Monday, December 31, 2012

Tilapia Fin—Shark Fin?



The number is dropping fast. We kill 100 million sharks annually for the lucrative Chinese market; that’s 3 sharks getting killed every second. You don’t need to be a Nobel Laureate to realize the unsustainable nature of this massacre.

Unlike most bony fish, sharks reproduce and grow relatively slowly. Sharks have relatively few (zero to around 100) offspring each year, and the mother invests much energy in each to increase the chance that it will survive. Some female sharks put so much energy into a litter that they must take two years to recover their strength before breeding again. 
Image: bigjimstangytunes.com
Several countries have banned the killing of sharks, but still the hunt continues. The threat of jail sentence becomes exiguous in the face of profit. Is there anything, anything at all that we can do to help save the species that outlived the dinosaurs?

Image: weddingguideasia.com
Wang Yi-feng, general manager of the Kouhu Fisheries Cooperative in Taiwan thinks there’s an alternative: he is selling farmed tilapia fins as a substitute for shark fins.

The tail fins of Taiwan tilapia are a perfect stand-in for shark fins because they have the same appearance and texture- Wang Yi-feng.

Both types of fin are just cartilage, tasteless and similar in shape. His company shreds the Tilapia fins and ships a ton of fins per month to restaurants in Taiwan for $120 per kilogram, about a quarter the price of shark fins. He claims that unlike sharks, farmed tilapias are sustainable, and this “guarantees stable supplies of the delicacy, which could prevent sharks from being wiped out.”
Image: en.wikipedia.org
Peter Knights, executive director of WildAid approves the substitution.

“I’m all for it,” he says, “Tilapia is a perfectly good, sustainable and healthier substiture.”

The idea, however, doesn’t really help to curb the demand for shark fin. “It’s all about privilege and expense,” he continues.
The demand for the soup, which symbolizes wealth, has been rising along with prospering Chinese economy. Now that Tilapia fins are available, people would definitely pay higher price to get shark fins, and thus exacerbate the problem further.
Image: en.wikipedia.org
To address the problem, the substitute for shark fin should be of the same status, for example an expensive bottle of wine. This would fulfil the Chinese’s insatiable desire to display wealth and status.   

“It’s really more about perception, the notion of hosts having spent a lot of money on their guests.” Knight says.

Sharks have walked thus far in the history of our planet, only to be ruthlessly eliminated by a younger species. We can do something to stop all this. Regardless of the nature of the idea, let’s hope that all the ideas could help fight for the survival of sharks.



info: http://blogs.scientificamerican.com/extinction-countdown/2011/10/18/could-farming-sustainable-tilapia-help-cut-demand-shark-fin-soup/

Friday, December 28, 2012

I Bought What I was Told, Why Are My Fish Still Sick?


I Bought What I was Told, Why Are My Fish Still Sick?


Successful resolution of an aquarium health problem involves one of the following:  either blind luck; or the fish would have recovered whether you did (or in spite of what you did) anything or not; or else a correct series of events involving diagnostic and treatment choices.  Since we can’t do much about the first two, I’m going to talk about the last one.

The steps involved in successful treatment of problems are:
1) correct identification of the problem
2) correct choice of therapy
3) therapy (such as drugs) contain sufficient active ingredient
4) therapy is actually getting to the pathogen, in sufficient quantity to kill it without being of harm to the patient
5) problem is treated for adequate length of time
6) conditions are optimized for the patient (this is not absolutely necessary but will definitely increase your chances of success)

As you can see, this makes the whole thing a little more complicated than it seems on the surface.  I’m going to discuss each of these points in more detail.

1) Correct identification of the problem.  This is WAY harder than you might imagine.  Many things look like many other things, and especially when one is going by a description given by another person, it’s difficutl to be accurate.  Access to a microscope and a book with good pictures helps; also, common things are common (that’s why most people can identify ich, for instance).  Not all red streaky fins mean septicemia, though, and not all cases of septicemia are caused by the same bacteria.  So if a disease isn’t responding as expected, the first step is to rethink the diagnosis.

2) Correct choice of therapy.  This step contains several implications - that it has any effective therapy at all, or that this particular strain is susceptible to the same things the usual strains are.  Bacterial infections, particularly in freshwater aquarium fish, are becoming increasingly resistant to the average antibiotics used (and this is partly the fault of being bombarded with antibiotics on a random basis).  Aeromonas and Pseudomonas, for instance, are common pathogens, and are notorious for developing resistance to drugs.  You might read in a book that most bacterial problems in fish are caused by Aeromonas, and that Drug  So and so kills it, but that may no longer be the case. 

3) The therapy you have now acquired is actually any good.  If you’ll notice, treatments (especially antibiotics) are labeled “for ornamental fish use only”.   There’s a good reason for this - the purity and strength of the drug may not be being monitored particularly closely, and indeed it’s possible that it is outdated or contaiminated. 

4) Proper delivery mode and adequate strength.  By and large, treating an internal infection (such as septicemia) with an external bath (putting meds in the water) is useless.  The fish’s skin is designed to keep foreign substances out, and the therapy simply isn’t getting to where the problem is.  Either buying a prepared medicated food or making your own (if the fish will eat) is more likely to be of help.  An exception to this is certainly problems like flukes, or columnaris while it is still external; baths may well help here.  As for adequate strength - commercial preparations are made with the idea of avoiding problems associated with overdose, so they are deliberately made to dose on the low side.  This may well be inadequate for treating many problems.  And realistically, little is known about adequate dosing in fish - absorption, drug breakdown, drug toxicity is probably different from species to species, and very little is known in non food type fishes.  Things tend to be extrapolated from trout and catfish  and salmon, and may not be truly valid.

