Conservationists from the Wildlife Conservation Society, the American Museum of Natural History, and other conservation and research groups have discovered that groups of dolphins in the western Indian Ocean do not mix freely with one another. In fact, dolphin populations are kept separate by currents and other unseen factors.
Specifically, the researchers have found that genetically distinct populations of the Indo-Pacific humpback dolphin may be formed in part by currents, surface temperature differences, and other environmental barriers, a finding made possible by using both genetic data from dolphins and environmental information from remote-sensing satellites.
The study appears in the advance online version of the journal Heredity. The study authors are: Martin Mendez of the American Museum of Natural History and the Wildlife Conservation Society; Ajit Subramaniam of Columbia University; Tim Collins of the Wildlife Conservation Society and the Environment Society of Oman; Gianna Minton of the Environment Society of Oman and the Institute of Biodiversity and Environmental Conservation, University Malaysia Sarawak; Robert Baldwin of the Environment Society of Oman; Per Berggren of Newcastle University; Anna Särnblad of Stockholm University; Omar A. Amir of the Institute of Marine Sciences, University of Dar es Salaam; Victor M. Peddemors of the University of KwaZulu-Natal and the Cronulla Fisheries Research Centre; Leszek Karczmarski of the University of Hong Kong; Almeida Guissamulo of Universidade Eduardo Mondlane, Museu de História Natural; and Howard C. Rosenbaum of the Wildlife Conservation Society.
The study represents a breakthrough in high-tech research on marine wildlife and a foundation for ensuring sound future management decisions on the Indo-Pacific humpback dolphin, a distant relative of the more familiar bottlenose dolphin. It is one of the first examinations of how environmental factors in marine environments can influence population structure in marine species, and can potentially enhance an understanding about the environmental factors that may drive the evolution of new species.
"Examining how environmental factors affect the population structure of marine species is a complex task. Doing this over entire regions is a challenge," said lead author Dr. Martin Mendez of the Sackler Institute for Comparative Genomics at the American Museum of Natural History. "Unlike studies of terrestrial species in easily observable environments, marine species are difficult to follow and the barriers they encounter are often invisible to us. Molecular technologies and remote sensing data can be combined to shed light on these mysteries."
The team started its examination of Indo-Pacific humpback dolphin populations using genetics, analyzing mitochondrial DNA data from more than 90 individual dolphins from the coastal areas of Oman, Mozambique, Madagascar, Tanzania, and South Africa. The scientists used this "genetic marker" to statistically measure gene flow between dolphin groups at different locations.
The researchers then compared their molecular findings with 13 years of data from NASA's satellites on environmental factors such as currents, temperature, turbidity, levels of chlorophyll, and dissolved organic matter.Dr. Mendez and his co-authors have succeeded in finding support for the hypothesis that environmental differences between regions could influence the population structure of marine species. Specifically, they found correlations between regional environmental differences and measurable genetic breaks between populations of dolphins from Mozambique and Tanzania in Africa, and Oman on the Saudi Arabian peninsula.
The researchers also found agreement on smaller spatial scales. Differences in temperature, chlorophyll, turbidity, and dissolved organic matter between regions also coincided with genetic differences between dolphin populations in Mozambique, Tanzania, and Oman. The two coastal regions without detectable genetic distinctiveness between dolphin populations—Mozambique and South Africa—also lacked significant environmental differentiation between them, a finding in agreement with the correlation of both genetic and environmental differences detected in other areas.
"With increasing development and potential threats to coastal habitats, understanding the population structure of the Indo-Pacific humpback dolphin in conjunction with environmental factors is an important step in formulating management recommendations and protection measures for the species," said Dr. Howard Rosenbaum, Director of the Wildlife Conservation Society's Ocean Giants Program.
Named for a distinctive hump under the dorsal fin of some individuals, the Indo-Pacific humpback dolphin grows up to 10 feet in length and ranges from dark gray to pink and/or white in color. The species generally inhabits coastal waters, deltas, estuaries, and occurs throughout the Indian Ocean basin to the coasts of Australia. The Indo-Pacific humpback dolphin is listed as "Near Threatened" by the International Union for Conservation of Nature (IUCN) and is threatened by habitat loss, disruption, and fishing activity.
John Delaney | EurekAlert!
How does the loss of species alter ecosystems?
18.05.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig
Excess diesel emissions bring global health & environmental impacts
16.05.2017 | International Institute for Applied Systems Analysis (IIASA)
Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.
Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....
Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.
The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
24.05.2017 | Event News
23.05.2017 | Event News
22.05.2017 | Event News
26.05.2017 | Life Sciences
26.05.2017 | Life Sciences
26.05.2017 | Physics and Astronomy