Deasy’s Taxonomia Vitae – ECOSYSTEM-SCALE ENERGETIC ACCOUNTING

124–133 — ECOSYSTEM-SCALE ENERGETIC ACCOUNTING

The Ecosystem-Scale Energy and Matter Accounting layer quantifies the aggregate production, respiration, transfer, retention, recycling, import, export, and dissipation occurring across all relevant producers, consumers, decomposers, detrital pools, and abiotic reservoirs within a defined ecosystem boundary.

Operational definition

Layer type: Aggregate system-flux layer Governs: Items 124–133

Governing question

When all component organisms and transfers are considered together, what is the ecosystem’s net energetic and material balance?

Included quantities and processes

gross primary production;
primary-producer respiration;
net primary production;
secondary production;
detrital production;
ecosystem respiration;
net ecosystem production;
trophic transfer;
biogeochemical cycling;
directional free-energy flow.

Aggregation rule

This layer integrates lower-scale processes but does not erase them.

For example:

ecosystem respiration
=
producer respiration
+
consumer respiration
+
decomposer respiration

Likewise, net production reflects the aggregate outcome of many organismal allocation decisions and metabolic processes.

Boundary rule

Every ecosystem balance must specify:

spatial boundary;
time interval;
atmosphere, water, and sediment inclusion;
lateral imports;
lateral exports;
disturbance;
storage-pool changes.

A forest may appear to accumulate carbon when only vertical atmospheric exchange is measured but show a different balance after harvest, river export, fire, or animal migration is included.

Core production relations

NPP=GPP-R_A

where:

GPP = gross primary production;
R_A = autotrophic or producer respiration.

And:

NEP=GPP-ER

ER = total ecosystem respiration.

Field studies estimate and partition gross primary productivity, ecosystem respiration, and net ecosystem exchange or production across real ecosystems, demonstrating the need for explicit temporal and spatial boundaries. (PubMed Central (PMC))

Carbon-versus-energy rule

GPP, NPP, and NEP are often reported as carbon fluxes:

g C m^-2 yr^-1

They are not automatically direct measurements of energy in joules.

Converting a carbon flux into an energy flux requires information or assumptions about:

chemical composition;
oxidation state;
heat of combustion;
biomass composition;
substrate identity.

Therefore this layer is properly called Energy and Matter Accounting, not energy accounting alone.

Trophic-transfer rule

Trophic transfer must distinguish among:

production available to consumers;
production actually consumed;
consumed matter assimilated;
assimilated matter converted into consumer production.

Each ratio has a different denominator and therefore describes a different efficiency.

Governing thermodynamic principle

Matter can be incorporated into repeated biogeochemical cycles.

Usable free energy moves directionally through transformations:

high-capacity input
→
biological conversion
→
work and biomass
→
respiration
→
dispersed heat

Total energy remains conserved, while the capacity to perform additional organized work declines. Whole-ecosystem models and measurements explicitly connect organismal metabolism with ecosystem carbon flow and production. (PubMed Central (PMC))