Coastal upwelling may overwhelm the effect of sewage discharges in rocky intertidal communities of the Peruvian coast

2010 ◽  
Vol 61 (3) ◽  
pp. 309 ◽  
Author(s):  
Fausto N. Firstater ◽  
Fernando J. Hidalgo ◽  
Betina J. Lomovasky ◽  
Juan Tarazona ◽  
Georgina Flores ◽  
...  
Keyword(s):  
Community Development ◽  
Coastal Upwelling ◽  
Spatial Scales ◽  
Rocky Intertidal ◽  
Nutrient Concentrations ◽  
Intertidal Communities ◽  
Isotopic Signatures ◽  
Relative Contribution ◽  
Important Input ◽  
Early Succession

In coastal productive environments, such as upwelling systems, sewage effluents might represent an important input of nutrients affecting intertidal community development and structure. Using descriptive and experimental approaches, the community spatial variation and early succession in relation to a point-source effluent discharge in a rocky intertidal of an upwelling affected area (Ancón Bay, Peru) was analysed. The relative contribution of herbivory to the observed patterns was also analysed. Dissolved nutrient concentrations, macroalgal isotopic signatures and N content revealed a significant input of nutrients at the outfall, although this contribution was not reflected in the algal assemblage, but in higher abundances of mytilids, ophiuroids and limpets. Cover of most sessile organisms (biofilm, Ulva spp., mytilids and barnacles) varied among sites throughout early succession, and grazers only enhanced the cover of the red algae Gelidium spp. Differences in succession patterns could not be attributed to discharge effects. The results of this study suggest that the community development is bottom-up controlled in the entire bay, which is likely to be due to the upwelling that operates at larger temporal and spatial scales. If so, nutrient input derived from coastal upwelling may sometimes overwhelm the role of anthropogenic nutrient loadings in shaping intertidal communities.

TESTING THE RELATIVE CONTRIBUTION OF POSITIVE AND NEGATIVE INTERACTIONS IN ROCKY INTERTIDAL COMMUNITIES

Ecology ◽  
1999 ◽  
Vol 80 (8) ◽  
pp. 2711-2726 ◽  
Author(s):  
Mark D. Bertness ◽  
George H. Leonard ◽  
Jonathan M. Levine ◽  
Paul R. Schmidt ◽  
Aubrey O. Ingraham
Keyword(s):  
Rocky Intertidal ◽  
Intertidal Communities ◽  
Relative Contribution ◽  
Negative Interactions

The influence of coastal upwelling on the functional structure of rocky intertidal communities

Oecologia ◽  
1987 ◽  
Vol 72 (2) ◽  
pp. 226-232 ◽  
Author(s):  
A. L. Bosman ◽  
P. A. R. Hockey ◽  
W. R. Siegfried
Keyword(s):  
Coastal Upwelling ◽  
Rocky Intertidal ◽  
Functional Structure ◽  
Intertidal Communities

Stability of rocky intertidal communities, in response to species removal, varies across spatial scales

Oikos ◽  
2021 ◽  
Author(s):  
Nelson Valdivia ◽  
Daniela N. López ◽  
Eliseo Fica‐Rojas ◽  
Alexis M. Catalán ◽  
Moisés A. Aguilera ◽  
...  
Keyword(s):  
Spatial Scales ◽  
Rocky Intertidal ◽  
Intertidal Communities ◽  
Species Removal

scholarly journals Method for monitoring intertidal communities in a steep rocky shore: a combination of digital image technology and field operational strategy

2007 ◽  
Vol 55 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Danuza Nogueira Moysés ◽  
Andréa de Oliveira R. Junqueira ◽  
Helena Passeri Lavrado ◽  
Sérgio Henrique Gonçalves da Silva
Keyword(s):  
Digital Image ◽  
Field Work ◽  
Benthic Invertebrate ◽  
Rocky Intertidal ◽  
Estimation Methods ◽  
Rocky Shores ◽  
Percent Cover ◽  
Intertidal Communities ◽  
Time Reproduction ◽  
Over Time

This paper introduces a method for temporal studies of steep rocky intertidal communities. It combines the use of digital image technology with field methodology, so that a wide area of the community can be sampled in a short time. Two current nondestructive percent cover estimation methods (visual estimation and point intersection) were compared in terms of cost, operational advantages and data quality, with a proposed method for a sucessional study . The proposed method used sequential photos to sample multiple fixed vertical transects over time. Reproduction of the mid-intertidal transect over time was possible by overlaying temporal transects in an image editing program. This method was similar to the point intersection quadrat method used to estimate percent cover. Benefits included reduced time on field work, economic advantages and other advantages of using digital photography, such as recording. Temporal photography of transects provided measurements of recruitment, mortality and population growth, and made it possible to manufacture an animation of sucessional stages. We suggest that this is the best method for providing information and understanding on the process of succession and for monitoring benthic invertebrate intertidal communities on steep rocky shores.

