Download Non-vascular plants

Benthic Community Types:
They are categorized by their depth zone, primary producers,
and/or bottom type (e.g.: rocky intertidal, mud flat, sandy beach,
kelp forest, seagrass meadow, coral reef, mangrove forest, salt
marsh, deep-sea floor, and hydrothermal vent).
Summary of some highly productive benthic communities:
Community
Latitude
Bottom
Depth zone
Mangrove
tropics
soft
intertidal
Salt Marsh
temperate
soft
intertidal
Rocky
Intertidal
both
hard
intertidal
Seagrass
both
soft
sublittoral
Coral Reef
tropical
hard
sublittoral
Kelp Forest
temperate
hard
sublittoral
Primary Production & Benthic Communities:
• Phytoplankton
• Symbionts of animals
• Benthic microalgae
(unicellular)
• Vascular plants
• Non-vascular plants;
macroalgae (multicellular)
Primary Producers & Benthic Communities:
The contribution of
phytoplankton
productivity to
benthic communities
is variable.
Can be very
important to shallow
sessile filter feeders
like clams and
oysters.
However, after
extensive
decomposition during
sinking deep, its
contribution is
exceptionally low in
the deep-sea.
Deep water sea cucumber
(family Holothuroidea)
Primary Producers of Benthic Communities:
In hydrothermal vent communities of the mid-ocean ridge
system there are animals in symbiosis with another type of
primary producer - autotrophic bacteria that are chemosynthetic.
The animal actually feeds off the bacteria inside them.
Primary Producers of Benthic Communities:
In shallow benthic
habitats animals are also
found in symbiosis with
autotrophs, but these
symbionts are
photosynthetic algae,
called zooxanthellae.
Hard (hermatypic) corals
are prime examples of
this. The coral polyp
gets food from both the
symbionts and the
capture of zooplankton
via their tentacles.
Nematocysts
(“Stinging Cells”)
* All Cnidarians (coral, sea-jellies,
anemones, hydrozoans) have
them.
* Strong toxins that paralyze prey
from zooplankton to small fish.
Why not Nemo?
Primary Producers of Benthic Communities:
In most shallow sunlit benthic communities may receive a
large amount of primary production from free-living benthic
unicellular algae (e.g. diatoms).
Benthic grazers like snails feed on the film of benthic algae on
this mud/sand surface.
Primary Producers & Benthic Communities:
There are also multicellular plants in intertidal (littoral) and
sublittoral benthic communities.
Mangrove trees and shrubs are unique to the tropics.
Salt marshes are mostly in estuaries at temperate latitudes.
These marshes and their estuaries are some of the most
productive and species rich marine ecosystems.
Unlike these intertidal vascular plants, seagrass is found in
the sunlit sublittoral waters of both tropical and temperate
latitudes. These vascular plants are not grasses, but flowers.
Mangrove forest of intertidal tropics.
Vascular marine plants (trees and shrubs)
specially adapted to tolerate low oxygen
sediments which result from tidal inundation.
Also adapted to salt water.
High productivity of these trees is supplied to
marine organisms in the form of detritus.
Mangrove slow wave energy, facilitating the
accumulation (accretion) of sediments.
Serve as an excellent habitat for rearing
juvenile fish and crustaceans.
Health of coral reefs is linked to health of
mangrove forests by trapping excess
sediments and nutrients from rivers and
providing cover for many reef fish.
Salt-Marsh in an Estuary Intertidal
Zone of Temperate Latitudes
Vascular plants (grasses and herbs) adapted to
salty and low oxygen sediments.
Like mangrove of tropics, they are extremely
productive and supply energy to the estuary
ecosystem in the form of detritus.
Salt marshes also trap sediments and nutrients.
Serve as an excellent habitat for larvae and rearing
juvenile fish and crustaceans.
Also provide critical habitat for migratory waterfowl.
Like mangroves, they are endangered by
development and pollution.
Seagrasses are typically found in shallow calm sublittoral depth.
They are vascular flowering plants, unrelated to grasses on land.
Macroalgae (“Seaweeds”)
• Non-vascular plants; no vein-like tissues.
• Extremely productive; yet a minor amount
of global biomass when compared to all
phytoplankton.
• Classified by their accessory pigments:
– Green Algae = Chlorophyta
– Brown Algae = Phaeophyta
– Red Algae = Rhodophyta
Chlorophyta
(green algae)
Found
shallow and
intertidal.
Some are
calcareous.
Ulva spp. and
others are
indicators of
nutrient rich
environments
Phaeophyta (brown algea)
Kelp forest are often on rocky coasts with
nutrient upwelling and high wave energy;
some species can reach 40 m long!
Macrocystis sp.
Kelp Forests:
Like terrestrial forests in that there are layers, or strata.
Recall the role of sea otters as keystone predators.
Rocky Intertidal
Note the macroalgae
covers rocks and a kelp
forest is just offshore.
These are very resilient
communities well adapted
to conditions of high wave
energy and tidal exposure
(desiccation).
Abundant and accessible
supply of phytoplankton and
detritus, as well as nutrients
and sunlight, support a
species rich community.
Rhodophytes
(red algea)
Found deep.
Some species
are encrusting,
helping to
cement reefs
together.
Coral reefs
Structured on limestone
produced by calcareous algae
and hard (hermatypic) corals;
the community is rich in animals
and plants.
In a pristine state, these are very
stable ecosystems having high
species diversity and
characterized by extreme
competition for food, territory,
and reproductive opportunities.
Hard corals are very susceptible
to damage due to low tolerance
range for light, temperature,
nutrient, and salinity conditions.
Where you see mangrove in the intertidal there is seagrass and coral reef in the
sublittoral.
Where you see Kelp forest in the sublittoral, the wave energy is too high and
substrate too rocky for seagrass; the intertidal is usually also rocky.
Areas without kelp or mangrove may have salt marsh in the intertidal and
seagrass in the sublittoral.