Zooplankton of the Atlantic and Gulf Coasts
A Guide to Their Identification and Ecology
Publication Year: 2012
Published by: The Johns Hopkins University Press
Title Page, Copyright
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Marine zooplankton can be appreciated by anyone with access to the shore. Tow a net of fine mesh for five minutes in virtually any estuarine or nearshore water, and you will collect hundreds or, more likely, thousands of organisms. Most will be barely large enough to see if you put them in a jar. Slight magnification will reveal the fantastic world of...
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The first of many thanks go to our wives, Valerie Chase and Wendy Allen, without whose understanding, encouragement, and support this book would probably not have materialized. As professional marine science educators with a passion for advancing the world’s understanding for our oceans and coastal systems, they inspired and energized our effort...
Introduction to Zooplankton
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Plankton (from the Greek word for wanderer) are the small organisms suspended in the water, neither attached to the bottom (benthos) nor able to swim effectively against most currents (nekton). Phytoplankton include the photosynthetic unicellular protozoans and bacteria. Zooplankton include both unicellular and multicellular organisms. Most...
Identification and Biology of Common Zooplankton
How to Use This Book to Identify Zooplankton
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Quick Picks is the first step in identifying unfamiliar organisms. This section divides the taxa into distinctive groups in which members share similar size, shape, and general appearance. Within each group, find the best match for your specimen, then turn to the proper taxonomic section for identification...
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Use this section to find the group that most closely matches your specimens or interests, and then go directly to the pages indicated for species identifications. Since some groups share many of the same general characteristics, the right match may not be found on the first try. Remember that this guide does not cover many of the less widely...
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Phytoplankton is a general term for largely photosynthetic single-celled organisms found in the water column. Phytoplankton form the base for many planktonic food webs, and the type and size of the phytoplankton often dictate which zooplankton will be abundant. However, many of the common phytoplankton are too small...
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The nonphotosynthetic, single-celled organisms historically referred to as Protozoa are important components of the marine plankton. This is a diverse assemblage encompassing many unrelated groups. Our treatment of protozooplankton is limited to the larger, singlecelled heterotrophic groups likely to be retained and noticed...
Cnidarians: Anemones, Jellyfishes, and Related Metazoans
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The Phylum Cnidaria, sometimes called Coelenterata, contains the simplest of the true metazoans. These radially symmetrical animals have a central mouth, usually surrounded by tentacles. The simple tissues, an outer epidermis and inner gastrodermis, surround a layer of gelatinous mesoglea. Cnidarians are distinguished by...
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Hydromedusae are roughly umbrella or bell shaped, transparent, and usually only a few millimeters in diameter. They are primarily marine to mesohaline; few occur in low salinities. These small, delicate creatures are often mangled in plankton samples. If alive, their pulsing movement is unmistakable. Many species occur...
Scyphozoans and Cubozoans
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Scyphozoan medusae are the familiar large jellyfishes more often seen from the surface than caught in plankton tows. Many of the roughly 200 currently recognized species reportedly have broad or even global distributions. The largest Atlantic jellyfish, Cyanea capillata, may reach a diameter of 2 m with tentacles...
Ctenophores: Comb Jellies and Sea Walnuts
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Ctenophores are among the most common macrozooplankton in estuarine and coastal waters in summer. The marine Phylum Ctenophora (pronounced with a silent “c,” as “teen-ofour- ah” or “ten-o-four-a”) has more than 150 species, but only several species are common in nearshore waters in our area. Ctenophores share...
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Rotifers are among the smallest of the true metazoans; most are less than 1 mm in length. The Phylum Rotifera (or Rotatoria) includes about 2,000 described species. Most rotifer species occur in freshwater, a few occur in seawater, and some are abundant in brackish waters, especially at river-estuarine transition...
Cirripedes: Barnacle Larvae
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Barnacle larvae are common and, occasionally, abundant in marine and estuarine plankton samples. The larvae pass through six similar naupliar stages before metamorphosing into the cyprid stage. Most nauplii use their anterior appendages for both swimming and feeding. Nauplii typically feed on phytoplankton, but some...
Cladocerans and Ostracods
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While water fleas like Daphnia are among the most common and conspicuous of freshwater zooplankton, only a few of the 600 species of cladocerans occur in brackish or marine waters. Nevertheless, marine cladocerans can be abundant and, at times, dominate the mesozooplankton. The traditional Order Cladocera has...
