Organismal Overview (Why should be care about the organismal impacts of GMOs?)
Effects of GMOs also occur on an ORGANISMAL level. The largest concern in aquatic environments is the negative effects that genetic modification can have on organisms and their ability to reproduce. If an organism is no longer able to reproduce, then it no longer has a purpose in nature because it cannot pass on its genes. Knowing this, it is important to fully understand how much genetic modifications can impact organisms in aquatic ecosystems.


There have been many different studies done in order to find the effects that GMOs have on land organisms as well as aquatic organisms. With much less research being done on aquatic ecosystems, it is necessary to look at some studies done on land organisms and make inferences into what body systems could be affected in an organism on land as well as in water.
One important aspect to look at is the consumption of GMO feed by organisms. A study performed on male and female rats determined the impacts of the ingestion of GMOs.Some important factors to look into include the effects on overall health and reproduction. The study used MON863 (which is a Monsanto Company GMO) that was given to the rats as feed. During this study, the overall physiological health was monitored. There were small variations in growth shown in the experimental rats. This included a 3.3% decrease in weight in males compared to the control rats and a 3.7% increase in females compared to the control rats as well as signs of kidney toxicity and their tryglyceride levels increased by 24-40% in the females (Seralini et al., 2007). These changes could affect the long-term health and reproduction of these rats in the future. A decreased weight in males could mean a decreased muscle volume, decreased strength, and decreased survival rates. The increased weight in females could lead to increased body fat, and this unhealthy weight gain could lead to more serious health problems. An example of this could be that the heart has to work harder, therefore causing more stress to the heart and decreasing its effectiveness and agility. This could also cause decreased fertility for the female rats. The kidney toxicity would eventually lead to kidney failure and a high tryglyceride level could lead to heart failure. These impacts could occur before the rat has the ability to reproduce, decreasing the number of offspring produced. All of these detrimental affects caused by the GM feed show how these crops, if ingested by non-target organisms, can be harmful.

In a study done on a headwater stream ecosystem, nontarget stream insects were fed Bt corn (genetically modified corn). The caddisflies who were fed the Bt corn showed reductions in growth and increase mortality rates (Rosi-Marshall, 2005). Their reductions in growth and increased mortality rates may also lead to changes in reproduction, as the numbers of offspring are likely to decrease since fewer caddisflies are present for reproduction.


In another study conducted on rats, researchers looked at five different generations to see if being fed GMO potato as well as non-GM potato would have any reproductive or toxic effects. Experimental rats were fed a pellet that contained 5% GM potato 10 weeks prior to mating (Rhee, 2005). There were no GM potato-related changes in body weight, food consumption, reproductive performance, or organ weights. This study advocates that there were no negative or adverse effects on the reproduction or toxicity in the rats that were studied. Since this study concluded very different results than the study above by Gilles-Eric, the difference between GM crops and their effects must be taken into account. There were detrimental effects from GM corn but this study done by Rhee concluded no detrimental effects from GM potato. Further investigations must look into the differences in these case studies in order to answer the question, “Do certain GM crops have negative/positive/no effect on organisms?” Just by looking at this data, it is clear that different crops (maize, potato, grass, ect.) have different effects on organismal body systems. To pinpoint what ingredient in the GM food is causing the impacts, if there are any impacts, it is necessary to look into the composition of the feed.

Another group of researchers looked at livestock and the impacts that GM feeds on nutrition and physiology. They also took the time to make sure that the GM and non-GM feeds were made up of similar components, and they were substantially equivalent in composition. After these feeds were distributed among the control and experimental groups, it was found that food intake, body weight, body condition, and reproductive abilities were unchanged between the two (Bertoni, 2005). This assessment emphasizes the fact that livestock remain unaffected when fed GM food. Perhaps if the GM feed and non-GM feeds in all of the experiments were checked for their compatability, the results found would vary.

