Species Breeding Grounds

Estuaries are unique ecosystems  with distinctive community compositions.  Estuaries are delineated as areas where fresh waters from streams mix with salt water from the ocean.  The fresh water entering the estuaries is very rich in nutrients that have been carried by rain, and other water, running over the land.  The salt concentration of an estuary's waters is largely determined by the rising and lowering of tides.   On Arida, the tides of the Unola Ocean fluctuate daily, on a  cycle set by their relative position to the "Ring of Fire."  Many organisms are thought to have evolved in the relatively sheltered and rich waters of the estuary habitat.  Many species give birth to their young in the sheltered waters of the estuary ecosystem.  Large numbers of organisms are found in the nutrient rich and shallow waters of the estuaries on Arida.  Many large estuaries are found upon the north eastern shores of the Unola Ocean, near the mouths of the Evita and Chopin Rivers. 

Community Members

The estuaries of Arida harbor a vast array of animal and plant species, each filling a particular niche within a specific habitat within the ecosystem.   There are several dominant organisms filling essential roles in the estuary ecosystem of Arida.  Primary Producers, Primary Consumer,  and Secondary Consumers are all found in the estuaries.  Primary Producers harness the energy of the star Venda and produce their own food.  They are eaten by the primary consumers, who in turn are eaten by the secondary consumers.  (Microscopic Decomposers are assumed to assist in the decomposition and recycling of organic matter in the estuary environment.)


     Primary Producers

     Primary Consumers

     Secondary  Consumers

      P. Photosynthia     

     Salt Snails        Sand Wedge 
     Asperdoma      Quick Fish  
     Heliotropus       Squat Jellies
     Mud Foot       Flapeelia 



The Primary Producers in the estuary are the plant-like organisms which photosynthesize and generate energy in the estuary ecosystem.  Primordia Photosynthia and other Plankton found in the estuary environment are prominent primary producers.  The multicellular green algae-like Asperdoma is very wide spread in Aridan estuaries.  It is commonly found covering rocks throughout the estuary's clear and shallow waters.  

The free floating Heliotropus plant is also a common primary producer found in the estuary.  Its mixed green and brown pigmentation is adapted to surviving in murkier estuary waters.  Heliotropus is a favorite food of Flapeelia.  

Biforma biforma, or the Mud Foot, is the most ubiquitous plant found in Aridan estuaries.  It provides excellent food and shelter for fish and other organisms.  The Mud Foot also functions as a Consumer, in that it "eats" the insect-like creatures it catches in its false flower.  The Mud Foot also helps stabilize muddy substrates in the estuary.  Several species, including the Quick Fish and Salt Snails, munch on the Mud Foot's foliage.


The Quick Fish and Salt Snails are the most abundant Primary Consumer species found in Aridan estuaries.  Squat Jellies are found in the estuary as well.  Quick Fish constitute an enormous fish family whose members include both fresh and salt water varieties.  In the estuaries many Quick Fish species are represented.  Some spend their entire lives within the estuary environment.  Many others enter the estuaries for spawning and reproductive purposes.  There are other Quick Fish species which migrate from the fresh water streams to the ocean and back again.  They, like the salmon species on Earth, spawn in the fresh waters and return to the ocean for an extended time, only to return again to the fresh waters to eventually complete their life cycle.

The Squat Jelly is a curious organism.  As a true heterotroph,  It feeds upon the Plankton and also the small Flapeelia eel-like organism.  Salt Snails inhabit the estuary environment in impressive numbers.  The Salt Snails are similar to marine species on Earth except that their shells have assumed a hexagonal rather than circular shape. Salt Snails forage on Asperdoma and the Mud Foot plant.  Salt Snails are also scavengers, they will feed upon dead animals and plants in the estuary. The Flapeelia is a small eel-like creature endemic to the estuary environment.  It eats plankton in addition to its chief source of food, the Heliotropus plant.  Flapeelia hide amongst the water plants' foliage from its primary prey species.  Squat Jellies, Quick Fish, and Sand Wedges feast upon the defenseless Flapeelia whenever possible. 


The Sand Wedge reigns supreme as the top consumer in the estuaries of Arida.   Sand Wedges will eat most of the animals found in the estuary waters. Their diet is chiefly composed of Quick Fish, Squat Jellies, Salt Snails, Flapeelia.  Like other Wedge species, the Sand Wedge is extremely quick and can capture and devour its prey in short order.  Sand Wedges often bury themselves in the sand and mud of the estuary bottom, then strikes out at their prey as it swims near.   Sand Wedges also forage through loose sands in search of smaller more sedentary foods such as shelled animals and worms.  




Estuary Food Web


Energy Distribution

The movement of energy through the Aridan estuary ecosystem is generally as expected.  The amount of kilocalories generated by the primary producer species is an impressive 10000 kilocalories per square meter per year.  This number is higher than what is typically found on Earth.  The difference is most likely due to Aridan climatic factors.  The average amount of starlight  received on the plant surface is greater than on Earth, and the angle that it strikes the planet is less acute.  Arida is a low albedo planet - it absorbs much more energy than Earth.  As a consequence, plant life on the planet grows extremely well, given adequate water.  The abundance on the base of the energy pyramid helps assure overall ecosystem health.  Aridan estuaries are particularly rich with life.



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created by G.Moore