PISCINE AQUA CULTURE—NO FREE FISH LUNCH—NOT WHAT WE EXPECTED?

 

In the 1990s I traveled to a small coastal village in Italy, for an extended vacation. Each morning I would arise and walk down to the village center, reaching my destination - a small cafe—by eight thirty or nine in the morning, where I would enjoy an espresso and purchase a fresh loaf of crusty bread. On the way back to our residence, I often passed by the village fish market. But the display window with its clean glass window displaying a well scrubbed, sloping wood display counter which was always clean and empty. 

One day my curiosity got the better of me, and I poked my head in to ask, “Excuse me, I see your sign, but tell me, how do you keep in business? I never see any fish here?”

“Sir, the fishermen arrive here at 5:30 AM, we put their catch out for sale at 6:00, and by 7:00 or 7:30 all of the fresh daily catch is sold. To buy fish here, you must come early.                 

Italians prefer only absolutely fresh fish. Fish was available, every day in the week, but was very expensive…and you had to arise early to get it. 

From the late 1960s on fish prices were constantly rising. Increased demand, larger and more efficient trawlers sent wild fish stocks into decline. Aquaculture seemed like a good solution. 

In the 1990s fish aquaculture became well established and we all welcomed the concept of fresh fish at lower prices and the support for the protection of wild fish stocks. By that time the earth’s human population had exceeded the 6 billion mark and ocean fishing had reached its maximum production limit.More factory ships could be built, but the world’s fish stocks could not sustainably produce any more fresh-fish tonnage.

Aquaculture seemed a reasonable solution. By growing fish on land in ponds or in cages off shore, it was thought that these fish could help satisfy the human demand for fish, slow the decline of wild fish stocks which for many species (such as the Atlantic Cod) which were approaching the critical point beyond which these species  could not recover and begin to recover populations.  

Fish farming was born!  Today more fish sold in fish markets are farmed fish than wild caught. But the problem aquaculture was touted to solve, did not materialize.  Aquaculture has exacerbated fish stock problems rather than offering  a solution.

 Aquaculture has put more strains of wild stocks of many species of fish since much of the food farmed-fish and shrimp are fed is derived from wild fish stocks. Then too, the massive tonnage of forage fish, such as anchovies, herring, and other small schooling fish which serve as major sources of food for predator fish and sea mammals has has exacerbated the food shortage plight of these other wild species—even those not sought for as food sources such as sea mammals. 

The reason?  The most popular farmed fish sold are Salmon and Tuna. These fish are predators or piscivorous, that is: they eat other fish. Piscivorous fish such as Tuna and Salmon  require about 5 pounds of wild fish to produce one pound of farmed fish.  A ten pound Salmon requires about fifty pounds (50lbs) of wild caught fish to reach market size.

As it functions today aquaculture of fish is not sound economics or effective natural resource management, and will only exacerbate the problems fish farming was meant to solve.

We should be cognizant of the impact of over-harvesting of the forage fish schools which are heavily impacted by over-harvesting as sources for fish farming.  These practices result  in population crashes of these primary food sources which in turn have a deleterious effect on the general ecology of the oceans and directly on the populations of other natural predators such as whales and porpoises.   

There is no free lunch. Humans can not continue to take fish resources from the oceans without impacting the well being of general marine ecology. 

 

ON THE ORIGIN OF SEX, WHAT IS IT GOOD FOR?

In the dim past of Earth’s long, 4.5 billion year history, perhaps 2.5 billion years ago, single celled organisms reproduced, but had no sex.  Reproduction, and evolutionary change, the main function of sex, occurred only by simple cell division. In this process each cell when it reached “maturity” and with no further need for stimulation, simply divided into two equal parts…equally sharing the parent cell’s genetic material to create two almost physically identical offspring cells.

This reproduction process has been variously termed “budding”, “cell division”’ “sporulation”, etc. The end products of the process are two new growing daughter cells with little change in their physical properties (which are the expression of their genetic material). In simple cell division the only genetic change is that caused by random and probably rare DNA mutations…perhaps as a result of ionizing radiation, chemical exposure, or other random alterations to DNA during the physical division (mitosis)  of the parent cell.  Ionizing radiation was likely much more common on the surface of ancient Earth. 

