Papers on Tardigrada published in 9 [ 5 4 references listed]. Bavan, S. BioMed Central Evolutionary Biology, 9: Bartels, P.
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Nulla lorem massa, consectetur vitae consequat in, lobortis at dolor. Nunc sed leo odio. Browse Collections About Login Help. Advanced search. Print Send Add Share. Item Data. Notes Abstract: This study surveyed the abundance and diversity of Phylum Tardigrada across four different substrates: rock, log, live tree, and canopy, in Monteverde, Costa Rica. Tardigrades are understudied micro-invertebrates that inhabit every biome on the planet.
I collected twenty-eight samples, or subsamples, by hand, soaked them in water for a minimum of four hours, and surveyed for tardigrades. I found and documented forty-five tardigrades. Ninety-one percent of tardigrades found were Class Eutardigrada, while the remaining nine percent were Class Heterotardigrada. Five genera were identified: Echiniscus, Pseudechiniscus, Macrobiotus, Paramacrobiotus, and Minibiotus. The canopy and live tree substrates produced equal abundance and diversity levels, each with 18 Eutardigrades and two Heterotardigrades.
The log substrate had three tardigrades and the rock substrate had only two, all Eutardigrada. Although the canopy and live tree substrates yielded the same results, tardigrades found in the canopy were more consistently found in all seven of the canopy samples. The tardigrades found on the live tree substrate, however, were primarily found all in one sample. This may indicate that tardigrade abundance is consistently higher in the canopy, but has a more patchy, random distribution in live trees.
In conclusion, tardigrades are abundant and diverse in the canopy of the cloud forest in Monteverde, Costa Rica. Postcard Information Format: Book. PAGE 1! Tardigrades are understudied micro invertebrates that inhabit every bio me on the planet. I collected t wenty eight samples or subsamples, by hand, soaked them in water for a minimum of four hours, and surveyed for tardigrades. I found and documented forty five tardigrades Ninety one percent of tardigrades fou nd were Class Eutardigrada, while the remaining nine percent were Class Heterotardigrada.
Five genera were identified: Echiniscus, Pseudechiniscus, Macrobiotus, Paramacrobiotus, and Minibiotus The canopy and live tree substrates produced equal abundance and diversity levels, each with 18 Eutardigrades and two Heterotardigrades. The log substrate had three tardigrades and th e rock substrate had only two, all Eutardigrada. Although the canopy an d live tree substrates yielded the same results, tardigrades found in t he canopy were more consistently found in all seven of the canopy samples.
The tardigrades found on the live tree substrate, however, were pr imarily found all in one samp le. This may indicate that tardigrade abundance is consis tently higher in the canopy, but has a more patchy, random distribution in live trees.
Tardigrades are microscopic, aquatic animals more commonly referred to as "water bears" or "moss piglets". These bilaterally symmetrical micro invertebrates have five body segments; one cephalic segment and four trunk segments, all somewhat indistinct Miller Adults range from 0.
These tiny organisms have a surprisingly complex anatomy and physiology. Like larger animals, they have a full aliment ary canal and digestive system, a dorsal brain atop a paired ventral nervous system, well developed muscles, a nd separate sexes Miller Unlike larger animals, however, they lack respiratory and circulatory systems, and instead use open hemocoel in their body cavity to circulate nutrient s and gas to every cell Miller There is relatively little information known about the invertebrate phylum Tardigrada, although they inhabit every biotope on th e planet from the Arctic tundra to the driest of deserts to the high h umidity of rain forests Miller Although tardigrades are found everywhere, they are strictly aquatic.
The tardigrade species that do not inhabit marine or freshwater environments are limno terrestrial. Limno terrestrial is defined as being or inhabiting a moist terrestrial environment that is subject to immersion and desiccation, as in leaf litter or between moss cushions. In this thin film of water, there is a diverse micro world where tardigrades eat bacteri a, alga e, nem atodes, rotifers, as well as o ther tardigrades Miller Tardigrades are best known for how the y have adapted to surviving extreme environmental changes.
Limno terrestrial species have three basic sta tes of being: an active state where they eat, grow, and reproduce an anoxybiotic state in response to lack of oxygen, and a cryptobiotic state in response to desiccation Miller Terrestrial tardigrades can be found in bryophyte cushions, lichens, bark, leaf litter, and soil, all of which are quite susceptible to desiccation Northcote Smith According to William R.
