TITLE:
Nutrient Enrichment and Saline Conditions Decreases Growth and Photosynthesis of the Mangrove Heritiera littoralis Dryand
AUTHORS:
Mwita M. Mangora
KEYWORDS:
Heritiera littoralis, Mangrove Seedlings, Nutrient Enrichment, Salinity, Waterlogging
JOURNAL NAME:
Open Journal of Marine Science,
Vol.6 No.2,
April
21,
2016
ABSTRACT: Inundation associated with
flooding and sea level rise is predicted to have major impacts on survival,
growth and productivity of mangroves. A manipulative mesocosm experiment was
conducted to assess whether nutrient enrichment enhances growth and
photosynthesis of waterlogged and salinity stressed seedlings of the mangrove Heritiera littoralis Dryand. Seedlings were fertilized
with a three-component granular farm NPK (Nitrogen-Phosphorous-Potassium,
20:20:20) at varied loads under waterlogging with four levels of salinity.
Growth was assessed through biomass accumulation, and photosynthesis through
photosynthetic quantum yield and leaf Chl content. When seedlings were exposed
to both nutrient enrichment and increased salinity, a significant shift of
biomass to roots was observed. Seedlings had low value of Chl a/b ratio and photosynthetic distraction
resulting in mortality was high in the highest salinity and nutrient levels.
These results are useful in explaining failure of regeneration in natural
stands of riverine and freshwater bound mangroves following unprecedented
flooding events that accrue land based nutrient loads into estuaries and
deltas.