And some things work just fine, but can be toxic easily - formalin (formaldehyde solution) is a good example.  It’s a pretty effective killer of many bad things, but unless used very carefully, can be pretty hard on the fish (the environment as well).  So you really have to know what you’re doing to use it.

5) Problem treated for adequate length of time.  Often, the signs go away, but some of the bad guys are still present; if treatment is stopped too soon, they can come back with a vengeance (since it tends to be the sturdier one who are killed last).

6) And finally, the fish with the immune system that is functioning at its best will have the best chance of getting it over the problem.  Optimal living conditions will help the immune system. 

So, as you can see, a failure in one of these steps will lead to treatment failure.  Develop a systematic way of looking at problems and formulating a treatment plan, and you will have the most likely chance for success.

Wednesday, December 26, 2012

What is Marine Bioluminescence?



The only glow-in-the-dark creature familiar to most of us is the lightning bug. A few other land creatures, such as glow worms and types of mushrooms also shine in the dark. This phenomenon is known as bioluminescence. Although rare among land animals, bioluminescence is widespread in the marine environment. Along with bacteria and algae, nearly every major group of marine animals has members that glow.

Who can forget that childhood experience with fireflies on a warm summer night? Although the illumination they produce conjures up images of magic and fairy tales, this delightful effect is nothing more than a biological process called bioluminescence, created by a chemical reaction taking place within a living organism’s body. It can be used for a number of purposes, including mating, hunting, camouflage, and communication. Though a firefly sighting may not be all that common in some reaches of the globe, marine bioluminescence occurs on a wide scale, and can be even more ethereal than that of its terrestrial counterparts.

Most people don’t realize that the tendency for creatures to emit light is actually more common in the sea than on land. In fact, marine bioluminescence becomes quite common in the depths of the sea where sunlight does not penetrate, with scientists estimating that as much as 90 percent of deep sea creatures use some form of bioluminescence! Marine biologists exploring great depths in submarines have long told tales of the peculiar twinkling lights they encounter in the deep sea, far from any natural light from above. Marine bioluminescence seems to be common across a diverse group of organisms, from alga that floats high in the water column to many species of deep sea fish and invertebrates.



Basic Facts of Bioluminescence

Bioluminescence is the light produced by a chemical reaction that occurs in an organism. It occurs at all depths in the ocean, but is most commonly observed at the surface. Bioluminescence is the only source of light in the deep ocean where sunlight does not penetrate. Amazingly, about ninety percent of the organisms that live in the ocean have the capability to produce light.
Four main uses for an organism to bioluminesce have been hypothesized. It can be used to evade predators, attract prey, communcate within their species, or advertise (Nealson, 1985). For example, the angler fish uses the Lure Effect (attracting prey). This fish has a dangling lure in which bioluminescent bacteria live. The lure hangs in front of its mouth; fish swim toward the light and may become food for the angler fish. Some fish use bioluminescence for mating signals or as territorial signals (intraspecies communication), and some use it to communicate interspecies (advertisement). Some organisms employ it for more than a single reason.

Most bioluminescence is blue for two reasons. First, blue-green light travels the farthest in water. Its wavelength is between 440-479 nm, which is mid-range in the spectrum of colors. Second, most organisms are sensitive to only blue light. They do not have the visual pigments to absorb the longer or shorter wavelengths. Red light, which has a long wavelength, is quickly absorbed as you descend in water- this is why underwater pictures appear blue. As with every rule, exceptions exist. Some cnidarians emit green light and one family of fish, the Malacosteids (known as the Loosejaws) emit and are able to see red light. The red light they produce is almost infrared and not visible to the human eye. This is a huge advantage to these fish because they can produce light to see their prey, but their prey can not see them!

Each luminescent organism has a unique flash. Factors that can vary are color, rise time, decay time, and total flash time (Nealson, 1985). Some organisms can emit light continuously, but most emit flashes with varying durations and brightness. The luminescence of one dinoflagellete lasts for 0.1 seconds and is visible to humans. Larger organisms, such as a jellyfish, can luminesce for tens of seconds.
In most multi-cellular organisms, the ability to produce light is controlled neurally. However, the transmitter that signals the change to take place is unknown in most organisms. Luminescence can also be induced by the presence of another luminescing organism.

A few characteristics are common to all bioluminescent reactions. All bioluminescent reactions occur in the presence of oxygen. Two types of chemicals are required- a luciferin and a luciferase (lucifer means light bringing). The luciferin is the basic substrate of the reaction and produces the light. The luciferase catalyzes the reaction. In the basic reaction, the luciferase catalyzes the oxidation of luciferin, which results in two products- light and inactive oxyluciferin. In most organisms, new luciferin must be brought to the system either by diet or internal synthesis for each reaction. Sometimes the luciferin and luciferase are bound together in one unit called a photoprotein. The photoprotein is then triggered when a particular ion is added to the system- frequently calcium. Most of the energy released in this reaction occurs in the form of light, therefore, bioluminescence is commonly called “cold light.”

Five main types of luciferins are known. Bacterial Luciferin is a reduced riboflavin phosphate and found in bacteria, some fish, and squid. Second, Dinoflagellate Luciferin is thought to be derived from chlorophyll because it has similar structure and is found in dinoflagellates and euphasiid shrimp. The third type, Vargulin, is found in the ostracod Vargula and is also used by the midshipman fish Poricthys. This is an interesting dietary link because the fish can not luminesce until they are fed luciferin bearing food. Fourth, Coelenterazine is the most common luciferin; it is found in many phyla- the radiolarians, ctenophores, cnidarians, squids, copepods, chaetognaths, and some fish and shrimp. The fifth is firefly luciferin, which requires ATP as a cofactor in its reactions.

