Soil genesis on hypersaline tidal flats (apicum ecosystem) in a tropical semi-arid estuary (Ceará, Brazil)

Soil Research ◽  
2014 ◽  
Vol 52 (2) ◽  
pp. 140 ◽  
Author(s):  
A. G. B. M. Albuquerque ◽  
T. O. Ferreira ◽  
G. N. Nóbrega ◽  
R. E. Romero ◽  
V. S. Souza Júnior ◽  
...  

Wetland soils, especially those under a semi-arid climate, are among the least studied soils in the tropics. The hypersaline tidal flats on the north-eastern Brazilian coast, locally named apicum, are coastal wetland ecosystems in the peripheral portions of semi-arid estuaries. Despite their great ecological importance, they have been highly impacted by anthropogenic activities. Morphological and analytical data of six soil profiles, representative of the different coastal compartments (mangroves, apicum and coastal tablelands) of the north-eastern Brazilian coast, were examined to better understand the pedogenesis of apicum soils. The hypersaline tidal flat soils were classified as Typic Fluvaquents and Typic Sulfaquents with the following main characteristics: predominance of sand fraction (62–77%); presence of high-activity clays (>24 cmolc kg–1 clay); clay fraction comprising kaolinite, illite, smectite and an interstratified smectite/illite; exchangeable complex dominated by Na+ (ESP ≥15%); elevated levels of salinity (electrical conductivity, EC 25–44 dS m–1); alkaline pH values (7.5–9.5). The sandy texture and quartz-dominated composition of the hypersaline, tidal flat soils indicate a pedogenesis associated with the superficial addition of mineral material. This upbuilding process would have lowered the watertable (relatively to the ground level) and decreased the flooding frequency by the tides, favouring salinisation and solonisation processes at the hypersaline tidal flats. Furthermore, the still-existing hydromorphism would have promoted the maintenance of gleisation and sulfidisation. The presence of pyrite on the hyper-saline tidal flat soils further corroborates the formation of apicum soils from/over buried mangroves.

Author(s):  
Fernando José König Clark ◽  
André Luiz Machado Pessanha

The feeding biology of bahia sprat (Rhinosardinia bahiensis) was studied in two habitats of a tropical semi-arid estuary, on the north-eastern Brazilian coast. Samplings were collected on a monthly basis (January 2010–February 2011), and fish were caught during the day using an 8 m beach seine. Habitat use was size-dependent, with tidal mudflat occupied by higher size-classes than tidal creeks, which were occupied by smaller conspecifics. The diet analysis of different size-classes revealed that all sizes of fish consumed similar taxa (Calanoida, Cyclopoida and Decapoda larvae), and that the relative proportion of taxa consumed reflected fish size. Dietary differences between the two nursery areas mainly reflected prey availability. Although high diet overlap was only found between some size-classes in tidal mudflat, these results seem to demonstrate a strategy for efficient use of space potential; intraspecific competition was probably minimized by a differential habitat use patterns.


Author(s):  
Humberto F. M. Fortunato ◽  
Thierry Pérez ◽  
Gisele Lôbo-Hajdu

AbstractThe Order Suberitida is defined as a group of marine sponges without an obvious cortex, a skeleton devoid of microscleres, and with a deletion of a small loop of 15 base pairs in the secondary structure of the 28S rDNA as a molecular synapomorphy. Suberitida comprises three families and 26 genera distributed worldwide, but mostly in temperate and polar waters. Twenty species were reported along the entire Brazilian coast, and although the north-eastern coast of Brazil seems to harbour a rich sponge fauna, our current knowledge is concentrated along the south-eastern Atlantic coast. A survey was implemented along the northern coast of Brazil, and the collection allowed the identification of six species belonging to the Order Suberitida. Two of them are considered new to science: Suberites purpura sp. nov., Hymeniacidon upaonassu sp. nov., and four, Halichondria (Halichondria) marianae Santos, Nascimento & Pinheiro, 2018, Halichondria (H.) melanadocia de Laubenfels, 1936, Suberites aurantiacus (Duchassaing & Michelotti, 1864), and Terpios fugax Duchassaing & Michelotti, 1864, are re-described. Taxonomic comparisons are made for Tropical Western Atlantic species and type species of the four genera. Finally, an identification key for the Western Atlantic Suberites species is provided.


1999 ◽  
Vol 26 ◽  
pp. 65-73
Author(s):  
S.J.G. Hall

SummaryCharacterisations are given of the little-known Sabi sheep and the local population of the Small East African goat in two areas in NE Zimbabwe. The southern area had been more affected by drought in 1991–92. For sheep (both areas combined; n = 28 in 10 flocks) the mean declared age of breeding females and the median age at first parturition were surprisingly high (6.1 years and 4 years respectively). Breeding female goats in the southern area were younger (4.9 vs. 6.4 years), and their age at first kidding was lower (3 years vs. 5 years), than in the north (n = 122 in 25 flocks total). These advanced ages could be an after-effect of the drought. Juvenile mortality and the proportions of young that were ultimately marketed were similar to what has been found elsewhere in semi-arid Africa. Breeding females were found to be smaller than their counterparts in semi-arid areas in West Africa with mean withers heights of 56.5 cm (n = 112 goats) and 60.4 cm (n = 36 sheep). Conditions in this area appear difficult for small ruminants and the populations sampled may be well adapted to marginal environments and thus worthy of conservation.