Darwinian Natural Selection depends on minor variations in the physical characteristics of each species.  For species to evolve, physical variations must exist in a species, these are exposed to a trial for adaptation in the existing environment.  Those that are adaptive or provide some advantage for survival are conserved while other manifestation of those variations are lost. The physical variations of species permit  the potential of selection to take place.  Few variations in a species tends to slow or retard speciation (formation of a new more adapted species) —and adaptation of these new species to a modified environment. If species have little physical (genetic) variation natural selection is limited. Those species best adapted to the environment survive and others perish. 

As a result, the slow rate of mutagenic change or alteration of the genetic material, as in asexually reproducing species—must have resulted in corresponding slow rates of evolutionary change. Speciation -the evolution of new species—slowed down. As the Earth evolved—its physical environment changed—those species formed in earlier times, were not variable enough to adapt and thus perished. Asexual reproduction simply did not produce enough variations in physical form for biological evolution to keep pace with the slow physical alteration of the planet upon which these organisms lived.  

Our planet Earth is in constant flux undergoing continual slow change in temperature, atmosphere and oceans, even the locations and positioning of the continents themselves on the Earth’s globe are in constant change.  These early sexless simple organisms were likely less competent to adapt to the new physical conditions of Earth as continents moved over its surface, rove into and under each other , produced mountain ranges and continents split apart to form ocean basins. Inability to adapt resulted in death and die off of these early “sex starved” species.  In this early sexless world organisms evolved only slowly as they struggled to adapt to a constantly altering planetary environment.  But competion was coming. 

THE DEVELOPMENT OF SEX

About two billion years ago, during the Proterozoic Era, some single celled organisms which reproduced had reprduced asexually by simple “budding” or fission evolved a more costly and complex process known as sexual reproduction.   Sexual reproduction provided a survival benefit for these new cells.  

In sexual reproduction the cell nucleus undergoes a complex intracellular process called a“reduction division”. The nucleus of these cells divide in a special way (meiosis) to form offspring cells or “gamete” cells which have only one-half of the genetic material of the parent cell. To form a new individual (offspring cell) these (gamete) cells must combine with other gametes of the same species (each with only half of the genetic material of a parent cell) to form a new offspring.  

This sexual process is more costly to the individual, requires more time and more energy, but it provides an evolutionary advantage, by producing greater genetic variation in the gamete offspring cells (more variation ) as a result of the more complex, (more “accident prone”?) reduction division, and then the random recombination of the often free moving gametes, which often must combine in an alien environment (as in marine organisms). Sexual reproduction provides many more chances for gene alteration, intracellularly during the more complex formation of gametes, and then during the process of sexual combination of the gametes often in an alien chemically challenging extracellular environment. 

All of these circumstances results in greater genetic variations and higher levels of physical diversity of offspring. As the result of these developments of the process of sexual reproduction increased the rate at which evolution progressed. Such a process favors the evolutionary selection and adaptation to a rapidly changing environment like that of planet Earth. Perhaps without sex, Earth as a planet may have altered physically over time but, with only a very primitive level of biosphere and little or no advanced living organisms. Humans may have never evolved on such a planet.  The difficulty of this transmission from asexual to sexual reproduction may be one reason that our near-by known habitable planets remain radio silent and leave us seemingly very much alone in the near by universe. 

That is why all paramecia and pachyderms vary both genetically and in their physical manifestation (termed the phenotype). All humans too!  Diversity is a natural manifestation of almost every living organism. Its benefit lies in the necessity of evolution to operate by moulding each species to evolve into specimens better adapted to the environment in which it lives. 

Sexual reproduction provided offspring cells which had greater variation  than sexless cells. That greater ability to adapt to continuously changing environments gave “sexy cells” a great advantage for survival. 

Thus by nature and for over two billion years all life is by natural design, unequal, and diverse.  We can not change that.

So what is sex good for?  Evolution.  Sexual reproduction permitted evolutionary change which was rapid enough to keep pace with a rapidly changing Earth. It permitted the living earth (its biosphere) to continue to survive and to become more complex and better adapted to its changing surface.

