Dinosaur Engineers, Laterite Plateau, Social Insects

The latest batch of readings and a video for you readers.

1) How the death of the dinosaurs reengineered Earth. Here is an interesting linkage between dinosaurs, sedimentary rock type distribution and river geometry. Fluvial sedimentary environments are different before (Cretaceous) and just after (Paleocene) dinosaur extinction.

In the latest Cretaceous, large bodied dinosaurs destroyed riverside vegetation, destabilizing banks and preventing stable meanders. Natural levees were breached causing sand to spill onto the floodplains, resulting in an open riverine environment. Post dinosaur extinction, vegetation growth stabilized banks, forming stable channels and meander belts, promoting a sharper division between the constrained channel sands and surrounding floodplain fine mud and organic rich swamps.

Ecosystem engineering by dinosaurs!

2) The Rocky Life: Plateaus of the Monsoon. South of the town of Satara in Maharashtra, the crest of the Western Ghats is mantled by a thick hard iron rich soil known as laterite. This red crust is a deep weathering profile that developed by chemical breakdown of the Deccan basalts (in Maharashtra) and of Precambrian metamorphic rocks (Goa and southern Western Ghats) around 50 million years ago in the Eocene during a warm and wet climate phase. For long, these high regions were treated as "wastelands", devoid of vegetation and wildlife. 

But as biologist Varad Giri explains in this excellent video, there is a hidden world that a careful observer will notice. 

And conservation biologist Neha Sinha writes about (under paywall) the plant life on these rocky plateaus- Why India's "wastelands"are biodiversity hotspots in disguise.  As she evocatively wrote about the Kaas Plateau near Satara on her X timeline- "Lakhs of flowers - carnivorous, parasitic, wild, mesmerising, ephemeral, resilient".

3) One mother for two species via obligate cross-species cloning in ants.  Social insects must rank as some of the most amazing creatures.

In one species of ants, the mother gives birth to offspring of two different species! This happens because the mother uses sperm from another species male to produce the worker caste.

Yes, they have caste too!

I’ll reproduce the abstract here and leave you to roll your eyes in wonder-

“Living organisms are assumed to produce same-species offspring. Here, we report a shift from this norm in Messor ibericus, an ant that lays individuals from two distinct species. In this life cycle, females must clone males of another species because they require their sperm to produce the worker caste. As a result, males from the same mother exhibit distinct genomes and morphologies, as they belong to species that diverged over 5 million years ago. The evolutionary history of this system appears as sexual parasitism that evolved into a natural case of cross-species cloning, resulting in the maintenance of a male-only lineage cloned through distinct species’ ova. We term females exhibiting this reproductive mode as xenoparous, meaning they give birth to other species as part of their life cycle”.

I love the first line-  Living organisms are assumed to produce same-species offspring. After all, we never tried too hard to prove it!

Ganga Earthquake, Nile, Deep Sea Habitats

Some readings over the past few weeks:

1) An Earthquake Changed the Course of the Ganges. Could It Happen Again?  Sediment load carried by big rivers like the Ganga often choke up channels and force the river to cut another path. Sudden channel shifts can also occur due to tectonic movements. A recent survey of the Ganga about 100 km south of Dhaka, Bangladesh , identified an old channel of the Ganga. Exploring this area, researchers came across veins of sand cutting across the sediment layers. These veins or sand dikes were  injected into the surrounding sediment. They are a sign of major ground trembling triggered by a large earthquake. Ground motion may pressurize buried sand and inject it  upwards. Further studies showed that this event may have been a 7-8 magnitude earthquake that occurred 2500 years ago. Kevin Krajick writes about this discovery and the larger geologic context.

2)  Lessons from the Nile about rivers and society. The Nile river has sustained agriculture, human habitation, and royal dynasties for millennia. A Nature Geoscience editorial summarizes a collection of sedimentological and geomorphologic studies that track the evolution of the Nile through the Holocene. Phases of the river cutting a deep valley changed to phases of the river flooding laterally and building fertile floodplains. This geomorphological evolution driven by climate change and more recent dam building have influenced agriculture and social systems in the past as well as the present. 

3) Ocean Exploration: Meet The Deep. I highly recommend this site. National Ocean and Atmospheric Administration, U.S.A., has compiled some stunning photographs and videos of deep sea habitats and the diverse forms of life that inhabit this little understood world. Corals, sponges, brittle stars, molluscs, worm tubes- attached to the bottom, living around energy sources such as hydrothermal vents and cold seeps. It is an absolutely fascinating exploration of the biodiversity of the deep sea. 

Octocoral and Brittle Star: Source NOAA Ocean Exploration

As a bonus, these images make great wallpaper for your mobile phone!

Mid Oceanic Ridges: Geodiversity And Biodiversity

Mid Oceanic Ridges. Unlike continental mountain chains, these undersea mountain ranges are invisible to our day to day gaze. 

Source: Gretchen L. Früh-Green et.al. Diversity of magmatism,hydrothermal processes and microbial interactions at mid-ocean ridges.

