Prevalence and genetic diversity of avian haemosporidian parasites in islands within a mega hydroelectric dam in the Brazilian Amazon

The Brazilian Amazon supports an extremely diverse avifauna and serves as the diversification center for avian malaria parasites in South America. Construction of hydroelectric dams can drive biodiversity loss by creating islands incapable of sustaining the bird communities found in intact forest sites. Besides anthropogenic actions, the presence of parasites can also influence the dynamics and structure of bird communities. Avian malaria (Plasmodium) and related haemosporidian parasites (Haemoproteus and Leucocytozoon) are a globally distributed group of protozoan parasites recovered from all major bird groups. However, no study to date has analyzed the presence of avian haemosporidian parasites in fragmented areas such as land bridge islands formed during artificial flooding following the construction of hydroelectric dams. The aim of this study is to assess the prevalence and molecular diversity of haemosporidians in bird communities inhabiting artificial islands in the area of the Balbina Hydroelectric Dam. The reservoir area covers 443,700 ha with 3546 islands on the left bank of the Uatumã River known to contain more than 400 bird species. We surveyed haemosporidian infections in blood samples collected from 445 understory birds, belonging to 53 species, 24 families, and 8 orders. Passeriformes represented 95.5% of all analyzed samples. We found a low overall Plasmodium prevalence (2.9%), with 13 positive samples (two Plasmodium elongatum and 11 Plasmodium sp.) belonging to eight lineages. Six of these lineages were previously recorded in the Amazon, whereas two of them are new. Hypocnemis cantator, the Guianan Warbling Antbird, represented 38.5% of all infected individuals, even though it represents only 5.6% of the sampled individuals. Since comparison with Plasmodium prevalence data prior to construction of Balbina is not possible, other studies in artificially flooded areas are imperative to test if anthropogenic flooding may disrupt vector-parasite relationships leading to low Plasmodium prevalence.

Temperature patterns along an arid coastline experiencing extreme and rapid urbanization, case study: Dubai

Today more than one billion people are living in coastal regions, and coastal urbanization is rapidly growing worldwide. Here, we explore the impact of an extreme and rapid coastal urbanization on temperature patterns, based on MODIS data. We study Dubai, one of the fastest growing cities in the world over the last two decades. Dubai's urbanization centers along its coastline - in land, massive skyscrapers and infrastructure have been built, while in sea, just nearby, unique artificial islands have been constructed. Studying the coastline during the years of intense urbanization, we show that the coastline exhibits surface urban heat island characteristics, where the urban center experiences higher temperatures, by as much as 2.5 °C and more, compared to the adjacent less urbanized zones. During development, the coastal surface urban heat island has nearly doubled its size, expanding towards the newly developed areas. This newly developed zone also exhibits the largest temperature trend along the coast of over 0.1 °C/year on average. In addition, an opposite linear relation was found between the surface temperature and albedo trends. In sea, temperature decreases were observed, particularly over the artificial islands, exceeding -0.1 °C/year, in one of them. The positive trends in land along with the negative trends in sea decreased the coastal sea-land temperature gradient by up to about -30% in only 12 years, which also decreased the land breeze intensity. The findings shown here directly affect the local coastal population and ecosystem, exacerbate the thermal comfort, and add additional burden to this area, which is already considered as one of the warmest in the world.

Effects of Artificial Islands Construction on the Spatial Distribution and Risk Assessment of Heavy Metals in the Surface Sediments from a Semi-closed Bay (Longkou Bay), China

Artificial islands construction can significantly influence the spatial distribution of heavy metals in inshore sediments. In this study, the distribution and contamination of heavy metals (Cd, Co, Cr, Cu, Ni, Pb, Zn, As and Hg) in inshore sediments of the Longkou Bay and artificial island adjacent areas were investigated in 2013 and 2014, respectively. Results showed that the contents of heavy metals increased in the Longkou Bay and decreased in the west of the artificial island in 2014 compared with 2013. The contamination and potential eco-risk of heavy metals in the sediments were higher in 2014 than those in 2013. Cd and Hg showed a high potential eco-risk in LK02, and other metals were in the lower level. The results indicated that after the construction of artificial islands in the Longkou Bay, the contamination and eco-risk of heavy metals in the sediments markedly increased in the Longkou Bay.