Download Shallow Seas

Shallow Seas
Seagrass, Algae, and Coral Reefs
Seagrass vs. Algae
 Seagrasses
Found in the plant
kingdom
Have actual roots below
the mud, transport
tubes (xylem and
phloem) for transporting
nutrients and water
around the plant
 Algae
Found in Kingdom
Protista
Can be multicellular or
unicellular
Have structures to
attach them to surfaces,
but no underground
root systems
No transport tubes
Seagrass Beds
General Characteristics
The only flowering plants that live entirely in the
sea
Growth of Seagrasses
Grow best in shallow, sandy areas with
clear water, like lagoons or enclosed bays
Thrive in tropics
Tolerant of varying salinity levels
Structure
 Roots – (unlike seaweeds)
absorb nutrients from the
sediments / mud and anchor
the plant
 This recycles nutrients that
would otherwise be locked up
below the surface
Underground Roots are
intertwined, wrapped around
each other
 This helps Stabilize the sand
and sediment of the ocean
bottom
Protects from erosion
Encourages buildup of
sediments
 helps other species to gain a
foothold in the shifting sand.
Structure
 Leaves
Perform
photosynthesis,
providing the plant with
a source of glucose
 Flower
Structure for
reproduction
Seagrass Bed Communities
Seagrass beds are highly complex
Attracts a high biodiversity of species that
live and rely on them
Biodiversity in Seagrass Beds
Seaweeds (algae) grow on the leaves or
fronds of the seagrasses
Biodiversity in Seagrass Beds
Sedentary organismslive on the grasses
Ascidians
Hydroids (sea lace)
bryozoans
Camoflauge in Seagrass Beds
Some animals live in
seagrass beds their
entire life, and have
evolved to be adapted
for it
crabs
 Seahorses & seadragons
Seagrass Beds as Nurseries
Some species use seagrass beds to raise
their young
Seagrass Beds as Food Sources
Some animals eat the seagrass plants
dugongs
manatees
Sea urchins
Algae – Kelp Forests
General Characteristics
Kelp refers to a type of brown seaweed
Kelp forests grow best in cold, nutrient-rich
waters, extending into polar regions
Kelp Growth
Live attached to rocks in semi-shallow water,
top edge of some kelp beds can be seen at
the lowest tides.
Grow densely on rocks and rocky slopes down to
around 30-70 feet deep
Need light for photosynthesis
Can grow deeper in clearer water, but sparsely due
to less light for photosynthesis
Kelp Structure: multilayered environment that
different organisms live on
 Holdfast- Instead of roots, kelp has a root-like
anchor that helps keep the kelp to the rocky
bottom
 Frond- palm like leaf structure, One stipe, with
pneumatocysts (gas bladder) and blades,
make up a single frond.
 Blade- like a leaf. It extends horizontally in the
water to get sunlight for photosynthesis
 Gas Bladder- floats on the stem; Gas-filled
sections of the stipe, called pneumatocysts,
help keep the kelp upright and oriented
towards the surface
 Stipe-stem or trunk, transports nutrients to the
holdfast below and the blades above.
Kelp Communities: within the kelp
forests the water is calmer
 Supports rich marine communities
 Used mostly as shelter
 Only about 10% of kelp is eaten directly
 The rest enters the food chain as detritus or dissolved organic
matter.
Holdfast Habitats
 Small animals hide from predators in the small
spaces of the holdfast
 Sea urchins and limpets found grazing on the
ocean bottom, on the red seaweeds growing on
the kelp in deeper water
Frond Habitats
 Actively growing kelp Fronds
are coated in slime for
protection from being eaten
Bryozoans
 as growth slows later in the
season, the fronds may become
covered with bryozoans,
hydroids, and tube worms.
 Some species grow or live on
the fronds
Hydroids
 Reduce the light reaching the
fronds for photosynthesis
 Kelp shed their fronds to get rid
of the pests
 sea floor beneath the kelp may
be covered with marine growth,
or relatively barren if heavily
grazed by sea urchins
Tube worms
Seagrass and Kelp Nurseries
Seagrass beds and kelp forests are
important refuges for young fish that need
to hide from predators until they reach
maturity.
Many fish do not live among seagrasses
or kelps as adults, but come into these
habitats to spawn, giving their young a
greater chance at survival.
Seagrass and Kelp Nurseries
Small fish find an abundance of small prey
in the form of tiny worms, crustaceans, and
mollusks among the seagrasses and in the
sediment beneath.
These young fish are often camouflaged in
shades of green and brown to avoid
detection.
Seagrass and Kelp Nurseries
Some herbivorous fish from surrounding
reefs come into seagrass beds only at
night.
Seagrass beds are important nurseries for
some commercial invertebrates, including
shrimp and cuttlefish
Many young fish are camouflaged for this
environment, and look completely different
than the adults