    

ON INEQUALITY, HUMAN’S NATURAL STATE

 

In Middle Way of American Equality,11/22/2024, by Daniel Mahoney (Tom Klingenstein.com) , the author calls the world we inhabit “obsessed with inequality”.   According to Mahoney doctrinaire proponents of egalitarianism rail over “equity” and “social justice” and posit that all “disparities” we see in the economic and social status of our citizenry are the result of racism or oppression of “the underclass”.  Blame too often falls on “the white ‘privileged’ majority” when the real cause of disparities is the simple fact that humans—though belong to the same species —are not clones of each other…we are all unequal in our physical manifestation, our physiology our mental capacity and even our proclivity to disease. 

Mahoney defends the US Declaration of Independence which states that “all’ men (i.e. human beings) are “created equal”in the eyes of the state.  according to Mahoney the Founders did not propose that all humans were “equal”. They knew better. Though the term “equity” (an “all come-out-even” policy) was likely not part of their lexicon. It is certain they would have claimed it unattainable.

For the Founders inequality must have been a manifest fact of Nature. Mahoney supports his contention against this false vision of equality by way of intriguing and eloquent quotes from Tocqueville, Abe Lincoln, Thomas Sowell, Burke, Hawthorne, and even Dostoevsky. In each case these authors underscore how this corrupt unnatural vision of equality has always had the potential to threaten actual democratic equality of opportunity. These seekers of equity supported oppressive totalitarian regimes, which, generate instead a form of oppression and injustice. Any move toward equity goes against the natural order of the universe. 

In July of 1776 Thomas Jefferson (in the Declaration of Independence) wrote: “We hold these truths to be self evident, that all men are created equal, …..endowed by Creator with certain unalienable Rights, that among these are Life, Liberty and the pursuit of happiness.”  

And we find that many years later, the UN, Universal Declaration of Human Rights states: “All human beings are born free and equal in dignity and rights”, no one claims the right to absolute equity.  

There is no absolute equality….thankfully we are all very different form each other. Each of us is a unique individual (and perhaps there i no need for all those supposedly distinguishing marks like tattoos).  And for this reason we must expect natural variation in physical, physiological mental and other factors, even response to disease and environmental stimuli. 

 

I write here to underscore the position of our brilliant and enlightened 18th century Founders who understood well that no humans are “equal” in the sense that they have identical abilities traits or characteristics. Human “inequality” is the natural state of “man” and Nature.

The natural world supports this idea.

Every living organism from a paramecium to pachyderm is a unique individual with established genetic variation which clearly distinguish every individual from every other one of its species. Variations in genetic material is expressed in the physical, physiological and other aspects of every living organism and assures, that each one varies in some small way from every other. As is well known, DNA analysis can precisely identify each one of us from the 8 billion others of our species on this Earth.  

In fact the entire biosphere—is based on the fact of individual genetic diversity, expressed in the physical manifestation (phenotype) of the genetic material carried in the nuclei of each cell. These variations are expressed in the inequality of each member of a species.  In fact all of evolutionary change is based on the necessity of the inequality of individuals. Indeed, there would be no humans on Earth, had the primitive organism from which humans evolved—been asexually formed as genetic clones of each other. The process of biological evolution requires individual inequalities, which then permit the environment, in which these natural beings exist to select for those better adapted.  In this way the process of Natural Selection- nature “selecting” those organisms which are best adapted to survive and reproduce their species has occurred over the four billion plus years of earth history.

We as a species would not exist were it not for nature’s assurance of inequality!

LONG ISLAND’S RAIL PATH IN LATE OCTOBER 2024

 Late October has been warm, dry and sunny here on Long Island’s north shore. Perhaps this weather pattern is a result of an early “La Nina”.  The result of cool Pacific water pooling up off the coast of Ecuador.  The cool ocean water displaces the flow pattern of the Mid-Latitude Jet Stream to the north bringing warmer weather to the NE in winter. Recently the MLJS has been streaking across the sky at about 10km (6 miles, 33,000 ft) tracking north of us above southern Canada.

For whatever reason, the sky today is deep blue with lovely white puffy cumuli. These form each day as sea born southwesterly winds carry moist air over our sun warmed island. The rising air condenses its moisture which drifts like majestic white airy sculptures, altering shapes as they flow gently overhead.  Below, vibrant red, gold, orange and chestnut-brown foliage contrasts with the blue sky, making a stroll along  Brookhaven Town’s Rail Path a pleasant and colorful excursion on this late October day.

