The contribution of occult precipitation to nutrient deposition on the west coast of South Africa.
The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly...
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doaj-5b52c53e9b014e889bffbdc4440361922020-11-25T01:34:34ZengPublic Library of Science (PLoS)PLoS ONE1932-62032015-01-01105e012622510.1371/journal.pone.0126225The contribution of occult precipitation to nutrient deposition on the west coast of South Africa.Justine M NyagaJason C NeffMichael D CramerThe Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3(-), NH4(+) and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation.http://europepmc.org/articles/PMC4446095?pdf=render |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Justine M Nyaga Jason C Neff Michael D Cramer |
spellingShingle |
Justine M Nyaga Jason C Neff Michael D Cramer The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. PLoS ONE |
author_facet |
Justine M Nyaga Jason C Neff Michael D Cramer |
author_sort |
Justine M Nyaga |
title |
The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. |
title_short |
The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. |
title_full |
The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. |
title_fullStr |
The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. |
title_full_unstemmed |
The contribution of occult precipitation to nutrient deposition on the west coast of South Africa. |
title_sort |
contribution of occult precipitation to nutrient deposition on the west coast of south africa. |
publisher |
Public Library of Science (PLoS) |
series |
PLoS ONE |
issn |
1932-6203 |
publishDate |
2015-01-01 |
description |
The Strandveld mediterranean-ecosystem of the west coast of South Africa supports floristically diverse vegetation growing on mostly nutrient-poor aeolian sands and extending from the Atlantic Ocean tens of kilometers inland. The cold Benguela current upwelling interacts with warm onshore southerly winds in summer causing coastal fogs in this region. We hypothesized that fog and other forms of occult precipitation contribute moisture and nutrients to the vegetation. We measured occult precipitation over one year along a transect running inland in the direction of the prevailing wind and compared the nutrient concentrations with those in rainwater. Occult deposition rates of P, N, K, Mg, Ca, Na, Al and Fe all decreased with distance from the ocean. Furthermore, ratios of cations to Na were similar to those of seawater, suggesting a marine origin for these. In contrast, N and P ratios in occult precipitation were higher than in seawater. We speculate that this is due to marine foam contributing to occult precipitation. Nutrient loss in leaf litter from dominant shrub species was measured to indicate nutrient demand. We estimated that occult precipitation could meet the demand of the dominant shrubby species for annual N, P, K and Ca. Of these species, those with small leaves intercepted more moisture and nutrients than those with larger leaves and could take up foliar deposits of glycine, NO3(-), NH4(+) and Li (as tracer for K) through leaf surfaces. We conclude that occult deposition together with rainfall deposition are potentially important nutrient and moisture sources for the Strandveld vegetation that contribute to this vegetation being floristically distinct from neighbouring nutrient-poor Fynbos vegetation. |
url |
http://europepmc.org/articles/PMC4446095?pdf=render |
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