scholarly journals Succession in rocky intertidal benthic communities in areas with different pollution levels at Guanabara Bay (RJ-Brazil)

2005 ◽  
Vol 48 (6) ◽  
pp. 951-965 ◽  
Author(s):  
André Breves-Ramos ◽  
Helena Passeri Lavrado ◽  
Andrea de Oliveira Ribeiro Junqueira ◽  
Sérgio Henrique Gonçalves da Silva
Keyword(s):  
Community Development ◽  
Species Composition ◽  
Benthic Communities ◽  
Organic Pollution ◽  
Polluted Area ◽  
Rocky Intertidal ◽  
Percent Cover ◽  
Guanabara Bay ◽  
Pollution Levels ◽  
Resilient Communities

The aim of this study was to describe and compare the succession of intertidal benthic communities in two areas at Guanabara Bay, RJ, Brazil: Urca, an area submitted to moderated organic pollution and Catalão, an extremely polluted area. Three transects in each area were scraped one month before the beginning of this study in order to evaluate the recruitment (recruitment-treatments). Three other transects were monitored without manipulation (monitoring treatments). Species composition and relative abundance were evaluated monthly between September and December, 2000. A total of 26 species was found at Urca and 13 at Catalão. The percent cover of the most abundant organisms was not similar between treatments at Urca after four months, while in Catalão, the similarity was 72% in the second month. The faster community development and recovery at the most polluted area was probably related to the existence of simple and resilient communities in more impacted areas.

scholarly journals Verifying Operational Forecasts of Land–Sea-Breeze and Boundary Layer Mixing Processes

2020 ◽  
Vol 35 (4) ◽  
pp. 1427-1445
Author(s):  
Ewan Short
Keyword(s):  
Boundary Layer ◽  
Diurnal Cycle ◽  
Spatial Scales ◽  
Sea Breeze ◽  
Absolute Error ◽  
Wind Fields ◽  
Mixing Processes ◽  
Relative Contribution ◽  
The Mean ◽  
Diurnal Wind

AbstractForecasters working for Australia’s Bureau of Meteorology (BoM) produce a 7-day forecast in two key steps: first they choose a model guidance dataset to base the forecast on, and then they use graphical software to manually edit these data. Two types of edits are commonly made to the wind fields that aim to improve how the influences of boundary layer mixing and land–sea-breeze processes are represented in the forecast. In this study the diurnally varying component of the BoM’s official wind forecast is compared with that of station observations and unedited model guidance datasets. Coastal locations across Australia over June, July, and August 2018 are considered, with data aggregated over three spatial scales. The edited forecast produces a lower mean absolute error than model guidance at the coarsest spatial scale (over 50 000 km2), and achieves lower seasonal biases over all spatial scales. However, the edited forecast only reduces errors or biases at particular times and locations, and rarely produces lower errors or biases than all model guidance products simultaneously. To better understand physical reasons for biases in the mean diurnal wind cycles, modified ellipses are fitted to the seasonally averaged diurnal wind temporal hodographs. Biases in the official forecast diurnal cycle vary with location for multiple reasons, including biases in the directions that sea breezes approach coastlines, amplitude biases, and disagreement in the relative contribution of sea-breeze and boundary layer mixing processes to the mean diurnal cycle.

scholarly journals Interhemispheric consistency of scale-dependent spatial variation in the structure of intertidal rocky-shore communities

2018 ◽  
Author(s):  
Alexis Catalán ◽  
Nelson Valdivia ◽  
Ricardo Scrosati
Keyword(s):  
Community Structure ◽  
Spatial Variation ◽  
Spatial Scales ◽  
Vertical Gradient ◽  
Sampling Interval ◽  
Biological Variation ◽  
Rocky Intertidal ◽  
Vertical Variation ◽  
Horizontal Variation ◽  
Sampling Intervals

In rocky intertidal environments, the vertical gradient of abiotic stress generates, directly or indirectly, significant spatial variation in community structure. Along shorelines within biogeographic regions, abiotic changes also generate horizontal biological variation, which when measured at large sampling intervals may surpass vertical biological variation. Little is known, however, on how vertical variation compares with horizontal variation measured at multiple spatial scales in habitats with similar environmental conditions. Here, we compare spatial variability in rocky-intertidal communities between vertical stress gradients and three horizontal spatial scales (sampling interval) across habitats experiencing the same wave exposure on the Northwest Atlantic (NWA) and Southeast Pacific (SEP) coasts. For both regions, the vertical variation in species richness and composition (Raup-Crick and Bray-Curtis indices) was higher than the variation measured at all horizontal scales, from a few cm to hundreds of km. The patterns of variation in community structure matched those of abundance for the dominant sessile organisms, the foundation species Ascophyllum nodosum (seaweed) in NWA and Perumytilus purpuratus (mussel) in SEP. This interhemispheric comparison reveals the tight link between environmental and biological variation, indicating that studies comparing spatial scales of biological variation must consider the underlying environmental variation in addition to simply scale alone.

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