Eastern Skunk Cabbage

Not everything in nature is equally attractive or glamorous but, with a little investigation, they can be equally interesting. Case in point – The Eastern Skunk Cabbage:

Eastern Skunk Cabbage - Symplocarpus foetidus

Eastern Skunk Cabbage – Symplocarpus foetidus

Text from Wikipedia:

Breaking or tearing a leaf produces a pungent but not harmful odor, the source of the plant’s common name; it is also foul smelling when it blooms. The plant is not poisonous to the touch. The foul odor attracts its pollinators, scavenging flies, stoneflies, and bees. The odor in the leaves may also serve to discourage large animals from disturbing or damaging this plant which grows in soft wetland soils.

Eastern skunk cabbage has contractile roots which contract after growing into the earth. This pulls the stem of the plant deeper into the mud, so that the plant in effect grows downward, not upward. Each year, the plant grows deeper into the earth, so that older plants are practically impossible to dig up. They reproduce by hard, pea-sized seeds which fall in the mud and are carried away by animals or by floods.

Powdermill Phacus

Phacus triqueter

Phacus triqueter

Phacus is a genus in the same family (Euglenaceae) as the previously mentioned Euglena. Note the red eyespot that is present in both genera.

From this angle one gets the impression that the Phacus is rather bulbous; but they are really flat. They are active swimmers and will show their true shape as they move about.

Powdermill Euglenas

 

Euglena spirogyra var. marchica

Euglena spirogyra var. marchica

Euglena spirogyra var. marchica

Euglena spirogyra var. marchica

Members of the genus Euglena are numerous and varied. Both of these organisms are variations of the same species. Euglenas are very flexible and can present different aspects as they move about. Note that in the upper image the Euglena is longer and narrower than in the lower image. This is just a matter of the organism being extended or contracted. This species is quite large and were plentiful in the Powdermill pond water.

Powdermill Algae (2)

A continued search of the Powdermill pond water revealed the next stage in the colonization of the Tetrabaena socialis algae; a very nice symmetrical cluster of eight cells.

2015-0701b

In addition to these small algae cells (bottom in photo below) there were quite a few that were similar in appearance but appreciably larger (top in photo). I have yet to ID the larger cells but that is not unusual; it is the nature of microscopic algae.

2015-0701a

Powdermill Algae (1)

2015-0630aWe recently made a visit to a local nature reserve. I returned with dozens of photos, two clusters of moss, and a pint of water from a small man-made pond.

Man-made Pond at Powdermill Nature Reserve

Man-made Pond at Powdermill Nature Reserve

The first slide from the pond water was dominated by spherical green algal cells. Some were single and others in pairs; but those in clusters of four showed their gelatinous sheath most clearly.

Green Algal Cells – Tetrabaena socialis

 

 

What is Life?

NASA  ASTROBIOLOGY

What is life? It’s a Tricky, Often Confusing Question.


What is life? This is a question that is often asked and typically confused.

The confusion starts from the several uses of the word “life” in English. There are at least three usages as exemplified by the following questions:

1) Is there life on Mars?

2) Is there life in this organism?

3) Is life worth living?

The definition of “life” in these three usages is quite different. In the first case, life refers to a collective phenomenon, in the second case it refers to the ability of an individual organism to metabolize and grow, and in the third case life refers to the history of activities that an organism undertakes. The first two usages are of direct relevance to astrobiology.

The usual definition of life, as used in the first case, is that it is a system of material entities that can undergo evolution, which implies reproduction, mutation and selection. This is what we are looking for on Mars and on other worlds. We would be most interested if it represented a second genesis, in other words an independent origin of life. It is often pointed out that the definition of life as a system capable of evolution implies that single, isolated individuals not of child-bearing age are not “life.” This is nonsense and confuses the first and second cases of “life.”

Many commentators hold the view that an effective search for life on other worlds requires that we first have a concise, agreed on, definition of life. This is not the case. Along this line, it has been suggested that once we understand life we will be able to produce a completely mechanistic and predictive theory of life. The example of water is sometimes used. Water is simply defined as two hydrogens joined with one oxygen. However, life is not a simple substance like water, rather it is a process, more like fire than water. There is no simple definition of fire. If life is like fire then even with a complete mechanistic and predictive theory of life we may still not be able to define it in any simple closed form. The search for life on other worlds can be based on what life does rather that its definition. One of the things that life does is build up large specialized molecules, such as DNA and proteins.

Viking, the only mission to search for life on another world (that being Mars), focused on the second case. The Viking biology experiments searched for something alive in the sample. The assumption was that if something was alive it would be able to consume organics and release gases; it would have a metabolism. Hence the operational definition of “life” in the Viking biology experiments was the ability to metabolize in the conditions of the experiment.

There are several problems with this operational definition. First, there are many non-biological processes the can consume organics and/or release gases. Second, experience on Earth shows that many micro-organisms are picky eaters and do not grow in laboratory conditions with nutrients added. Perhaps the most severe problem with the Viking approach is that it cannot detect organisms that are dead, which unfortunately is the most likely state of organisms on Mars (or on the surface of Europa, or in the plume of Enceladus). In fact, in the search for life in our solar system what is needed more than a definition of life is a definition of death.

What does it mean to be dead? It means that the organism was once alive and is composed of organic molecules that are specific to life — molecules such as DNA, ATP, and proteins. These are biomarkers that would be compelling evidence that the organism was once alive and is the product of a system of life that has undergone evolution over time. The search for such biomarkers is the basis for life-search methods now being considered. The challenge is to design instruments that can search for biomarkers for Earth-like life and also can detect biomarkers of unknown alien life.

Pompeii Worms

NASA   ASTROBIOLOGY:

Thermal Limit of Animal Life Redefined. First laboratory study of Pompeii worms identifies new temperature limit for animal life.

Pompeii worm (Alvinella pompejana), head at bottom left. Image Credit: University of Delaware

Pompeii worm, head at bottom left.   Credit: University of Delaware

Forty-two may or may not be the answer to everything, but it likely defines the temperature limit where animal life thrives, according to the first laboratory study of heat-loving Pompeii worms from deep-sea vents, published May 29 in the open access journal PLOS ONE by Bruce Shillito and colleagues from the University Pierre and Marie Curie, France.

The worms, named Alvinella pompejana, colonize black smoker chimney walls at deep-sea vents, thrive at extremes of temperature and pressure, and have thus far eluded scientists’ attempts to bring them to the surface alive for further research. Many previous studies conducted at these sites has suggested the worms may be able to thrive at temperatures of 60 C (140 F) or higher. As Shillito explains, “It is because several previous papers had come to this conclusion that Alvinella had become some sort of thermal exception in the scientific world. Before these studies, it was long agreed that 50 C was the limit at which animal life survived.”

In this new study, researchers used a technique that maintains the extreme pressure essential to the worms’ survival during their extraction, allowing them to bring Pompeii worms to their labs for testing. They found that prolonged exposure to the 50-55 C range induced lethal tissue damage, revealing that the worms did not experience long-term exposures to temperatures above 50 C in their natural environment. However, their studies found that the temperature optimum for survival of the worms was still well over 42 C, ranking them among the most heat-loving animals known.

Weather Station

2015-0625The latest addition to my study of nature is a weather station which measures temperature, humidity, air pressure, dew point, wind direction, wind speed, and rain fall. It also tracks data like the highest and lowest temperatures over various periods, rain fall for the month, highest wind ever recorded, etc. The handiest feature is that it is wireless and sends readings directly to a data center indoors.