Oceans

Seabed Mining

The limited opportunities to mine for minerals on land is making the world consider deep seabed mining as an alternative. But this can pose major destruction to marine biodiversity, given our limited knowledge of the effects of disturbing the high seas, especially in oxygen-minimum zones.

Oceans

An Ocean at Risk

Climate change and anthropogenic factors, are causing many marine species to die out, resulting in a devastating impact on coastal populace. Replenishing mangrove ecosystems can provide a viable solution to tackle this problem.

Environment # Oceans

Analyzing past monsoons with foraminifera

Stable oxygen isotopic composition (δ18O) of foraminifera from the sediments of the Northern Indian Ocean has been used to decipher past changes in the intensity of the South Asian Monsoon. The interpretation of planktonic foraminifera δ18O is mostly based on a combination of sea surface temperature, monsoon runoff and the global ice-volume effect. During summer, the eastward flowing summer monsoon current carries the high salinity water from the Arabian Sea to the Bay of Bengal, whereas the Bay of Bengal...

Oceans

Coral Reefs in India: Status Report

The study of coral reefs have had a late beginning.  Earlier studies had accounted for only 218 species. Successive surveys made between 2008 and 2013 have reported the occurrence of 519 hard corals in India. Among the four major reefs in India, Andaman and Nicobar Islands are rich in coral as compared to the relatively poorer Gulf of Kachchh.  The isles of Lakshadweep, similarly,  have more species than the Gulf of Mannar.  Among the deepwater (ahermatypic) corals, 227 species have been reported...

Oceans

Why are our oceans salty?

What is salinity? Ocean salinity, defined as the salt concentration in the seawater, is measured in unit of PSU (practical salinity unit), which is a unit based on the properties of seawater conductivity. It is equivalent to per thousand or (o/00) or to g/kg. The commonest way to record salinity is to measure the amount of salt in 1000g of water, so it is referred to as ‘parts per thousand’ or ppt. Most of the ocean has a salinity of between 34ppt and 36ppt. (www.goo.gl/4AvV6G) Global...

Oceans # Wildlife

The Olive Ridleys of Gahirmatha

Before you start presuming that we are referring to Mr. Riddle of Batman fame, let us quickly clarify that Olive Ridleys are poor green turtles, high on the endangered list, while Gahirmatha is this muddy beach beside a luxuriant patch of mangrove forest, along the coast of Odisha. Have you ever wondered about the many beautiful creatures that are lost forever in the onslaught of our ever-growing concrete jungles? Encased prettily in jars filled with liquid, creatures large and small will meaninglessly...

Oceans

Seafloor Spreading

The floors of sea are not one contiguous basin. It just like the world that you see, with valleys, plateaus and mountains, except that it is all covered with water. Moreover, there are areas in the sea floor that are more 'active' than the rest. These areas are prone to faulting, fracturing, volcanic activity and spreading. Sea floor spreading is a basic premise that helps postulate the theory of plate-tectonics. The first stage in plate separation is the initiation of a new pattern of convection...

Oceans # Pollution | VOL. 13, ISSUE 79, July-August 2013

Calculating Carbon Uptake by the Oceans

Nitrogen-15 is an isotope that is useful in determining how much of the anthropogenic carbon dumped in the atmosphere is taken up by the oceans. Our efforts in the Indian Ocean to determine this rate is outlined here.

Oceans | VOL. 12, ISSUE 75, November-December 2012

Islands of the World

Islands differ in their geological and geomorphologic settings; and in their physical, biological, climatic, social, political, cultural, and ethnic characteristics. Yet they share a distinct underlying concern that marks their overall vulnerability in the context of sustainable development.

Oceans | VOL. 12, ISSUE 70, January-February 2012

Fortunes under the Sea

Oceans hold precious resources buried in seabeds and continental shelves. Despite legislations and international bodies upholding the Law of the Seas, fear about restrain of rights has begun to grow in developing nations with technologically advanced countries leading exploitation activities.