On this colorful day I share the Rail Path walk with a hen turkey and her flock which emerged clucking happily from the brushy growth and adjoining woodlands through which this former railroad ROW path courses. This hen had taken up residence on this section of Path two years ago. I have been observing her regularly over that period. She had eight poults early in the year (See “Attack By A Hen Turkey”).  Today her surviving four poults are now almost full grown. One can only identify “mom” by the fact that she leads the flock and the youngsters follow her. They exploit the grassy margins of the path pecking the remnant seed heads of Timothy grass then quietly disappear into the woods.  

Today October 23, 2024, after a few weeks of cool nights and warm very dry days there are few flowering plants to identify. But those that do persist in flowering so late in the season are a notable few. On the south side of the path at the base of a tall clump of still green Giant Knotweed (Reynoutria sachalinensis?)  I observed a place where several small ivory-white flowers, each with a hairy bulbous base stood out sharply among the shadowy green and dry brown grasses around them. These are the lovely White Campion (Silene latifolia) which often persists flowering into late fall. 

Further east a few Chicory (Chicorium intybus) plants with their cornflower-blue ray flowers grew along the path margin. These plants, much reduced by the mower’s blade, somehow survived that event  to persist and add a singular contrasting azure to an otherwise dull brown, red and yellow landscape. (I thought about their roots too, my grandpa and I would dig them up in late summer.  He would dry them, then roast them with coffee beans to prepare his favorite morning brew).  Further on, a late flowering vine of Japanese Honey suckle (Lonisera sp ), with light goldenrod yellow blooms from which protruded characteristic long, arched stamens. As children my sister and I pulled those long thin stamens to suck the sweet nectar of clinging to the stamen ends of this fragrant sturdy vine. It was among the few species other than moss and lichens which grew in our urban back garden. 

In another place, the aptly named “Butter and Eggs” a  yolk-orange and butter-yellow member of the snapdragon family (Linaria vulgaris) survived  with its gray-green leaves and stems by growing just beyond the reach of the mower blades.  But closer to the asphalt path a chopped down, ferny remnant of Queen Anne’s Lace (Daucus carota) was not so fortunate. Yet it somehow managed to produce (though not to normal size) its characteristic flat, white, compound umbel flower with its typical “dried blood drop” center spot. Not far away, a White Bindweed vine its arrow shaped leaves and tendrils climbed the knobby stems of the Giant Knotweed patch. There, a single,  lonely and barely opened  flower of White Bindweed (Calysegia sepium) bloomed about six feet above ground.  The last one of the many white flowers of the this same vine which, only a few short weeks ago, had graced the dull green of  Knotweed banks. These above were it seemed the last flowers of the 2024 season. 

But this day was not for end of season flower species, but for magnificent fall colors. 

The Rail Path’s two dominant species are the dull, gray-green-leafed Russian Olive (Elaeagnus angustifolia) a low bushy tree, and the invasive weed which grows to ten to fifteen foot tall, the dark green leafed Giant Knotweed.  At this date both of these species remain determinately green with only a few yellowing leaves. But they represent the canvas upon which the vibrant colors of many other local species make their seasonal appeal to the eye. 

The magnificent lemon yellow (or gold) of a mature Catalpa (Catalpa speciosa ? ) which rises here well above 100 feet. (But not far away the look-alike Empress tree (Paulownia tomentosa) remains a dull green at this date. The greenish yellow Black Walnut (Juglans nigra) which hides away all summer nearly invisible among all that is green, stands out in fall when loses it leaves and takes on it yellow coat well before the other species.  Here too we find the (Ailanthus altissima) turned a grayish yellow and burdened with large clumps of numerous light brown samara-type seeds. These swriling fliers help to disperse this invasive tree. (It is noteworthy too that A. altissima is also the host of the troubling Japaneses Lantern Fly (Lycorma delicatula) of which I have observed four spotted and colorful specimens along this one mile path during this 2024 season— and dutifully stomped them out.). 

