Describe how the animal species richness found in the Galeolaria caespitose clump biotype could be affected by pollution
Marine ecosystems are known to have rich biodiversity of species and therefore generally thought of as being stable and resilient to natural progressions of the earth (Johnson, Roberts, 2009) Disturbances in the habitat by unnatural means, such as pollution, can harm the balance of these ecosystems as the species are unable to adapt to the unusual contaminants that would not naturally encounter. One part of this ecosystem is the calcareous tubes secreted by the polychaete worm called Galeolaria caespitoa which are found in large clumps on pier pilings and in the intertidal zones of rocky shores (Ladiges et al. 2010). When viewing the calcareous tubes for the first time it appears that there is only one species, the Galeolaria caesplitoa, present but upon further inspection a diverse range of species can be found including annelids, molluscs and arthropods. These species all exist in this clump and benefit from the stability and protection that the clumps provide, but the introduction of a unnatural occurrence such as pollution can affect the way these animal feed, breed and breathe.

The main source of pollution that comes into contact with marine ecosystems is sewerage which contains waste materials from everyday human activities such as slaughterhouse wastes, animal remains, domestic wastes, industrial wastes, faecal matter and many others (Islam, Tanaka, 2004). The addition of these waste materials leads to an increase in the nutrients in the water and the main nutrient is nitrogen. Nitrogen is a limiting nutrient in natural marine ecosystems and keeps the growth of marine plants in check (Constanzo, O’Donohue, Dennison, Loneragan, & Thomas, 2001). The first organisms to benefit from this increase are algae which increase rapidly in population and create an algal bloom. This limits the sunlight available to organisms that live on the bottom and causes a rapid decrease in the oxygen supply in the water (Sellner, Doucette, & Kirkpatrick, 2003) A drop the oxygen content will cause the marine organisms, such as those in the Galeolaria clump, to suffocate and thus tips the balance of the ecosystem.

Most of the species in the clump would need water for at least part of their reproductive cycle and the depletion of oxygen will definitely have effect on the success of the young. If there are no further generations produced then the species would eventually become die out and possibly become extinct (if this is the only area that they occupy), leaving the niche that they fill to become occupied by some other species that is able to thrive in this environment. The surge in nutrients could be a benefit for the clump in terms of feeding and this could lead to an increase in size and population of the species in the clump depending on how well they are able to adapt.

Pollution can have positive and negative effects on marine ecosystems and it depends on the species and the niche that you occupy as to what the effect would be. For the species present in the Galeolaira caespitoa clump the effect is both positive and negative, but mostly negative. This would lead to the species richness of the clump to decline as some of the species will be able to surivive but others will die out as the pollution becomes too much for them to be able maintain their lifestyle. Adaption to the pollution may also occur in some of the species if the pollution is ongoing and they are able to benefit in some way from it.

References:

1. Constanzo, S.D., O’Donohue, M.J., Dennison, W.C., Loneragan N.R., & Thomas, M. (2001). A New Approach for Detecting and Mapping Sewage Impacts. Marine Pollution Bulletin 42 149-156 2. Islam, S., & Tanaka, M. (2004). Impacts of pollution on coastal and marine ecosystems including coastal and marine fisheries and approach for management: a review and synthesis. Marine Pollution Bulletin 48, 624-649. 3. Johnston, E L., & Roberts D A. (2009). Contaminants reduce the richness and evenness of marine communities: A review and meta-analysis. Environmental Pollution 157, 1745-1752. 4. Ladiges, P., Evans, B., Saint, R., & Knox, B., (2010) Biology: An Australian Focus (4th ed.). North Ryde, Sydney, N.S.W. :McGraw-Hill 5. Sellner, K.G., Doucette G.J., & Kirkpatrick G.J. (2003). Harmful Algal blooms: causes, impacts and detection. Journal of Industrial Microbiology and Biotechnology 30, 383–406.