Confusion regarding Lindeman's law

Question

I came across Lindeman's 10% law at school. It states that 10% of the total energy entering a trophic level is available for transfer to the next trophic level.

I was reading Ecology: Principles and Applications By J. L. Chapman, M. J. Reiss and they mentioned two contradictory statements:

1. The 10% law, i.e. the trophic efficiency is always 10%
2. The trophic efficiency increases with trophic level (which was substantiated by data).

This is the statistics:

What is right? Is Lindeman's 10% law actually valid?

Answer 1

Lindeman's "law" is not a true "law" like the laws of thermodynamics, it's more of a catchphrase for a concept.

The true, valid concept from Lindeman is that "lots of energy is typically lost as you go to the next trophic level, especially at early stages...but there might be exceptions." This is characteristic of most of the "laws" of biology: there is always a lot of flexibility and leeway in biology.

The data in the chart you provide support this generalized version of the law: namely, most of the energy is lost at each trophic level, and a rough average or rule-of-thumb is that it's about 10%.

The usefulness of the 10% number is that it presents a nice benchmark: when you look at these data, you should notice and remark on the relatively high 22.3% level for secondary consumers on the Cedar Bog Lake: you should wonder "what features of this ecosystem or these consumers mark the relatively high energy transfer here?" Without the "10% law" you wouldn't know which numbers should stand out and which are unremarkable.