1.8 Sheldon et al. (1972) have argued that the concentrations of particles rangi
ID: 801842 • Letter: 1
Question
1.8 Sheldon et al. (1972) have argued that the concentrations of particles ranging from microscopic algae to tuna and whales varies by no more than a factor of 2–3 in the ocean. In other words, there is an ecological pyramid of biomass, but the biomass of microscopic algae is only two to three times greater than the biomass of tuna and whales. How can we account for this observation if the ecological efficiency of the food chains leading from algae to tuna and whales is only 20%? More recently, Longhurst (1991) has presented data concerning the relative size of predators and prey in a wide variety of marine food chains and covering a range in organism size from protozoans to whales. The median ratio of predator length to prey length in Longhurst's data set is about 10. Assuming that organism biomass scales as length cubed, the implication of Longhurst's analysis is that the biomass of a predatoris roughly 1000 times greater than that of its prey. Assume that
a) The biomass of individual predators is 1000 times greater than the biomass of their prey
b) Metabolic rate scales as individual biomass raised to the 0.75 power
c) Ecological efficiency is 20%
GIven these assumptions, in a grazing food chain what would you predict the biomass on trohpic level 6 to be relative to the biomass on trophic level 1? Is this result roughly consisten with the observations of Sheldon et al.?
Explanation / Answer
answer- Land or ocean each ecosystem is characterised by the interaction food chain and also the interaction of biotic and abiotic components of eocsysystem. Abiotic component includes Temperature, vegetation, soil, rocks and relief etc. and Biotic factor includes
1- Producers which prepare their own food Ex- Plants (by the process of photosynthesis).phytoplankton, Blue green algae , Cyanobacteria and
2- Consumers who depends upton producers they ranges from Primary consumers to quaternary consumers. And
3-Decomposers who feeds on dead organism or fecal material etc
Ecological pyramid represents the flow of Biomass or bioproductity in each level (trophic level) in an ecosystem it may be aquatic ecosystem or marine ecosystem.
In marine ecosystem is producers are those micro size phytoplankton who obtain energy from the sun light by the process of photosynthesis. the phyzooplankton feeds by the zooplankton (primary consumers), which feed by Small fishes (secondary consumers) which is feed by large fishes like shark (tertiary consumers).
In the ecological pyramid of energy the energy level is decrese by 10% on incresing in tropic level. (according to the law of lindemann). the energy level is highest on trophic level one which include producers and enery level is lowest on trophic level 5 or 6 which includes quaternary consumers.
there 2 type of food chain in each eocsystem aquatic and terrestrial
1- grazing food chain- which starts from green plants and end to carnivores
2- detritus food chain- which starts from the green plants and end to decomposers
we know the biomass of individual predators is 1000 times than biomass of prey and its metabolic scale raised by 0.75 power. So in Grazing food chain the biomass will reduce by 10% on increasing each trophic level
if amount of biomass on trophic level 1 is 100. on trophic level 2 the biomass will be about 10 and then 1 on level 3 , 0.1 on trophic level 4. On the trophic level biomass will be about 0.01. and In the trophic level 6 the biomass is about 0.001.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.