The deep subsurface is, in addition to space, one of the last unknown frontiers to human kind. A significant part of life on Earth resides in the deep subsurface, hiding great potential of microbial life of which we know only little. The conditions in the deep terrestrial subsurface are thought to resemble those of early Earth, which makes this environment an analog for studying early life in addition to possible extraterrestrial life in ultra-extreme conditions. Early microorganisms played a great role in shaping the conditions on the young Earth. Even today deep subsurface microorganisms interact with their geological environment transforming the conditions in the groundwater and on rock surfaces. Essential elements for life are richly present but in difficultly accessible form. The elements driving the microbial deep life is still not completely identified. Most of the microorganisms detected by novel molecular techniques still lack cultured representatives. Nevertheless, using modern sequencing techniques and bioinformatics the functional roles of these microorganisms are being revealed. We are starting to see the differences and similarities between the life in the deep subsurface and surface domains. We may even begin to see the function of evolution by comparing deep life to life closer to the surface of Earth. Deep life consists of organisms from all known domains of life. This Research Topic reveals some of the rich diversity and functional properties of the great biomass residing in the deep dark subsurface.

A radically thought-provoking account of a major shift in how we understand our Earth, not simply as an inanimate planet on which life evolved, but rather as a planet that came to life. 'Full of achingly beautiful passages, mind-bending conceptual twists, and wonderful characters.' – Ed Yong, author of An Immense World, winner of the Royal Society Science Book Prize 'The ambition, eloquence, and erudition in this dragonfly droneflight of a book are absolutely exhilarating.' – John Vaillant, author of Fire Weather, winner of the Baillie Gifford Prize The notion of a living world is one of humanity’s oldest beliefs. Though once scorned by many scientists, the concept of Earth as a vast interconnected living system has gained acceptance in recent decades. Life not only adapts to its surroundings – it also shapes them in dramatic and enduring ways. Over billions of years, life transformed a lump of orbiting rock into our cosmic oasis, breathing oxygen into the atmosphere, concocting the modern oceans, and turning rock into fertile soil. Life is intertwined with Earth’s capacity to regulate its climate and maintain balance. Through compelling narrative, evocative descriptions, and lucid explanations, Ferris Jabr shows us how Earth became the world we’ve known, how it is rapidly becoming a very different world, and how we will determine what kind of Earth our descendants inherit for millennia to come. 'Fascinating, thought-provoking, and, ultimately, inspiring.' – Elizabeth Kolbert, author of The Sixth Extinction, winner of the Pulitzer Prize for General Non-Fiction

The book discusses the ways in which high hydrostatic pressure (i.e. water pressure) affects all grades of life which thrive at pressures much greater those in our normal environment. The deep sea is the best known high pressure environment, where pressures reach a thousand times greater than those at the surface, yet it is populated by a variety of animals and microorganisms. The earth’s crust supports microorganisms which live in water filled pores at high pressure. In addition, the load bearing joints of animals like ourselves experience pulses of hydrostatic pressure of a magnitude similar to the pressure at mid ocean depths. These pressures affect molecular structures and biochemical reactions. Basic cellular processes are drastically affected – the growth and division of cells, the way nerves conduct impulses and the chemical reactions which provide energy. Adaptation to high pressure also occurs in complex physiological systems such as those which provide buoyancy. Probably the greatest challenge to our understanding of adaptation to high pressure is the stabilisation of the nervous system of deep sea animals to avoid convulsions which pressure causes in shallow water animals. Additionally the book provides insight into the engineering required to study life at high pressure: equipment which can trap small deep sea animals and retrieve them at their high pressure, equivalent equipment for microorganisms, laboratory microscopes which can focus on living cells under high pressure, incubators for bacteria which require high pressure to grow, high pressure aquaria for marine animals and lastly and briefly, manned and unmanned submersible vessels, Landers and deep drill hole sampling. Rather like the organisms studied many laboratory instruments have been adapted to function at high pressure.

