Sex, Drugs, and Sea Slime: The Oceans' Oddest Creatures and Why They Matter

Sex, Drugs, and Sea Slime: The Oceans' Oddest Creatures and Why They Matter

by Ellen Prager
Sex, Drugs, and Sea Slime: The Oceans' Oddest Creatures and Why They Matter

Sex, Drugs, and Sea Slime: The Oceans' Oddest Creatures and Why They Matter

by Ellen Prager

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Overview

When viewed from a quiet beach, the ocean, with its rolling waves and vast expanse, can seem calm, even serene. But hidden beneath the sea’s waves are a staggering abundance and variety of active creatures, engaged in the never-ending struggles of life—to reproduce, to eat, and to avoid being eaten.

With Sex, Drugs, and Sea Slime, marine scientist Ellen Prager takes us deep into the sea to introduce an astonishing cast of fascinating and bizarre creatures that make the salty depths their home. From the tiny but voracious arrow worms whose rapacious ways may lead to death by overeating, to the lobsters that battle rivals or seduce mates with their urine, to the sea’s masters of disguise, the octopuses, Prager not only brings to life the ocean’s strange creatures, but also reveals the ways they interact as predators, prey, or potential mates. And while these animals make for some jaw-dropping stories—witness the sea cucumber, which ejects its own intestines to confuse predators, or the hagfish that ties itself into a knot to keep from suffocating in its own slime—there’s far more to Prager’s account than her ever-entertaining anecdotes: again and again, she illustrates the crucial connections between life in the ocean and humankind, in everything from our food supply to our economy, and in drug discovery, biomedical research, and popular culture.

Written with a diver’s love of the ocean, a novelist’s skill at storytelling, and a scientist’s deep knowledge, Sex, Drugs, and Sea Slime enchants as it educates, enthralling us with the wealth of life in the sea—and reminding us of the need to protect it.


Product Details

ISBN-13: 9780226678733
Publisher: University of Chicago Press
Publication date: 11/22/2011
Sold by: Barnes & Noble
Format: eBook
Pages: 200
File size: 23 MB
Note: This product may take a few minutes to download.

About the Author

Ellen Prager, a marine scientist, was formerly the chief scientist at the world’s only undersea research station, Aquarius Reef Base in the Florida Keys. She is the author of several books, including Chasing Science at Sea, which is also published by the University of Chicago Press.

Read an Excerpt

SEX, DRUGS, AND Sea Slime

THE OCEANS' ODDEST CREATURES AND WHY THEY MATTER
By ELLEN PRAGER

The University of Chicago Press

Copyright © 2011 Ellen Prager
All right reserved.

ISBN: 978-0-226-67872-6


Chapter One

The Invisible Crowd

For many people the oceans inspire a sense of peace, a feeling of serenity. Yet even in the calmest of waters, in the bluest of blue, there is a crowd jostling about and a timeless battle being waged. When you swim in the sea, they surround you. When you look into the oceans' depths, they are there unseen, right before your eyes. Much of the sea is actually a crowded place, swarming with organisms struggling to survive and aspiring to reproduce. The majority of these creatures are small, too small to see, including tiny plants, animals, bacteria, and other microbes. In just one teaspoon of seawater there may be millions of organisms. Drinking seawater—not a good idea for a whole host of reasons! The oceans' invisible realm is packed with a strange menagerie of life forms whose diversity comes from the struggles of living in the sea's zone of small. They must find ways to stay afloat and obtain the necessary resources to grow and to reproduce, all the while staying in favorable conditions and if possible, avoiding becoming someone else's lunch. Within the oceans' invisible crowd there is great beauty along with some serious slime and a monster or two, albeit in miniature.

SMALL DESIGNS

For the oceans' tiny floating plants, the phytoplankton, wants are relatively simple: they need sunlight, nutrients, carbon dioxide, and favorable temperatures. These, the needs for photosynthesis, seem like uncomplicated desires, but satisfying them is not always so easy in the oceans. Phytoplankton tend to sink, and most of the oceans' living space is dark, well below the reach of sunlight. The small creatures of the sea must also deal with the oceans' incessantly changing patterns of flow produced by currents, circular eddies, waves, upwellings, downwellings, and the wind. The concentrations of nutrients in the sea, which phytoplankton need as fertilizer to grow, also vary strongly over depth, in time, and geographically.

