The function of algae in biotic association

The relationship among different living beings within their living habitat and feeding habit is termed as biotic association. The sequence of eating and being eaten in the community is called food chain and the network of the food chain is called food web. Food web is the biotic association of diverse organism interacting to each other within a particular habitat. Likewise other organisms the algae also have amazing relationship with other organism. Algae provide the food for amphipods and other terrestrial animals and also support the growth of decay microorganisms. Algae show the symbiotic association with prokaryotes, protists, fungi, animals and plants.

Some algae function in food wed as predators as they feed the large number of bacterial population.  Some other eukaryotic algae prey on both bacteria and small eukaryotic cells. Certain saprophytic algae ingest the organic material and most algae are photoautotroph.  Heterotrophic microbes consume dissolved and particulate organic carbon released from algae. Algae play an additional role in food web as they defend themselves against herbivorous by means of toxins. When such toxins reach in higher concentrations, they influence food webs dramatically by causing illness and death of other organisms, which may affect the health of humans and other vertebrates also. Algae secrete the detritus which supports the growth of heterotrophic protists and other prokaryotic organisms. The algal detritus may be completely or partially consumed by decomposer bacteria and fungi, as well as the animals like ostracods, amphipods, copepods, salps, fish etc. Algae secrete the various kinds of organic compounds which include amino acids, peptides, amino sugars, carbohydrates, lipopolysaccharides and dimethylsulfoniopropionate.

Microscopic protists also consume the algae by the process of endocytosis, they are termed as phagotrophs. They are either phagotrophic flagellates or ciliates or amoebae. The marine herbivorous rotifers, crustacean, cladocerans and copepods also consume the algae. The larger herbivorous animals like oligochaete worms, freshwater depteran larvae, marine amphipods and pteropods are also consume the algae. Other larger animal like limpets, mussels, crabs, sea urchins, insects and fish also consume the algae. The rotifers are known to grow better on some types of algal food than others. The algal species vary widely in their ingestibility, digestibility, content of mineral nutrients and other essential organic compounds. The algal species may be used for cultivation of shellfish thus providing human food too. Some species of algae like Asthrospira has traditionally been harvested and consumed in sauces.

Therefore algal food web associates the organic exudates and detritus that fuel microbial loops, herbivory interactions and algal defensive mechanism that may also affect the life of human and other animals. The different types of microorganisms attack the algae causing disease and death. Such disease microbes recycle the organic carbon of their algal hosts and influence the food web.