The tiny flashes of bioluminescence made by dinoflagellates result from a chemical process inside their cells. The enzyme luciferase allows molecules of oxygen and luciferin to combine. In the process, light is given off. This luminescent light is different from the light we normally see.

The light we normally see is “hot” light. Light emitted from incandescent bulbs or the sun results from the glowing of objects (or gases) brought up to very high temperatures. Bioluminescent light is “cold” light. With bioluminescence, most of the cell’s energy goes into producing light, not heat.

With its small heat loss, bioluminescence is the most efficient method of light production known. The cell releases less than 1 percent of its energy as heat during bioluminescence. Compare this to other cell activities, which typically result in a 60 percent energy loss as heat, or to combustion in a gasoline engine, which results in a 75 percent energy loss as heat.

The dinoflagellates most commonly found in glowing surface water include Noctiluca (Latin: night light), Pyrocystis (Greek: fire bag), Peridium, Gonyaulax, and Gymnodinium. Gonyaulax is also responsible for causing certain red tides. Thus, these creatures cause a red tint by day and a bluish-green glow by night. Comb jellies, copepods, and jellyfish also add to surface water luminescence.
An enchanting experience with marine bioluminescence can be had by paddling through salt lagoons and bays where comb jellies happen to be migrating. Comb jellies are translucent, gelatinous creatures shaped like little footballs lined with eight rows of longitudinal cilia. Although they are similar to cnidarians, or what are commonly referred to as jellyfish, they are actually ctenophores. These odd, graceful creatures often display bioluminescence, creating beautiful blue-green trails in the water at night as small vessels dip their oars into the sea. If a bioluminescent alga is present, you may get to enjoy the rare thrill of watching your footprints glow as you walk down the beach under the inky blackness of the night sky.
One of the more fascinating examples of marine bioluminescence is found in deep sea anglerfish. These amazing fish have an elongated appendage protruding from their heads complete with a bioluminescent tip. When the illuminated tip flashes, it lures the prey closer to its awaiting jaws under the cover of darkness, and before the victim has a chance to realize it’s a trap, the anglerfish swiftly snaps it up. The anglerfish is just one incredible example of life adapting to its environment in the most clever of ways.
 Most marine bioluminescence is in the blue and green ranges of color. These colors are the wavelengths of light that best penetrate sea water. However, other bioluminescent colors have also evolved among marine creatures, especially those in deeper water. These colors include red, pink, yellow, violet, and white light.

Luminescence among shallow-water fishes is limited, but many mid-water and deep-sea animals (see “The Deep-Sea,” Dive Training, June 1997) exhibit glowing lights. A wide diversity of bioluminescent functions takes place within these groups. Some of the most interesting functions lie within the realm of disguise and detection.

Light from the surface, although dim, can outline the bodies of mid-water fish. So to avoid detection, many mid-water dwellers have luminescent bellies. They camouflage themselves by matching their belly lights with the intensity of light from above. Unfortunately, this clever deception is only a thin disguise to some predators. The hatchet fish is equipped with a special yellow eye filter that allows it to easily detect blue-green luminescent bellies.

Most of the fishes who produce bioluminescence in the blue and green ranges see these colors. However, they may not see red light. The fishes Aristomias, Pachystomias, and Malacosteus use this to their advantage. First, their eyes can detect red light, and second, they emit red light by which to hunt. Their red hunting lights are invisible to their prey.

Many sea creatures, such as prawns, are red. Red light absorbs rather than reflects green and blue light. As a result, this renders them invisible to predators hunting with blue or green lights. However, under the red light of Pachystomias, red prawns light up brightly and become easy prey.





Monday, December 24, 2012

Dung Beetles Love Human Poops


Dung Beetles Love Human Poops

Why would anyone want to check out whose manure taste the best, I don't know. But it's exhilarating to know that we've won the interspecies dung contest (or rather, the first runner up).

The judges for the contest would happily chomp on any manure, and yes, they're a group of nine thousand dung beetles.
Image: scientificamerican.com
Two entomologists, Sean Whipple and W. Wyatt Hoback set out to an organic cattle ranch where there were plenty of dung beetles crawling around. They took dungs from several animals native to North America (bison, cougar, moose), and also from animals from other parts of the world (tiger, lion, zebra), and presented them to the panel of dung experts.

Different beetle species favored different types of dung. But dungs from omnivore were clear winners, and chimpanzee and human feces were right there at the top. Carnivore dungs were more attractive than most herbivore dungs. And even more amazing, the two least attractive dungs were those coming from two native species, the bison and the moose (clearly I was expecting the beetles to stick to their staple diet).
Image: blogs.discovermagazine.com
The researchers then tested the nutritional level of the dung, and found out that human dung had the highest nitrogen content, which meant the human dung were of the highest quality.

This, however, is not the reason why our dung were so sought after. As for the difference in diet, the authors said the exotic dungs were collected from a local zoo, where the carnivores were fed the same diet, so were the herbivores. So, the fact that the beetles favored different types of poops suggested there was more to poop flavor than the diet.

