The Earth Story

Zombie Worms The Zombie worm is a colloquial name for Osedax, which is a species of worms that eats bones. These worms are a finger length long, found worldwide at 4000m depth in the ocean, and interestingly enough all adults are female. These adults have no mouth or digestive system so instead penetrate bone by using ‘roots’ to absorb collagen and lipids from the bone. The collagen and lipids are then converted to energy by a bacteria living in their roots. They then use feathery plumes at the opposite end to the roots to absorb nutrients. Males of this species do exist, however never mature past a microscopic larva. Between 50-100 of these undeveloped males live inside the female at any one time.

We’ve briefly mentioned before (http://on.fb.me/1yOVedv) that Osedax eats whale carcasses, however new evidence suggests it evolved up to 100 million years ago. Researchers have found marks on plesiosaur fossil suggesting Osedax was alive and bone-eating far earlier than we’d previously believed. These worms would have then fed on giant marine reptiles such as plesiosaurs and sea turtles. This may mean that it prevented many fossils of these marine reptiles fossilising.

~SA

Picture: http://bit.ly/1DyYg10 by Nick Higgs Paper: http://bit.ly/1Fc716w by Robert C Vrijenhoek , Shannon B Johnson and Greg W Rouse Paper: http://bit.ly/1OCBQSJ by S.Danise and N.D.Higgs

A mineralian worm

Light green Prehnite combine with dark green Epidote to produce a wonderful specimen resembling a shuffling catterpillar, measuring some 7.5x4.2cm, mined in Mali. Both of these were born in the metamorphic alteration of mafic volcanic rocks (low silica, such as basalt). These hydrated calcium aluminium iron silicates often occur together in low grade *ie transformed at low temperatures and pressures, as opposed to those created in the depths of forming moumntain chains) metamorphic rocks.

The prehnite-pumpellyite facies, named after these distinctive minerals produced in such conditions is associated with hydrothermal circulation in basalts at mid ocean spreading ridges, and represents the transition in between zeolite and greenschist conditions of 250-350 degrees Celcius and 2 to 7 kilobars of pressure. The mineral assemblage in metamorphic rocks always depends on a combination of pressure/temperature conditions and the chemical composition of the starting matter (known as the protolith).

Epidote is actually a group of minerals, with a solid solution between low iron clinozoisite and high iron epidote, with other versions based around elements such as cerium. Its properties such as colour and refractive index depend on the iron content. It is usually a very dark toned green displaying strong pleochroism (see https://bit.ly/2ROVS54), occurring as vertically striated monoclinic crystals.

As well as altered basalts, it is a common mineral of contact metamorphic rocks (where the heat and juices of intruding granites have baked and stewed the surrounding rocks) such as hornfels and skarns ( the latter formed when granites intrude into limestone), in hydrothermal veins and, rarely, granite pegmatites. In altered basalts it is a product of ex feldspars, pyroxenes, micas and amphiboles.

Prehnite usually forms stalactitic or botryoidal polycrystalline aggregates with few crystal faces. As well as occurring in altered basalts, it has been found in intrusive igneous rock such as syenites. It was the first mineral to be named after a person, the Dutchman Hendrik von Prehn, who described a locality near Idar-Oberstein, of gem carving fame.

Both of these minerals are occasionally faceted for the collector's market.

Image credit: LGF Foundation https://lgfmuseum.org/

Epidote: http://www.mindat.org/min-1389.html http://webmineral.com/data/Epidote.shtml http://geology.com/minerals/epidote.shtml http://www.minerals.net/mineral/epidote.aspx http://www.galleries.com/Epidote http://bit.ly/1O9urjN

Prehnite: http://www.mindat.org/min-3277.html http://webmineral.com/data/Prehnite.shtml

Skolithos - Western Australia The vertical structures which you can see weathering out of the sandstone are fossilised burrows, perhaps made by an ancient worm. Skolithos, as these burrows are called, are relatively common trace fossils, and generally indicate that the environment was high energy. The presence of sandstone, rather than mudstone, would support this interpretation. Sedg Image credit (non-commercial): Eric Baker (https://flic.kr/p/dfpnRt)

Venus Flytrap finds a worm

Invasive Species: Earthworms

As you begin to plant the seeds that will become your summer garden take a minute to think about all the worms you see. They are so numerous and widespread that it would appear they have always been a part of the ecosystem. In the northern United States and Canada, this was not always the case, as all native worm species went extinct in the last Ice Age. So how is it that earthworms exist in almost any place you can find a spot of bare ground? As you may have already guessed, the spread of earthworms across North America closely follows the spread of humans.