Microbial Diversity in the Genomic Era presents insights on the techniques used for microbial taxonomy and phylogeny, along with their applications and respective pros and cons. Though many advanced techniques for the identification of any unknown bacterium are available in the genomics era, a far fewer number of the total microbial species have been discovered and identified to date. The assessment of microbial taxonomy and biosystematics techniques discovered and practiced in the current genomics era with suitable recommendations is the prime focus of this book. - Discusses the techniques used for microbial taxonomy and phylogeny with their applications and respective pros and cons - Reviews the evolving field of bacterial typing and the genomic technologies that enable comparative analysis of multiple genomes and the metagenomes of complex microbial environments - Provides a uniform, standard methodology for species designation

Colorectal Cancer: Disease and Advanced Drug Delivery Strategies examines the combined impact of basic clinical and medical treatments as well as recent advances in the field of colorectal cancer. With a strong focus towards colorectal cancer diagnosis, disease drug delivery, and diagnosis, the book also examines the Tumor microenvironment-responsive and site-specific nanoparticles for cancer theragnostics. In 16 chapters Colorectal Cancer: Disease and Advanced Drug Delivery Strategies not only provides the opportunity to understand and diagnose the disease, but it also describes screening methods, drugs including nano- and immunotherapy, and gives insight into the role of nanoparticles, lipids, and biomarkers in colorectal cancer. Content includes clinical trials in colorectal cancer research and disease models. This book directs researchers and clinicians how to better diagnose and treat colorectal cancer. Provides a wealth of information on the latest research and developments in the science and treatment of colorectal cancer Contains new and innovative ways to treat colorectal cancer Reflects on basic clinical and medical methods and recent advances in colorectal cancer science Gives specific details about how nanoparticles can be used to target cancer cells or cancer treatment Covers tumor microenvironment, their challenges, and opportunities in colorectal cancer research

Obtaining and analyzing samples is challenging in subsurface science. This first-of-its-kind reference book addresses accomplishments in this field-from drilling to sample work-up. A collaborative approach is taken, involving the efforts of microbiologists, geochemists, hydrologists, and drilling and mining experts to present a comprehensive view of subsurface research. The text provides practical information about obtaining, analyzing, and evaluating subsurface materials; the current status of subsurface microbial ecology; and describes several applications that will interest a variety of readers, including engineers, physical, and life scientists.

Deep subsurface microbiology is a highly active and rapidly advancing research field at the interface of microbiology and the geosciences; it focuses on the detection, identification, quantification, cultivation and activity measurements of bacteria, archaea and eukaryotes that permeate the subsurface biosphere of deep marine sediments and the basaltic ocean and continental crust. The deep subsurface biosphere abounds with uncultured, only recently discovered and – at best - incompletely understood microbial populations. In spatial extent and volume, Earth's subsurface biosphere is only rivaled by the deep sea water column. So far, no deep subsurface sediment has been found that is entirely devoid of microbial life; microbial cells and DNA remain detectable at sediment depths of more than 1 km; microbial life permeates deeply buried hydrocarbon reservoirs, and is also found several kilometers down in continental crust aquifers. Severe energy limitation, either as electron acceptor or donor shortage, and scarcity of microbially degradable organic carbon sources are among the evolutionary pressures that have shaped the genomic and physiological repertoire of the deep subsurface biosphere. Its biogeochemical role as long-term organic carbon repository, inorganic electron and energy source, and subduction recycling engine continues to be explored by current research at the interface of microbiology, geochemistry and biosphere/geosphere evolution. This Research Topic addresses some of the central research questions about deep subsurface microbiology and biogeochemistry: phylogenetic and physiological microbial diversity in the deep subsurface; microbial activity and survival strategies in severely energy-limited subsurface habitats; microbial activity as reflected in process rates and gene expression patterns; biogeographic isolation and connectivity in deep subsurface microbial communities; the ecological standing of subsurface biospheres in comparison to the surface biosphere – an independently flourishing biosphere, or mere survivors that tolerate burial (along with organic carbon compounds), or a combination of both? Advancing these questions on Earth’s deep subsurface biosphere redefines the habitat range, environmental tolerance, activity and diversity of microbial life.

Over the last two decades, exploration of the deep subsurface biosphere has developed into a major research area. New findings constantly challenge our concepts of global biogeochemical cycles and the ultimate limits to life. In order to explain our observations from deep subsurface ecosystems it is necessary to develop truly interdisciplinary approaches, ranging from microbiology and geochemistry to physics and modeling. This book aims to bring together a wide variety of topics, covering the broad range of issues that are associated with deep biosphere exploration. Not only does the book present case studies of selected projects, but also treats questions arising from our current knowledge. Despite nearly two decades of research, there are still many boundaries to exploration caused by technical limitations and one section of the book is devoted to these technical challenges and the latest developments in this field. This volume will be of high interest to biologists, chemists and earth scientists all working on the deep biosphere.