The amount and intensity of solar radiation that a location or body of water receives depends on a variety of factors.
The energy of the wavelength increases with the frequency and decreases with the size of the wavelength 16.
Sunlight, or the solar radiation spectrum, includes bands between 100 nm and 1 mm, which encompasses ultraviolet, visible and infrared radiation. Nearly all of UV-C, half of UV-B and some of UV-C radiation is absorbed by ozone in the stratosphere before it can reach the surface.
UV-B radiation can reach greater depths in saline waters than in fresher water (Image courtesy Vasilkov et al., JGR-Oceans, 2001 via NASA).
UV-B (280-320 nm) is an energetic, photoactivating band of radiation that is only partially absorbed in the stratosphere 1. UV-A (320-400 nm) has less energy than UV-B, and is not absorbed by ozone in the atmosphere. Phytoplankton are microscopic organisms that reside in water and use photosynthesis to convert sunlight to energy 16.
Phytoplankton require light for photosynthesis, but UV radiation can reduce their production. Photosynthetically Active Radiation (PAR) is the light wavelength range that is best fit for photosynthesis to occur. Photosynthetically active radiation is the range of visible light that plants can use for photosynthesis.
In particular, the level of photosynthetically active radiation (PAR) that an area receives is important. Although the main benefit of photosynthesis is energy for the plant, it has other important results. The solar irradiance received by a particular location or body of water depends on the elevation above sea level, the angle of the sun (due to latitude, season and time of day) and scattering elements such as clouds 9.
The lower the angle of the sun, the larger amount of ozone the light has to pass through 9.
During the day, the sun’s angle to any given location will decrease from sunrise until noon, and then increase until sunset. Cloud coverage and air pollution can also reduce the amount of radiation that reaches Earth’s surface. Sunlight is responsible for warming the Earth, oceans and atmosphere through infrared radiation. Photosynthesis is the process by which plants and other organisms, also known as photoautotrophs, use energy from sunlight to produce glucose.
Glucose is a kind of sugar that is later converted into Adenosine Triphosphate (ATP) via cellular respiration 3. Although increased temperatures can speed up photosynthesis, too much heat can be detrimental 11. Optimal photosynthetically active radiation is the band from 400-700 nm, which encompasses the visible light spectrum. Visible light is the only band of light on the spectrum to be considered photosynthetically active. Solar radiation levels are dependent on the time of day and on the sun’s angle toward Earth. Over most of Earth’s surface, the solar radiation received is measured by the solar irradiance. In the summer, solar radiation (measured by irradiance) will be greatest over the equator and the hemisphere tilted toward the sun.
As seen on the graph to the left, the equator has the steepest solar radiation curve, giving it the shortest sunrise and sunset periods. A hemisphere tilted toward the sun would reach a similar peak radiation level as the equator, but with more gradual curves, meaning longer sunrises and sunsets. At the geographic North and South Poles (90° latitude), solar irradiance seems to stay constant throughout a single day 15. The further a city is from the equator, the more the solar radiation received will fluctuate throughout the year. The hole in the ozone layer is a patch of atmosphere with significantly less ozone than the rest of the stratosphere (Image courtesy NASA GSFC Scientific Visualization Studio). Unusually high or low levels of sunlight can cause problems for both land and water habitats. On cloudy days, or if a previously sunny location becomes shaded, photosynthetic production can be halted. Removing shade trees from an urban stream increases the temperature of the water, making it unsuitable for coldwater fish like trout.
When water is exposed to excessive amounts of sunlight, the infrared radiation will heat the water. On the other side of the spectrum, radiation can be limited by cloudy days, shade sources or low sun angles. The amount of radiation received by the Earth varies, and much of it is reflected back into the atmosphere. Radiant energy can be measured in joules, though it is more commonly measured as radiant flux, or radiant power, which is expressed as energy over time. The amount of irradiance that reaches the surface can vary due to Earth’s elliptical orbit, solar flares and the amount of atmosphere the radiation must pass through (due to the sun’s angle to the surface or cloud cover present). Only 56% of the solar radiation that reaches the atmosphere makes it through to earths surface.
The sun’s radiation must make it through multiple barriers before it reaches Earth’s surface. The water column of the ocean can be divided into zones based on how much light reaches certain depths.
The last zone starts about 3,300 ft below the ocean’s surface and is called the aphotic (midnight) zone.
