In Shark Bay, off the westernmost tip of Australia, meadows of sea grass carpet the ocean flooring, undulating in the present and being nibbled on by dugongs, cousins of Florida manatees. A brand new research revealed one thing sudden about these sea grasses: Many of them are the identical particular person plant that has been cloning itself for about 4,500 years.
The sea grass — to not be confused with seaweed, which is an algae — is Poseidon’s ribbon weed, or Posidonia australis. Jane Edgeloe, a University of Western Australia Ph.D. candidate and an creator of the paper, likens its look to a spring onion.
Ms. Edgeloe and her colleagues made their discovery as a part of a genetic survey of Posidonia grasses in completely different areas of Shark Bay, the place she SCUBA dived in the shallow waters and pulled up shoots of Posidonia from 10 completely different meadows. On land, the researchers analyzed and in contrast the grasses’ DNA.
They printed their outcomes Wednesday in the journal Proceedings of the Royal Society B. It turned out the DNA of a lot of these seemingly completely different crops was nearly similar. Elizabeth Sinclair, additionally of the University of Western Australia and an creator of the research, recalled pleasure in the lab when she realized: “It’s only one plant.”
While a few of Shark Bay’s northern meadows reproduce sexually, the remainder of its Posidonia clones itself by creating new shoots that department off from its root system. Even separate meadows had been genetically similar, indicating that they had been as soon as linked by now-severed roots. Based on how outdated the bay is and the way shortly sea grasses develop, the researchers surmise that the Shark Bay clone is about 4,500 years outdated.
In addition to being a clone, the grass appears to be a hybrid of two species and possesses two full units of chromosomes, a situation known as polyploidy. While polyploidy may be deadly for animal embryos, it may be innocent and even useful in crops. However, it could consequence in sterility: Much of the clonal grass doesn’t flower and may solely reproduce by persevering with to clone itself.
This mixture of additional genes and cloning might need been the important thing to the grass’s survival throughout a interval of historic local weather change: Cloning made replica simpler as a result of the grass didn’t should hassle discovering a mate. The additional genes may have given the ocean grass “the ability to cope with a broad range of conditions, which is a great thing in climate change,” Dr. Sinclair mentioned.
The Shark Bay Posidonia didn’t simply survive this historic local weather shift, it unfold. And unfold. And unfold some extra.
Today, it’s arguably the world’s largest residing organism. Utah’s Pando, a clonal colony of 40,000 aspen trees linked by their roots, is the reigning “largest individual plant,” masking an space greater than 80 soccer fields. The Humongous Fungus is even bigger, weaving a internet of mycelial tendrils underground and beneath tree bark throughout 3.5 sq. miles of Oregon’s Malheur National Forest. By comparability, the Shark Bay clonal sea grass is 77 sq. miles, in regards to the measurement of Cincinnati.
While the Shark Bay clone has reached huge measurement and age, the query has remained of whether or not it might be capable of face up to trendy local weather change. Julia Harenčár, a Ph.D. candidate on the University of California, Santa Cruz who was not concerned with the research, praised the venture for “trying to understand in greater detail why polyploidy has been advantageous at these big environmental flexion points,” which may provide classes for the local weather disaster.
Sea grasses are notably necessary to guard, says Marlene Jahnke, a biologist on the University of Gothenburg in Sweden who additionally was not concerned with the research. She added, “they are comparable to coral reefs, really, in the sense that they host a lot of other species,” together with purifying water and storing atmospheric carbon.
While the stakes are excessive for sea grasses, Dr. Sinclair stays hopeful that the Shark Bay Posidonia will preserve its standing because the world’s largest residing plant: While it was harmed in a warmth wave from 2010 to 2011, “we’ve seen a lot more increase in shoots, a lot more leaf density, so it’s recovering,” she mentioned. “I think this polyploid is actually probably in a pretty good state in terms of persisting.”
