Integrative Case Study: The Integration of Atlantic Salmon on The Cellular, Organismal, and Ecological Levels.


To aid in the understanding of the effects of genetically modified organisms in the environment, it is necessary to evaluate the cellular, molecular and organismal levels. Atlantic salmon have been studied for effects by genetically modified organisms in all three of these categories. This case study demonstrates how each level of biology relates to the others, and how integrating multiple fields may lead to a better understanding of current topics in science.

At the cellular level, the consumption of genetically modified crops via runoff in aquatic systems can alter osmoregulation in Atlantic salmon. This cellular and molecular effect is necessary for the survival of salmon as it regulates Na+, K—ATPase activity in both saltwater and freshwater habitats. One important aspect of this regulation is the increase in growth hormone during smoltification when Na+, K—ATPase activity increases (Handeland, et. al. 2003). An increase in growth hormone will increase the size of the organism as a whole. The variation of salinity and feed further confirms that diet is a key factor in osmoregulation as well as mineral regulation in these salmon (Imsland, et. al., 2011). Both the potential alteration in growth and minerals will lead to further ecological effects in these salmon.


One obvious effect is the increase in growth, leading to alterations on the organismal level. This change further extends to the ecological level as increased or decreased size will alter the amount of food and mineral consumption by other organisms. If there are changes in the amount of food consumption (increased or decreased), this will lead to changes in food availability for other populations.


Mineral deposition is one important factor, as nutrient deposition by salmon is also important in primary productivity (Yanai, 2005), direct consumption by bears, birds and macroinvertebrates (Bretherton, 2011), and microbes that release the nutrients into water (Kline, 2007). These nutrients are necessary for the stability of aquatic ecosystems (Holtgrieve, 2011), meaning that the failure of cellular mechanisms and reproduction cause alterations in the function of the ecosystem.


There are several other cellular mechanisms affected by GM crops, including cellular D-glucose levels and the recruitment of macrophages after consumption (Bakke-McKellop, et. al., 2008). These likely lead to further organismal consequences, but are currently unknown. On the organismal level, one study found decreased growth rates in salmon in relation to decreased food intake (Sagstad, 2007), possibly because of the feed taste. There are further studies needed in order to piece these results together, and determine how they will alter the ecosystem.


Overall, it is clear that GM feed may alter ecological functions, as the alterations in the cellular and organismal function may lead to changes in population dynamics and biodiversity. If GM feed negatively or positively impacts salmon, this will alter the population dynamics of other organisms that depend on them for consumption or their deposition of minerals. Alterations in the populations of pike (Kekäläinen, 2008), other fish, birds, and seals could occur (Thompson, 1999) if salmon populations change. This could also change the population densities of the prey of Atlantic salmon including fish and amphipods (Fraser, 1987).


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Further integration occurs in the below syntheses that relate the cellular, organismal, and ecological levels in one specific area for future research.



Future Directions 1

Future Directions 2

Future Directions 3