Transcript Marine life 2: phytoplanktons to invertebrates

Marine Life
and Ecology
2. From phytoplanktons
to invertebates
Virtually all primary
productivity on land comes from large plants
… seaweeds such as these do exist, but they
need shallow water where Sunlight is available
and firm substrate for anchorage by their
holdfasts.
… whereas microscopic unicellular plants
(diatoms, dinoflagellates) and algae account
for most of the ocean’s primary productivity.
Phylum Phaeophyta or
Brown Algae
Seaweeds are large
marine multicellular
algae. These nonvascular plants are
grouped as green, red
and brown algae.
Phylum Rhodophyta or
Red Algae
Phylum
Chlorophyta or
Green Algae
Unicellular
Marine Life
Size
Bacteria
<5 m
Skeletal
material
None
Habitat
Benthic
Producers
(photosynthesizers)
None
5 m
Surface waters
CaCO3
3-10 m
warm open ocean
SiO2
5-40 m
cool open ocean
SiO2
20-80 m
upwelling
10-50 m Cellulose warm quiet waters
or none
Blue-green algae
Coccolithophores
Silicoflagellates
Diatoms
Dinoflagellates
Consumers (Oxidizers)
Protozoans
Radiolarians
Foraminifera
50-500 m
100-1000 m
SiO2
SiO2
Surface waters and
sediments
Moss
Fern
Marsh grass
Kelp bed
Cell counts per 50 cm3 of water
800
Diatoms
Coccolithophores
400
Dinoflagellates
0
0
800
1600
Distance from shore (km)
2400
Land plants
Marine plants
Spermatophytae
Spermatophytae
(seed bearing plants)
(seed bearing plants)
Pteridophytae
(ferns)
Bryophytae
(moss)
Thallophytae
Thallophytae
(algae and fungii)
(algae and fungii)
Mangroves thrive in warm tropical
waters, kelp prefers cooler waters.
Photomicrograph
of tiny marine
bacteria (~1 m)
attached to the
larger diatoms.
Cyanobacteria
(x 3000 magnification)
Diatoms
Coccolithophores
Dinoflagellates
Marine animals
Marine invertebrates


Phylum Porifera (Sponges)
Phylum Cnidaria
(Corals, Portugese Man-of-War, Jellyfish)

Phylum Mollusca
(Clams, Snails, Octopi)

Phylum Anthropoda
(Crabs, Shrimp, Lobsters, Copepods)

Phylum Echinodermata
(Sea Stars, Brittle Stars)

Marine worms (Polychaeta,
Vestimentifera)
Marine vertebrates
As Robert May (Scientific American, October 1992) has
argued, most of the species display a predictable
relation between physical size and population
size: the smaller they are, the more
abundant they tend to be.
Implication: More species
< 1 mm await discovery
than ones > 1 cm.
1 mm
1 cm
Characteristic size (meters)
1m
Jellyfish are cnidarians which lack the polyp stage of the life
cycle. Therefore, they are always in the medusae stage. They
are considered plankton because they cannot swim on their
own--they are dependent upon the current to take them
places. They are normally found in the epipelagic layer of the
ocean.
The deep scattering layer
Zooplankton concentration
shows two peaks in the very
productive summertime
subarctic or cold temperate
waters:
• some are feeding at the surface,
while
• others are resting, or metabolizing
what they have consumed, just
below the photic zone.
In contrast, in the tropics, the
zooplankton concentration is
on the photic surface waters.
Yellow sponges
on a reef.
Sponges are
filter feeders they filter their
food particles
from water that
passes through
them.
An anemone is a cnidarian, a simple animal
consisting of an open gut surrounded by
tentacles - stinging cells in these tentacles
help paralyze small prey that the tentacles
then help bring into the gut.
Jellyfish, a cnidarian, consuming a fish that it
has captured
Is Jellyfish a plankton or a nekton?
Different species of jellyfish have different innate buoyancies, so when
they are not swimming, some hang neutrally in the water, while others
slowly sink when passive; a few float. Some of them are rather small,
often less than an inch (or 2.5 cm) and also often found in freshwater
as well are subject to the oceans currents, tides and waves for their
large-scale movements.
But giants like the Lion’s Mane Jellyfish*
are known to be excellent swimmers. This
is the largest known species of jellyfish,
and is mostly found in cold waters north
of 42°N (Arctic, North Atlantic and the
North Pacific) and off Australia and New
Zealand. The largest recorded specimen,
found washed up on the shore of Massachusetts Bay in 1870, had a bell (body)
with a diameter of 2.3 m (7 feet 6 inches)
and tentacles 36.5 m (120 feet) long. It
was longer than a Blue Whale, the longest
known animal in the world.
* The Sherlock Holmes story, The Adventures of the
Lion’s Mane, is centered around a professor who is mysteriously killed. At the end of
the story, Holmes discovers the killer is a huge Lion's mane jellyfish.
Bizarre new jellyfish discovered
18:03 07 May 03
NewScientist.com news service
A bizarre new species of jellyfish
has been discovered in the deep
waters off the Californian coast.
The bell-shaped creature spans a
meter in diameter and has been
nicknamed "big red", because
of its unusual deep red color.
The US and Japanese teams
that discovered it say the species
deserves its own subfamily.
Tiburonia granrojo was
discovered using video cameras
on deep-diving remotely operated
vehicles (ROVs). Its color and
shape set it apart from its other
gelatinous relatives, but it has
another unusual characteristic —
a complete lack of tentacles.
Phylum Porifera
Purple and Yellow Tube Sponge
Orange Finger Sponge
The animals of the
class hydrozoa
have both a polyp
and medusa
stage.
Siphonophores
are a type of
hydrozoan with a
float for buoyancy.
Probably the most
famous of these is
the species
physalia, the
Portugese-man-ofwar, which is a
type of colonial
siphonophore.
Marine worms include
Octopus
Mussels
krill
crabs
barnacles
sea urchin
starfish
sea cucumber