Yet, they are among the most dynamic of geologic features. They form where tectonic plates split and move apart, and new ocean floor is generated by upwelling magma. Sea water percolates through the cracks in this new crust, heats up in the subsurface and then rises carrying with it gases and metals. These vigorous hydrothermal circulation systems provide a link to exchange chemicals between the mantle and the crust. Varied microbial and macrofaunal communities colonize these environments depending on proximity to magma, the strength and chemistry of hydrothermal systems, and the nature of bedrock composition and fault controlled topography. 

Some specific geologic settings, those with serpentinite rocks,  have recently attracted great interest because they are thought to have provided the right combination of heat and chemicals to stimulate pre-biotic chemistry and the origin of life.

Gretchen L. Früh-Green and colleagues review this fascinating underworld, bringing out, both, the diversity of geologic processes at work and the resulting biodiversity that depends on this varied geology and energy supply. The introductory paragraph shared below gives an idea of the importance of this geological environment.

"Mid-ocean ridge (MOR) systems extend approximately 60,000 km around the globe and are the most dynamic and continuous tectonic feature on the planet (Fig. 1). On average, about 3.3 km2 yr−1 of new oceanic crust is generated at global spreading centres, which account for >70% of the total volcanism, and where about 60–70% of the Earth’s surface has been produced over the past 160–180 Myr (ref.2). Mantle melting, volcanism and faulting at MORs drive hydrothermal circulation that allows the transfer of heat, chemical compounds, metals and volatiles from the asthenosphere to the hydrosphere and biosphere. Approximately 75–80% of the Earth’s total heat flux occurs as the oceanic crust ages, and it is most pronounced at ridge flanks, where low-temperature fluid flow continues off axis for millions of years and contributes to global biogeochemical cycles. It is estimated that the volume of the ocean circulates through the oceanic ridge system in much less than 1 Myr (ref.6).

Spreading centres are one of the most extreme environments on Earth that can support oases of life at high temperatures and thriving in perpetual darkness. Microorganisms obtain energy from magmatic gases and chemical compounds of altered oceanic crust, rather than from light, through a process called chemosynthesis. In turn, many of these microorganisms symbiotically sustain macrofaunal communities that populate hydrothermal vent environments. The microorganisms with the highest known growth temperature on Earth are found within MOR hydrothermal systems and investigation of their genetic diversity has changed the current view of the tree of life".

I have put the last sentence of the first paragraph in bold to highlight the scale of this geological system. This is rich and rewarding reading. The paper is open access.

Gretchen L. Früh-Green, Deborah S. Kelley, Marvin D. Lilley, Mathilde Cannat, Valérie Chavagnac & John A. Baross: Nature Reviews Earth & Environment- Diversity of magmatism, hydrothermal processes and microbial interactions at mid-ocean ridges.

Links: Long Covid, Galapagos Islands, Origin Of Life

 I enjoyed reading these over the past few days.

1) Clues to Long Covid:  The disease that has affected us over two long years is still quite a mystery. Jennifer Couzin-Frankel has written a very informative article on the quest to understand Long Covid and how to treat it. 

2) The Galapagos Is a Glimpse of Eternity.  Geology influence organismal habitat and life habits. Penguins nesting in lava tubes. Tortoises finding warm volcanic vents to raise their body temperatures. Paul Stewart describes the landscapes of the Galapagos Islands with its amazing biodiversity, now threatened by climate change. 

3) From Pre Biotic Soup To Fine Grained RNA World. I often come across new articles breathlessly announcing that organic molecules of various types have been found on asteroids. But whatever the source of different molecules, it is specific conditions on early earth that we need to understand to arrive at a sensible theory of the origin of life. Fine article by Philip Ball.

Links: Noisy Soils, First Art, Mars Geology

A few readings for your perusal.

1) Biologists are poking senors into soil to listen to the hum of life. Amazing article by Ute Eberle on what we can learn from acoustic signals given off by animals living within a soil profile.

Life in the soil was thought to be silent. What if it isn’t?

2)  When was the first 'árt' made? Is there a neat sequence from abstract scratches on rock and bone to representational art that adorns the walls of caves? Excellent article by Amy McDermott on this question, bringing together the viewpoints of archeologists and cognitive scientists. 

What was the first “art”? How would we know?

3) One year on, NASA's Mars Perseverance has been drilling into rock, collecting samples and finding some surprises along the way. It will now head towards an ancient delta to look for past life! Alexandra Witze reports on the progress.

A year on Mars: How NASA’s Perseverance hit a geological jackpot.

 

In Praise Of The Estuary

Be sure to take some time out and watch his lovely documentary on the Mulki Estuary by Dakshina Kannada Wildlife team.

Email subscribers who can't see the embedded video can watch it here - The Mulki Estuary.

This estuary has formed at the confluence of the Sambhavi and Nandini rivers (the documentary wrongly calls it the Gurpur river) on the Karnataka coast. Estuaries are particularly rich ecosystems. The confluence of fresh and saline waters, changes in water temperature and turbidity, nutrient supply by the river and coastal upwellings, the rise and fall of tides, and a meeting and interference of shore parallel and river currents create conditions suitable for a thriving biosphere. The documentary brings these aspects out beautifully in its capture of coastal landforms and varied wildlife.

