Lesson Outline

1
Lesson Outline
I. Phytoplankton
II. Benthic Algae
III. Spermatophytes

• Mangroves

• Seagrasses

• Intertidal

• Submerged

2
Algae

• The most abundant of the plants in the sea are
  the algae.

While all algae are single cells, some remain
attached when cell division occurs to form
colonies.
3
Diatoms

• The most abundant algae in the sea are the
  diatoms.

Diatoms are often called the golden brown algae
because of a brown pigment in their cells in
addition to the green pigment chlorophyll.
Diatoms have a two part shell, made of silica
(glass), with a top and a bottom, much like a
petri dish.
Diatoms are found in all waters, coastal and
offshore, warm and cold.
4
Dinoflagellates

• The dinoflagellates get their name from the two
  small flagella that they use for swimming.

The center flagellum rotates the plant around its
axis, while the lower flagellum pushes water away
from the cell, cork-screwing the plant forward.
Armored dinoflagellates have a cell wall of
cellulose plates, referred to as a theca.
Naked dinoflagellates lack these plates.
5
Harmful Algal Blooms

• Dinoflagellates are important primary producers
  in the sea, but a few species produce harmful
  toxins that can kill fish and even cause acute
  illness in humans.

In southwest Florida, the most well-known of the
dinoflagellates is Karenia brevis, the red tide
algae.
This dinoflagellate produces a neurotoxin inside
its cell as it grows, which is released into the
surrounding waters when the organism dies.
This poison is lethal to all fish and some higher
animals.
6
Red Tide Blooms

• K. brevis is always present in Florida coastal
  waters, but the number of cells and the amount of
  the toxin in the water are usually low and cause
  no problems.

Periodically, the algae population undergoes a
sudden explosion, called a bloom, and the water
takes on a reddish brown color and becomes deadly
to fish.
The mechanism that triggers the onset of a red
tide bloom is still unknown.
FMRI Red Tide Page
7
Ciguatera

• Gambierdiscus toxicus, found in coral reefs
  throughout the world, is the source of Ciguatera
  Fish Poisoning (CFP), the most common form of sea
  food poisoning.

G. toxicus produces ciguatoxin, which is passed
up through the food chain to accumulate in high
concentrations in tissues of top predators.
While ciguatera does not hurt the fish, it is
toxic to humans when they consume the fish. This
is why you should never eat large moray eels or
barracuda from South Florida.
8
Coccolithophores

• The coccolithophores have a small spherical shell
  made out of calcium carbonate plates, called
  coccoliths.

During a coccolithophore bloom, the water takes
on a milky color.
When the coccolithophore dies, the coccoliths
fall to the sea floor. In some regions of the
ocean, coccoliths are a significant portion of
the sediment on the sea floor.
9
Benthic Algae

• The benthic algae live most of their life on the
  sea floor in coastal waters.

Algae differ from other plants by their lack of
vascular tissues (roots, stems, and leaves).
Most algae belong to one of three major classes
Chlorophytes (green algae), Phaeophytes (brown
algae), and Rhodophytes (red algae).
Most species of benthic algae have a short
planktonic stage in their life cycle to allow for
dispersion to other parts of the sea floor.
10
Comparing Algae to Leafy Plants
Algae differ from other plants by their lack of
vascular tissues, such as roots, stems, and
leaves.
11
Blue-Green Algae

• The blue-green algae are the most primitive of
  all plants in the sea., so primitive that many
  scientists now consider then to be large
  bacteria.

The blue-greens have no nucleus in their cells,
no chloroplast, nor any other of the structures
that organized cells have. The blue-green algae
are probably much like the first plant cells in
the evolution process.
They are commonly growing on rocks and boat ramps
in the intertidal zone, and since many produce a
slime coating, they can make surfaces very
slippery.
12
Chlorophytes

• The green algae are the most common of the
  benthic algae, and many of these are large enough
  to be seen without a microscope.

One common type of local green algae is sea
lettuce, Ulva, often used as an indicator of
pollutants because it blooms in high nutrient
waters.
Velonia, another green algae found in the Keys,
resembles a large green grape.
13
Phaeophytes

• A good example of the brown algae are the giant
  kelp in California waters.

Kelp grows up from rocky bottoms in cooler waters
of the Pacific, forming large beds that support a
wide variety of other marine life.
Most of these once extensive kelp beds are now
gone, victims of pollution and over harvesting.
In recent years scientists in California have
started to replant some of these kelps with
limited success.
14
Sargassum

• Another member of the brown algae is Sargassum, a
  tropical algae common to Florida waters, both in
  the keys and off Clearwater.