The earthworm colonization of North America is a direct consequence of European settlement of the continent. Earthworms hitched a ride across the ocean and quickly established themselves in an ecosystem that did not have any worms for at least 10,000 years. Successful invasive species, no matter what kind of animal, typically thrive in an ecosystem where they have limited competition from other species. They often do this by creating a new role (niche) for themselves. In the case of earthworms, they found the vast amounts of decaying organic matter as a prime source of food and shelter.

Since the end of the last Ice Age, forests had adapted to not having earthworms to break down organic matter. The forests would have a very thick layer of dead leaves and trees which would take years and years to decompose. With the introduction of earthworms, the ground level of many forests was altered by the quick breakdown of organic matter. This releases many chemicals and nutrients into the soil much faster than would naturally occur, so this has the impact of altering plant populations significantly. Within a few years, earthworms can turn a forest floor blanketed with a variety of plants into one of mostly bare soil.

Note: Invasive, exotic, and/or introduced species is a topic of great interest to me. I have written about starlings in the past and I hope to cover them more in the future. If you have any species in your part of the world you would like me to mention, feel free to let me know in the comments.

JRA

Image Credit: Wisconsin Department of Natural Resources http://bit.ly/1qln91p

Sources: http://1.usa.gov/237VQpk http://bit.ly/1GlL1o4 (This is a good image of a forest floor before and after earthworm introduction) http://bit.ly/1GlL1o4

Zombie Worms The Zombie worm is a colloquial name for Osedax, which is a species of worms that eats bones. These worms are a finger length long, found worldwide at 4000m depth in the ocean, and interestingly enough all adults are female. These adults have no mouth or digestive system so instead penetrate bone by using ‘roots’ to absorb collagen and lipids from the bone. The collagen and lipids are then converted to energy by a bacteria living in their roots. They then use feathery plumes at the opposite end to the roots to absorb nutrients. Males of this species do exist, however never mature past a microscopic larva. Between 50-100 of these undeveloped males live inside the female at any one time.

We’ve briefly mentioned before (http://on.fb.me/1yOVedv) that Osedax eats whale carcasses, however new evidence suggests it evolved up to 100 million years ago. Researchers have found marks on plesiosaur fossil suggesting Osedax was alive and bone-eating far earlier than we’d previously believed. These worms would have then fed on giant marine reptiles such as plesiosaurs and sea turtles. This may mean that it prevented many fossils of these marine reptiles fossilising.

~SA

Picture: http://bit.ly/1DyYg10 by Nick Higgs Paper: http://bit.ly/1Fc716w by Robert C Vrijenhoek , Shannon B Johnson and Greg W Rouse Paper: http://bit.ly/1OCBQSJ by S.Danise and N.D.Higgs

WAITOMO GLOW WORM CAVES, WAIKATO NEW ZEALAND These caves are most known for the glowworms that inhabit them, Arachnocampa luminosa. The glowworms are endemic to New Zealand, and are around the size of an average mosquito. The walls of the caves are covered with a mushroom like fungi related to the genus Pleurotus. Albino cave ants and weta (giant crickets) also inhabit this cave system.  The limestone from which these caves were carved formed more than 30 million years ago, when most of the New Zealand continent was under water. The limestone contains fossilized corals, sea shells, bryozoans, fish skeletons and other marine organisms. The limestone became exposed when tectonic movement caused it to bend and buckle then rise aboved the sea floor. The rainfall in Waitomo averages 1800-2400mm per year; this rainwater acidifies when combined with dissolved Carbon Dioxide from biological activity in the soil. This acidic water flowed along the fractures in the limestone and slowly ate away at the cavities, enlarging them over millions of years into the cave system we see today. These caves also contain stalactites and stalagmites; formed from water dripping from the ceiling and leaving limestone deposits. The name Waitomo comes from the Maori words ‘wai’ for water and ‘tomo’ for hole or shaft. The caves were first explored in 1887 by local Maori Chief Tane Tinorau and English surveyor Fred Mace. -TEL http://www.glowworm.co.nz/geology.html; http://www.waitomo.com/waitomo-glowworm-caves.aspx Photo: http://i.ytimg.com/vi/cK3FONyYc5M/0.jpg