Over millions of years, phytoplankton have evolved a remarkable array of beautiful and odd forms that allow them to satisfy their needs and to flourish. Three of the most common and abundant phytoplankton are illustrative of the beauty and strange diversity within their diminutive ranks; these are the delicate diatoms, the spaceship-resembling coccolithophores, and the multitalented dinoflagellates.

Diatoms are small, single-celled algae with a thin, glassy test, or shell, made of silica. They are akin to miniature greenhouses with tiny glass walls surrounding specks of golden-green plant material. In today's oceans, there are believed to be thousands of diatom species with a wide variety of architectural forms. They may form disks or cylinders, or take on the shape of a square, triangle, or oblong pendant. To reduce sinking, diatoms often link up (not to be confused with the popular term "hooking up") to create delicate linear, circular, or twisting chains. Under a microscope, such chains resemble elegant necklaces of spun glass bejeweled with light-colored emeralds. Pits, perforations, spines, or spikes add ornamentation to the diatoms and also help to reduce sinking and facilitate more efficient exchange of nutrients and wastes. In addition to leading a life afloat, diatoms may dwell at the seafloor and can grow on just about any surface within the shallow sunlit waters of the sea. The slimy black goo that makes a dock slippery, grows on your boat, or adorns the belly of a whale is in all likelihood a lush coating of diatoms.

The diatoms have evolved an especially efficient means to reproduce. They multiply through simple asexual division in which the top and bottom parts of the diatom split apart and each produces a smaller new half. The only problem with this quick-fire method of reproduction is that over time and with successive generations, diatoms get smaller and smaller, potentially replicating themselves into extinction. Eventually, a tiny diatom must cast off both portions of its silica test and form a special type of cell that can produce a larger-sized diatom. When temperature, nutrients, and light are all favorable for growth, diatoms can reproduce rapidly and in great abundance. In less than three weeks just one small diatom can produce as many as one million daughter cells.

Coccolithophores are the oceans' alien spacecrafts in miniature, with a really big one growing to some 40 microns in size, about half the width of a thick piece of human hair. They are unicellular brown algae that have a spherical hull or covering of overlapping, microscopic plates, called coccoliths. Each coccolith is made of calcium carbonate (limestone) and bears a striking resemblance to an ornately designed hubcap. Among the different coccolithophore species, there is a wealth of hubcap designs, and each individual may be covered with as many as one hundred of them, though the average appears to be about ten to twenty. Some coccolithophores constantly shed their coccoliths and then produce replacements, while others make them only if a repair is needed. It is unclear what purpose the coccoliths serve. One theory suggests that the calcite sheath they create offers protection from high-intensity sunlight, allowing the coccolithophores to flourish at the surface in the tropics and subtropics. Another thought is that the coccoliths actually concentrate light toward the organisms' interior so that they can survive in low light conditions. Then again, others hypothesize that the coccolithophores' hubcaps provide physical protection or act as floatation devices.

Like diatoms, coccolithophores can reproduce in great abundance under favorable conditions. Images from space have documented huge, milky white blooms of coccolithophores hundreds of miles across, encompassing an area as large as England. The famed white cliffs of Dover are a massive accumulation of coccoliths, evidence of a once enormous population of coccolithophores. Many of the coccoliths that get deposited on the sea-floor and create such accumulations have probably been transported via special delivery—packed in a protective coating of poop-produced slime. In the oceans, many organisms release their wastes in gooey pellets, which aggregate fine particles into bigger, slime-encased packets. Because they sink faster than smaller bits of waste, the oceans' balls of poo are less likely to be consumed, drift away, or dissolve before reaching the seabed.