I believe it's the smell.



info: 
Whipple, S., & Hoback, W. (2012). A Comparison of Dung Beetle (Coleoptera: Scarabaeidae) Attraction to Native and Exotic Mammal Dung Environmental Entomology, 41 (2), 238-244 DOI: 10.1603/EN11285 

Friday, December 21, 2012

Phytoplankton - Mysteries Unveiled


Phytoplankton




What is phytoplankton? Lets take a moment to break the word down into its parts. We have Phyto and plankton Phyto is greek for plant and plankton means free swimming. Technically, plankton is any orgamisn, plant or animals that cannot swim against the current of the ocean. So, phytoplankton is plankton life that is comrpised of plants, and algaes.






http://earthobservatory.nasa.gov/Features/Phytoplankton/





It is known that green plants liberate oxygen and produce carbohydrates, a basic link in the food chain of plants to animals to people. Collectively, this chemical process is referred to as photosynthesis (photo = light, synthesis = to make). In these tiny food factories, there is a chemical compound called chlorophyll that, in combination with sunlight, converts carbon dioxide, water, and minerals into edible carbohydrates, proteins, and fats. Thus, these phytoplankton are the basis for the oceanic food chain.
Sea animals cannot perform this biological food-making process. Two-thirds of all the photosynthesis that takes place on this earth occurs in the oceans that yearly create 80 to 160 billion tons of carbohydrates. So numerous are these tiny plant forms that they often turn the water green, brown, or reddish, and are called red tides.

Plankton in general are passivlely drifting or weakly swimming organisms found in both freshwater and marine environments. They can be microscopic single celled organisms, to giant jellyfish tha are meteres in total length. They can be plankton their whole life, like copepods and are called holoplankton. Or they can be plankton just for the larval stages, as is the case with certain fish, arthropods and molluscs and they are called meroplankton. As we have learned, there is plant plankton, aka phytoplankton, and there is also zooplanlton, or animal plankton. Zooplankton are all the larval fishes, mollsuks, and copepods to name a few species.
Plankton make up the basis of the food chain throughout the ocean. These single cell phytoplankton are the main food for millions of other organisms that in turn are food for larger predators, and we can follow this all the way up the food chain to humans. The role of phytoplankton, or microalgae is to cycle andconvert nutrients. Because phytoplankton can utilize sunlight for energy, photosynthesis, they can take minerals and nutrients from their surroundsing and use the light enegry and make enegery. One of the end products of photosynthesis is the production of oxygen. Because the biomass of phytoplankton is so large, the end result oxygen production helps keep our planet hispoitable for us humans to live here.

Like all plants, phytoplankton play a role in nutrient cycling as well. They utilize inorganic minerals and organic compiunds to help themselves grow. By utilizing compounds like ammonia, urea, nitrates, phosphates and potasium and metals like iron, zinc and copper they help distribute these to other organsims and help remove them from the water column. However, this removel is not permanent, as its constantly rereleased by the death and decomposition of the algae cells.

Microalages are the main source of nutrients for many smaller organisms like zooplankton. Because phytoplankton are a rich source of carbohydrates, proteins and fats they are the building block of life in the seas. In a balanced ecosystem, phytoplankton provide food for a wide range of sea creatures including whales, shrimp, snails, and jellyfish. When too many nutrients are available, phytoplankton may grow out of control and form harmful algal blooms (HABs). These blooms can produce extremely toxic compounds that have harmful effects on fish, shellfish, mammals, birds, and even people.
Why do we care? For one, phytoplankton absorb a lot of CO2. In this link, it supports that without phytoplankton the world would be a very different place. This is important to us on land because we can influence the balance of these micro organisms. Our pollution, run off and fertilizers can unbalance this ecosystem and cause the harmful blooms and knock out of whack this balanced system.When conditions are right, phytoplankton populations can grow explosively, a phenomenon known as a bloom. Blooms in the ocean may cover hundreds of square kilometers and are easily visible in satellite images. A bloom may last several weeks, but the life span of any individual phytoplankton is rarely more than a few days.




We all need to be aware of what we put into the ocean and how it can impact the systems. Afterall we depend on the ocean for our health and comfort too.

Monday, December 17, 2012

The Challenger Deep Revealed



The Mariana Trench is the deepest place on Earth. It is located to the east of Mariana Islands, running for about 2550 kilometers but has a mean width of only 69 kilometers.

The deepest point, known as the Challenger Deep, which had hitherto been measured at 10919 meters, is now estimated to be 10994 meters.

From Wikipedia "The Challenger Deep is the deepest known point in the Earth's sea floor hydrosphere, with a depth of 10,898 m (35,755 ft) to 10,916 m (35,814 ft) by direct measurement from submersibles, and slightly more by sonar bathymetry (see below). It is in the Pacific Ocean, at the southern end of the Mariana Trench near the Mariana Islandsgroup. The Challenger Deep is a relatively small slot-shaped depression in the bottom of a considerably larger crescent-shaped oceanic trench, which itself is an unusually deep feature in the ocean floor. Its bottom is about 11 km (7 mi) long and 1.6 km (1 mi) wide, with gently sloping sides. The closest land to the Challenger Deep isFais Island (one of the outer islands of Yap), 287 km (178 mi) southwest, and Guam, 304 km (189 mi) to the northeast. It is located in the ocean territory of the Federated States of Micronesia, 1 mi (1.6 km) from its border with ocean territory associated with Guam.
The depression is named after the British Royal Navy survey ship HMS Challenger, whose expedition of 1872–1876 made the first recordings of its depth. According to the August 2011 version of the GEBCO Gazetteer of Undersea Feature Names, the location and depth of the Challenger Deep are 11°22.4′N 142°35.5′E and 10,920 m (35,827 ft) ±10 m (33 ft).
June 2009 sonar mapping of the Challenger Deep by the Simrad EM120 (sonar multibeam bathymetry system for 300–11,000 m deep water mapping) aboard the RV Kilo Moana indicated a depth of 10,971 metres (35,994 ft; 6.817 mi). The sonar system uses phase and amplitude bottom detection, with a precision of better than 0.2% of water depth; this is an error of about 22 metres (72 ft) at this depth.[4][5] Further soundings made by the US Center for Coastal & Ocean Mapping in 2011 are in agreement with this figure, placing the deepest part of the Challenger Deep at 10,994 m (36,070 ft), with a vertical precision of approximately 40 m (130 ft).
Only four descents have ever been achieved. The first descent by any vehicle was by the manned bathyscaphe Trieste in 1960. This was followed by the unmanned ROVs Kaikō in 1995 and Nereus in 2009. In March 2012 a manned solo descent was made by the deep-submergence vehicle Deepsea Challenger. These expeditions measured very similar depths of 10,898 to 10,916 metres (35,755 to 35,814 ft)."