Photosynthesis can occur in the littoral and limnetic zone, as enough light is available for photosynthesis. The amount of light absorbed in a body of water can be greatly affected by ice and snow cover.
An ice-covered lake may not receive enough light for aquatic plants to continue photosynthesis. Photosynthesis, which requires light, produces oxygen as a byproduct and helps maintain dissolved oxygen levels in a body of water.
Fish that live near the surface have similar visual abilities to those of organisms on land.
Species like shrimp and squid can see the polarization of underwater light in addition possessing color and UV vision. Enter the discount code: EMS_PAR at checkout to receive additional savings on the LI-COR LI-250A Light Meter.
Cloning is a way of propagating plants through asexual reproduction of the plant by cutting and rooting a healthy shoot.
Cloning, over many thousands of years humans have exploited this ability to select plants that have particular desirable properties like high yields or pleasant flavors.
When you have a high yielding, good tasting, or particularly potent individual plant you can replicate it. Although we recommend elsewhere on this site that you spend as much money as possible on good seeds from a reputable company, this is only to get you going. Very popular with small grow-tent and closet farmers, enjoy faster growth rates, tight internode spacing, prolific flowering.
New MCOB LED looks to be the way of the future for LED Growlights, E-Shines 5 g show great results in Medical marijuana Testing trials.
Down side: 5gs tend to over heat leading one Grower to rewire the power supply on the outside of 10 units!
From what we have seen,GrowthStars, Spider 4x MCOB provides the best of output and spectrum blending. No doubt 2015 will see the mass introduction of MCOB to Medical marijuana growers who have been disappointed with 3 and 5 watt LED arrays. I purchased this bulb at my local London drugs, there was a manufacturers $10 rebate coupon meaning the bulb cost me less than $25.
Upon removing from the packaging you’ll notice this bulb is quite solid, the main body is cast aluminum and nicely finished powder coat. This type of LED lamp known as an A19 emits Light in a very wide pattern, similar to a standard incandescent lightbulb also known as A19. Unfortunately Philips “Ambient” LED A line dimmable is an awkward shape and some hanging shades and other types of lights may have a problem with it.
Unlike lower wattage LED ambient, this bulb gets extremely hot during operation and definitely should not be touched until it has cooled down substantially.
Although the package claims the bulb is instantly on, we found a slight delay, maybe not even a full second but still longer than other dimmable LED bulbs, although not as long as some that took up to 1 second before illuminating. Realistically, a 12.5 W LED lightbulb that replaced a 60 W light bulb for under $25 was completely unheard of just one year ago. Because of the unique craftsmanship and on-board electronics and LEDs, the price will never drop to the familiar two dollars or less like it’s incandescent counterparts.
Horticulturists have been using electric lamps to grow plants for nearly 150 years, and the path of their development followed from incandescent lighting through to LED Grow Lights. When the plants were supplemented with orange 622 nm, yellow 595 nm, and green 520 nm, the light was not suitable to the growth of tomatoes, there were even negative effects of these spectra , revealed later in the growth cycle. High brightness LEDs are already available the entire spectrum relevant for our horticulture purposes. The above mentioned brands, use premium quality, high brightness- 3watt-5watt  LEDs , that can target individual nanometers. Early LED grow lights came in a mix of red and blue DIP LEDs with little concern over color spectra. By concentrating light output in key bandwidths energy use is minimized, while growth and flowering maximized.
During the noon day sun when light is at its most intense the color temperature is a very blue 5000 “Kelvin” to 7000 K.
Flowering and fruiting plants often have a type of trigger, such as shorter days signal a plant to flower before the oncoming of winter.
Metal halide and high pressure sodium lamps have a dead spot at the bottom of the bulb directly underneath. LEDs can be a fantastic choice for turn signals, brake lights, license plate lighting and interior lighting and new LED headlights are among the most promising so far. High brightness LEDs for use as headlights are quickly becoming the norm for manufacturers such as Toyota, Mercedes-Benz and of course Audi, and while these lighting packages are often options, the newer trend of incorporating LEDs completely into the automobile is becoming industry-standard. Way back in automotive history, a decision was made about universal standards regarding brake light base types and turn signal (markers), making replacement bulbs easily available for safety reasons. Always choose correct color; Amber for front turn signals, red for brake lights and white for reverse, license plate and interior.