With many different conclusions being drawn from GM feed effects, it is difficult to determine the complete impact on organisms as a whole.When looking specifically at potential reproductive issues dealing with GMOs and their effects, it is difficult to identify what exactly is causing the differences in experimental findings. To test specifics, a risk assessment is needed to ensure the problem-causing agent is truly the GMO being fed to the organism. There have been some detrimental results from genetic modification being included in the organism’s diet, as well as results that show there to be no detriment to the organism at all. The only way to further our knowledge on this concern and pinpoint what is causing these differences is to conduct more in depth research in aquatic ecosystems. Also, with most aquatic research being done in captivity, more accurate information could be found from testing these organisms in their wild habitat. That way the ecosystem, organism, and cellular levels could all be taken into account as they are in nature.

Integrative Case Study: How GMOs Affect Atlantic Salmon on The Organismal Level
When looking specifically at Atlantic salmon and the impacts of GM feed, there have been numerous studies conducted in the past 10 years. By looking at the same species throughout all levels of biology, it became apparent that there is a common link making it possible to integrate the effects that GMOs have on Atlantic salmon.


In a primary study done on Atlantic salmon, the intestinal and histological health of the salmon was observed when being fed either traditionally or GM plant products. For this study, six different fishmeal diets (each with various percentages of GM in the composition) were created in order to test the amount of GM food, if any, caused a change in the health and overall characteristics of the Atlantic salmon. After eight months of observation, it was shown that there were no effects on the intestines of the salmon fed with GM food. There were also no histological changes to the caeca or mid-intestine of the salmon. These findings show that the level of safety between GM and non-GM products is the same, and that no impacts were observed for the ability for these salmon to reproduce (Sanden, 2005).There were also no changes noticed in an additional study done on Atlantic salmon that were fed a GM diet.
In this study, many details were taken into account in order to ensure accuracy of the results. GM feed in this study was checked to make sure that all of the diets were composed of the same 'compositional equivalent' (Hemre et al., 2005). This was an excellent way to ensure that the same starch, sugar, and carbohydrate levels were available in both the GM and non-GM feeds. The food was then provided to the Atlantic salmon and no significant differences were noted. The relative sizes of the liver and kidney were the same for both dietary groups. Along with body size and composition, there was no increased mortality or changes in hematological values. The importance of making sure that the compositions of the feeds were the same for both dietary groups is demonstrated in the fluency of this data.
Another study done on Atlantic salmon in 2007 showed different results than the studies above. They had the objective of evaluating fishmeal diets with an increasing amount of GM maize and their impact on the salmon (Hemre, 2007). After 82 days of the study, there was a significant lower food intake in the fish fed the GM maize. This could mean that the fish either had a decreased appetite, or some body system change was not allowing them to consume the same amounts as the fish fed non-GM maize. This could have an impact on the salmon’s ability to reproduce since they cannot consume enough food to have energy to produce the same amount of offspring as salmon fed non-GM feed. This study also concluded a lower final body weight in those fish fed the GM maize, which also has an impact on salmon energy and the salmon’s ability to reproduce.

An Atlantic Salmon being observed for intestinal changes after being fed GM maize.

A further study also confirmed the data above showing a negative impact on Atlantic salmon fed GM maize. It was found that GM maize led to a decreased growth rate as well as a lower food intake for similar diet groups (Sagstad, 2007). This was said to have happened because of a "secondary effect" that the GM maize had on the salmon's taste in feed. They may have a preference for the taste of non-GM feed so they did not eat as much when given feed containing genetically modified materials. The changes were so slight, though, that they did not result in significant morphological changes. Even though there was a change detected in the Atlantic salmon being fed GM feed, the change was not large enough to have an impact on the organism’s well-being, health, or reproduction abilities.

Based on these findings, it is apparent that there are changes occurring on the cellular level, as previously talked about, as well as the organism level. These organismal changes, however, may eventually have an impact on the ecology and population dynamics of these salmon. This “full circle” approach allows researchers to view the impacts of GMOs as a whole, not just in pieces.