Question

In an Antarctic pelagic community, the primary producers are phytoplankton, which serve as food for the dominant grazing zooplankton, especially krill and copepods, both of which are crustaceans.
These zooplankton species are in turn eaten by various carnivores, including other plankton, penguins, seals, fish, and baleen whales. Squids, which are carnivores that feed on fish and zooplankton, are another important link in these food webs, as they are in turn eaten by seals and toothed whales (Figure 1).

Figure 1: Arrows follow the transfer of food from the producers (phytoplankton) up through the trophic levels. For simplicity, this diagram omits decomposers.

Antarctic krill (Euphausia superba) is an important source of food for whales, seals, squid, fish, and many species of birds. Its abundant biomass is one of the largest on Earth. Figure 2 compares the effects of krill harvesting on species richness within two small sections of the Antarctic region; one section was subject to krill harvesting and the other section was not.

Describe how the autotrophs facilitates the flow of energy through the Antarctic ecosystem. In the Antarctic pelagic community, there are three types of seals. The leopard seals eat birds, but the crabeater and elephant seals do not. Explain how the interactions between seals and other species may affect their food sources.
Identify the independent variable of the data graphed in Figure 2. Explain one way this variable is affecting the biodiversity of the Antarctic food web.
Analyze the change in species richness with or without krill harvesting. Predict how the removal of krill from the Antarctic ecosystem will affect its long-term structure.
Justify the claim that the Antarctic krill is a foundation species, not a keystone species. Provide evidence to support your claim.

Answer 1

Answer:

a) the autotrophs produce their own energy in their system and synthesize surrounding energy, which allows for the flow of energy as they are the primary producers at the bottom of the food web shown in figure 1 who transfer and facilitate their energy when they are consumed by the organisms in higher levels. This facilitation of energy continues where the population of these autotrophs is stable and the cycle of consumption and synthesis of energy from one trophic level to another and there is a diverse amount of energy distributed in the ecosystem. The leopard and Elephant seals have a similar food preference which may cause competition for resources in the ecosystem between the two more than that of the crabeater seal as they rely solely on krill in the ecosystem to survive. If there was more competition for the krill or a decrease in population, their population is sure to suffer as well.

b) The year is independent of the number of species in the data graphed. This variable affects the biodiversity in the food web where we witness the number of species (hundreds) likely to witness an increase over time when krill are harvested and a decrease in the number of species without krill harvesting. This, in turn, may prove that krill is a keystone species crucial in the food web and ecosystem where the antarctic krill population's presence will influence the number of species as well.

c) The changes in species richness with krill harvesting, as per mentioned, will show an increase in species number as the krill's energy is transferred throughout the ecosystem by consumption, as implied in the food web. The changes in species richness with a lack of krill harvesting, or some organisms unable to consume the energy of the krill, was shown to have a decrease in species # over the years. This will affect the long term structure of the ecosystem as the organisms who rely on krill and even those in the trophic levels which rely on species who consume krill will drop dramatically, and the lowering of the number of organisms in a keystone species will cause a decrease in speciation of the ecosystem (possibly quite rapidly due to the dependence we witness on it) as well as a disruption in the energy flow.

d) we can affirm that the krill are in fact not a foundation species, but a keystone species as they show no specific traits of facilitating the populations of the species in the ecosystem, and don't appear to benefit other species in the ways foundation species do (ie. they are autotrophs and cannot provide shelter for other species, but we can also say that they are the sole energy producers for the crabeater seals, which can be a trait of a foundation species)- instead exhibiting the traits of a keystone species as they produce an abundance of energy in the ecosystem and the removal of them (as shown in figure 2), causes a population decrease all around.

Explanation:

ur welcome i just did this myself so pls paraphrase as much as u can also like a bit of an explanation its kinda obvious from the chart that they all rely on the krill and stuff so removing it (or not harvesting or something) would be bad. again pls paraphrase as much as u can and good luck