Symbiosis pertains to the existence of two different organisms in a similar habitat. This ecological relationship thus involves a close interaction that lasts for an extended period of time. It should be understood that symbiotic relationships between two species may be of different forms. A mutual relationship exists when two different organisms live together as obligates and this form of cooperation technically facilitates in the survival of both organisms. A parasitic relationship is a facultative interaction which involves the dependency of one organism on the other.
A commensal relationship, on the other hand, is also a facultative interaction yet this exists between two different organisms which do not affect the existence of the other. Symbiotic relationships have been comprehensively studied in also all animal kingdoms yet majority of the reports that have been published are focused on terrestrial organisms. The recent interest in symbiotic relationships among marine organisms has mainly increased due to the observations that marine species are promising organisms that could serve as resources for drugs.
There is an accumulation of marine natural products that have been isolated from different marine species yet the only information that have been gathered from these organisms are mainly based on its habitat, as well as its unique taxonomic classification. The fluctuating population size of specific marine organisms has been an elusive topic in marine biology and it has been suggested that pollution, as well as food resources may be possible factors that influence population dynamics of marine organisms.
However, it has been lately observed that ecological relationships, especially symbiosis, are the major forces that influence the abundance and distribution of marine organisms in the sea. One of the most interesting marine organisms is the invertebrates, which are commonly characterized to interact with bacterial, as well as fungal species. This symbiotic relationship often results in the abundance of both species and thus may facilitate in the widespread distribution of both species in different marine ecosystems around the world.
For the last few decades, a number of natural products have been isolated from marine species that are collected from marine areas that are featured with symbiotic interactions with other marine organisms (Althoff 529). A well-studied symbiotic relationship is that between the sponges and the prokaryotic species (Lee 254). It has been established the sponges serve as optimal substrates for growth of microorganisms. Sponges are simple marine invertebrate species that thrive through adhesion to solid substratum which are commonly found in the benthic region of the ocean.
Sponges feed through the use of filters, which are equipped with minute pores that serve as passageway for water to flow through. These pores are adapted with smaller canals for microcirculation and these are the sites where microbes, as well as organic molecules are selectively filtered by the sponge. Most of the microbes caught within these filters are engorged, yet for those microorganisms that are resistant to engulfment, these prokaryotes are capable of thriving within the canals. The persistent presence of microbes in the canals of sponges renders these invertebrates as a rich resource for natural products.
The microbes living in the canals of the sponges are inherently capable of inhibiting specific enzymes and thus the appropriate manipulation of these isolates can be beneficial for biomedical applications. In addition, sponges are also good resources of inhibitors of cell division and other cellular pathways. The most common microbes that have been reported to symbiotically thrive within sponges are the cyanobacteria, dinoflagellates, as well as the diatoms. The occurrence of microorganisms within the sponge is considered as a unique ecological setting and may vary depending on the geographic location of the marine ecosystem in the globe.