4.2 Fractionation in Corals

Expected values from (Ferrier-Pages et al. 2018)

• Algae and phytoplankton δ13C −20‰ to −18‰

• δ13C enriched 0.4‰ to 1‰ between each trophic level

• host and symbionts display similar δ13C values -11‰ to −16‰

• shallow corals have more positive values δ13C −10‰ to −14‰

• Shallow POM δ13C -20‰

• δ15N value of a consumer is enriched by 2.3‰–3.4‰ from diet

• δ15N fractionation in carnivores is usually 3.2‰ ± 0.4‰

• δ15N fractionation from plants to herbivores 2.5‰ ± 2.5‰

Tissue Turnover Rates

Tanaka 2018

Authors used N and C tracers to determine the turnover rates of symbionts and corals. They found that N turnover was 370 days in the symbionts and 56 days in the host. They also developed detailed energy flow models:

Tanaka 2006

Used labeled isotopes to calculate turnover rates:

• N host turnover - 210 days

• N sym turnover - 13 days

• C host turnover - 18 days

• C sym turnover - 8.2 days

* see Rangel et al. 2019 if needed