The Challenger Deep is well, deep. Inverted it dwarfs Mt. Everest in comparison.


To put the figures into perspective;
The tallest mountain in the world, Mount Everest, is only 8848 meters.
The world record for scuba diving is 330 meters.
Image: whoi.edu
Let's do some calculation.

Water pressure, P is given by hρg 

since h = 10994 m, g = 9.81 m/s^2, and  ρ = 1097 kg/m^3

Therefore P = 110763120.78 Pa, or 110.7 MPa. For those that are not as well versed in physics that is a LOT of pressure.  Bone crushing pressure.

So it's really dark,  cold and pressurized down there. One might not expect to see any living organism here. Afterall life needs sunlight and something less than bone crushing pressures 24 hours a day- right?
Not here.  In the Challenger Deep, along with other deep water life biomes some life does exist.  Deep sea shrimp, seacucumbers, and a plentiful assortment of plankton and marine micro fauna exist.  Not unlike the deep sea hydrothermal vent zonesthere is life, for example the Vent Crab, and bacterias. Lots of them. These animals are kept alive probably by hydrothermal vents, which release hydrogen sulfide and other minerals, as well as heat.

Scientists are still not sure of the food chain in the Challenger Deep, but the abudnance of small shelled animals and a hierarchy of food chain organisms suggests life does just fine down there.

Pretty cool isn't it?



info:

Mangroves - Walking Trees


Mangroves
‘Walking Trees’
Jonathan Lowrie


A mangrove is a type of tree that grows in tropical regions at river mouths, bays, coastal lagoons and islands.  They occur in many regions through out the world; some of the best-studied mangrove forests are in the Florida ecosystem. In the Florida Keys, they create a fringing network around most islands and grow at hundreds of shallow locations offshore.  They are one of Florida’s true native species.  They thrive in their salty environment because they are able to obtain freshwater from saltwater.  Some of the species do this by excreting salt through their leaves; others block absorption of salt at their roots.

Mangrove roots act as a physical traps to filter the water systems. They trap debris and silt, stabilizing the near shore environment, and clarifying adjacent waters, and facilitate photosynthesis in other marine plants.  They also provide an attachment substrate for various marine organisms.  Many of these attached organisms filter water through their bodies and, in turn trap and cycle nutrients. Sponges, barnacles, oysters, mussels, shrimps and oysters are all efficient filter feeders that attach to mangrove root systems.  The Florida ecosystem has an estimated 470,000 acres of mangrove forests, and they all contribute to the purification of the state’s water quality.  This ecosystem traps and cycles various organic nutrients, chemical elements, and acts as a nutrient sink for important nutrients. Mangroves shed and drop about 7.5 tons of leaf litter per acre per year.  The constantly shed leaves are quickly broken down by bacteria and fungi and released into the water, providing food for sealife.

I cannot overemphasize the relationship between mangroves and their associated wildlife.  Mangroves provide a secure and safe haven for young fishes, crustaceans, and molluscs.  They also provide food for many marine species like snapper, damselfish, tarpon, and shrimp.  Without a healthy mangrove system, the vitality and health of the sport and commercial fisheries would decline.  74% of the game fish and 90% of the commercially valuable sealife in Florida depends on the mangrove.

Most animals find shelter in the roots, or the complex branch structures of mangroves.  The upper branches serve, as rookeries for coastal birds, like the brown pelican.  The roots also offer habitat for mammals, amphibians, reptiles, countless unique plants, and other invertebrate life. This root structure that penetrates into the water provides substrate for a variety of bivalves, and macro-algaes to attach.  This dense coverage provides shelter for juvenile invertebrates and fish.

Worldwide, more than 50 species of mangroves exist.  Of these, only three are found in Florida waters.  The best known is the Florida Mangrove, Rhizophora mangle.  It’s characterized by aerial roots and concealed prop roots, which provide support for soft muds and stabilize sediments. It typically grows along the water’s edge, where tidal flushing is sporadic and the water is nutrient poor.  The red mangrove is easily identified by the tangled mass of reddish roots called prop roots.  These projections from the trunk have earned this mangrove the name ‘walking mangrove’.  This tree can easily reach 30 feet in nature.

The Black Mangrove, Avicennia germanans, usually occupies higher elevations than the Red Mangrove.  They are characterized by the presence of small pencil-like vertical root shots called pneumatephores.  These root shoots stand in dense arrays near the high tide line, enabling the tree to get oxygen from the atmosphere.  The underside of the leaf surface has a whitish residue, which is excreted salt.  This will remain unless rinsed by a passing thundershower.

The White Mangrove, Laguncularia racemosa usually occupies the highest elevations farther upland than the red or black mangroves.  It grows on elevated grounds above the high tide mark.  Unlike its counterparts, it has no visible aerial root system, as the root system resembles that of most terrestrial trees.  The leaves are thick and succulent, rounded at both ends, and appears uniform in color on both sides. 

