Icebergs fall into a category all their own. Even though they are composed of water, they are solid and can be seen as distinct from the liquid water in the oceans and seas surrounding them. Even though you may think of an iceberg as just a small piece of ice, the truth is that some icebergs can be absolutely massive. They can be larger than cities and even entire countries in some cases!
What Is an Iceberg?
You may know that an iceberg is made of ice, but what exactly is it? Basically, an iceberg is a piece of freshwater ice that is more than 49.2 feet, or 15 meters, long. It has broken off of an ice shelf or glacier. Typically, it is freely floating in saltwater. Smaller pieces of ice, which have sometimes broken off larger icebergs, are referred to as bergy bits or growlers. With a larger iceberg, it is often the case that the majority of the iceberg will be below the surface. This means that there is much more to it than what you are able to see from a ship or boat. Icebergs are considered to be a significant maritime hazard. You may already know that a collision with an iceberg was what led to the sinking of the Titanic in 1912. Ever heard of the saying, “tip of the iceberg”? Usually, it’s about 10% of an iceberg’s volume that’s above the water. This is a result of Archimedes’ principle of buoyancy, as the density of pure ice is approximately 90% of that of seawater.
What Was the Largest Iceberg in Recent History?
B-15 was the largest recorded iceberg in recent history in terms of area. Originally, as measured in 2000, it was 159 nautical miles long and 20 nautical miles wide (a nautical mile is approximately 1.15 miles). This is approximately the size of Jamaica and more than 10 times the area of New York City! In 2006, B-15 was 34 miles long and 11 miles wide. It also had a depth of 820 feet, although we wouldn’t think of a city in terms of depth. This iceberg contained 136 billion tons of freshwater. All you need to do is watch this video of this iceberg as it could be seen in 2006. You can then easily see just how impressive it was in terms of size. Although there have been larger icebergs on record, such as an Antarctic iceberg that in 1956 was more than 12,000 square miles (31,000 square kilometers) in area, the B-15 is the largest iceberg in recent history. You may wonder why we’re talking about the dimensions of B-15 in the past tense, and why the measurements changed. And we will explain that next!
What Is the History of This Iceberg?
Just like all the other largest icebergs recorded in history, the B-15 broke off from the Ross Ice Shelf, close to Roosevelt Island, Antarctica. This breaking off, also known as calving, took place along cracks that were already in the ice shelf. This happened in the final weeks of March 2000. Further fragmentation of this iceberg occurred later in 2000, as well as multiple times in the coming years. The largest fragment, known as B-15A, was about 1900 square nautical miles in area. B-15A started to drift away from Ross Island in November 2003. Throughout its journey, this fragment has undergone multiple collisions and fragmentations. Pieces broke off as it moved through the water. In 2018, B-15A had split into several pieces, four of which were sufficient in size for the National Ice Center to track them. The largest piece, at this point, was in the southern Atlantic Ocean, melting more rapidly as it drifted northwards. The majority of icebergs will melt before they wander this far north. By the year 2020, there were only two pieces of the original iceberg that were big enough for tracking. The next year, in 2021, there was only B-15ab, which was still situated off the coast of Antarctica. As massive as this one once was, as it migrated toward the equator, there was no way that it was going to last forever. At this point, the largest piece of this once staggeringly grand iceberg is still close to Antarctica. The rest of it has fragmented or melted.
Impact of Icebergs on the Ecosystem
When they migrate from one of the poles to the equator, they tend to melt because of rising temperatures as they approach the equator. When this happens, the icebergs basically release freshwater into the surrounding ocean. This ends up changing the density of the seawater around the iceberg. The freshwater is lighter with a lower density. This makes it more buoyant than the surrounding saltwater. Because of this, the freshwater ends up rising to the surface. Icebergs also often contain certain concentrations of minerals and nutrients that they end up releasing into the surrounding water as they melt. There is also often nutrient-rich dust that accumulates on the surface of these icebergs over the decades and centuries that they exist, both before and after they split off of their original ice shelves. Sometimes, iron is one of the nutrients that the icebergs release into the surrounding ocean. This can lead to blooms of phytoplankton in the surrounding area. Krill, zooplankton, and small fish will have plenty of nutrition as well. The presence of these small organisms can even lead to significant areas that attract larger animals for feeding, such as great whales. A lot of the time, icebergs can be very attractive for seals, penguins, and other marine predators, as they allow them an area of respite. In addition, these predators can often find their typical prey living in these areas, such as the smaller animals that are attracted to the nutrients released by the icebergs. B-15 was the largest recorded iceberg in recent history in terms of area. Originally, as measured in 2000, it was 159 nautical miles long and 20 nautical miles wide (a nautical mile is approximately 1.15 miles). This is approximately the size of Jamaica and more than 10 times the area of New York City! What is an iceberg? You may know that an iceberg is made of ice, but what exactly is it? Basically, an iceberg is a piece of freshwater ice that is more than 49.2 feet, or 15 meters, long. It has broken off of an ice shelf or glacier. Typically, it is freely floating in saltwater.