Estuaries are of great interest to geologists too. The present configuration of our coastline has developed relatively recently in the geologic past. Before 15,000 years ago, during the Ice Age, sea levels were  about 100 meters lower than present. The coastline would have been tens of kilometers to the west of today's shore, and rivers like the Sambhavi and Nandini would have carved a valley across this stretch of the continental shelf and would have met the sea at a far westward location. As the Ice Age ended and the earth warmed, the rising seas progressively inundated the continental shelf. The estuaries along the Indian coast as with other coastlines are really drowned river valleys.

Coastal environments like beaches, mud flats, sand bars, mangroves, lagoons, and marshes, are in a state of constant adjustment to the movement of tides and currents, sediment supply from rivers and their distribution and deposition, and the impact of vegetation in stabilizing these features. Shore currents and sediment supply have an outsize effect on the evolution of the coast. One interesting example is found at Mangaluru, just south of Mulki, where another estuary has formed at the confluence of the Gurpur and Netravati rivers. The map shows this coastal setting. 

A geological investigation by B. R. Manjunatha and K. Balakrishna has shown that the Gurpur river once flowed a shorter route to the sea (paleo-course outlined in blue). Starting a few thousand years ago, excessive sediment deposition blocked this channel and strong southerly currents began building a barrier spit, forcing the Gurpur river to turn south and flow parallel to the coast for a good 8 kilometers before eventually joining the Netravati river in a joint exit to the sea. The Netravati river too has shifted slightly northwards over time. A quick survey along the Karnataka and Maharashtra coast show many similar situations where the river makes an abrupt turn and flows parallel to long sand spits before entering the sea. Do these rivers too have a similar history of course change? Its an intriguing observation.

Besides such adjustments to the coast due to currents and sediment deposition,  fluctuations in sea level too will change the prevailing geography. A sea level rise will push beaches and lagoons landwards, while a fall will cause rivers and deltas to extend seawards and bury past shorelines.

The estuary being a low lying region and a sediment trap preserves this history of sea level change. Geologists love to drill and take out sediment samples from the estuary bed and associated marshes and mangroves, because they contain, in its changing sediment and biological composition, clues to earlier environmental shifts. Understanding how past sea level change affected the coastal system is of great value in tuning our expectations and our preparedness of how the ongoing sea level rise will impact our present day coastlines.

I must confess that this post was inspired not just by this documentary but by my own memories of an estuary. During my student days, I had visited the coastal town of Malvan at the end of a small trek along the west coast of Maharashtra. A friend suggested we spend the day boating and exploring an estuary south of town. It turned out to be a most relaxing and enjoyable experience.

Taking inspiration from these children, we too rowed vigorously and covered quite a bit of distance. 

Malvan then was a small sleepy place and this meeting of river with the sea even more so. Not a soul was in sight, as hour after hour the waters of the estuary gently lapped against our boat. A salty sea breeze kept us refreshed. As the sun beat down upon us we finally decided to take a break. In search of something to eat and drink we scoured the shore for a small settlement. Up ahead in the middle of the estuary was our savior. 

 A luscious looking coconut island beckoned.

Plate Tectonics And Coral Reef Distribution And Diversity

Plate tectonics drive tropical reef biodiversity dynamics- Fabien Leprieur, Patrice Descombes, Theo Gaboriau, Peter F. Cowman, Valeriano Parravicini, Michel Kulbicki, Carlos J. Melian, Charles N. de Santana, Christian Heine, David Mouillot, David R. Bellwood & Loıc Pellissier

Interesting work!

Tropical coral reefs require sunlit shallow sea water to thrive. This is provided by coastlines and continental shelf areas. Plate motions has shifted continents. The geography of shallow sea habitats in which corals thrive has accordingly shifted. This study reconstructs this dynamic over the past 140 million years of the breakup of Gondwanaland and the movement of continents since. It is summarized beautifully in this graphic.

Source: Leprieur et al 2016

The optimum locations of coral habitats moved as the configuration of the Tethyan ocean changed. The fossil coral record shows that coral diversity was maximum in the Western Tethys in the Eocene (55 -33 ma), then shifted to the Arabian Peninsula and Western Indian Ocean during the Late Eocene - Oligocene (37-15 ma). Finally as the Tethys Ocean closed due to the India Asia collision, coral biodiversity hotsposts shifted since the middle Miocene to the Indo- Australian Archipelago.

There is a further step. The study models species diversification based on the distribution of estimated paleo-bathymetry and the residence time of habitat (both controlled by plate tectonics). The reasoning is that the frequency of evolution of new species (biodiversity) depends on the distribution of optimal habitat and how long these habitats remain in place. Large long lasting shallow continental shelves will offer an opportunity for populations of ancestral species to disperse over broad areas and diverge into new species. Tectonically complex areas like western Tethys (in the Eocene) and Indo-Australian Archipelogo in Pliocene-Quaternary have sea floor topography and shelf configurations which fragments habitats based on changes in water depth, current and wave strength and direction and nutrient availability. Populations get split and isolated in such regions leading to genetic divergence and speciation. This is mimicked well by the simulations.  Over time, rich diversity can evolve in such long lasting optimas by the process of dispersal and isolation. The locus of evolution of biodiversity can then shift as plate motions move ideal habitats across the globe. New species can arise from parapatric speciation (adjacent to the range of the ancestor) or sympatric speciation (within the range of the ancestor). The study finds that for either modes of speciation, their simulation matches the observed distribution of fossil and extant coral diversity.