Dinoflagellates are also small and single-celled; they are the oceans' version of miniature whirling dervishes. Two tiny, whip-like tails, or flagella, cause them to whirl and spin when they swim. Dinoflagellates are a diverse and versatile bunch, with amazing, and in some cases harmful, attributes. One common form resembles a miniature grappling hook, while others are tooth-shaped or take on the appearance of a spinning top. Some dinoflagellates have an outer coating of chitin (a very thin version of a crab or shrimp's shell), while others go naked. They may sport spines, wings, or even horns. Dinoflagellates often contain chlorophyll for photosynthesis, but some can also engulf food particles like an amoeba—they are switch-hitters, able to behave like plants or animals depending on the situation. Many dinoflagellates are stowaways within other organisms, such as corals, living in a mutually beneficial or symbiotic relationship with their hosts. Others of these tiny organisms harbor harmful toxins or can form cysts and lie temporarily dormant on the seafloor—just waiting for their time to prosper. Dinoflagellates are also responsible for much of the oceans' remarkable nighttime bioluminescence; producing the bright twinkling of light in a ship's wake or the sparkling trail that traces a diver's movements. Given the right temperature, light, and nutrient conditions, like diatoms and coccolithophores, the dinoflagellates can bloom, reproducing quickly and in great number. A thousand or so species of these superadaptable organisms are recognized today, but undoubtedly there are many more yet to be identified.

Another member of the phytoplankton clan that deserves at least a quick mention are the cyanobacteria, some of the oldest organisms on Earth, believed to have originated about three billion years ago. Cyanobacteria are often abundant in nutrient-poor areas where other phytoplankton are scarce. The cyanobacteria trichodesmium is common in warm, tropical waters and is often mistaken for little bits of pollution or floating pieces of general ocean "schmutz." It forms small floating chains that look like short needles, tufts or little tan puffs. Trichodesmium can also aggregate into larger mats that provide an important habitat for small fishes and other organisms at the surface. Some of the cyanobacteria have the ability to do something that is rare in the oceans: they can "fix" nitrogen, or transform it from a free molecular state into a more plant-friendly form. There is growing recognition that the cyanobacteria probably play a more important role in the sea than previously thought.

The zooplankton are the sea's floating or weakly swimming animals and are more diverse than its host of tiny plants, with an even greater array of small designs. They populate the world's oceans in abundance, from the deepest of deep-sea trenches to the shallowest tide pool. Within this varied group of creatures there are some strange goings-on: slime-wielding grazers, gluttonous predators that are small in scale, but huge in appetite, and even a few cross-dressers that can photosynthesize like plants, but when needed, switch sides and capture prey as animals. Within the sea, zooplankton are just about everywhere and they make up a large proportion of what goes on, unseen, in seawater.

ARMS OF GOO

Two of the most common and beautiful members of the zooplankton are the small foraminifera and radiolarians. The foraminifera are essentially amoebas that live within a shell of calcium carbonate, typically the size of a sand grain. Their limestone homes may be a single small orb or a cluster of them, or form a miniature nautilus-like encasing. As foraminifera grow, they add additional rooms to their homes by producing new chambers in their shells. Some have long, calcite spines, and many have pits and perforations; they have been likened to tiny, pitted potatoes. Except this potato has arms of goo that it can extend out of its shell to use as a slimy net to capture smaller organisms, such as bacteria and phytoplankton. Some foraminifera also have dinoflagellates living within their tissues that aid in growth through photosynthesis. These foraminifera are much like sophisticated satellites that open their solar panels at daybreak. In the morning, the foraminifera transport the algae out of their shells to the ends of their spines and gooey arms (plate 1). There, the dinoflagellates capture sunlight and grow through photosynthesis; in the process they use up the foraminiferas' wastes while producing oxygen. As darkness falls, the algae are drawn back inside the foraminiferas' shells. Thousands of symbiotic algae may be housed within a foraminifera's tissues, making it a floating, dense packet of productivity. There are some forty species of planktonic foraminifera, with additional varieties living at the seafloor.