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Copepods are the most abundant animals in most mesozooplankton collections and often outnumber all other animals combined. This diverse group of small crustaceans (adults mostly 0.5–5.0 mm) contains more than 200 families and more than 10,000 marine species. Because of their abundance, copepods are...
Mysids: Opossum Shrimps
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Mysids are small, shrimplike crustaceans that, like the amphipods, isopods, and cumaceans, brood their young in a ventral brood pouch. Most of the nearly 1,000 described mysids are coastal and estuarine species <15 mm in total length. Most nearshore species are epibenthic and are found near the bottom...
Amphipods, Isopods, Tanaidaceans, and Cumaceans
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Amphipods, cumaceans, tanaidaceans, and isopods are primarily benthic or epibenthic, but many species make excursions into the water column, especially at night. Like the mysid crustaceans, amphipods, isopods, tanaidaceans, and cumaceans brood their young in a ventral brood pouch, or marsupium, made of...
Decapods: Shrimps, Crabs, and Related Crustaceans
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Although some decapods are planktonic for their entire lives, most spend their adulthood on the bottom. Their planktonic larvae bear little resemblance to the benthic adults, a source of confusion for many decades. Even now, the larval stages of many decapod species have not been described. This is not...
Stomatopods: Mantis Shrimps
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Occurrence. Squilla empusa is the most common stomatopod in nearshore waters, both along the coast and in higher-salinity reaches of estuaries from Maine to Texas. Other stomatopods, including Neogonodactylus spp., are widespread from North Carolina south to Texas. Cloridopsis dubia occurs in Southeast estuaries. Larvae...
Sea Spiders, Mites, and Insects
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This section contains two groups of primarily benthic arthropods that are occasionally swept off the bottom and then caught in plankton samples plus insects often incidentally collected at the water’s surface. These animals are particularly common in saltmarsh creeks and other shallow inshore habitats...
Annelids: Segmented Worms and Nematodes
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The most common and familiar annelids (segmented worms) in marine waters are the polychaete worms. Several species of polychaetes are holoplanktonic, spending their entire life cycles in the plankton, whereas many of the more than 9,000 benthic species currently described have planktonic larvae...
Molluscs: Gastropods, Bivalves, and Cephalopods
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Many of the familiar coastal and estuarine gastropods (snails) and bivalves (clams, oysters, and scallops) have planktonic larvae that are often abundant in nearshore plankton samples. Less familiar are the holoplanktonic gastropods seen nearshore when pulses of offshore ocean water come ashore. Although...
Chaetognaths: Arrow Worms
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The Chaetognatha constitutes a distinctive phylum of about 100 marine species ubiquitous in the world’s oceans. These flattened, transparent-to-opaque creatures are easily distinguished from all other taxa. They may reach 1–2 cm, but most inshore arrow worms are smaller. Arrow worms are common along the...
Echinoderm Larvae: Starfishes and Sea Urchins
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The Phylum Echinodermata contains starfishes, brittle stars, sea urchins, and several additional classes. Most of the familiar coastal and estuarine echinoderms have planktonic larvae that are occasionally common in nearshore plankton but rare in brackish waters. Fertilization and larval development occur in the...
Less Common Ciliated Invertebrate Larvae
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Many benthic invertebrate groups produce ciliated larvae that are minor constituents of the plankton. Although uncommon, they are interesting creatures and worthy of observation when alive. Larvae of Phoronida, Brachiopoda, Echiura, Entoprocta, and Sipunculida are rare in the nearshore plankton of our geographic...
Lower Chordates: Larvaceans, Sea Squirts, Salps, Doliolids, and Lancelets
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Phylum Urochordata contains the benthic sea squirts (or ascidians), most of which have planktonic “tadpole” larvae. The phylum also contains some holoplanktonic groups (larvaceans, salps, and doliolids), all highly modified for planktonic life and bearing little resemblance to the more familiar sea squirts. The...
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Ichthyoplankton, fish eggs and larvae, are common in estuaries and nearshore areas. Protected coastal regions and especially estuarine areas are critical spawning and/or nursery areas for most of the common commercial, sport, and forage fishes along our coasts. The larval stage is one of the most crucial and is, perhaps...
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Sources of Models for Illustrations
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Page Count: 432
Illustrations: 30 line drawings, 110 plates
Publication Year: 2012
Edition: second edition