The low growing trees or bushes of Winged Sumac  (Rhus copalina), Smooth Sumac (Rhus glabra), Staghorn Sumac (Rhus typhina) all turn a firebrick red in fall. While the tall Black Oak (Quercus velutina) turns a chocolate brown, and the Scarlet Oak (Q. coccinea) true to its name turns a maroon or dark red color. This is true for the common Red Maple (Acer rubrum  )also true to its appelation turns a striking bright red and yellow. 

The vines of greenish-yellow Japanese Bittersweet (Celastrus orbiculatus) encase and entangle many trees along the Path. The vines produce bright yellow berries which when ripe, peel back a bright yellow three part seed coat to reveal a bright scarlet twinned berry within. The vines eventually loose their leaves but the colorful red and yellow berries remain.  These are often cut for fall and winter season indoor displays. 

The Fox Grape (Vitis sp ) turn a greenish yellow, while Virginia Creeper the five leafed climbing vine (Parthenocissus quinquefolia) turns a bright scarlet. Black Cherry (Prunus serotina) adds a mix of yellow and dark green. Escapes from suburban gardens, often found growing beneath powerlines where birds roost such as the flowering Pear ( Pyrus sp domesticated) turn from dark green to magenta in this season. Many of these flowering fruit trees  (cherries and apples too) retain their tiny inedible hard fruits, but which hungry Blue Jays,Cardinals, and many other species will exploit for survival food. 

So don’t pass by too rapidly on the Rail Path in fall (or any other season) there is more to see here than a straight asphalt exercise route. 

OSPREY (PANDION) CHOOSE TO NEST ON STEEL PYLONS IN SUFFOLK COUNTY, NY

 

August 18, 2024

In recent weeks I have observed a pair of Osprey (Pandion haliaetus ) nesting at the top of a 36 meter (118 ft) steel, single-pole electric transmission pylon just west of Peachtree Lane at: 40. 56. 21 N, 73.00.35 W in Brookhaven, Township, near the village of Mount Sinai, on Long Island in New York’s Suffolk County.  The pylon nest site is well away from surface bodies of water such as ponds, marshes or the marine environment. Long Island Sound is about 2 miles (3.2 km) from the nest. The only significant fresh water ponds are located in a golf club about two mies from the nest site. The Peach Tree Road nest site is about 2 miles due south of the Long Island Sound shore, and two miles (3.2 km) from Mount Sinai Harbor. It is also about four (4) miles from Port Jefferson Harbor which is located to the northwest. 

 The question this author asked was where were these inveterate piscivorous “fish hawks’ exploiting fish upon which they depend for 99% of their diet?  Or were they exploiting in part the small mammals such as woodchucks, marmots, field mice and cotton tailed rabbits which were all very common along the transmission line right-of-way clearings just below their nest? Or have they found adequate source's of fish? How far away did they have to fly to feed? Were they successful? 

Several examinations of the area below the 118 foot high nest revealed only fish remains which were dropped or fell from the nest above.  This author observed fragments and parts of fish bodies, such as gill covers, fish vertebral bone and ventral fins of small bony fish. The species of these scant piscine remains were not apparent.  

How far away from potential fishing sites? 

The Peachtree Lane nest site is located on the North Shore of Long Island about 1.8 miles from the center of Mount Sinai Harbor, a body of water of about 500 acres in area which is confluent with Long Island Sound about two miles (2 miles 3.2 km) to the northwest of the nest site. There are two active Osprey nest sites at the Harbor. 

Potential Fishing Sites Inland.

A number of fresh water man-made ponds are located to the southeast of the nest site or inland. Twelve of these small ponds ( estimated average size about 360 ft x 170 ft or @ 1.4 acres surface area ) are located within the bounds of the Willow Creek Country Club golf course, situated to the southeast of the nest site. The center of the Club is about two (2) miles south-southeast of the nest site. The farthest pond in this group is 1.6 miles distant while the closest is about 4,200 ft ( 0.79 miles) from the nest site. The largest pond has an area of 800 x 100 ft (1.8 acres surface area). There may be a total pond surface area in this area of about 16-17 acres at the Willow Creek Club located  about two miles (as the crow flies) from the Peach Tree Road pylon nest site 

Other than these, a solitary small pond about 1+/- acres in area (also man-made) is located just 3,500 feet (0.7 miles) due south of the nest site. 