The graphic below captures the comparison between fossil coral diversity and simulated coral diversity. Eocene, Miocene and Quaternary observed diversity (left side)  matches the model results (right side).

Source: Leprieur et al 2016

The scientists caution that local fluctuations like sea water temperature and acidity and ecological complexity will also play a role in evolution of  diversity and call for further validation of their work. But overall, its a nice demonstration of the role of plate tectonics in controlling coral habitats and diversity.

Rocky Plateaus Of Western Ghats Need Protection

The Times of India Sunday Pune Edition (Nov 21) carried a good article (the print edition has a more detailed write up) by Dipannita Das on the ecological importance of the rocky plateau landforms of the Western Ghats. These outcrops are often termed "wastelands", a terminology that reflects classification of landscapes by their economic potential, a classification tradition that goes back to the days of the British Raj. Rocky plateaus were thought to be unproductive and were termed wastelands.

Here is a classic example of one of these rocky plateaus from Panchgani, a hill station south of Mumbai. The cap is made up of an early Cenozoic laterite. At other locations the plateaus are hard basalt flows.

And here is a view of the surface of such plateaus.

It may seem mostly barren, but as the article details, such plateau environs are teeming with plant and animal life, specialized to live in crevices and along the slopes and depressions and hollows and water seeps that have formed by the action of physical and chemical weathering.

There is a national level effort going on to map the biodiversity of the Western Ghats (see site WesternGhatsIndia.. not working at the time of writing ) and one hopes that many of these ecologically rich and interesting rocky plateaus will be afforded protection from various anthropogenic activities. These plateaus are of geological importance too. As I wrote in an earlier post, many of these "rocky" surfaces tell a story of the erosional, uplift and weathering history of the Western Ghats.

Over the last couple of years I have come across increasing number of reports in newspapers on various environmental issues. Reporters are talking not just to a few well known and politically connected scientists, but also to faculty and researchers from local colleges and institutes that are on the front line ... doing field work, collecting data and conducting research on various biological and geological aspects of the surrounding landscapes.

That marks a positive change in terms of increased science outreach by the media and raising awareness of these issues in the communities that are going to be directly affected by the unplanned development of the nearby environment.

Planting Trees Will Provide Clean Air To Pune?

Pune has several hills scattered throughout its extents. About 1600 odd hectares of them going by the various sources. Some of the hill land is owned by government and is managed by the forest department, some is government owned and is covered by slums and some is under private ownership.

There is a grand plan to convert all or most of this 1600 odd hectares into bio-diversity parks. While the idea of setting aside large swaths of hills as open spaces is creditable, reporting by the media on the supposed benefits of these parks verges on the side of being silly.

Here are a couple of examples I see again and again in media reports on this issue, most recently in yesterday's Times of India (Nov 12 2010, Pune edition):

Air pollution in Pune is a threat to health and well being. The United Nations recommends at least 12 sq m of green area per person for adequate environment for physical and mental health.

An average family of five will require 60 sq m of green area to survive and breathe. Once it comes up, the BDP's will provide clean air for approximately 35 lakh people.

BDP's are the bio-diversity parks and 35 lakhs equals 3.5 million.

Reading this strange environmental calculus makes me wonder how people in Tokyo, Hong Kong, Dubai and Las Vegas, cities with either hyper dense populations or ones bereft of any greenery manage to live healthy lives.

Going by the U.N criteria as presented in the Times of India (TOI) all the people in these cities should be diseased wrecks by now.

The fact is that the greening of the hills will not make a dent in either offsetting carbon dioxide emissions or preventing other types of air pollutants. Pune by a rough estimation of the number of vehicles (approaching 2 million) likely emits more than a million tons of carbon dioxide a year from vehicles alone (here is another estimate). There are other sources that add to this.

1600 hectares of the Utopian forest that may or may not come up on these hills will sequester at most a few thousand tons of carbon dioxide per year. That is the best case scenario. Most likely the number will be disappointingly smaller. Currently the forest on these hills sequester a few tens of tons per year according to this study on carbon sequestration in Pune.

Besides trees don't suck in particulate matter and sulfur and nitrous compounds which have ill effects on health. More than CO2, these pollutants pose an immediate threat to our health. These continue to be emitted in large quantities mostly as vehicular emissions and tree plantations won't reduce their presence in the air above Pune.

I would like to see at least parts of these hills being left as open spaces..there are clear benefits in terms of providing cool recreational spaces for citizens and as a refuge for the urban bird and animal populations. But whether those hills are left barren or are built upon or are completely covered by trees won't make a difference in terms of providing clean air to the city.

That will happen only through cleaner and more efficient use of energy sources particularly a move towards cleaner vehicular fuels.

Environmental Impact Assessments In India Are Becoming A Joke

...time for another rant on the Environmental Impact Assessment ( EIA) process (which is required for clearing large developmental projects) in India.

What do you do to get a green signal for a development project in a bio-diverse wetland frequented by migratory birds?