Many threats abound to mangrove habitats.  Hurricanes can damage 100,00 acres in a few hours, as did Hurricane Donna in 1960. Even the recent Hurricane Georges that swept across Puerto Rico and the keys was responsible for mangrove habitat damage. However, all of the storm damage cannot equal the impact humans have had on these forests.  Shoreline development has replaced Mangroves with marinas, dredged channels, airports, seawalls and commercial and residential construction.  Over 55% of shallow water mangroves were lost in the upper keys in past 15 years.  Forty percent of the loss was from filling of the habitat to make way for new construction.  This staggering loss occurs not just in the keys, but all over the Florida coastline.  Other threats include illegal dumping, oil spills, agricultural run-off that contains herbicides and pesticides.  Freshwater and street water runoff has also altered the salinity in some habitats causing mangrove die-backs.

Many organizations are studying habitat loss of the mangroves.  Looking at aerial photos of the same habitats from the 1940’s and 1950’s, scientists can see how pronounced the habitat destruction is.  In Florida, state and local laws were enacted to protect the mangroves.  Local laws vary, but most in municipalities it’s illegal to take any rooted plant, or disturb the trees or associated wildlife in any way.  The penalty includes heavy fines and possible jail time.

Mangroves are even now being kept in home aquariums.  They certainly can make a lovely habitat tank, allowing a touch of realisms for the shoreline tidal flat, or mangrove forest.  With the uptake of nutrients, they will certainly contribute to the overall vitality of the captive ecosystem, but because of slow growth, an uptake, they are not ‘miracle natural filters’.  The most common species for home aquariums is the Red Mangrove. It’s available as a propagule, and ships well, in moist bags.

This species does well in most seawater tanks, given a deep substrate to plant it in, and plenty of light.  I have had success with normal fluorescent bulbs, but have found compact fluorescent bulbs or metal halides to work best.  Salinity is less critical, as long as rapid fluctuations do not occur.  One way to jump-start these ‘seeds’ is to soak them in a separate container of water containing a small quantity of miracle Grow or similar fertilizer.  Its important to note that you should never put the fertilizer in your main aquarium display.  These propagules should be firmly embedded in the sediment, so that the bottom 2 to 3 inches is covered.  If you have a healthy propagule, then you should see the beginning of growth in just a few weeks.  I have also had some that take as long as six months before noticeable growth shows- so patience is vital.  Its best not to disturb the root system once it has begun to grow.

Before any mangroves are added to the tank, a few considerations must be made.  They are coastal vegetation, and are not found on the reef, but as an associated habitat.  One could never find mangroves, and small polyped corals grouped together.  Planting one in a typical reef, would only cause problems for the tree or the corals.  Mangroves are relatively slow growers, yet seem to expand by leaps and bounds when confined in a small aquarium.  Considering the overall height of 45 feet, they do grow slowly, but they can get over three feet tall in an aquarium in less than 6 months with adequate lighting.  The size of aquarium, and how much room you have to offer the tree plays a critical role in keeping mangroves.

I have some mangroves in a lagoonal system, complete with sea grasses, and some coastal corals, like Sidastrea, and Condylactus anemones.  I also have a system utilizing mangroves from Indo-Pacific and have the roots structured to create a land mass, where mudskippers, archer fish, can call home.  The possibilities for little captive microcosms are nearly endless.  Its best to get the mangroves as propagules with just a few roots starting.  If the plant is more established, it commonly fails from system shock.

Mangroves are a vital habitat we should all strive to preserve.  They most certainly add beauty and habitat to our home aquariums, and open up many new avenues of aquascaping.  If you ever have a chance to visit the coastal regions of Florida, I highly recommend a visit to a mangrove forest, as the abundance of wildlife makes this habitat one of the most diverse anywhere on earth.

Saturday, December 15, 2012

How Many Viruses Are There Around Us?


How Many Viruses Are There Around Us?

We first need to briefly discuss what a viirus is.  A trip over to Wikipedia will help further define what a virus is. The fact that we're constantly surrounded by viruses and bacteria is nothing new. But exactly how many?

A virus is an infective agent that requires a living cell in order to replicate.  They can cause anything from the common cold to HIV to Ebola. Other diseases are under investigation as to whether they too have a virus as the causative agent.  Diseases like Chronic Fatigue Syndrome, and even cancer can possibly be linked to viruses.  

Most of the time these viruses are relatively hard to catch.  Yes, the common cold is one sneeze away or one contaminated door knob from infecting you, but in general viruses are fragile and often tough to transmit.So what if a virus was truly airborne?  What if it were capable of sustained survival floating on the breezes?  What then?  The threat of a world pandemic and widespread disease certainly comes to mind.

A team of Korean scientists set up some traps to catch viruses and bacteria floating in the air. They set the traps in Seoul, in an industrial complex in western Korea, and in a forest. Their work was published in the August 2012 issue of The Journal of Virology.
Virus. Image: ucmp.berkeley.edu
Based on their study, they found out that the abundance of airborne viruses exhibited a seasonal fluctuation. The abundance increased from autumn to winter, and decreased toward spring. Perhaps a strong reason behind why we get 'colds' in the winter most often.  That and the forced sequestering inside, and drier air.

They also came up with some estimates: there are between 1.6 million to 40 million viruses, and 860,000 to 11 million bacteria in each cubic meter of air. So we're basically wading through a soup of viruses. Fortunately most of these are not thought to cause harm to humans.  Emphasis on thought.

You need not be worried by the figures though, because the scientists found out that a majority of these viruses were plant-associated viruses, followed by animal-infecting viruses. The rest were unknown virus species, meaning they might or might not be dangerous at all.

Given that we breathe in roughly 0.01 cubic meters of air each minute, the results above suggest that we suck in at least several hundred thousand viruses every minute.