Two gravel extraction companies are active southeast of the nest site. One of them (with no name) is located just west of Yaphank-Miller Place Road at 2.9 miles distant fro pylon site. 

While the Roanoke Gravel and Sand Pit pond is 4.5 miles southeast of the nest site. This body of water has an estimated 113 acres of surface area. 

Conclusion: 

Though the Peachtree Lane nest site is not situated on the shore of a marine embayment or of a lake, the distance to such bodies of water are relatively short. A number of small fresh water ponds occur at 3.2 km away with about 16-20 acres of total surface area. At the same 2 mile (3.2 km) distance lies the expansive Long Island Sound, which is confluent with shallow water marine bays and harbors with large areas of surface water at similar distances.  Thus the nest site seems sited in a location which provides easy access to both fresh or marine exploitation areas for Osprey at almost equal distances away. 

The 118 foot high transmission line pylon provides a structurally sound base for a bulky heavy nest and its height and metal surface provides almost absolute security from terrestrial predators. To protect the power lines from damage from growing trees the surroundings are clear cut of trees by the L.I.utility company. This tends to provides unfettered flying space around the nest as well as security from avian predators such as crows and other raptors.  Osprey may prioritize the location of a nest sites for its security from predators and its structural soundness over the distance to its fishing sites. 

While boating in Mount Sinai Harbor this author observed an osprey flying directly over head carrying a small fish in its talons. I assumed it was one of the two pairs nesting on the shore at the Harbor. The fish hawk appeared to be returning to its nest site with its prey.  As it passed over-head, a second large black bird with prominent white head appeared flying close behind the hawk. The American Bald Eagle (Haliaeetus leucocephalus) seemed to make an attempt to force the fish hawk to release its hard won prey (a small fish about the size of a sea perch, cunner or bergall). The osprey twisted and turned in the air, but encumbered with the fish held head-first in its talons, failed to out pace or out-maneuver the larger bird. Finally, perhaps to get away, it dropped the fish into the bay, where it dissapeared below the surface. The eagle swooped down over the location, but abandoned the chase and flew off in one direction, while the osprey flew in another..but with no fish. 

Note: On this date the author observed the response of the (assumed male?) Osprey at the Peachtree Lane  Nest to the presence of a Red Tailed Hawk (Buteo jamaicensis). The Ospreys ignored the presence of the hawk while it perched on an adjoining pylon about 100 meters (328 feet) away.  When the hawk flew off its perch, it passed within a 50 meter radius of the nest, the smaller Osprey, then took off in pursuit. The hawk descended quickly and flew into the forest canopy presumably to escape.

Addendum: On August 29, 2024 I observed the Peachtree Lane nest site again. The nest atop the pylon appeared to be deserted. I searched the grassy area around the base of the pylon where I observed several dried gill covers of what appeared to be clupeiform (herring like) fish and the dried head of what appeared to be a Bunker or Atlantic Menhaden (Brevoortia tyrannus). This seems to confirm that the Osprey were fishing in Long Island Sound or Mount Sinai Harbor about two miles away. 

SCIENCE BEHIND AN AIR TRAGEDY IN SAO PAULO, BRAZIL AUGUST 9, 2024

 An air tragedy in Brazil, wing icing in the tropics, supercooled droplets, Bernoulli effect, airfoils and Newton’s Third Law. 

August 10, 2024 Sao Paulo, Brazil

On Friday afternoon, August 9, 2024 a VoePass  ATR 72-500 aircraft, with 62 passengers and crew on board crashed just 45 miles short of its destination in the City of Vinhedo, while on its way to Sao Paulo City’s  International Airport at Guarulhos, Brazil. Sadly there were no survivors.  The ATR 72-500 turbo prop plane was manufactured in Europe by a ATR, a French-Italian consortium of the Airbus and Leonardo firms. Since the early 1990s this plane has had 15 air crash incidents with almost 500 fatalities. A similar plane, an ATR 72-200 crashed in 1994, in Roselawn, Indiana in which the probable cause was icing of wings. The crash caused 68 fatalities. A US Federal Aviation Agency investigation concluded with a warning to pilots not to use autopilot in icing conditions when flying these planes. 