Answer: Do the EIA in the summer months..when the wetlands are naturally drier and there are no winter migratory birds! Then file a report saying that there is no ecological value to this area...go ahead and build your project!

According to Dr Asad R. Rahmani of Bombay Natural History Society and Prof Asha Rajvanshi of the Wildlife Institute of India, that is what is happening in the case of the Naupada swamps in coastal Andhra Pradesh where an EIA report filed neglected to do a multi-year survey and instead considered only the period of 3 months from March to May.

How ludicrous.....how absurd can the process get?!!

The problem begins with how the state classifies the land. This piece of wetland is considered a "wasteland" by the district authorities. The hired consultants use that as a baseline and make no attempt to seriously evaluate the ecosystem.

That's how increasingly the EIA system seems to work...terms of reference and baselines are purposely kept narrow, limited and ill-considered and consultants with a past history of saying what the government wants to hear are favored. By relegating the EIA to a side-show with no real powers to halt a project or make its design conditional to the EIA finding,  a culture of shoddy science, incompetence and sheer dishonesty is being encouraged.

Beyond popular articles in mainstream media the EIA is coming under some more serious scrutiny in science publications as well. In the January 25 2010 issue of Current Science Devendra Kumar Agrawal, Mahendra S. Lodhi and Shradha Panwar do a case study of the potential impact of planned hydroelectric projects in the Alaknanda catchment in Uttarakhand and conclude that the EIA process is inadequately equipped to evaluate the region wide ecological impact of these projects. The EIA considers each project as separate and its larger impact on adjoining areas is not included in the scope of the EIA study. This piecemeal approach does not consider cascading and other non-tangible effects of these projects.

The Ministry of Environment and Forest which has the final say on these reports and projects is applying different clearance standards for different issues.

Here is what the Minister of Environment and Forest Mr. Jairam Ramesh said recently about the decision to withhold introduction of Bt Bringal (Times of India February 10 2010):

"It is my duty to adopt a cautious, precautionary principle based approach till such time independent scientific studies establish to the satisfaction of both the public and the professional the safety of the product".

Fine words..Mr Minister..but how about extending the same principles ...caution, precautionary principle based approach...independent science...satisfaction of both the public and the professional...to the EIA process?

Why has the EIA process been rendered so toothless that a project can begin even before the relevant EIA is completed..?

You Mr. Minister are overlooking and presiding over a grotesque perversion of science and the consequent loss of valuable biodiversity, ecological services and the livelihoods of people who depend on them.

India is a signatory to the Ramsar Agreement... a commitment to protect valuable wetlands.

Don't be a mute spectator.

Nice Talk On The Origins Of Life and Astrobiology

From NPR Science Friday a talk on Astrobiology and the Origins of Life.

This is before a live audience at Arizona State University, Tempe. So there is a lot of interaction between the scientists and the audience and also callers across the U.S. Guests are Peter Ward a biologist from Univ. of Washington, Paul Davies Cosmologist, Physicist, Astrobiologist from Arizona State Univ, Barry Blumberg Winner, 1976 Nobel Prize in Physiology or Medicine and Founding director, NASA Astrobiology Institute and Ariel Anbar, Principal Investigator, NASA Astrobiology Institute team at Arizona State University.

Two points stood out for me:

1) Where are earth rocks older than 4 billion years likely to be best preserved . Answer - The Moon! Early in the evolution of our solar system, meteorite bombardment of planets caused ejecta to travel and contaminate other planets and their satellites. On earth, rocks that old have been recycled and reconstituted , but the moon has been geologically inert for more than 4 billion years. About 1% of the Moon's soil is extraterrestrial in origin. So material from Venus, Earth and Mars is out there in the Moon's top soil layers.

2) Alien life does not necessarily mean life of extraterrestrial origin. There is the intriguing possibility that life evolved more than once on earth. Only one type proliferated, but is it possible other truly "alien" life forms, those that had an origin independent from our lineage still exist on earth? The point was made that most microbial life on earth has not yet been cataloged and we still have only a dim idea about life's variability. What would such "alien" microbes be made up of and what are the best places to look for them?

A very interesting topic and a great example of science outreach.

Download the podcast and listen.

Coral Ecosystems of India's West Coast

I came across a small news report in this Sunday's Times of India of the recent discovery of a thriving coral ecosystem about 80 nautical miles from Panjim in Goa. This coral reef system has developed atop a shallow 40 km long bank known as Angria Bank. The sea floor surrounding this bank is about few 100 feet or so deep and suddenly rises to just 20 meters or so. The image below shows the location of Angria Bank.


