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Typical Habitats
of the Bay
and
its Tributaries

Eight Types of Habitats

Sand 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 100s 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

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