Temporal variations in morphology and biomass of vulnerable Halodule wrightii meadows at their southernmost distribution limit in the southwestern Atlantic

2011 ◽  
Vol 54 (1) ◽  
Author(s):  
Laura Sordo ◽  
Jérôme Fournier ◽  
Verônica M. de Oliveira ◽  
Fabiana Gern ◽  
Andrea de Castro Panizza ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Halodule Wrightii ◽  
Southwestern Atlantic ◽  
Distribution Limit

Temporal variations of Halodule wrightii meadows and associated fauna near their southern distribution limit in the southwestern Atlantic

2020 ◽  
Vol 63 (3) ◽  
pp. 215-228
Author(s):  
Laura Sordo ◽  
Paulo Lana
Keyword(s):  
Temporal Variations ◽  
Halodule Wrightii ◽  
Associated Fauna ◽  
Benthic Species ◽  
Southern Limit ◽  
Distribution Limit ◽  
Seagrass Biomass ◽  
Sw Atlantic ◽  
Number Of Leaves ◽  
Ecosystem Changes

AbstractHalodule wrightii meadows in Southern Brazil have been regressing in an unsheltered area of the subtropical Paranaguá Bay, near their southern limit in the SW Atlantic, since 2006. To identify early indicators of regression events, we assessed variations in plant and macrobenthic structure in two local meadows under unsheltered and protected conditions. Differences between sites increased after an epiphytic overgrowth of the alga Hincksia mitchelliae at the unsheltered site. Seagrass growth was suppressed and the numbers of burrowing and opportunistic benthic species increased with the increase of algal biomass. In the protected meadow, seagrass biomass and number of leaves changed seasonally, but macrobenthic abundance and species richness remained stable. Ecosystem changes were evident when the unsheltered meadow was already collapsing. The number of leaves per shoot, the horizontal internode length, the abundance and structure of the macrofaunal associations, and the host-epiphyte surface interactions, were the first variables to reflect the early stages of seagrass regression. Our results suggest that the persistence of H. wrightii meadows at their southern distribution limit in the SW Atlantic will be affected by local hydrodynamics and their ability to compete with ephemeral macroalgal species under stress conditions.

scholarly journals Responses of the molluscan fauna to environmental variations in a Halodule wrightii Ascherson ecosystem from Northeastern Brazil

2013 ◽  
Vol 85 (4) ◽  
pp. 1397-1410 ◽  
Author(s):  
KCRISHNA V.S. BARROS ◽  
CRISTINA A. ROCHA-BARREIRA
Keyword(s):  
Seasonal Changes ◽  
Common Species ◽  
Temporal Variations ◽  
Northeastern Brazil ◽  
Halodule Wrightii ◽  
Hypnea Musciformis ◽  
Spatial And Temporal Distributions ◽  
Environmental Variations ◽  
Vertical Variations ◽  
Molluscan Fauna

ABSTRACT This study observed the spatial and temporal distributions of molluscs in a Halodule wrightii meadow, verifying if they respond satisfactorily to seasonal changes in this seagrass ecosystem. Twenty-four species were identified. Chitons were rare, bivalves had greater number of species (11), followed by gastropods (9) which were also the most abundant class (73%). All classes were more abundant in the belowground. The most common species was Tricolia affinis, especially in aboveground. The occurrence of some species in both strata or out of the expected stratum may have been influenced by shallow layer of the sediment considered in this study, hydrodynamic, and low biomass of the studied meadow. According to univariate and multivariate analyses, despite of molluscan descriptors had been related to variables associated with rainfall, the seagrasses had an important role on the seasonal and vertical variations of the molluscan fauna. The biomass of the epiphyte Hypnea musciformis was correlated to temporal variations of the species from aboveground, indicating its secondary role for this community. The molluscs were sensible to environmental variations, and also reflected seasonal changes of the seagrass, showing that damages on these meadows reflect even at lower levels of the marine food web.

Reproductive trade-off of the copepod Acartia tonsa in a hypersaline estuary of the Southwestern Atlantic. Temporal variations in the morphology of eggs

2016 ◽  
Vol 12 (8) ◽  
pp. 817-829 ◽  
Author(s):  
Anabela A. Berasategui ◽  
Melisa D. Fernandez-Severini ◽  
M. Clara Menendez ◽  
Florencia Biancalana ◽  
M. Sofia Dutto ◽  
...  
Keyword(s):  
Temporal Variations ◽  
Acartia Tonsa ◽  
Southwestern Atlantic ◽  
Trade Off

Spatio-temporal variations of winter wheat water requirement and climatic causes in Huang-Huai-Hai Farming Region

2012 ◽  
Vol 20 (3) ◽  
pp. 356-362 ◽  
Author(s):  
Xiao-Lin YANG ◽  
Zhen-Wei SONG ◽  
Hong WANG ◽  
Quan-Hong SHI ◽  
Fu CHEN ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Temporal Variations ◽  
Water Requirement ◽  
Spatio Temporal
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