The bathymetric surface is also seen in the image and although generalized you can still see the topography of the sea-floor on a regional scale. The dotted line marks the edge of the continental shelf of India. The shelf is the drowned extension of the continental crust of India. When you say that plate tectonic movements caused India to split away from Africa, the split did not occur at the position of the present coastline but roughly at the edge of the continental shelf. Back during the Pleistocene glaciation much of this shelf may have been exposed as sea-levels periodically dropped by a few hundred feet worldwide. As the glaciation ended around 12,000 years ago, sea-levels rose up to the present coastline, drowning large parts of the shelf. The Angria Bank as you can see is at the edge of the shelf. At the point marked Angria Bank you can see couple of elongated humps on the sea floor. That is the raised shallow bank. To the west the sea floor suddenly becomes deeper along a steep slope that grades into the deep sea plains. This marks the transition from the continental crust of the shelf to the ocean crust of the deep sea plains. The banks topographic high above the surrounding sea bed is probably structural in nature. The west coast shelf of India is riddled with coast parallel faults which originated with the tectonic breakup of India first with Africa and then with Madagascar. Vertical movements along these faults produce horst and graben structures, elongate ridges and depressions. The Angria Bank is likely such a horst. The coral community there must have started developing after the Holocene sea-level rise few thousand years ago and coral growth continues today. I am not sure what the composition of the foundation of this reef is. It could be basalt rock, the submerged continuation of the continental flood basalts that are exposed all over Maharashtra or it could be older Cenozoic sediment or even Pleistocene reefs developed during the interglacial phases of the Pleistocene glaciation when sea-level was high.

Such isolated shallows as ideal environments for coral growth. Far from continental rivers, the water are clear and devoid of terrigenous sediment which can make water turbid. Such turbidity can prevent sunshine from penetrating the water, inhibiting the symbiotic algae that lives within corals from efficient photosynthesis. Too much suspended sediment may also clog up the coral animals feeding mechanism. Many of the world's major coral ecosystems such as the Bahamas, Bermuda, Lakshadweep, Maldives are situated in such isolated shallows, some distance away from major continental river mouths and deltas.

The newspaper reports that the Maharashtra tourism department hopes to make this into a hot eco-tourism spot. I searched for Angria Bank and found several private tourist operators already offering a "four hour ride on speed boat" from Panjim for world class diving to the Angria Bank. Exploring coral ecosystems is one of the great experiences. My graduate adviser and I used to teach a class in carbonate depositional systems and took students to study the Florida Keys. I can tell you no matter how many nature documentaries you have seen, nothing prepares you for your first encounter with coral reefs. That world on the sea floor is something else. Besides just catering to tourists this newly found ecosystems needs to be studied in detail. Reef Watch a Mumbai based organization has already started a research program to document and study the biodiversity. And I hope the government steps in and works towards making the Angria Bank a marine bio-reserve. Better tourists with a camera than fishing trawlers.

India's Tigers and Forests

I have been blogging quite a bit about the state of India's wildlife and forests. There has been a lot of news about this topics lately. Not all of it bad. Recently the Indus dolphin was sighted in Punjab river Beas after the gap of about 70 years. But overall the news has been depressing. Bharatpur bird sanctuary has virtually dried up. According to the latest census the tiger numbers in the country are now thought to around 1400 only, much below the earlier figure of about 3000 given by the government. And there is more bad news of the state of the forests. The latest census of the Forest Survey of India reveals that between 2003 and 2005 India lost about 700 sq km of prime forest land and suffered lots of degradation of dense to moderately dense forests. By a coincidence I had posted on this topic a few days before this report (2003-2005) came out. That post used data from an earlier census (2001-2003). That census showed that forest cover has actually increased by around 2700 sq km. But the devil is in the details. All that "growth" is either an artifact of better mapping due to improved satellite resolution or counts monocultures planted on degraded land away from any critical wildlife habitats. The core forests in and around tiger reserves for example continue to vanish and become degraded. Afforestation is not being directed to where it is most needed. I had used the Nameri tiger reserve in Assam to illustrate this point using images more recent that those used in the 2003 survey. Now this latest report confirms that prime forest areas are shrinking.

All over the world, not just India the basic problem has been that population pressures have altered the landscape in often irreversible ways. Contiguous forested areas have become fragmented. They are now islands surrounded by human presence and activities. In India nowhere is this illustrated with more clarity and devastating realization than where the Himalayan foothills grade into the north Indian plains. Below image shows this situation where the ranges suddenly give way (green dotted line) to irregular jagged pieces of forest, isolated from other such pieces, islands surrounded by intense agriculture land use.

The brown dotted polygons mark the approximate boundaries of the Dudwa tiger reserve in Uttar Pradesh. Three patches of forest which are becoming increasingly fragmented and frayed at the edges literally. How do you manage healthy tiger populations is these isolated islands? They are few 100's of sq km large, able to sustain a few ten's of tigers at most in each of the forest patches. How do you ensure a healthy gene pool with such small numbers? Some years ago when I was living in Florida, wildlife authorities were faced with a similar problem with the Florida panther. A small population showing signs of debilitating health effects from inbreeding. So, the Texas cougar a close relative of the panther was introduced in the Florida habitats of the panther. The results are encouraging. Florida panther populations today are healthier. Increasingly it is not going to be enough to just manage the physical aspects of the ecosystem. Our wildlife management plans currently claim to focus on afforestation, resolving human animal conflicts at forest margins, controlling logging and poaching. These are worthy goals. Poaching especially is suspected to have disproportionately contributed to the recent decline in tiger numbers. But even if our reserves become well protected against poaching we have to live with the reality that most of our tiger habitats are never going to connected to each other again and animals trapped in isolated habitats will need more help. We will have to manage their biology for them as well. Conservationists often talk about setting up migration corridors but take a look at the above image of Dudwa which for administrative purposes is one tiger reserve. The three forest patches are separated by 10's of km of intense agriculture land use. It is inconceivable that we can change land use and relocate humans on this scale. Most reserves in India are now separated by 100's of km of no forest areas and migration corridors cannot be thought of as a general solution to habitat isolation. In this context saying India has a total of 1400 tigers or 3000 tigers or some other number becomes less meaningful than assessing what viable population can be maintained in each of the forest islands across which natural migration and gene flow is now impossible. By such separate assessments may come the unpleasant knowledge that 1500 to 2000 is the total healthy population that can be sustained given the limited amounts of forests left. Off course this number will be hopefully much more, but to come to a stage where we are in a position to develop a tiger management plan backed by some hard science we will need increasingly focussed biological information on individual tiger populations. This means developing genetic databases of tigers to understand the genetic structure of populations. Regular screening for signs of inbreeding and setting up a well funded programme for induced gene flows across our tiger reserves. Are we geared up for a biological management plan for tigers?