F our substrates consisting of rock, fallen log, living tree, and canopy were chosen for their accessibility and because they are often home to moss and lichen. PAGE 3! Glime speculates that this moisture relationship might explain why mosses on rotten logs seem to have few tar digrades, assuming that they exceed preferred moisture levels. A study done by Miller in confirms a high abundance of tardigrades in the canopy.
Despite the fact th at Costa Rica is known for its biodiversity and scientific research, there have b een very few studies done here about Phylum Tardigrada. I intend to study the abundance and diversity of tardigrades here in Monteverde on four different substrates: rock, fallen log, living tree, and canopy. I collected between the dates of 21 November through 2 December I defined one sample as a handful of moss, approximately ten grams I obtained c anopy samples from freshly fallen branches that fell from the top layer of trees I placed samples in plastic bags where I recorded the substrate type, area, and date of collection.
Samples were then placed in mason jars and immersed in water for a minimu m of four hours Miller Five subsamples of about two millilit ers each were extracted from each mason jar and placed in petri dishes with blackened bottoms.
Each subsample was thoroughly searched using a dissecting microscope at 30x magnification w ith an LED light at a forty five degree angle to t he petri dish. I extracted tardigrades with a thin glass pipette and placed them on a slide to be observed and identified under a compound microscope.
I took pictures and videos of each tardigrade. Some pictures were sent to a tardigrade taxonomic specialist, William R. Miller, for genera and specie level identification. Five genera were identified. Figure 1 Tardigrade abundance found in 28 samples across four different substrates. Minibiotus sp. Macrobiotus sp. Paramacrobiotus sp. Macrobiotus hufelandi E. PAGE 6! Only 13 tardigrades found could be identified to genera level. Although there is no published literature directly supporting these findings, there have been studies on tardigrade ecology that may offer some insight as to why tardigrades were much more abundant in the canopy and on live trees According to a study done by Chang and collaborators in , there was a s tatistically significant increase in tardigrade density with incr eased height ascending into the canopy Another study done by Miller in speculates that tardigrades are picked up by wind in their cryptobiotic tun and dispersed across the world, settling wherever wind runs out, often over a forest.
These two studi es support the high abundance of the canopy results but provide no insight to the live tree samples' equal abundance and dive rsity.
For example, of the 20 tardigrades found on live trees Fig. The l ack of equal distribution across all live tree samples could indicate that tardigrades are not necessarily abundant on all live trees, but that that sample was rich in tardigrades by chance In contrast, the canopy samples more consistently contained tardigrades; five out of the seven samples contained at least one tardigrade, and two samples c ontained seven or more.
The live tree sample's pattern is supported by a study done by M eyer that concludes that tardigrades have a very patchy distribution while the canopy sample's pattern is supported by Miller's study that corroborates the high abundance of water bears in the canopy. An extensive study by Kaczmarek on the ecological factors determining tardigrade distribution in Costa Rica discovered that, of all analyzed factors, substrate had the weakest influe nce on tardigrade distribution.
Although comprehensive, this study did not investigate local differences in altitude thereby excluding the canopy. Therefore, it can be said that the results of my study reflect a conglomerate of the conclusions reached by aforementioned tardigrade literature. The high abundance and diversity of the canopy is substantiated b y Chang and collaborators and Miller , while the high abundance and diversity of the live tree samples can be considered somewhat of a fluke, or due to high variation and patchy distribution, discussed in Meyer In addition, the low ab undance and diversities of the rock and log substrates can be explained by the conclusions reached in Kaczmarek as well as Meyer that state tardigrade distribution does not rely on substrate type, and that their distribution is patchy, respec tively.
Altho ugh tardigrades are ubiquitous around the world there are some places where they appear to be more prevalent. The canopy of the cloud forest in Monteverde, Costa Rica is abundant and diverse in Phylum Tardigrada. Tardigrades do also inha bit bryophyte cushions on other substrates in the cloud forest, but their distribution is uneven and inconsistent.
O ne thing is certain however : there is much more work to be done in understanding Phylum Tardigrada. Despite their overall abundance and worldwide distribution, little is known regarding their ecological requirements and the phylum's contribution to the biodiversity of the world.
For example, e ighty percent of described species are Eu tardigrades Miller, Is this percentage reflective of the phylum as a whole, or just a result of studies being concentrated in terrestrial mosses and lichens? What is the role of tardigrades in the micro ecosystems they inhabit? How do interspeci fic interactions affect their daily lives?
Further research options are endless and it is important that we continue to explore the world of these tiny water bears.
PAGE 8! I cannot forget to give a shoutout to the tiny squad, Jenna and Taryn for keeping me sane through endless hours of looking at tiny things in the tiny lab.