Download 1. Zooplankton ID Guide - Swampscott Middle School

Zooplankton
“The Crustaceans”
Crabs, Lobsters, Barnacles, Copepods
Kingdom: Animalia
Phylum: Arthropoda … “Arthropods” … (invertebrates including insects,
spiders, and crustaceans)
Arthropod means “jointed leg”…. Arthro = Joint pod = leg or foot
Subphylum: Crustacea: the crustaceans are a very large group of Arthropods
which includes lobsters, crabs, barnacles, and shrimp.
• mainly aquatic, most species are marine
• hard exoskeleton (shell) which must be shed (molt) as they grow
• multiple pairs of jointed appendages including legs, antennae,
mouthparts or claws
An appendage is an external body part that projects from the body such as a leg, arm, or
antenna.
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Crustaceans Continued
Copepods… Holoplankton.. plankton for life
Copepods are the most common animal in the world and are almost always
found in plankton collections. One of these Calanus finmarchicus is a
major part of the zooplankton community in the Gulf of Maine and is
an important source food for many smaller fish as well as the very endangered
North Atlantic Right Whale. These copepods are a much sought after food source as
they have a lot of oil in their bodies; oils store a lot of energy.
Copepods go through a nauplius larva stage before developing into an adult.
Nauplius larvae of copepods magnified 100x
Adult Copepod Calanus finmarchicus magnified 100x
A Harpaticoid Copepod. (magnified 100x)
note the tiny antennae.
Crustaceans Continued………
These copepods live in sand and
sediments but are sometimes seen in
plankton collections where net is towed
near the seafloor.
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Barnacles …… Meroplankters begin their lives as plankton..larvae
Barnacles are one of the most common and numerous crustaceans. They are benthic
animals that as adults grow attached (sessile) to all sorts of hard surfaces. The animal
is housed in a structure made up of hard plates which can be sealed tightly for
protection. When feeding the animal opens the protective
plates and extends its feathery legs (modified for feeding) into the current to capture
food particles and plankton.
Barnacle feeding from Lippson, A.J. & Lippson, R.L. 1984. Life in the Chesapeake
Bay. Johns Hopkins University Press.
As juveniles, the barnacles are a common part of the zooplankton community and are
regularly found in plankton samples.
The first stage of development is the nauplius larva eventually morphing into the cypris
larval stage before attaching to a surface and living a sessile existence.
Cypris larva of barnacle magnified 100x
Nauplius larva of barnacle magnified 100x
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When adult barnacles shed their exoskeletons or “molt” their empty exoskeltons
or “molts” are often found in plankton collections.
Molted exoskeleton of Barnalce
magnified 100x
Crustaceans Continued………
Crabs…… Meroplankters
Crabs are benthic animals but begin their life as a part of the zooplankton community
after hatching from their eggs.
Their metamorphosis happens in in two major stages. The first stage is the
Zoea followed by the Megalops stage.
Crustaceans Continued………
Crab megalops magnified 100x
Looking more like an adult crab.
Pincers are developed
Crab Zoea magnified 100x
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Crustaceans Continued………
Cladocerans ….. holoplankton
Nicknamed “Water fleas”.. Tthe Cladocerans are an order of Crustaceans in found
zooplankton community.
Two genera Podon sp. and Evadne sp. are often found in plankton collections
The Cladoceran:
Evadne sp.magnified 100x
The Cladoceran:
Podon sp.magnified 100x
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“The Mollusks”
Clams, snails, mussels, squid..
Kingdom: Animalia
Phylum: Mollusca a large phylum of soft bodied aquatic creatures
most (not all) with one or two hard limestone shells that grow along
with the animal... snails...clams...oysters.. mussels
(octopus and squid belong to this group)
Most familiar molluscs are benthic creatures. A few such as squid are swimmers or
nekton. However, many mollusks begin their lives as a part of the
plankton community and are meroplankters.
Class: Bivalvia. “Bivalves” are those mollusks with two hinged shells.
This group includes: clams, mussels, oysters and scallops.
Bivalve Larva magnified 100 times.
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Molluscs continued…. “Snails”
Class: Gastropoda. Gastropod means stomach foot
(gastro = stomach (pod = foot)
Gastropods are a group of mollusks most with a single spiral shell or caplike shell. They have a large muscular foot used for gliding, burrowing,
or suction. These are the snails, whelks, conch, limpets and sea slugs.
Gastropod larvae magnified 100 times.
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Jellyfish
Kingdom: Animalia
Phylum: Cnidaria
pronounced: “ nie – dare - ee - ah”
This group of aquatic invertebrates includes jellyfish, anemones, and corals.
They are radially symmetrical… no right or left side.. no back or front side …theyʼ have
a round body plan… like a jar, or wheel, or umbrella.
Cnidarians have a mouth in the center of their body surrounded by tentacles for
capturing food. After digesting their food the waste exits the mouth.. as they do not
have a complete … flow through.. digestive system.
Some of the largest members of the zooplankton community in our waters are jellyfish
such as Moon jellies or the Lionʼs Mane.
We often see microscopic jellies in plankton collections such as the common
medussa: Obelia sp.
Obelia sp. magnified 40 x above left and 100 x above right.
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Polychaetes.. Sea worms
Phylum: Annelida
Annelids are segmented worms which include earthworms, leeches , all sorts of
seaworms such as clam and scale worms.
Although theyʼre benthic , worms belonging to the Class: Polychaete pronounced :
“polly keets” often have their larval forms in the plankton community.
Polychaete larva magnified 40 times.
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The Bryozoans or “Moss animals”
Phylum: Bryozoa ( a.k.a. Ectoprocta).
Bryozoans are tiny colonial animals that form colonies as crusts on all sorts of surfaces
from seaweeds to the shells of other animals. They may look like plants forming
branched colonies as well.
Each tiny animal or “Zooid” is encased in an exoskeleton made from Calcium Carbonate
or a material made of Chitin (kite – in) a tough material which also makes up insect
exoskeletons and the cell walls of fungi.
Horseshoe Crab shell covered in a Bryozoan Colony
Ectoproct larva … juvenile form of Bryozoa. Magnified 100 times.
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Zooplankton I.D.
“Crustaceans” pp. 1-5.
Phylum Arthropoda
Subphylum: Crustacea
Copepods p. 2.
Nauplius larvae of copepods
Adult Copepod Calanus finmarchicus
A Harpaticoid Copepod.
note the tiny antennae.
Barnacle Larvae p.3-4.
.
Nauplius larva of barnacle
Cypris larva of barnacle
Molted exoskeleton of Barnalce
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Crab Larvae p. 4
Crab Zoea larva
Crab megalops magnified 100x
Looking more like an adult crab.
Pincers are developed
Water Fleas p. 5
Evadne sp.magnified 100x
Podon sp.magnified 100x
Phylum: Mollusca p. 6-7.
Bivalve Larvae:
Clam, Mussels,
Oysters
Gastropod larvae
Snails.
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Phylum : Cnidaria … Jellyfish p. 8.
Obelia sp.
Phylum: Annelida … Polychaetes (Seaworm Larvae) p. 9.
Polychaete larva
Phylum: Bryozoa (a.k.a. Ectoprocta) .. Moss Animals p.10.
Bryozoa./ Ectoprocta Larva.
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