Playa

Sea turtles are highly susceptible to plastic ingestion and entanglement. Beach debris were surveyed along the most important sea turtle nesting beaches in Brazil (Costa dos Coqueiros, Bahia State). No significant differences among developed and undeveloped beaches were observed in terms of total number of items. Local sources (tourism activities) represented 70% of debris on developed beaches, where cigarette butts, straws, paper fragments, soft plastic fragments, and food packaging were the most abundant items. Non-local sources (domestic and fishing activities) accounted for about 70% of debris on undeveloped beaches, where the most abundant items were rigid plastic fragments, ropes, soft plastic fragments, caps, and polystyrene. The projected surface area of beach debris did not vary among developed and undeveloped beaches. Overseas containers accounted for about 25% of regional plastic pollution, implying that international pollution prevention agreements are not being respected off the Brazilian coast.

Landsat Enhanced Thematic Mapper imagery (ETM) of 2002 and aerial photography of 1955, combined with published charts and field observations were used to interpret geomorphological changes in the coastal zone between Kitchener drain and Damietta spit in the northeastern Nile delta previously recognized as a vulnerable zone to the effects of any sea-level rise resulting from global warming. The interpretation resulted in recognition of several changes in nine identified geomorphological land types: beach and coastal flat, coastal dunes, agricultural deltaic land, sabkhas, fish farms, Manzala lagoon, saltpans, marshes and urban centers. Reclamation of vast areas of the coastal dunes and of Manzala lagoon added about 420 km 2 to the agricultural deltaic land. About 48 km 2 of sand dunes, marshes, sabkhas and salt pans have been converted to productive fish farms. The main urban centers have expanded, and new urban centers (Damietta harbor and the New Damietta city) have been constructed at the expense of vast areas of Manzala lagoon, coastal dunes, and backshore flats. As the consequence of human activities the size of Manzala lagoon has been reduced to less than 50%. Short-term shoreline changes along the coast of the study area established from beach profile survey, spanning the years of 1990 to 2000, reveal longshore patterns of erosion versus accretion. The rate of shoreline retreat has increased in the downdrift side of Damietta harbor (- 14 m/year), whereas areas of accretion exist within the embayment of Gamasa and in the shadow of Ras El Bar detached breakwater system, with a maximum shoreline advance of ~ 15 m/year. A sandy spit, 12 km long, has developed southeast of Damietta promontory. These erosion/accretion patterns denote the natural processes of wave-induced longshore currents and sediment transport, in addition, the impact of man-made coastal protection structures.

The concept of equilibrium plan form and equilibrium profile has been widely used as an engineering tool in order to design beach nourishment projects. The scope of this paper is to further explore this “equilibrium beach” concept in crenulated bays, as a long-term tool for beach nourishment projects. The proposed methodology is based on González and Medina (2001) and combines the static equilibrium plan and profile for long-term analysis. This methodology includes a modified equilibrium plan form, which is able to define the orientation of the local wave front in the diffracting point, and also to locate the downcoast starting point of the static equilibrium beach from which the parabolic plan form of Hsu and Evans (1989) is valid. This methodology permits the application of any equilibrium profile formulation. An example of the application of this methodology and long-term formulations to the design of the Spanish nourishment project of Poniente Beach (Gijón) is presented. Ten years after its construction, the beach has still got a static equilibrium and remains pretty close to the predicted equilibrium beach in plan and profile.

This study was carried out in the Lop Nor basin, a large arid closed drainage basin in Western China. The objective was to contribute to the understanding of the hydrological and hydrochemical processes of the Lop Nor basin by analysis of the chemical composition of different water sources and associated mineralogical characteristics of the playa sediments. The dominant river inflow

Stabilized sand deposits from arid regions are often used as palaeoenvironmental proxies for past periods of enhanced aeolian activity. Although widespread use of optically stimulated luminescence (OSL) dating techniques has opened up the possibility of systematic analyses of dune building chronologies, palaeoenvironmental histories cannot be reconstructed from chronological data alone. The reconstruction of regional palaeoenvironmental histories should consider all available evidence – stratigraphic, sedimentological and micromorphological, and chronological. This paper highlights potential issues with the interpretation of dune records in the context of stratigraphic preservation, using examples from the Tirari Desert in Australia and the Kalahari Desert in southern Africa.
Sedimentological characterisation of linear dunes in the Tirari Desert demonstrates that reworking of underlying dune sediments and buried soils is common, thereby calling into question simplistic interpretations of dune formation involving sequential deposition and pedogenesis. This case study highlights the limitation of the augering technique, although useful information can be gained nonetheless. Three OSL age estimates confirm the presence of at least two Holocene dune building episodes, but cannot constrain the timing of the onset of dune building. Higher frequency sampling and micromorphological analyses may further elucidate the palaeoenvironmental history of individual dunes.
In the southwestern Kalahari, interdune sediments have been described as the least sensitive part of the aeolian landscape, thus offering the potential for longer records of aeolian deposition. This is found not to be the case at Witpan, where interdune sands are extensively mixed and probably younger than the linear dune cores. The lunette at Witpan records numerous short-lived and rapid deflationary events from the nearby pan (playa). These are considered to reflect changes in sediment source rather than pedogenesis. These examples highlight the value of combining micromorphological, sedimentological and chronological studies for palaeoenvironmental reconstruction.