Briefing Notes: Anadromous Salmon As Vectors In Energy Transfer

Anadromous Salmon as Vectors in Energy Transfer
Anadromous Salmon as Vectors in Energy Transfer
Purpose/Issue
The importance of this briefing note is articulated in numerous studies with information concerning the Migratory Atlantic salmon which act as the main vectors as far as the transfer of energy and nutrients between marine and freshwater or terrestrial environments are concerned (Thienpont, 2017).There is minimal consideration of higher trophic levels such as animals when it comes to trophic dynamics, despite the fact that such dynamics play major roles in nutrient cycling in addition to energy transfer (Thienpont, 2017).
Summary of Facts
Background Information
Terrestrial animals consume a small proportion of the net primary productivity (NPP), which is the level of carbon uptake and less plant respiration (RES) from the gross primary productivity (GPP). The focus of this briefing note is based on the soil-plant interactions. Approximately 90 percent of energy transfer takes place within these reservoirs. Quite a number of biogeochemical studies targeting classical terrestrial and marine energy transfers tend to entirely ignore animals (Thienpont, 2017). Nevertheless, recognition of the role of animals and their influence is gradually changing, owing to the fact that humans are constantly altering the general outlook of landscapes.
Interactions with other Processes
The marine- to- terrestrial energy transfers are best illustrated using food webs. In the trophic transfers, for example, a living organism tends to feed on the dead organic matter. In this scenario, visualizing the transfer of energy packets in a system is simple. The trophic system is further broken down into detritus and plant-based systems. The movement of energy into heterotrophic consumer organisms from the autotrophic primary producers takes place.
The food web energy regulation takes place either through the bottom-up control or the top-down control. In the bottom-up control, the production at higher level trophic levels tends to be limited by the availability of food at the base of the food web. On the other hand, in the case of top-down control, the abundance of prey species tends to be regulated by predators in the food webs. It must be acknowledged that there is a temporary and spatial variation in the control of energy movement and this owes to the fact that food webs are indeed a complex system.
Critical Facts
With reference to marine-to-terrestrial energy transfer, for this case the anadromous salmon in River Imsa in Norway, the annual energy, nitrogen, carbon as well as phosphorus fluxes by Atlantic salmon across the river mouth has been assessed between 1974 and 1994, a span of 18 years (Jonsson& Jonsson, 2003). According to the studies, it was found that the emigrating smolts total energy contents between years showed variation, but with a standard mean value of about 237*10 3 kJ. On the other hand, the returning adult smolts also showed variation between the years recording a mean average value of 141*104 kJ. This is 5 times more energy coming back to land with adults. Additionally, a single sea salmon would make up to 65 percent as far as the total energy content of the spawners in the river is concerned. Lastly...