The Aquatic Ecosystem

biotic Factors: the living factors in an ecosystem

Fish, Sharks, Sea turtles, Coral Reef, Echinoderms, Dinoflagellates, Nymphaealba, Seaweeds, Amazon water lily

Abiotic factors: the non-living factors in an ecosystem

Temperature, water, air, ice (sometimes), rock, sunlight, salinity, nutrient levels, amount of dissolved oxygen

carrying capacity and changes in population

Check Out NBC TODAY Show: 100 Sharks Target School of Fish on hulu

In the link above the NBC TODAY Show news reporters caught sight of the predation in the aquatic ecosystem. In this video the population of the sharks outnumbered the fish causing the fish to get eaten, and the population of the fish to decrease.

carrying capacity- The largest number of individuals of one species that an environment can support.

  Over time the aquatic ecosystem starts to change in different ways, such as there could be over fishing of any species from humans if there is not enough shelter for all the animals. Also, if you have a year in which the carrying capacity of one organism is larger than another organism and they both eat the same food, the larger populated species will beat the other organism to the food, causing the other organism to get none or very little amounts of food. Eventually if this keeps happening, there will be a decrease in one species' population, and a very big increase in another species' population. Another reason for change in the aquatic ecosystem is predation. Take fish and sharks for an example. If one year the carrying capacity of fish is high and the carrying capacity of sharks is low, most of the fish will survive. But if one year the sharks reproduce and the shark population increases, more fish will get eaten causing the population of the fish species to decrease.

Limiting Factors in the aquatic

"Cc3s" by The original uploader was Kils at English Wikipedia - Transferred from en.wikipedia to Commons.. Licensed under CC BY-SA 3.0 via Wikimedia Commons - taken using ecoSCOPE, of juvenile Atlantic herring (38 mm) feeding on copepods – the fish approach from below and catch each copepod individually. In the middle of the image a copepod escapes successfully to the left.

  Limiting factors- any factor or condition that limits the growth of a population in an ecosystem.    Ex. Predation, competition, temperature of the water, sunlight, the amount of nutrients, and dissolved oxygen content.

     A predator/ prey relationship in the aquatic ecosystem is common, sharks and fish, algae and goanna, water snails and tadpoles, and many more other combinations. But one example that stuck out to me was herring rams and copepods.

  Copepods eat microalgae so if one year the copepods food is scarce and they can't survive and they start to die out, the herring rams that feed off of them will eventually start to die too because they won't have food. So their relationship is that if one organism doesn't get food they all don't get food. But, if there is a year where the copepods have lots of microalgae to feed on and the copepods can reproduce using the energy they get from the microalgae, the more that the herring rams can eat, and the more they can reproduce. A limiting factor for this predator/ prey relationship is food.


This is a picture of herring rams
This is a picture of a herring ram's food, a copepod
This is what the copepod's eat to survive, microalgae

energy roles

Energy roles- quantitative measure of the production or consumption of energy by any organism.    Ex. producer, consumer, or decomposer in an ecosystem. Some producers (these are also autotrophs) are, photoplankton, dinoflagellates, seaweeds, and algaes. Some consumers (these are all heterotrophic) are, primary consumer; crustaceans, fish, etc. Secondary conumer; herrin, mackerel, etc. Tertiary consumer; cod, haddoc, etc. (fish)

Each of the energy roles receive their energy from the sun.

The sun gives the producers energy to grow and develop. Without the sun the producer wouldn't be able to get energy for itself to reproduce. A very important role in the energy roles is the producer. Without the producer, the consumer won't have enough energy to use to reproduce, or to survive. The consumers, and everything else depends on the producer for energy.

food webs & chains

A food web is more realistic in the aquatic ecosystem because some organisms eat more than one thing. Some types of fish, sharks, and insects either eat or get eaten by more than one animal. Take sharks for example, they eat fish, but not only fish, they also eat things like dolphins, and sea lions.

A food web in the aquatic would look a little something like this;

If we removed the diatoms from this food web, all the zooplankton animals would have one less resource. Also the dinoflagellates population would decrease because the zooplankton would only feed off of the dinoflagellates. That means more organisms eating the dinoflagellates.

Trophic level &  energy pyramid

producer- 100,000% First level consumer- 10,000% Second level consumer- 1,000% Third level consumer- 100% Top consumer- 10%

The reason behind using a pyramid rather than any other shape is because in an energy pyramid shows the amount of energy that enters each level. Also the pyramid shows how not every bit of energy is transferred over to the next level. You can't show this using a square of circle.

The reason why the producers are at the bottom of the pyramid is because they get 100% of the sun's energy while the primary consumer, secondary consumer, and teritary consumer only get 10% of its prey's energy.   