Sargassum grows up one to two meters off the
bottom, held up in the water column by small
round air chambers.
When Sargassum breaks free from the bottom, it
floats to the surface and continues to grow
floating free in the water.
Floating sargassum accumulates in the center of
the North Atlantic, in an area called the
Sargasso Sea.
15
Rhodophytes

• The rhodophytes (red algae) have a red pigment in
  addition to chlorophyll.

One common red algae in British waters is a flat
sheet like algae shaped called Irish Moss.
Along the coast of the British Isles, Irish moss
washes up on the shore during the winter, and
some local farmers gather it for use as mulch or
cattle feed.
16
Corallina

• A common rhodophyte in shallow coral reef
  environments like the Florida Keys is the benthic
  algae Corallina.

Corallina incorporates calcium carbonate into its
tissues, making the plant rigid.
Often as much as 40 of the carbonate formed from
a coral reef is contributed by coralline algae.
17
Spermatophyta

• The spermatophytes appeared very recently in
  evolutionary history, having evolved originally
  on land.

Now a few species of these land plants are
starting to invade the sea.
All marine spermatophytes are benthic and live in
shallow coastal waters where sunlight is
available.
18
Mangroves

• Mangroves are intertidal shrubs that inhabit
  tropical and subtropical shorelines.

All mangroves are halophytes, capable of
extracting freshwater from salt water.
19
Mangrove Species

• Worldwide, there are 69 recognized species of
  mangrove plants.

Locally, four types are common, all very
important to the coastal ecosystem.

• Red Mangrove

• Black Mangrove

• White Mangrove

• Buttonwood

20
The Red Mangrove

• The red mangrove (Rhizophora mangle) is easily
  identified by its prop roots that extend out into
  the water.

21
The Black Mangrove

• The black mangrove (Avicennia germinans) lives
  with all of its roots under the mud, but small
  spear-like projections called pneumatophores
  pushing up out of the mud all around the tree.

22
The White Mangrove

• The white mangrove (Laguncularia racemosa) grows
  with only its roots in the salt water, the trunk
  and branches are above the water line.

23
The Buttonwood

• The buttonwood (Conocarpus erectus), also found
  landward of the red and black mangroves,
  possesses salt glands on the underside of its
  leaves. Its name is derived from the button-like
  seed case it produces.

24
Mangrove Habitats

• Mangrove roots provide attachment surfaces for a
  host of marine algae and animals, protection for
  juvenile species of fish, nesting areas for
  coastal birds, and stabilize the shoreline.

Mangrove leaves falling into the water also
provide an important source of detritus that
feeds many estuarine animals.
25
Intertidal Grasses

• Another type of spermatophyte the intertidal
  grasses.

These are very similar to the types of grass
found in lawns, but adapted for life in the
intertidal zone.
There are two main types of intertidal grasses in
our area

• Cord grass

• Black rush

26
Cord Grass

• The most common species is Spartina, which is
  often along causeways and spoil islands in the
  bay.

Cord grass has a thin flat blade with the stems
and roots located under the mud.
27
Black Rush

• The most common species in Florida is Juncus.

The black rush has a round leaf, with a point on
the end.
In general, the black rush grows in the lower
salinity part of the estuary, farthest from the
sea.
The leaves of cordgrass and black rush provide
habitat and detritus for herbivores in estuarine
waters.
28
Submerged Seagrasses

• The submerged sea grasses live completely under
  water and cannot tolerate exposure to air for
  long periods of time.

Shoal grass (Halodule) has a thin, round leaf and
resembles pine needles sticking up from the mud
or sand.
Shoal grass grows up to the high tide line and
can withstand exposure to air for few hours a day
during low tide.
29
Turtle Grass

• Turtle grass (Thalassia), so named because it is
  fed upon by green turtles, cannot stand exposure
  to the air for more than a few minutes at low
  tide.

Turtle grass has a flat blade about the width of
a finger, with roots and stems under the mud or
sand.
30
Manatee Grass

• Manatee grass (Syringodium), easily identified by
  its thin cylindrical leaves, is a favorite
  portion of the diet of the Florida manatee.

All of these submerged grasses are very important
to coastal or estuarine waters for the food they
produce and the habitat they provide for many
species of marine life.
At one time our local waters were carpeted with
submerged grasses, but most of the grass beds
have been destroyed by coastal development and
pollution.