Lecture 3: Components of Estuarine Communities
Gaytha A. Langlois, Ph.D.
Site
Map
Managing Mixed Use Coastal Areas
Organisms and Their Interactions
What
is a Species?
Kind of organism that
can interbreed
Each species has a
scientific name
Homo sapiens
for humans
Vorticella marina
for marine ciliated protozoa
Italicize or underline
scientific names
Individuals are organized
into populations
What
is a Population?
Group of the same
kind of organism
Comprised of the same
species
Characteristics of
a Population
Numbers/Size
Density and Distribution
Reproductive Rate
Growth Rate
Populations are part
of communities
What
is a Community?
Group of interacting
populations
Biotic component of
an ecosystem
Characteristics of
a community
Species diversity
Diversity of species
interactions
e.g., predation, competition,
symbiosis
Food Webs / Trophic
Pyramids
Types
of Estuarine Communities
Seagrass communities
Tidal mudflats
Salt marshes
Coastal ponds
Mangrove swamps
How
do we name organisms?
Taxonomy – the science
of naming organisms
Based on a few large
groups, divided into smaller groups
Scientific names allow
scientists in different locales to share technical information
Taxonomic
Schemata
Kingdom
Phylum
Class
Order
Family
Genus
Species
EXAMPLES
OF TAXONOMIC CLASSIFICATION
Whittaker’s
Five Kingdoms
Procaryota (Monera)
Unicellular, no membrane
bound organelles
Protista
Unicellular, may be
motile, have organelles
Plants
Multicellular, not
motile, photosynthesize
Animals
Multicellular, motile,
complex organ systems, heterotrophic
Plants
Multicellular, non-motile,
often detritovores
ILLUSTRATION
OF FIVE KINGDOMS
Types
of Organisms
Procaryota (Monera)
Bacteria, Cyanophyta
(blue-green algae)
Very important to
detritus food chains
Act as decomposers
of dead organisms and waste materials; active in sediments
Important to Biogeochemical
Cycles
Sulfur Bacteria
Nitrifying and Phosphatizing
Bacteria
Pathogenic Bacteria
associated with sewage
Protista
Unicellular Algae
– photosynthetic
Important as phytoplankton
Live in photic zone
- shallow sediments
Serve as basis of
estuarine food chains
Protozoa – usually
not photosynthetic
Amoeboid forms, ciliates,
flagellates
Active in plankton
and benthos
Intermediate level
in food chains
May have very elaborate
behavior patterns
Protista
(continued)
Examples of Unicellular
Algae
Diatoms (characteristic
shapes, silicaceous)
Dinoflagellates (outer
shell, flagellates)
Desmids (green algae,
two-part shell)
Euglenoids (small,
green, flagellated)
Examples of Protozoa
Amoebae (pseudopods,
change body shape, may have an outer shell, like Radiolarians)
Ciliates (e.g., Vorticella,
Euplotes, Pleuronema, Condylstoma, tintinnids)
Flagellates (colorless,
small, e.g., Phacus)
Protista
(continued)
Multicellular algae,
found in rock pools, or in deeper water
Green algae (Ulva,
Cladophora)
Red algae (Polysiphonia)
Brown algae (Kelp,
Fucus,
Ascophyllum)
Plants
Grasses, usually found
in near-shore, shallow water communities
Eelgrass (Zostera
marina)
Cord grass (Spartina
sp.)
Juncus
Saltworts
Phragmites
(indicates presence of fresh water)
Animals
Porifera (sponges)
Small, sac-like animals
that filter water
Coelenterates (hydroids)
Cylindrical bodies
with one opening, ringed with tentacles (anemones, corals, jellyfish)
Platyhelminths (flatworms)
Live under rocks (important
to detritus cycle)
Animals
(continued)
Molluscs (clams &
snails)
Hard shells, soft
bodies (soft shell clams, quahags, razor clams, oysters, scallops,
periwinkles, oyster
drills, Thais, Littorina)
Annelid Worms – segmented
bodies
Marine worms (polychaetes,
like Nereis)
Very active in soft
muds (salt marshes, mud flats, shallow sediments)
Animals
(continued)
Arthropods-hard shells,
jointed appendages
Class: Crustacea (live
in water habitats)
Crabs, lobsters, “bugs”,
horseshoe crabs, hermit crabs, amphipods, shrimp, isopods, copepods
Must shed their shells
as they grow
Very important in
plankton, pelagic, and benthic communities.
Echinoderms
Spiny skinned animals,
radial organization
Starfish, brittle
stars, sand dollars & sea cucumbers
Animals
(continued)
Chordates (vertebrates)
Fish (aquatic habitats,
cartilaginous or bony, scales, fins)
Common New England
species (cod, haddock, flounder, bluefish, skate, sharks)
Birds (wings, feathers,
hard-shelled eggs)
Common N.E. species
(gulls, terns, osprey)
Species
Interactions
Symbiosis (mutualism,
commensalism)
Resource sharing
Beneficial to at least
one of the two species
Predation (predator/prey)
Parasitism (parasite/host)
Competition (space,
food, nutrients, water)
Glossary
of terms
Species
Population
Community
Kingdoms
Detritovores
Photic zone
Phytoplankton
Benthos
Monera
Protista
Algae
Protozoa
Porifera
Coelenterata
Platyhelminths
Molluscs
Annelids
Arthropods
Primates
Zostera marina
Spartina alterniflora
Detritus food chain
Phytoplankton
Zooplankton
Keystone species
Productivity
Biotic diversity