Intense storms and the delivery of materials that relieve nutrient limitations in mangroves of an arid zone estuary

Date

2011

Authors

Lovelock, Catherine
Feller, Ilka C
Adame, Maria Fernanda
Reef, Ruth
Penrose, Helen M
Wei, Lili
Ball, Marilyn

Journal Title

Journal ISSN

Volume Title

Publisher

CSIRO Publishing

Abstract

Tropical cyclones can be devastating to ecosystems, but they can also result in pulses of fresh water and sediments delivered in floodwaters to the coastal zone. In the arid zone the pulses provided by cyclones may be particularly important for the maintenance of productivity. We examined the impacts of Cyclone Pancho on growth and nutrient limitations to growth in mangroves on the arid coast of Western Australia. We found that growth of trees was enhanced after the cyclone, more than doubling their rates of stem extension. Fertilisation studies showed that before the cyclone tree growth was nutrient limited. After the cyclone fertilisation treatments had no significant effect on growth, indicating nutrients had been delivered during the storm. Additionally, before the cyclone the efficiency of resorption of phosphorus and nitrogen from senescent leaves was higher than after the cyclone, suggesting that nutrient availability was enhanced. Analysis of stable isotopes of leaf tissue indicated that the cyclone was associated with small changes in water use efficiency, consistent with decreased soil salinity associated with the cyclone. There was, however, significant reductions in δ15N indicating enhanced N supply potentially from a new source. We conclude that in the arid zone, floodwater associated with cyclones is important for the delivery of nutrient subsidies that stimulate mangrove growth and that predicted future reductions in the frequency of cyclones will have negative impacts on the productivity of these ecosystems.

Description

Keywords

Keywords: arid environment; estuarine environment; flood deposit; growth response; mangrove; net ecosystem production; nitrogen; nutrient limitation; phosphorus; resorption; salinity; sediment transport; senescence; soil profile; tropical cyclone; water use efficie d15N; Avicennia marina; Cyclone Pancho; Exmouth Gulf; Giralia Bay; nitrogen; phosphate; resorption efficiency; Western Australia

Citation

Source

Functional Plant Biology

Type

Journal article

Book Title

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Restricted until

2037-12-31