This VoePass ATR 72 was on a domestic flight from Parana State to Sao Paulo City with 62 passengers and crew on board, when at 11.21 PM the flight, cruising at 19,000 feet, began losing altitude over Vinhedo City about 45miles NNW of Sao Paulo City. The plane dropped 250 feet in 10 seconds, then climbed back up 400 feet in 8 seconds. Seconds later it lost 2000 feet and then it began a rapid spiraling downward fall, dropping 17,000 feet in one minute. It crashed and burned among houses in the City of Vinhedo. No local residents were hurt as the plane plummeted to the ground in a clear area among homes and burst into flames. 

Video photographs published by onlookers on the ground show the intact ATR turboprop, falling, with no horizontal speed, plunging almost straight down. The video is frightening to watch since it is clear that the plane had lost all ability to fly and was in an uncontrolled deadly death spiral to the ground.  The plane provided no visible reason to fall, it appeared unaltered, there were no flames or smoke, the wings, tail and body were intact.  The ATR 72 was simply plunging straight down like a huge piece of silvery metal.

What could have caused such a crash?  

It is winter in Brazil which is in the southern hemisphere. Though Sao Paulo and Vinhedo are located in a tropical-temperate zone, at about 23 deg south latitude, close to the Tropic of Capricorn, winter is relatively mild there. (Sao Paulo is far south of the equator as semi tropical Tampico, Mexico is north of the equator.) Average southern hemisphere “winter” temperatures for August in Sao Paulo range from 60-70 degrees F during mid day.  

Since for the most part, air is heated from the bottom up, not by the sun’s rays passing through air, but indirectly by the sun heating the earth, and then the warmed earth transferring that heat to the air. For this “bottom up heating” reason the air cools at a regular rate at higher elevations. The Normal Lapse Rate is average rate at which the air temperatures drop when measured from the ground upward. That rate is about 3.5 F per 1000 feet. 

Yesterday, (Friday, August 9, 2024) mid-day temperatures on the ground at Vinhedo were about 70F.   But the air temperature at 19,000 feet was much cooler. Using the Normal Lapse Rate to calculate the approximate temperature at the ATR 72”s cruising height indicates that the air temperature aloft where the VoePass airliner was flying was probably around 4.5F.*  

Thus where the ATR 72 was cruising the air temperature at 4.5 F was well below freezing (at 32F).  Clouds at this level often contain moisture in the form of ice crystals, and water droplets which have been cooled below freezing but remain in the liquid state, these tiny liquid drops are called “supercooled water droplets”. These tiny drops of water  less than 0.05mm in diameter, are so small that even at temperatures well below freezing (32F) they simply can not organize their relatively small number of water molecules within the drop into the typical ice crystal lattice.  So they remain in the liquid state.  However, if they come in contact with a solid surface, an ice crystal, dust, or pollen particles which may act as nuclei of crystallization, they freeze instantly. 

When the leading edge of an airplane wing flies through such a cloud with supercooled water droplets,  the drops freeze instantly to the plane wing, tail, sensors like pitots, antennae and other parts.  This ice—called “rime ice”—is heavy and adds weight to the plane but it is most dangerous on the wings where it can interfere with lift.

As you would expect, the wing is what permits the plane to rise up off the ground and also provides the  “lift”which keeps the plane aloft.  The process is complex and probably not fully understood, but in simple terms we can think of the wing as an “air foil” with a cross sectional shape characterized by a flat undersurface and a slightly rounded or cambered upper surface. The wing functions as an airfoil (to create lift) only when it is moving forward through the air. In simple terms, the air flows smoothly over the top and bottom of the wing in cross section. The flow of air over the top surface is forced to speed up as it traverses the curved surface (a longer distance). It is this more rapid flow which creates lift. The Bernoulli Principle states that the pressure of a fluid in motion is inversely proportional the speed of the flow. Thus the pressure above the wing (air foil) is lower on the upper, curved, cambered surface than that of the bottom flat surface where pressure remains unaltered.  Imagine  “stretched out” or lower density molecules generating a zone of lower pressure along the upper wing surface.  This does not occur on the undersurface where pressure remains at its original higher level of pressure. 

