionality: that the molecular weights of genomes are proportional to the size of the nuclei. The weights of genomes of microfossil eukaryotes: flagellates, foraminifers, and virus-like structures, estimated by the inclusions of apatite grains and by the size of the nuclei, averaged tens of thousands picogram and, consequently, could contain tens of thousands billion pairs of nucleotides. Presumably, the giant genomes of ancient eukaryotes consisted predominantly of non-coding sequences, that served as a reserve that ensures the vital activity of cells when exposed to streams of mutagens from the environment. One of the mutagenic factors could be significant radioactivity, both background and intracellular, caused by high concentrations of radioactive 40K isotope in seawater. The favorable ecological and geochemical environment and the abundance of biophilic elements (especially phosphates) in the waters of the inland basin could play the role of an evolutionary springboard in the history of biosphere evolution.

The emergence of subaerial crust and onset of weathering 3.7 billion years ago

Reconstructing the emergence and weathering of continental crust in the Archean is crucial for our understanding of early ocean chemistry, biosphere evolution and the onset of plate tectonics. However, considerable disagreement exists between the elemental and isotopic proxies that have been used to trace crustal input into marine sediments and data are scarce prior to 3 billion years ago. Here we show that chemical weathering modified the Sr isotopic composition of seawater as recorded in 3.52-3.20 Ga stratiform barite deposits from three different cratons. Using a combination of Sr, S and O isotope data, barite petrography and a hydrothermal mixing model, we calculate a novel Sr isotope evolution trend for Paleoarchean seawater that is much more radiogenic than the curve previously determined from carbonate rocks. Our findings require the presence and weathering of subaerial and evolved (high Rb/Sr) crust from 3.7 ± 0.1 Ga onwards. This Eoarchean onset of crustal weathering affected the chemistry of the oceans and supplied nutrients to the marine biosphere 500 million years earlier than previously thought.

Living Matter and the Laws of Thermodynamics for the Biosphere

The laws of thermodynamics have been developed for inert matter, and living matter has not been considered as a variable in these laws. Living matter possesses properties that have had major effects on biosphere evolution with time. The zeroth property is “Living matter is produced from living matter only.” The first property may be summarized as ”Living matter occupies the available spaces to the maximum extent when environmental conditions are favorable and no obstacles are present.” And the second property is “ Living matter mutates, changes, and adapts to maintain the continuity of life and size as large as possible when environmental conditions are unfavorable.” While the zeroth property is objective in nature, the first and second properties are subjective, in that they are driven by internal stimuli characterizing living matter. Their interaction with the laws of thermodynamics may be thought of as “philosophy intertwining with science.” Accordingly, the laws of thermodynamics are revised to factor in life as a variable. Mathematical expressions of the first and second laws are derived and some of their applicability to the biosphere and climate is explained and discussed. The main conclusion is that life changes climates and the fabric of the biosphere.

Closure of Earth’s Biosphere: Evolution and Current State

The existence of the biosphere is determined by the presence of a constant circulation of substances, carried out by a highly branched trophic network of mainly closed material loops. How this largely self-contained system formed remains unclear. The theory of evolution cannot help answer this question since the closure of the biosphere is not an adaptive trait of an individual – this is the essence of the Vernadsky-Darwin paradox. The present paper discusses stages of the formation of the biosphere in the context of closure – a key property and parameter of the biosphere – and possible approaches to resolving the paradox. The authors assume that the appearance of the first living organisms did not mean the appearance of the biosphere as a system of interacting components. The formation of the biosphere in the true sense of the word was associated with the appearance of predation approximately 500 million years ago and the emergence of a highly branched trophic network. The authors obtain simple estimates showing that, on the one hand, living organisms are potentially capable of changing their environment at the global level in a negligible geological time period but, on the other hand, are capable of maintaining an accurate balance of global material cycling for several tens of thousands of years. A simple model was used to show the effect of stoichiometric constraints on the formation of closed material flow in simple ecosystems and to demonstrate the need for increased diversity at trophic levels to overcome these stoichiometric constraints