Читать книгу Life in the Open Ocean - Joseph J. Torres - Страница 10

Preface

Most of the planet earth (over 60% of it) is deep ocean. Within the oceanic realm are two basic ecosystems, the ocean bottom, a two‐dimensional environment containing creatures that creep, crawl, burrow, or lie in wait for prey, and the immense, three‐dimensional pelagic region that lies above it, the largest living space on the planet, containing the swimmers and drifters. The deep ocean bottom has been the focus of a lot of excitement over the last 50 years, with many expeditions to the fabulous communities inhabiting the hydrothermal vents at our planet’s oceanic ridges. More recently, the thrilling discovery of deep coral reefs off Australia has captured the public eye, showing that still more oceanic discoveries may yet await us.

More fascinating yet are the communities of marine animals that inhabit the oceans’ pelagic realm, and the creatures’ adaptations to an environment devoid of barriers to movement in three‐dimensional space. Many people are familiar with the term “plankton,” the tiny plants and animals that drift with the ocean currents. More are familiar with the large pelagic species such as tuna, sharks, and swordfish, not only from pictures or fishing trips but also from the dinner table. The large, highly capable swimming species like tuna and sharks are termed “nekton.” In between the tiny drifters and the strong swimmers are an entire community of animals that are familiar mainly to oceanographers but are the critical link between the small and the large. Animals in the intermediate community are not as capable at swimming as the tunas but are better at it than the small zooplankton. Collectively, the creatures are known as the micronekton and macrozooplankton, and they make up one of the largest animal communities on planet earth.

The nekton, micronekton, and macrozooplankton include a variety of different animal groups. Several different families of fishes are represented, many with unusual adaptations such as light organs like fireflies, huge gapes to allow them to swallow prey larger than themselves, and large tubular eyes. Among the invertebrates are shrimp similar to the ones we enjoy in shrimp cocktails and other crustaceans that can produce clouds of biological light or live inside jellyfishes. Among the jellies are species larger than a meter across and those that can double their population size in a matter of days by reproducing asexually.

The blue water pelagic community is truly fascinating. The problem is, to learn about the wonders we have briefly described above, you currently need to access many sources. Life in the Open Ocean: The Biology of Pelagic Species gathers the information available on the wide array of taxa making up the pelagic community and presents it as one cohesive whole. It is a synthesis of the information available on the biology of all the groups you will see if you tow a scientific trawl net between the surface and bathypelagic depths. When you bring the net up and look at your catch, you are looking at a community of coexisting species with each group having its own way of solving the problems posed by nature. The book combines basic information about the different animal groups as well as their different strategies for solving natures’ challenges.

Topics covered in the book include basic physical oceanography, properties of water, physical variables that covary with depth such as light, temperature, and pressure and how animals have adapted to cope with each. Animal groups covered in depth (no pun intended) include the Cnidaria, or stinging jellies, the ctenophores or comb jellies, pelagic nemerteans, pelagic annelids, the Crustacea, the Mollusca including the “swimming snails” and cephalopods, the invertebrate chordates, including the salps, pyrosomes, and larvaceans, and lastly, the incredible fishes, focusing on the micronekton but also including the sharks, tunas, mackerels and mahi‐mahi.

Within each of the animal phyla the pelagic groups are identified and detailed coverage is provided for classification and history, internal and external anatomy, vertical and geographic distributions, locomotion and buoyancy, foraging strategies, feeding and digestion, bioluminescent systems and their function, reproduction and development, respiration, excretion, nervous systems, heart and circulation and all sensory mechanisms: vision, mechanoreception (touch, balance, and vibration) and chemoreception (smell and taste).

Life in the Open Ocean: The Biology of Pelagic Species is written so that it can be used as a textbook at the advanced undergraduate or graduate level of instruction, and as a reference for those interested in marine biology including professors, interested undergraduates, and perhaps for High School teachers teaching at the AP level. It is our fondest hope that it will make open‐ocean biology considerably more accessible, increasing its visibility and its presence in college‐level science curricula.

Joseph J. Torres

Thomas G. Bailey