As a result, the moving  aeroplane wing generates a region of lower pressure all along its upper surface.The longer the wing the more lift it can develop.  In a definitely non-scientific sense, the wing can be imagined as being “sucked” upward* by the air flowing smoothly over the upper cambered surface.  As long as the air can flow smoothly in streamline flow over that surface the wing provides lift (or is “sucked” upward ) and this disparity in pressure helps to keep the plane aloft.  (It is noteworthy that the angle of attack of the wing also creates lift. The angled upward wing tends to direct air downward creating a force (Newton’s Third (equal and opposite) Law) that pushes wings upward).  

Thus it is clear that any disturbance to this smooth air flow or “streamline flow” over the upper cambered wing surface,  such as turbulence caused by rime ice, can reduce the speed of the flow and destroy the Bernoulli (“suction”) effect of the upper curved surface.  This is the likely problem which caused this tragedy. 

How does ice form on wings?

As noted above high clouds at temperatures far below freezing have moisture in both solid and liquid form. When planes encounter supercooled droplets aloft ice can form along the forward or leading edge of the wing. Rime ice has a rough surface.  It causes the air to flow irregularly in what is called “turbulent flow”.  This form of air flow destroys the lift effect.  Rime ice thus destroys the rapid smooth flow over the upper wing surface. The slowed flow of air along the wing edge causes loss of lift, or when excessive may cancels out lift altogether.  On both wings,  icing may cause the plane to lose elevation instantly. When only one wing is impacted, that wing loses lift and the plane may bank sharply in that wing’s direction, causing the aircraft to begin an uncontrolled downward spiral. 

In the early years of flight, most planes flew well below levels of high clouds where supercooled droplets would likely be encountered.   When aircraft began flying at high altitudes, methods to control icing on wings became essential for safe flight.There are several methods used on the most modern airliners. One more modern solution is to direct heated air or other fluids derived from the jet engines or the prop engines to the wings when required .These “hot wing” planes melt rime ice which may accumulate on the wings and leading tail edge. Another method common on many older types of aircraft is a rubber boot which encases the forward edge of the wing. This flexible boot can be pumped up with air when necessary which causes the boot to expand and crack the adhering ice which then is driven off the wing by air flow. 

The ATR 72 model has this latter design. One problem with this system is that in cases when icing conditions are extreme or when such conditions are repeatedly encountered, multiple use of the system may form ice encrustations which break off and slide rearward only to refreeze onto the central cambered portion of the wing, beyond the rubber boot. When that occurs the aircraft  loses lift rapidly and plunge to lower levels. 

Though "icing" seems the likely cause of the tragedy in Brazil, what seems compelling when looking at the facts and circumstances from afar is often only the first hypothesis in perhaps a much more complex circumstance. We must await the full technical report on this sad air tragedy.

  One can only feel pain and sympathy for the families of the more than 60 passengers and crew who lost their lives in this terrible crash. One hopes those who investigate these tragedies can find the cause and make recommendations regarding flight safety that will make such tragedies very much less common.*  

(Though in relatively uncommon meteorological circumstances such as “ice storms” supercooled clouds may produce rain drops cooled to the freezing point. These liquid drops at freezing temperatures (not supercooled) fall into lower warmer levels of the atmosphere close to ground level.  There they strike power lines or tree limbs and branches and as they strike these surfaces minor evaporation further drops the temperature causing the drops to freeze on contact, and over time building up thick layers of ice with often devastating consequences to trees and power-lines.) 

* More recent (September 2024) reports indicate that indeed the Sao Palo crash was caused by wing icing. To this author, it seems reasonable to request that the ATR 72-500 turbo prop plane manufactured in Europe by ATR, a French-Italian consortium of the Airbus and Leonardo firms which in most circumstances appears to be a safe practical airship,  should be grounded and refitted with more modern deicing equipment than its original design system before it can be safely flown again.  Icing is not a mid latitude or cold climate issue. Rime icing can occur even close to the equator….. in Brazil.

  

*There is of course no such thing as “suction” but it may work as an idea aid.

*Normal lapse rate is about 3.5F per 1000 feet.

• (19 X 3.5F)- 70 F = Temp at 19,000 feet)) or 19 X 3.5 =66.5F, 70F-66.5 = 4.5F. 
• Brazilian meteorological company reported severe icing in Sao Paulo State at the time of the crash.