A deep-sea submersible shines its headlights through murky ocean depths at the start of this fact-packed read that spotlights an ecosystem thriving at the extremes. After discussing scientists' 1977 encounter with miles-deep hydrothermal vents on the ocean floor, Batten's instructive narrative details life forms found teeming around the vents, made possible by microbes that "eat the poisonous vent chemicals" to "produce simple sugars on which vent creatures depend." Gonzalez's strikingly realistic pastel, colored pencil, and airbrush spreads, meanwhile, offer close-up views of these "extremophiles," such as a snail that sports an iron-scaled shell. While detail-heavy passages sometimes read with a textbook's density, stunning scientific facts reward persistent readers, and a brief discussion of the oceanographic finds' significance rounds things out (e.g., a "study of an enzyme from a vent microbe helped in the creation of a test for the coronavirus"). Ocean facts, an author's note, glossary, and selected bibliography wrap up this fascinating glimpse into life that seemingly defies all odds. Ages 6--9. (June)

Batten turns from the extreme cold of Antarctica (Life in a Frozen World, 2020) to the extreme depths of the ocean floor, where it should be cold. However, this informational picture book focuses on the ocean's hydrothermal vents, "where volcanoes erupt daily, gushing superhot fluids above the seafloor" and where nothing should be able to live. Soft pastel, colored pencil, and airbrushed illustrations showcase luminous creatures and terrain along the dark ocean floor and present beautiful backdrops for Batten's vivid descriptions of this strange and striking ecosystem. The author exhibits her research as she explains early exploration of the hydrothermal vents and continuing scientific discoveries of unusual animals, such as blind shrimp, pale vent octopuses, and tube worms ("like giant lipsticks"), living in extreme darkness, pressure, and heat. She also asks and answers questions that curious readers are probably wondering, most notably how animals rely on chemosynthesis, rather than photosynthesis, to eat in this harsh environment. Pros and cons of seafloor mining and deep ocean facts conclude this attractive investigation of the lesser-known ocean world.