That is a lot of potential infection.  Some basic hygiene efforts certainly can keep us safer.  Washing hands well is a must.  Regular soap and warm water is all you need.  No need for fancy antimicrobial stuff.  In fact some research has shown that can make things worse.  The TIME is critical.  A general rule is to sing "Happy Birthday" in your head or recite the alphabet.  I do suggest in your head as you will get some stares in a public restroom when you break out a rendition of Happy Birthday.

Next, don't touch your eyes, nose and mouth.  General stuff here, but most of us are guilty at some point of touching a door knob, shopping cart then rubbing our eyes.  Major faux pas.

So be aware of what you do and wash up regularly.  All stuff you r mom told tyou as a kid.  She was right.

But lets not all get into a panic.  Yes, many viruses enter our body with every breath.  Throughout our evolutionary history some have been beneficial.  But it is food for thought the next time you take a deep breath to think of the splendid microbiological world you just inhaled.


Thursday, December 13, 2012

Seagrasses


Seagrasses
Jonathan Lowrie


Walk into a local fish store, and take a peek at the tanks.  You would see a variety of freshwater fish, plants, saltwater fish, corals, and inverts, supplies, etc.  But no saltwater plants.  You might find a bag of Caulerpa, most likely some excess from a local hobbyist who traded it in for a new fish. The freshwater hobby abounds with diversity in the plant arena.  In fact, veteran freshwater hobbyist consider a well-planted biome to be the saltless reef equivalent.  This seems to be true, as my planted freshwater tank is full of a diverse array of invertebrate life, as well as fish.  But for those of us with saltwater aquariums as well, don’t despair.  Plants too live in the ocean.

Seagrasses are the sole marine representatives of the angiospermae family of plants.  All seagrasses belong to order Helobnidae, and are in either family Potomogetonaceae, or family Hydrocharitaceae.  Currently, there are 58 species of seagrasses recognized.  The great land down-under, Australia, is home to over half, 30, of the species.  These species belong to only 12 genera.  Grasses that could tolerate the high salt environment and the rigors of ocean life have been around for many millions of years.  Fossil records indicate that early seagrasses were abundant in the Cretaceous period, and even before around the ancient Tethys Sea.  Geological history and archaeological history show that the habitat once occupied by seagrasses has been declining the past 50 million years. Rather than being early ancestors of terrestrial plants, seagrasses were thought be a migration back to the sea by terrestrial plants. 

Seagrasses spend the majority of their existence submerged, although they may be exposed to air with tidal changes.  Their flowers, when produced, are pollinated underwater.  They remain anchored to the substrate via a network of underground root/rhizomes.  Because they are photosynthetic, they tend to be found in shallow water, like coastal areas, salt marshes, estuaries, and in the tropics, associated with mangrove forests.

Seagrasses are unique plants, adapted to live entirely beneath the water.  However, they share many characteristics with their terrestrial cousins the grasses and flowering plants, or angiosperms.  As true vascular plants, they utilize the rhizome to obtain nutrients in the sediment, and use the blades and sunlight for photosynthesis.  Most of these grasses are located in soft, silty sediments, but some species like Phyllospadix do attach to rocks. This adaptation back to the saline environment involves some complex physiological adaptations and anatomical features to allow for a submerged lifestyle. 

As fully aquatic plants, they blades of the grasses must be buoyant to catch the suns light.  They have single layer of tissue (cholorphyllous) called the epidermis, below which is a thick colorless layer with large air canals running the length of the blade.  In the sea, food sources via light may be limited, because of silty conditions, so these plants utilize the rhizome, the large submerged root as a source of nutrient.  Like many plants- potatoes for example, seagrasses store starches in their rhizome. The roots also contain root hairs, which allow for absorption of nutrients from the substrate.  When they flower, the do so underwater.  And the pollination also occurs underwater.  With sexual reproduction, many seeds are produced and are spread via water currents.  Seagrasses may also reproduce asexually, using the rhizome to extend new blades out along the seafloor. 

As aquarists why should we even care about seagrass?  Simply because they form some of the most biologically productive habitats in the world.  They perform a vital function in the physical and biological relationships between plants and animals.  Seagrass meadows provide a nutrient source for fish, waterfowl and other wildlife.  The epiphytic communities living upon the blades of seagrasses provide a rich nutrient source for many other species, as well as a nursery ground for thousands of species. These nursery meadows provide protection from predators for juvenile fish, shrimp, crab and other animals.  They also serve as a major contributor of organic material for nutrient recycling in estuarine waters.  And dense crops of grasses help prevent soil erosion and stabilize sediment loss via their dense root system.

Widespread and dramatic changes to the terrestrial ecosystem often bring corresponding changes to the human populations which have to depend on this natural resource as a means of food and fuel.  In the past decades, increases in human populations and the closer pairing of man and the infringement on the ecosystem have impacted the balance of the ecosystem.  These changes are most noticed not in the loss of a few acres of seagrass, but in the change to the commercial fisheries community.  Because of the destruction of habitat, and the fact that many seagrasses now live only in protected areas, they have been tough to acquire for the hobby.

Some of the best seagrasses for the home aquarium are now available through limited channels.  Turtle grass, Thalassia testudinum is a grass that colonizes the deeper waters of many regions.  It can tolerate higher salinities, and is quite tolerant of salinity flux.  Eelgrass, Zostera marina is another coastal grass. Its blades are considerably thinner, and it appears as a much more wiry grass. Syringodium filiforme is yet another species that can make it into the hobby.  As for lighting, these all like high intensity light.  I have kept them all successfully in shallow tanks under 2 48-inch gro lux or vitalights.  I have found they do best with natural sunlight, or compact fluorescent lighting.  They have a constant growth cycle, and look healthy.