What has been the reaction of the government to the recent report that 700 sq km of prime forest has been lost?

"Overall, the decrease is insignificant. It is not worrying as India's forest cover has more or less stabilised and ranks number 10 globally on a per capita basis," said Devendra Pandey, director-general of Forest Survey of India.

It is a statement only an Indian bureaucrat can make. Factually correct in a very narrow sense but showing a contemptuous arrogant indifference to the ground ramifications of the finding. Pretending everything is fine because we rank number 10 globally on a per capita basis. How on earth is that hollow boast supposed to help the tiger? Dismissing the real loss of prime habitat by pointing out that our forest cover has more or less stabilized. In an earlier post I pointed out how meaningless this stabilizing is in the context of the health of critical wildlife habitats. Afforestation is simply an exercise carried out to balance the books of the ministry of environment and forest. Let's take another look at how this "stabilization of forest cover" is working out. Below is a forest cover map of Buxa tiger reserve in West Bengal. This data was complied from 2001 satellite images.

Source: Forest Survey of India

Green is dense to moderately dense forest and yellow is open forest which has about 10-40% forest cover. Look at the area around the red arrow. And compare it with a close up below of the same area taken in 2006.


If our afforestation programme really was meaningfully designed, this open forest shown in 2002 should have been targeted for improvement. The reality? By 2006 the entire area has been converted to farmland. "Ground Truthing" in remote sensing parlance refers to the validation of automated classification algorithms used in land cover mapping. Over here the term ground truth has taken on a much more urgent meaning. The truth is that our prime ecologically rich forest areas are disappearing but the government doesn't seem to care. Through its reports it is misleading it's citizens by creating statistical illusions of forest cover "balance" and "stabilization". As long as somewhere far away an equivalent amount of area is greened with monoculture plantations the forest department goals of "stabilizing" forest cover will be met and a false victory proclaimed.

Write to your state forest department and demand action. The link to the Maharashtra forest department is : Maharashtra Forest Officials

See also:

India Gains Forest Cover, But....
Bharatpur Bird Sanctuary Dries Up
Indus Dolphin Sighted in Punjab

Bharatpur Bird Sanctuary Dries Up

From the Times of India, an editorial on the world famous Bharatpur bird sanctuary or what used to be a sanctuary. It has dried up. The sanctuary known as the Keoladeo National Park is an artificial wetland created in the mid 1700's as a hunting ground for Rajasthan royals and relies on annual release of water from various nearby rivers. Lately water that was meant for the wetland is being increasingly diverted to farmland, progressively drying up the park. The birds have already left for wetter pastures. If wetlands are not resorted soon, it will lose recognition as a world heritage site. What a shame! Below is an image of the Bharatpur wetlands.


In this image at low resolution there appears to be plenty of green within the park but take a look a a close up below.


The entire area is dry. Only in the vicinity of the green dot could I find some water. Few green patches indicate the presence of moist soil, but no water, no wetland and no birds. Looking at the close up one can understand how precarious the health of the wetlands always has been. Being an artificial creation, the boundaries of the wetlands are sharp and are surrounded by intense agriculture land use. The light colored rectangular quilt like pattern you see surrounding the central dark former wetland are farm plots. The conflict for allocation of water for people versus animals is a perpetual problem in India and the needs of the people win out.

Such degradation of our national parks is happening to various extents all over the country. Bharatpur is an extreme example of a small sanctuary whose support system has completely collapsed. Take another famous sanctuary, the Gir Forest National Park. This is world famous for being the last natural habitat of the Asiatic lion. Image below shows the Gir forest area.


At this scale all appears well, large green patches with no apparent disturbance. But image interpretation is about pattern recognition. Take a look the areas at the southern margins of the forest around the green arrows. The green patches around these arrows have a more speckled appearance compared to the green patches in the center. Close up below reveals all.

Again those rectangular patches you saw around Bharatpur, farmland making its ways into the forest following the water courses, small streams, water holes, the same water sources that wild animals use. A conflict in the making.