2021 ◽  
Vol 8 ◽  
Author(s):  
Zehua Zhong ◽  
Zhan Hu

Reclamation is one of the most prominent anthropogenic activities affecting tidal flat morphology and the related ecosystem service. Two representative types of reclamation are upper-flat enclosure and lower-flat enrockment. From a historical perspective, different type of reclamation was adapted in different areas in ancient China. As previous studies on reclamation are often site-specific, the reason that leads to such a difference is unclear. The intertidal dynamic equilibrium theory (DET) provides a comprehensive framework for this quest. Here, we extend the DET with additional effects of reclamation. A model based on DET (DET-ESTMORF) was applied to investigate the impact of reclamation on tidal flats. The model was validated by comparing our results against previous records and observations. Results show that both types of reclamation induce morphological adjustment by enhancing local accretion, which upset the previous equilibrium. Specifically, upper-flat enclosure drives tidal flats into evolution toward wave dominance, whereas lower-flat enrockment causes adjustment toward tidal dominance. Next, the impact of reclamation on tidal flats in different states (prograding or retreating) was investigated. We show that both enclosure and enrockment can induce accretion despite the varying wave climate and sediment supply, with the mean accretion rate raised by 1.8 cm/year and 1.2 cm/year, respectively. However, the resulting profiles are different in shape, especially on retreating flats. Finally, we point out that tidal range and sediment supply are the potential reasons affecting the choice of reclamation types in practices.


2016 ◽  
Vol 6 (4) ◽  
pp. 91
Author(s):  
Melanie Rispel ◽  
Selma Lendelvo

Namibia is a semi-arid country and underground water sources have proven to be reliable water sources for drought-prone countries. Underground water has the ability to sustain conservation activities as long as water infrastructure is in place and maintained. Despite the different water requirements for the wildlife species, water remains an essential component of wildlife management in Namibia. Therefore, this study aims at understanding utilization of water points by various wildlife species in the Nyae Nyae conservancies, which is located in the north-eastern part of Namibia. This study used monitoring data from wildlife counts that are conducted by the Conservancy annually at water points coupled with key-informant interviews with local conservancy members and leaders as well as some stakeholders. The study shows that the Conservancy had a diverse number of wildlife species that were predominantly ungulates (70%). These species were detected at 29 water points distributed across the Conservancy. Most of the water points in the conservancy were artificial points with water drawn from the underground water sources, while a few of the water points were pans (17%). Water resources are very important resources for conservation, not only in terms of being used by wildlife but also in terms of being used to provide an indication of species diversity in the conservation.


2018 ◽  
Vol 40 (5) ◽  
pp. 527
Author(s):  
S. Saïdi ◽  
G. Gintzburger ◽  
L. Gazull ◽  
J. Wallace ◽  
S. Christiansen

We developed a GIS desktop model to accurately locate and map prospective areas for sustainable establishment and production of Atriplex plantations and other fodder shrubs in the desert in the north-eastern Jordanian Badiyah. The aim is to provide a tool to assist managers, local communities and development projects in Mediterranean arid and semi-arid rangelands. The model uses freely available data and GIS layers of current land use, land cover, settlement location, soil information, and derivatives from a digital elevation model to provide critical locations of drainage lines and to calculate Areas of Accumulated Water from concentrated runoff. The model identified, accurately located and mapped ~4500 ha (1.44% of the test zone) as technically appropriate for potential shrub plantations sites. The final site map must be field-checked and validated with the local communities and authorities. Our model has potential for wide application over arid and semi-arid Mediterranean rangelands from Morocco to Pakistan, with local adjustment of our parameters and rules. The model considerably reduces the risk and costs of fodder plantation establishment operations, thus increasing the feasibility of efforts to maximise fodder shrub establishment, survival and production.


2011 ◽  
Vol 91 (7) ◽  
pp. 1561-1566 ◽  
Author(s):  
Bruno Garcia Andrade ◽  
Paulo Márcio Santos Costa ◽  
Alexandre Dias Pimenta

The genus Opaliopsis from Brazil is revised based on three deep-water species. Opaliopsis atlantis (Clench & Turner, 1952) is confirmed as occurring in north-eastern and south-eastern localities. Opaliopsis opalina (Dall, 1927) is reported for the first time in the south-western Atlantic. A new species, Opaliopsis cearense, is described from the north-eastern Brazilian coast, and is distinguished by its large number of fine spiral cords per teleoconch whorl.


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