1. Fast detection of nutrient limitation in macroalgae NIFT technique and implications for reef management
Joost den Haan · Friso Dekker · Nienke ten Brinke · Amanda Ford · Jef Huisman · Mark Vermeij · Petra Visser

2. Which nutrient is currently limiting macroalgal growth?
Land runoff
River discharge
Sewage
NH4
NO3
PO4
Which nutrient is currently limiting macroalgal growth?

3. Method to detect nutrient limitation
Based on:
Nutrient Induced Fluorescence Transient (NIFT) experiments in phytoplankton
e.g. Beardall et al. 2001; Holland et al., 2004; Shelly et al. 2010
Mini PAM
Diving PAM

4. Direct estimation of current nutrient limitation
NIFT experiment
Light re-emitted (Fluorescence) alters when microalgae take up nutrients
Turpin and Weger, 1988; Wood and Oliver, 1995; Lippemeier et al. 2001
Diving PAM
Direct estimation of current nutrient limitation
Cuvette with microalgae
PAM sensor

5. Does the NIFT technique also work with macroalgae?

6. -N -P C
Ulva lactuca

7. Induced nutrient starvation-P
Can the NIFT technique detect specific nutrient limitation?

8. Ulva lactuca N limited  added NO3
Adaptation time Ft
F’m
Light pulses every 30s

9. Can we also detect nutrient limitation in macroalgae collected directly from the reef?

10. Which nutrient is limiting the growth of the macroalga
Lobophora variegata?
Lobophora variegata

11. Location: Curaçao
20m
Nutrient plume

12. What does this mean for the reef?
Playa kalki vs. Buoy 0
(less degraded)
(degraded)
p <0.001
(Two Sample Z-test)
NO3 NS
What does this mean for the reef?
Lobophora variegata are mostly PO4 limited
NH4 NS NS
PO4
Percentage of L. variegata limited by specific nutrient (n=36)

13. PO4 Lobophora currently nutrient limited? NO YES Limiting nutrient
NH4
Macroalgal overgrowth, given
other factors are not limiting NO
Lobophora currently nutrient limited?
YES
Limiting nutrient
PO4
No direct effect of nutrient pollution…
Non-limiting
nutrient

14. Conclusions
The NIFT technique can be used to estimate which nutrient is limiting Lobophora variegata growth
NIFT technique is a very rapid method compared to other methods (only 30 min/sample)
3. Lobophora variegata are currently PO4 limited, hence PO4 enrichment (e.g. sewage) will lead to rapid algal proliferation on the reefs of Curaçao

15. Future implications
Wider application of this method to other benthic algae,
and in other marine and freshwater ecosystems
Thalassia testudinum
Dictyota sp.

16. Implication for reef management
Early warning indicator to estimate the potential effect of future nutrient pollution
Lobophora variegata
Dictyota spp.
Halimeda opuntia
Benthic cyanobacteria

17. Thank you for your attention!
Questions?
Special thanks to:
FORCE project
Hannah Brocke, Katy Davis, Jelmer Pander, Anna Simeon, Laura Weiand