Radiolarians are also small, mainly spherical, creatures, but their shells are internal (skeletons), are made of silica, and tend to be highly decorated with spines. Their skeletal architecture is also more open than the shells of their calcareous relatives, like the structural framework of a minuscule building in the round. The radiolarians have arms of goo as well, which are used to dine on prey captured within a foamy net of slime that surrounds their shells and spines. In the tropics, radiolarians can also form unusually large colonies that may grow to be meters in length. Where radiolarians and foraminifera are abundant, a carpet of tiny shells may accumulate on the seabed, creating soft sediments known as siliceous or calcareous oozes, respectively.

AN EPIC BATTLE

The foraminifera and radiolarians float in relative peace about the sea, ensnaring their food in arms of goo and sometimes succumbing to the whims of nature as they are captured and ingested by other organisms. All around them, however, an epic but invisible battle is being waged. It is a struggle for survival, a battle for supremacy. Okay, maybe not quite that dramatic, in fact, it is more like Godzilla versus a cow. The combatants are two of the most common and abundant organisms in the sea, and the weaponry unleashed, at least by one of them, is formidable.

The opponents in this everlasting war are the copepods and arrow worms. Copepods are small, shrimp-like crustaceans that feed mainly on hapless bacteria, dinoflagellates, and other phytoplankton. They are simple grazers, foraging and filtering the oceans' waters. On the other side of the ring is the arrow worm, also known as a chaetognath (pronounced "kee-tahg-nath"). Though diminutive in size, the arrow worm is one of the sea's most voracious and lethal carnivores, driven by a constant hunger and equipped with an array of deadly armaments. It is clearly an unfair fight that leaves the copepod living a perilous life as the eternal underdog to the arrow worm.

What the copepods lack in weaponry, they make up for in sheer abundance. Copepods are considered the most numerous of multicelled organisms in water, and surprisingly, probably the largest source of protein in the sea (it is also surprising that we have not found some way to make them palatable for human consumption). They are found in all marine environments, from the surface to the oceans' depths, under the ice, and at deep-sea hydrothermal vents. There are thousands of copepod species, and when you see small dots flitting about in the sea or in an aquarium—a sure bet is copepods. Individuals are typically small, averaging just a few millimeters in length. Like other crustaceans, they have an external carapace or shell made of chitin and numerous jointed limbs. The copepod's body is short, segmented, and elliptical, and each has a single eye in the middle of its head—one freshwater species is appropriately named cyclops. Its two characteristic antennae may be long and delicate or short and stubby. Copepods also have oar-like swimming legs, which are used to move about, typically at a slow and steady pace. If, however, some speed is needed, copepods can swim at a faster clip through a series of jerky bursts. Copepods also use their swimming appendages to create currents that circulate water around their bodies and bring food particles into reach. While most of the oceans' copepods dine on small particles and phytoplankton, some have cannibalistic predilections and will feast on other copepods. There are also a few species that dine on pieces of flesh torn from unwary fishes or that live as parasites feeding on skin or blood. Though they are adaptive creatures and can produce quick bursts of speed, copepods are still, simply no match for the ever-voracious arrow worm.

In the oceans' domain of the unseen, the arrow worm is the top dog, the ultimate predator. It is built exceptionally well for the life of a microscopic hunter. Most are transparent, providing for excellent camouflage and stealth in the open sea. They are also torpedo-shaped for speed with lateral fins for stability and have relatively large paddles as tails that provide for efficient propulsion. To seek out their prey, arrow worms use a speedy darting or hop-and-sink pattern of swimming. Although they have two eyes, vision is probably not their most important sense when in search of food, aka victims. Their entire bodies are lined by hair-like receptors that attach to nerves, which can sense nearby vibrations or water movements, making each arrow worm one big (but actually small), sensitive motion detector.

(Continues...)



Excerpted from SEX, DRUGS, AND Sea Slime by ELLEN PRAGER Copyright © 2011 by Ellen Prager. Excerpted by permission of The University of Chicago Press. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Table of Contents

A Note on the Title


1. The Invisible Crowd

2. Mega-Slime, Seduction, and Shape-Shifting

3. Let’s Talk Snails

4. The Riddle of the Reef

5. Armed and Dangerous

6. Cabinet of Curiosities

7. X-Games

8. Radical Living

9. Danger Looms

10. The Good News

11. How You Can Help


Bibliography

Acknowledgments

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