Typical Habitats
of the Bay
and
its Tributaries
Eight
Types of HabitatsSand Beaches
Intertidal Flats
Piers, Rocks, and Jetties
Shallow Waters
Seagrass, Meadows, and Weed Beds
Marshes
Oyster bars
Deeper, Open waters
Organisms Categorized
Broad habitat occupied
Pelagic animals and plants
Open water
Nekton – free swimmers
Fish and plankton
Non-swimming organisms carried by tides and currents
Plankton
Most abundant and diverse
Microscopic and important
Major food source
Phytoplankton
Single-celled algae
Diatoms and dinoflagellates
consumed by zooplankton
( microscopic )
Larger sized like jellyfish, amphipods, shrimps,and certain worms
Most important – copepods
Hundreds occupy a quart of water
Benthic plants and animals
Live at or in the bottom
Microscopic algae
Green, red and brown seaweeds – along shorelines
Many species of rooted aquatic plants
Grow in shallow waters
Creeping, crawling and burrowing animals
Sessile animals – piers, rope, piling, shells, crab traps, etc.
Infauna – animals that burrow into bottom
Epifaunal – sessile and animals that move over the bottom
Summarize
The biological associations that exist in the Chesapeake Bay, whether pelagic or benthic, are largely dependent on the habitat type, which is delineated by type of bottom sediment, salinity, water depth, or other physical and chemical features.
Sand Beaches
Not buffeted by waves and winds
Different beach zones
According to tides
Lower beach find intertidal zone
Intermittently submerged
Ebb and flow tides
Upper beach
Wet only during highest tides
Fauna not as diverse as in muddy bottoms
Empty shells, debris along beach identifies life
Intertidal Flats
Occur along shore
Bottom is alternately exposed and covered by tides
Bottom very soft, oozy, fine silts, muds
Firm only if sands are mixed with muds
Landward boundary
Mud bank
Gradual rise to marsh habitat
Sandy mud flat often merge with sand beach
Deep slope towards channel - narrow band at low tide
Gentle slope – extend for 100’s feet towards channel
Wide range of plants and animals
Buried, crawling over surface
Bacteria, algae, worms, snails, amphipods
High tide becomes shallow inshore habitat
Pelagic marine life moving shoreward with rising water.
Piers, Rocks, and Jetties
Provide suitable habitat for many attached plants and sessile animals.
Food and haven for animals
Tidal range
Biota typical: crab traps, sunken logs, ropes, oyster shell beds, larger rocks and pebbles.
Small fish and invertebrates feed on food attached to hard substrates.
Shallow Waters
Only a few feet deep
Encountered by
Swimmers
Schools of fish darting away
Nipping toes
Streams of bubbles from bottom
Crabbers
Boaters
Benthic life similar to exposed intertidal zone
Pelagic life in abundant and varied
Too small or rapid to be identified
Seagrass, Meadows, and Weed Beds
Aquatic plant beds
Habitats for many diverse organisms
Softer mud and silt bottoms
Blanket bottom with waving leaves
Small fishes
Variety of invertebrates
Holdfast to roots, leaves or buried in substrate
Protection
Food
Upper Bay and tributaries
Form weed beds
Sago pondweed
Redhead grass
Horned pondweed
Widgeon grass
Mid and lower Bay
Predomiantely are:
Meadows of widgeon grass
Eelgrass
Low tides expose submerged plants
Pass over by boat
Marshes
Closer to shore
Aquatic plants take hold in muddy bottom
Low marsh areas
Plants give way to more diverse plant life in high marsh
High marsh merges with upland terrestrial plants
Each marsh type has its own community life
Attached or clinging to plants, burrowed in marsh soil
Fish and crabs during flooded periods.
Oyster Bars
Cover extensive bottom areas throughout mid and lower CB.
Substrate for sessile invertebrates.
Epifaunal invertebrates: Worms, snails, small crustaceans creep in and out of shells
Graze on attached animals
Graze on oyster
Boring into shell
Small fish
Eggs and larvae attach to empty shells for shelter.
Main beds are subtidal, not easily observed
Very important to Bay ecology
Deeper, Open Waters
Benthic flora and fauna change as water deepens
Light penetration is diminished
Seaweed and rooted plants disappear
Bottom sediments are finer, softer, silty ooze
Fewer invertebrates supported
Oxygen depleted in deepest channels
Specially in summer
Waters above bottom
Many fish and inveretbrate in pelagic zone
Menhaden. Anchovies, bluefish, striped bass, seatrout
Jellyfishes, blue crabs,squid, arrow worms
Not by direct evidence
Fisherman catches unusual fish
Ripples – school of menhaden
Swirl on surface for a moment – cownose ray