Chemical equation for photosythesis  

For photosynthesis  to occur the plant needs: sunlight, water (H2O),  and carbon dioxide (CO2)

Photosynthesis takes place in the chloroplasts of a leaf cell.  


Tropism is the turning of all or part of an organism in a particular direction in response to an external stimulus.

Some tropisms you might see in the aquatic are: water hyacinth, water lettuce, frog's bit, water fern, and mosquito fern. These are all plants that grow/move in the direction of the sun. Also known as tropism.

Without the sun, these plants couldn't survive. So without tropism, if the sun moved but the plant couldn't follow it, eventually the plant would die. Tropism allows plants to move towards the external stimulus, in this case the sun. So tropism allows the plant to get sun, and with the sun's energy given to the plant, photosynthesis can begin to happen. Also these plants are producers, they are food to all the consumers. So without tropism the plant gets not light causing it not to grow, and that gives the consumers one less thing to eat.


Each level in the food chain needs to be balanced for the survival and existence of life. So just as phytoplanktons ( the foundation of ocean food web ) are important to provide energy for higher level consumers, equally important is the role of decomposers to provide energy by decomposition of dead matter and releasing nutrients and making it available to the phytoplankton and clean up the aquatic.

Bacteria, fungi, hagfish, worms, zooplankton, and shrimp are some decomposers you might find in the Aquatic.


Adaptation is essential in order to survive and grow. The ability to adapt is very important for humans and animals. If you can't adapt to the weather or area of a certain place, there is a chance joy is not going to come to you. If there is an animal that can't adapt to their environment, there is a big chance that the animal will get eaten by another animal. There are different kinds of adaptations, there is structural, and behavioral.

  Aquatic plants have adapted to living in freshwater or saltwater, that is why they are called aquatic plants. Some plants that have to adapt are,  

  • Amphiphytes: plants that are adapted to live either submerged or on land.
  • Elodeids: stem plants that complete their entire life cycle submerged, or with only their flowers above the waterline. These types of plants have to adapt above water as well as below.
  • Isoetids: rosette plants that complete their entire life cycle submerged, they have to adapt to the kind of water they live in.
  • Helophytes: plants rooted in the bottom, but with leaves above the waterline. Plants have roots at the bottom and they need to adapt the the underwater. Also at the same time adapting to the above water environment.
  • Nymphaeids: plants rooted in the bottom, but with leaves floating on the water surface. Adapting to the outside and underwater.

Animals which live in aquatic habitat are adapted by structural modification of the structures of their body and also by developing the new structures. Aside from the salt concentration adaptation, freshwater and marine animals have similar adaptations. As mentioned before, water conditions can vary and thus can only support organisms specific to those conditions.Smooth, almost furless body helps aquatic mammals move through the water with little friction. Dense fur helps streamline the bodies of some aquatic mammals and keeps them warm. Webbed feet, formed from thin skin between the toes, work like paddles. Nostrils close when the animal goes under the water. They have fins and tails to help them in swimming. Their tails give them directions.

The gills on a fish
The webbed feet on many birds

If we placed a fish in the dessert, the fish would have a hard time adapting to the ecosystem because of the lack of water. The affect would be that the animal wouldn't get what it needed to survive and would most likely die. Also the animal wouldn't be able to reproduce, or get energy. If you took an animal out of one ecosystem and placed it into another, ultimately it would affect the food web, and population of that species, and/or ecosystem.

Natural Selection

Natural selection - the process by which certain inheritable traits become more common in a population over successive generations. An example of an organism that has been naturally selected in the aquatic ecosystem is a crocodile. A crocodile’s physical traits allow it to be a successful predator. Its external morphology is a sign of its aquatic and predatory lifestyle. Its streamlined body enables it to swim swiftly, it also tucks its feet to the side while swimming, which makes it faster by decreasing water resistance. They have webbed feet which, though not used to propel the animal through the water, allow them to make fast turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in shallower water, where the animal sometimes moves around by walking. Crocodiles have a palatal flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during submergence. These help crocodiles live and survive.

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2 years ago

I love your tackk! It is very neat and easily understandable. I love how your provide resources as well. Great job, Whitney!

2 years ago

This is awesome! Everything is well-written and accurate. I would just find another picture of the fish, it's a little blurry.

2 years ago

@emmagervasi Thank you Emma!

2 years ago

@kaitlynnorman Thanks so much Katie!

2 years ago

Wow, Amazing. The only thing i see wrong is having multiple single pictures next to each other. (One on top of another).

2 years ago

@sethmaginnis1 Thanks Seth! Yep that is one thing I don't know how to fix (the one on top of the other), but I will do my best to fix it.

2 years ago

I love all your pictures! They are very high quality pictures.

2 years ago

Overly good

2 years ago

@matthewfranco Thanks Matt!

2 years ago

@chloedillard Thank ya Chloe😜