Commodities: What next after the 'super-cycle'?
A large group of men stand huddled together, gazing intently at screens, hands occasionally raised in the air, shouting out numbers, with the odd expletive thrown in for good measure.
And so another day's trading begins in the "pit", or floor, of the New York Mercantile Exchange, the home of the city's energy and metal trading in downtown Manhattan.
The number of traders on the floor is a far cry from what it was 10 years ago, with the advent of electronic trading meaning more and more people now trade from offices or even the luxury of their own homes.
More recently, the commodities - or raw materials - market has undergone a different kind of change - what many are referring to as the end of the "super-cycle" - the run of gains seen in prices.
The price of gold, for instance, soared to record highs above $1,900 an ounce in August 2011, and as recently as October 2012 was trading at about $1,800. But since then it has dropped off to about $1,400.
Last week, commodity prices fell across the board. Gold, oil, copper and aluminium were all sharply lower after China's economic growth in the first quarter failed to live up to market expectations.
China has helped fuel demand for commodities in recent years, sending prices up, but fears that slowing growth there will hit demand is now having the reverse effect.
China is the "wildcard" because of its sheer size, according to Jeff Grossman, president of BRG Brokerage and a seasoned trader of 33 years.
"The last move that took place downward in crude oil was definitely spurred by a disappointing number for the growth of the Chinese economy."
Most analysts agree it is inevitable that what goes up must eventually come down.
"Commodities at the end of the day are cyclical," says Aakash Doshi, commodities strategist at Citigroup.
"Since the early 2000s up to the great recession you saw commodities rise around 20% on a compound annual growth basis. We think what those heightened prices did was lead to a supply response for commodities that are mined and drilled." That additional supply could now have a dampening effect on prices, he explains.
"We do think that the super-cycle is eating away, and that we are at the tail end of it."
Ruchir Sharma, head of emerging markets at Morgan Stanley and author of Breakout Nations, agrees.
"It takes a long time for supply to come onstream but once it comes it stays for a long period of time."
After many years of observing the markets, Mr Sharma has a broad rule that he uses when it comes to commodity prices - two decades down followed by one decade up.
"We've had that one up decade over the past decade," he says, pointing to a 600% increase in capital expenditure in the energy and mining sector over that period.
"The supply and demand dynamic we've had is now going into reverse."
'Air out of the balloon'
But with the end of the super-cycle, though commodity prices may continue to fall, few are predicting a market panic.
"I see prices moderating," says Mr Grossman, talking over the buzz of the trading floor. "I look at it as a reality check."
Having spent more than three decades in the "pit", studying the markets and looking at charts, he described himself as a "contrarian".
"I see a market that's up, I'm already assuming it's going to back off. A market's down, I'm looking for it to rally."
But he adds: "A little air is out of the balloon. A lot of prices were unnaturally and extremely blown out of proportion."
The world's largest maker of construction and mining equipment, Caterpillar, cut its profit forecast this week, citing a drop in demand from its mining customers.
Citigroup's Mr Doshi says the market faces certain headwinds, not only with growing supply, but also with the recent strength seen in the US dollar.
Commodities are priced in dollars so a stronger dollar weakens foreign buyers' purchasing power, leading to a drop in prices.
There is also the expectation that the US central bank, the Federal Reserve, may stop its quantitative easing programme, which has pumped billions of dollars into the US economy, reducing the rate of inflation in the US.
Inflation drives up commodity prices. Falling inflation is therefore likely to have a corresponding effect on commodities.
"We're generally bearish on most commodity prices," says Mr Doshi, "we're pretty bearish on Brent crude oil and pretty bearish on copper."
He also points to agriculture prices being significantly lower this year driven by a rebound in supply across the US, but also in Latin America, where Brazil and Argentina have seen strong harvests.
Winners and losers?
So if commodity prices are now in a different place in the cycle, what consequences could that have for economies around the world?
"If you look at the performance of economies in the last decade - in terms of relative economic growth [compared with global averages] and stock market performance - the best performing markets in the world, such as Brazil and Russia, they are all exporting commodities countries which got a huge lift," says Mr Sharma.
"Markets where commodity imports were very large were the worst performing. They started to get hurt in the last decade because of high commodity prices.
"So it's quite possible that that reverses itself this decade."
He points to Turkey, which does not export any commodities, as a potential "winner" from the downturn in prices, as well as India because 40% of its imports are gold and oil.
In general, western economies who are big importers of raw materials would receive a boost. But it would mean trouble for the likes of Brazil and Russia.