Monday is turning out to be a rough day for cryptocurrencies. Not only is bitcoin down by about 7%, but nine of the top 10 cryptocurrencies are in the red today.

The sole exception is Ethereum, which hit an all-time high Monday after a positive report on the currency's transaction volume. Here's a rundown of the price action in the cryptocurrency markets today and over the weekend, and what could be causing these moves.

Today's cryptocurrency prices

Here's a look at the 10 largest cryptocurrencies by market capitalization, and how much each has changed over the past 24 hours, as well as the change since before the weekend.

Cryptocurrency

Price in U.S. Dollars

1-Day Change

Change Since 1/5/18

Bitcoin (BTC)

$15,020

(7.1%)

(8.4%)

Ethereum (ETH)

$1,147.30

5.1%

17.5%

Ripple (XRP)

$2.47

(10.5%)

(6.8%)

Bitcoin Cash (BCH)

$2,390.30

(6.9%)

0.8%

Cardano (ADA)

$0.91

(11.5%)

(15%)

NEM (XEM)

$1.58

(7.6%)

(4.2%)

Litecoin (LTC)

$257.32

(5.2%)

4.4%

Stellar (XLM)

$0.64

(9.3%)

(4.5%)

IOTA (MIOTA)

$3.87

(7.5%)

0.5%

TRON (TRX)

$0.146

(3.7%)

(33.6%)

Data source: www.investing.com. Prices and daily changes as of 2:40 p.m. EST, and prices are rounded to the nearest cent where appropriate.

As you can see, cryptocurrency prices are down nearly across the board. The sole digital currency in the top 10 up for the day is Ethereum, which we'll get to in a bit.

Stacks of gold coins with bitcoin symbol.

Image source: Getty Images.

Bitcoin dropped more than 7% after surging late last week. According to Coindesk, fears that China may get tough on bitcoin miners could be weighing on the currency. After all, China accounts for over two-thirds of all bitcoin mining activity, and a crackdown on Chinese mining operations could produce negative pressure on bitcoin. According to people familiar with the matter, China intends to limit power use by miners. (Note: If you're not familiar with bitcoin mining, let's just say that it uses a lot of energy.)

Ethereum is today's big winner

Ethereum is moving against the grain, and hit a record high on Monday above $1,200. It has since retreated a bit, but is still up 17.5% over the weekend, and has reclaimed its position as the second-largest cryptocurrency, behind only bitcoin.

According to a report, transaction volume on Ethereum's network doubled and there have been periods where over 10 transactions per second were being processed. For comparison, bitcoin's blockchain network can only handle about three transactions per second.

A bad weekend for last week's momentum altcoins

The highlight of the cryptocurrency market last week was the big move in several alternative currencies, or altcoins. Ripple, Cardano, Stellar, NEM, and Tron all posted massive gains for the week, and all of them seem to be giving back some of those gains.

Tron in particular has been beaten up over the weekend, giving up roughly one-third of its value. However, even after the loss, Tron is still up by more than 215% over the past seven days. Cardano is another example, and has lost 15% since Friday.

Ripple and Stellar, both of which have partnerships with major financial institutions, are holding up better, but are still down, losing 6.8% and 4.5%, respectively, over the weekend.

To be clear, all five of these altcoins are still in the green over the past week, so the recent drop could simply be profit-taking after their impressive runs.