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Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology.

Reddin CJ, Docmac F, O'Connor NE, Bothwell JH, Harrod C - PLoS ONE (2015)

Bottom Line: Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae.Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands.We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom.

ABSTRACT
Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

No MeSH data available.


Related in: MedlinePlus

Geographical variation of standardised δ15N at sites along the coastline.The solid line shows size-corrected P. purpuratus δ15N, whilst the dashed line shows the mean (± SD) across standardised δ15N of all consumers (P. purpuratus, E. peruviana, S. viridula, T. atra) and putative resources (POM, epilithic biofilm, Ulva sp.). Site labels are presented below the graph in sequence around the coast, with the main geographical features summarised at the base of the graph (see Fig 1 for more detail).
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pone.0130789.g003: Geographical variation of standardised δ15N at sites along the coastline.The solid line shows size-corrected P. purpuratus δ15N, whilst the dashed line shows the mean (± SD) across standardised δ15N of all consumers (P. purpuratus, E. peruviana, S. viridula, T. atra) and putative resources (POM, epilithic biofilm, Ulva sp.). Site labels are presented below the graph in sequence around the coast, with the main geographical features summarised at the base of the graph (see Fig 1 for more detail).

Mentions: All consumers and putative resources (‘mean’ line with error bars in Fig 3) were relatively 15N enriched in Mejillones Peninsula and Mejillones Bay (locations 1–3). Antofagasta Bay and Coloso Point (locations 4–6) were relatively 15N depleted (Fig 3). Size-corrected δ15N values of the suspension feeding mussel, P. purpuratus, represented the 15N enrichment trend well, fitting assumptions of its validity as a pelagic resource baseline, and was used to represent general δ15N baseline from here on. Apparent agreement of the δ15N baseline with satellite-derived SST patterns (Fig 1 and caption) was validated statistically (Spearman’s Rho = -0.55, DF = 23.3, spatial p = 0.01), indicating that intertidal δ15N values reflect upwelling intensity. Coastal upwelling did not appear to underlie spatial variability in δ13C (mean across consumers and putative resources, and P. purpuratus; Spearman’s Rho = 0.21, DF = 10.5, spatial p = 0.69), which was highly variable within locations.


Coastal Upwelling Drives Intertidal Assemblage Structure and Trophic Ecology.

Reddin CJ, Docmac F, O'Connor NE, Bothwell JH, Harrod C - PLoS ONE (2015)

Geographical variation of standardised δ15N at sites along the coastline.The solid line shows size-corrected P. purpuratus δ15N, whilst the dashed line shows the mean (± SD) across standardised δ15N of all consumers (P. purpuratus, E. peruviana, S. viridula, T. atra) and putative resources (POM, epilithic biofilm, Ulva sp.). Site labels are presented below the graph in sequence around the coast, with the main geographical features summarised at the base of the graph (see Fig 1 for more detail).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4516361&req=5

pone.0130789.g003: Geographical variation of standardised δ15N at sites along the coastline.The solid line shows size-corrected P. purpuratus δ15N, whilst the dashed line shows the mean (± SD) across standardised δ15N of all consumers (P. purpuratus, E. peruviana, S. viridula, T. atra) and putative resources (POM, epilithic biofilm, Ulva sp.). Site labels are presented below the graph in sequence around the coast, with the main geographical features summarised at the base of the graph (see Fig 1 for more detail).
Mentions: All consumers and putative resources (‘mean’ line with error bars in Fig 3) were relatively 15N enriched in Mejillones Peninsula and Mejillones Bay (locations 1–3). Antofagasta Bay and Coloso Point (locations 4–6) were relatively 15N depleted (Fig 3). Size-corrected δ15N values of the suspension feeding mussel, P. purpuratus, represented the 15N enrichment trend well, fitting assumptions of its validity as a pelagic resource baseline, and was used to represent general δ15N baseline from here on. Apparent agreement of the δ15N baseline with satellite-derived SST patterns (Fig 1 and caption) was validated statistically (Spearman’s Rho = -0.55, DF = 23.3, spatial p = 0.01), indicating that intertidal δ15N values reflect upwelling intensity. Coastal upwelling did not appear to underlie spatial variability in δ13C (mean across consumers and putative resources, and P. purpuratus; Spearman’s Rho = 0.21, DF = 10.5, spatial p = 0.69), which was highly variable within locations.

Bottom Line: Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae.Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands.We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Queen's University Belfast, Belfast, United Kingdom.

ABSTRACT
Similar environmental driving forces can produce similarity among geographically distant ecosystems. Coastal oceanic upwelling, for example, has been associated with elevated biomass and abundance patterns of certain functional groups, e.g., corticated macroalgae. In the upwelling system of Northern Chile, we examined measures of intertidal macrobenthic composition, structure and trophic ecology across eighteen shores varying in their proximity to two coastal upwelling centres, in a hierarchical sampling design (spatial scales of >1 and >10 km). The influence of coastal upwelling on intertidal communities was confirmed by the stable isotope values (δ13C and δ15N) of consumers, including a dominant suspension feeder, grazers, and their putative resources of POM, epilithic biofilm, and macroalgae. We highlight the utility of muscle δ15N from the suspension feeding mussel, Perumytilus purpuratus, as a proxy for upwelling, supported by satellite data and previous studies. Where possible, we used corrections for broader-scale trends, spatial autocorrelation, ontogenetic dietary shifts and spatial baseline isotopic variation prior to analysis. Our results showed macroalgal assemblage composition, and benthic consumer assemblage structure, varied significantly with the intertidal influence of coastal upwelling, especially contrasting bays and coastal headlands. Coastal topography also separated differences in consumer resource use. This suggested that coastal upwelling, itself driven by coastline topography, influences intertidal communities by advecting nearshore phytoplankton populations offshore and cooling coastal water temperatures. We recommend the isotopic values of benthic organisms, specifically long-lived suspension feeders, as in situ alternatives to offshore measurements of upwelling influence.

No MeSH data available.


Related in: MedlinePlus