What is the future for India's wildlife and biodiversity? There are conflicting signals from the politicians. Yesterday the centre announced a package of Rs 600 crore for project Tiger, to be used for the tiger conservation programme. This for now should be seen as good news. On the other hand, political interference and interest in the exploitation of forests is alive and well. India Today recently reported on poaching rings in UP, and yesterday several Kashmir politicos have been accused of illegal exploitation of timber. The culture needs to change from viewing forests and wildlife as a resource to be exploited, as some obstacle to development, to one where our biodiversity is seen as an integral and important component of our development. Until then, tiger rescue packages notwithstanding, conservation plans will always be at the mercy of local political winds. I mean as a scientist I can well imagine the frustration of a senior forest officer who having carefully drawn conservation plans for a particular area is told by the local politico, oh-sorry no water for you this year!

Another big danger besides the increasing human wildlife conflict is climate change. Today's conservation plans are drawn on the assumption that the current ecological boundaries will remain so for the foreseeable future. But what if in response to shifting climatic belts, ecological boundaries also shift? This is an imminent danger facing India. Our current conservation plans are barely able to cope with problems of human encroachment into forest areas by rehabilitation and relocation plans for humans. What will happen if forests further fragment in response to climate change and ecological belts move? Where will the animals go?

Indus Dolphin Sighted in Punjab

How long since the last sighting of a creature for it (the species) to be declared extinct? There is no clear answer to this. It is very difficult to definitively say that all populations of the species have vanished across its entire range. The Indus dolphin Platanista minor is one of the few freshwater dolphin species in the world. Besides the Indus dolphin the Indian subcontinent also has the Ganges Brahmaputra freshwater dolphins. Both species are endangered with numbers estimated to be at most in the several hundreds each. The Indus dolphin's range extends beyond the Indus main channel to its many tributaries such as the Sutlej and Beas. It was last seen in the Punjab rivers in the 1930's which is why the sighting of this animal in the Harike wildlife sanctuary south of Amritsar couple of weeks ago has caused delight among wildlife enthusiasts. The image below shows the Harike wetlands formed at the confluence of the Sutlej and Beas rivers.

It is astonishing that there was not a single confirmed sighting of this dolphin in the Punjab for about 70 years. These are not some isolated stretches of rivers. Punjab is heavily populated, with extensive agriculture land use along the banks of its rivers. Biologists are not sure if the Indus dolphin is really broken up into semi-isolated sub populations or there are regular encounters between populations in the Sutlej-Beas with those in the Indus main channel. Is it possible that the Sutlej population went extinct and these latest sightings represent a new population recently migrated from the Indus channel. Do the many barrages on the Punjab rivers pose a serious barrier to migration or can the dolphin negotiate these barriers especially at flood times? Many questions and I hope wildlife authorities take this opportunity to extensively study this species. Just to give you an idea of the range of this species the image below shows the Indus river basin from its delta up to the Harike wetlands.

Sightings such as these makes me think about how many species are yet to be discovered. The focus in recent years and correctly so has been on the accelerated rate of extinction. But around 300 new species are being formally described by scientists daily across the entire range of life. A new mammal species is reported once every 3 years and a large new vertebrate from the open ocean once every 5 years. There are currently about 1.6 million species recorded but at the current rate of discovery these could represent about 10% of the total species currently living on earth. What rate of species loss can the biosphere sustain without shrinking overall? It is estimated that about 99% of species that have ever lived are now extinct. The diverse biota today must reflect then a slight excess of speciation over extinction. Using the fossil record the background extinction rate has been calculated to around 2.5 species per year which suggests a slightly higher speciation rate to maintain overall diversity. This estimate should be regarded as a canonical speciation rate and the variance around this mean speciation rate is more useful in understanding speciation patterns and diversity. A recent measurement suggests this approach to understanding the problem. If there are about 16 million species at present then every year the tree of life grows by an additional 16 million years of branch length. The average age of living species is about 5 million years. To maintain overall branch length i.e. to sustain current levels of biodiversity will require not more than 3 species per year going extinct. Measured extinction rates since the 1600's suggest that about 25 species have gone extinct every decade a figure that agrees with the above theoretical expectations. This rate however should be considered an underestimate since many extinctions would have gone unnoticed and has definitely increased recently. For example the last century has seen about 20 mammalian species alone going extinct. The effect of natural extinction on overall biodiversity is very different from a mass extinction such as the one human activity has almost certainly induced. Unlike natural background extinctions the current increased rates of extinction may be non-random i.e it may not just prune the branches of life but wipe out related branches of the tree of life causing similar types of organisms to selectively disappear. The overall structure of the tree of life may change with certain ecosystems or tiers within ecosystems disproportionately emptied than others, causing genuine reductions in biodiversity. Something like this may already be going on, for example amphibians have been assessed to be at greater risk from global warming than other vertebrate groups. Anyways its great to see the dolphins back in Punjab. May the force be with them.

Meanwhile in another wetland that dried up some time back, this sighting of an incredible rare creature.

From NASA Mars explorer image, what looks like a humanoid female clambering down the slope towards a dried up lake bed in search of .... maybe water, food or dry ice? The Indian media has had a field day with this with experts coming and giving long talks on the possibility of martian life. Amazing stuff!