I am yanking some world building material and caching it here.
Have fun. I had an interesting baby party this weekend. I'll discuss that another time.
This is the Argyre Sea on Mars and its different ecosystems:
The tubeworm-clam reefs.
The first ecology is the tubeworm and clam reefs. Very large tube
worms that grow to extraordinary heights (or from extraordinary
depths) compared to their Terran cousins form the central columns
of the reefs. These sometimes get tangled with one another. A
fast growing and breeding clam attaches itself outside the range
of the cleaning capability of the worms, these pile up over time
as clams die and grow atop the corpses of previous generations.
The reefs are generally pyramidal in shape, but shaped by currents.
They are often dotted with sea anemonaes and sponges. Where the
reefs breach the water, a specialized grass grows on the coral
along with a silica secreting semisponge that builds a twisted
skeleton up into the air. There is also a metalophillic mussel
that secrets metals into its shell as protection from most lifeforms.
The most important resident of the reef is the metalophillic
crab. It hunts for alien smelling lifeforms and eats them.
When there are none, or very few, the crabs eat the mussels. The
crabs shells are also laced with a very large portion of metal as
protection from each other and predators. The crabs are social.
They have two distinct living behaviors that is causing them
speciate. The first is the krem building subspecies. This one
takes young tubeworm reefs and shapes them into nests called
'krems'. They use this as fortresses. The second variety is that
which spreads to new ecosystems and acts a little like a mercenary,
eventually adopting itself into the local ecology and defending it.
The first is the intended behavior. The second is something that
has developed since the engineers introduced the crabs thousands of
years ago. Both varieties have a once-every-seven year mass exodus.
This is due to population pressure. The alien smelling life and
mussels get depleted and there are too many crabs. The vast majority
of them march off looking for new territory. OFten larva and seeds
stick to the crabs as they leave, helping to spread the tubeworm-clam
ecosystem. It also rips up any foreign ecosystems that the crab
marches encounter. The crab young are far more vulernable as that
they haven't accumulated much metal as yet and many fish eat them.
Designed in the same vein, but rather different in ancestry is the
gem crab. Its derived from landcrabs and is an airbreather. It lives
atop the reefs fighting off foreign lifeform invasions. Its a lot
rarer since there are a lot less water breaching reefs than on earth.
However, they do make use of semisponges like the wasps building their
own aerial krems.
Also living atop the reefs, annotating the semisponge growths are
the sea wasps. These secrete calcium through symbiotes to attach
onto the skeletal structures. The diving wasps' poison is a relaxant
and it uses it to hunt clams. The wasps are actually quite large,
being over 6" (15 cm) long.
The wasps' primary enemies are an armored lobefin fish and the
Aresian Archer. The lobefin that lays its eggs in the sea anemonaes
and crawls onto land to raid the wasp nests. The Aresian Archer
spits a jet of water and sticky saliva that takes down a wasp where
the sharp toothed archer fish deriv can tear it apart.
2. The Kelp Forests
The kelp forests are in deeper waters than the reefs can tolerate.
The kelp grows to much, much longer strands than on earth. There's
not much else that the kelp is noted for. However, some of the
animals that live there are quite interesting and exotic.
The flaminguin is one of those. Retaining its famous color, the
flaminguin has been radically altered from its original form.
The beak has been greatly enlarged, both in width and length, specificly
modified for supporting the filter feeder lifestyle that this bird
deriv lives. Secondly, the neck, while still quite long, is stouter
for the purpose of supporting that neck. The wings have grown immensely
to give the flaminguin a manta-like appearance when it is swimming.
Its legs are much reduced in length to almost, but not quite, penguin
proportions. It lives as a flocking filter feeder for most of the
year in the reefs save for breeding time. Then it seeks out the northern
isles of the Argyre Sea and nests in the beach sands.
The second notable creature is also a bird deriv, but it lives in, or
above, the kelp forest year round. These are the hive cormorant. its
name is a little bit of a misnomer. They do make large floating balls
of kelp that act as communal nests. There are no specific breeders or
nonbreeders, nor queens, workers, or drones. They are flightless.
Their role in the kelp forest is something of a defender and a tender.
Colonies are intensely competitive with each other. If a kelp forest
is large enough, you will see multiple colonies. If there's not
enough distance between the colonies, some very vicious territorial
fights will ensue.
Another resident is the very lethal dart snail. The dart snail breeds
quickly in the presence of food, but its normal food is metalophilic
crab that periodicly wanders it or wanders through in the form of mass
migration. It uses a poison tipped 'foot' that can pierce the weak
points in the crab's shell.
An interesting creature that inhabits the bottom waters of the kelp
forest almost exclusively is the filter feeding sea slug. It is a
free swimmer and grows to be about 10 cm in length. Recalling Amiskwia
of the Burgess Shale, it swims about acting as a filter feeder as well.
The kelp forests are also the spawning grown for the camouflage lobster.
This lobster migrates between the deeper parts of the Argyre Sea and
the Kelp Forests. There is only one thing that is really notable about
this lobster since by and far it is a standard lobster in most ways.
That one notable feature is that it has a symbiotic sponge that grows
on its shell. That sponge filter feeds while the lobster moves along.
It acts as a bit of camouflage for the lobster at times and as something
less than tasty should a predator try to eat the lobster.