The most crucial aspect to success with seagrasses in the home aquarium has to do with transplantation.  These grasses utilize their roots for nourishment, and stability. The rhizomes are also covered with fragile root hairs, and if these are severely damaged or torn, the acclimatization of the grass to the aquarium can be rough.  As with all plants that utilize roots, seagrasses have root tips with an apical meristem.  This region contains some undifferentiated cells and a high concentration of hormones.  If at all possible, make sure you plant grasses with the apical portion of the rhizome intact.  This will facilitate new shoots to grow in your tank.  I have found that the transport of these grasses should be semi- wet.  If the rhizomes were collected with the natural sediments, then these should be packed in wet newspaper and transported that way.  This will also ‘seed’ the tank with the associated fauna.

Besides creating habitat and providing décor for the lagoon system, seagrasses also play a role in nutrient conversion.  In nature, seagrasses are able to take light energy and store it as sugars starches, and fibers many grazers take advantage of this source of nutrients.  Since they also uptake nutrients from the sediment, they can provide a form of nutrient export and conversion.  In a closed system, they grasses will also provide a food source to the tank animals.  And they will also uptake nutrients from their root structures.  As for significant nutrient uptake in a closed system, you will have to look elsewhere.  Much like mangroves, seagrasses do uptake primary nitrogenous wastes from the sediment and water, but not in the quantities needed to perform sole denitrification in an aquarium.  Of all the algaes that could accomplish this task only the fast growing turf algaes have the growth needed to uptake the vast quantities of nutrients produced in a typical reef.

Seagrasses are gaining popularity with home aquarists, and a few facilities have begun to cultivate them for sale.  Not only is this beneficial for the natural grass beds, but it allows for a grass that is already adapted to typical lighting in an aquarium, and the mixture of sands and gravels commonly used in today’s aquariums.  Of course, not all systems are candidates for seagrasses.  If you have a reef crest tank, with many Acropidae species, then you would not find any seagrasses associated with this habitat.  But if you have a more lagoonal, or reef trough type of habitat, with corals that require slower currents, then seagrasses would make an excellent addition to your captive eco-system.

Sunday, December 9, 2012

Caution!! Tungsten filled Gold bars


Caution!! Tungsten filled Gold bars

While this is NOT my original content, I have added to an original blog post handed down through the inter-webs from an unknown origin.  I DID take some time to verify links and source stories.

This news item will have significant repercussions through the precious metals markets in the days and months to come. Australian Bullion Dealer ABC Bullion has advised that one of its suppliers has provided them photographic evidence of a tungsten filled 1 kilo gold bar discovered this week. The bar passed a hand-held xrf scan which showed 99.98% pure AU. The tungsten was only discovered when the bar was physically cut in half. After numerous reports of 400oz tungsten filled bars being discovered in Hong Kong, this is the first documented and verified report with photographic evidence that has been made public.

In addition there is some early buzz that eBay acquired silver and gold coins, bullion and such may have some level of weight shaving or impurities. For the casual investor or collector this is significant. 

This from ABC Bullion:

"Many pundits in the gold commentary space have commented on tungsten filled gold bars for many years, most notably Jim Willie, whilst the following does not prove his theories that US Treasury gold is compromised, it certainly makes the case more compelling.
ABC Bullion received the following email from one of our trusted suppliers this week.
Note: It was not ABC Bullion that purchased this bar, the email and photos were sent to us as a general warning. I xxxx'ed out the city's name to avoid any second guessing as to the name of the dealer. 

19/03/2012: Attached are photographs of a legitimate Metalor 1000gm Au bar that has been drilled out and filled with Tungsten (W). This bar was purchased by staff of a scrap dealer in xxxxx, UK yesterday. The bar appeared to be perfect other than the fact that it was 2gms underweight. It was checked by hand-held xrf and showed 99.98% Au. Being Tungsten, it would not be ferro-magnetic.
The bar was supplied with the original certificate. The owner of the business that purchased the bar only became suspicious when he realized the weight discrepancy and had the bar cropped. He estimates between 30-40% of the weight of the bar to be Tungsten. This is very worrying and reinforces the lengths that people are willing to go to profit from the current high metal prices.
Please be careful."


 
So what can a collector or investor do? For starters buy from legitimate and reputable sources.  If buying gold, due to the high cost get certified bars and rounds that are serialized and certified by groups such as Credit Suisse or PAMP.  Keep in kind if the deal is too good to be true, it IS.  Almost never will you find precious metals trading at below spot prices.  Even idiots selling off an old coin collection usually sell at spot since Google is so handy there.
Unless you know the reputation, source and history avoid or minimize your exposure from sites like eBay and Craigslist.  You want some means to go back if your metals prove fraudulent. Obviously those purchasing gold bars have a much higher investment and risk.  Tungsten filled bars is significant.  From Wikipedia Tungsten, also known as wolfram, is a chemical element with the chemical symbol W and atomic number 74. The word tungsten comes from the Swedish language tung sten directly translatable to heavy stone,[3] though the name is volfram in Swedish to distinguish it from Scheelite, in Swedish alternatively named tungsten.
A hard, rare metal under standard conditions when uncombined, tungsten is found naturally on Earth only in chemical compounds. It was identified as a new element in 1781, and first isolated as a metal in 1783. Its important ores include wolframite and scheelite. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all the non-alloyed metals and the second highest of all the elements after carbon. Also remarkable is its high density of 19.3 times that of water, comparable to that ofuranium and gold, and much higher (about 1.7 times) than that of lead. Tungsten with minor amounts of impurities is often brittle and hard, making it difficult to work. However, very pure tungsten, though still hard, is more ductile, and can be cut with a hard-steelhacksaw.
So be careful, be smart and happy collecting.