Colored automotive acrylic lenses block out all but the desired lighting wavelength, using a red LED behind a red lens, will allow all the available light to pass through unfiltered making it extremely bright. If your car is a newer model or an import, you may need to ensure that you use “Can Bus compliant” LED bulbs.
LED lights for automotive use are becoming widely available at automotive specialty stores such as Lordco.
From its early beginnings of display lighting, LED has matured into the forerunner of solid-state lighting technologies. Everyone benefits from LED lighting, saving cash in the short term on utility bills is just one of the ways LED positively impacts our immediate environment. No matter how great the technology is or how massive the savings are, LEDs are constantly noted as: “too expensive or not bright enough”. Only recently announced is a LED replacement for a 100 W(incandescent bulb), there are many 60 W equivalent running between eight and 12 W, with the new Philips L prizewinner available across Canada soon. Unlike other lighting technologies that have stalled over time and have been engineered to maximum efficiency long ago, continuous breakthroughs in LED manufacturing are announced almost daily (recently demonstrating replacing sapphire substrates with silicone to greatly reduce manufacturers material costs). Cities and municipalities struggling with shrinking budgets, are finding that; although LEDs are more expensive up front, the return on investment (ROI) offers superior long-term savings. Schools and other institutions pay exorbitant amounts (up to 80% of their electricity needs are for lighting) and can be among those to realize the most benefit from LED lighting retrofit or LED lighting installation. Low-voltage 12 V LED flex in one form or another has been in existence for many years now, and many attempts have been made at waterproofing these long strips of flexible circuit board. Epoxy covered LED strip can become brittle and crack and then become easily vulnerable to water ingress. Package contained ; Completely PU (polyurethane) encapsulated 1 m strip with power supply and infrared remote control. Somewhat similar to epoxy covered LED strip, polyurethane encapsulates the entire strip front and back, but unlike its counterparts it is an incredibly flexible, clear, jellylike polyurethane compound.
We received a 1 m RGB LED polyurethane encapsulated LED flexible strip with remote control and power supply from Trump LED lighting. Immediately we were struck with the texture of the strip itself, the polyurethane is crystal-clear and many times more flexible than the epoxy encapsulated strips. The three common types of flexable circuit board you will find in LED strips are: Copper-lowest quality available, most common flexable circuit board. Although the compound feels sticky to the touch, and in fact even sticks to glass without any adhesive, it has a Teflon™ like ability that prevents foreign material permanently sticking yet is easily installed with silicone adhesive. Only two connections and we were able to plug in the included AC adapter and had instant control via the remote. After 24 hours of operation, the strip itself even directly around the chip, was barely warm to the touch, allowing me to temporarily install it on a clear acrylic art piece, without fear of heat damage or fire risk. This is the first strip we’ve seen that is IP 68 rated, meaning completely waterproof beyond 5 m. The manufacturer was quick to note, if the product is shortened or modified it may lose its IP 68 rating. Trump LED offers a wide selection of polyurethane encapsulated flexible LED strip, definitely the best of all waterproof LED flexible stripTechnology currently available. The good news is yes LED grow lights can work quite well for growing a great many varieties of plants in sunless environments or supplemental lighting in naturally lit greenhouses. First generation grow lights adopted mixes of red and blue LEDs, as these spectrum were recognized as the most important to plant growth. Plants absorb light in different quantities and levels, there are known maximum lighting levels for certain species.
Unlike other lighting technology that has stalled or simply cannot be engineered more efficiently, LED breakthroughs continue on an almost daily occurrence with no real end in sight. Carefully chosen, LED grow lights can provide years of economical service, while providing your plants with the full spectrum required for normal plant growth. 3: Most solar LED lighting uses standard AA rechargeable batteries that are incorporated or included with the product.
4: Slightly angle your solar panel to catch the most sunlight possible, avoid shaded areas that will prevent recharging.
Solar powered LED lights come in many different types for many different purposes; there is even a solar powered streetlight with self-contained battery box. Fence post top: these ingenious LED lights lanterns are designed to be installed on existing fencepost tops, and remain completely inconspicuous by day. LED for landscape lighting is taking off throughout North America as a low environmental impact outdoor landscape lighting solution. There are many advantages to using this type of independent set up; lights can be added or removed at any time with no wiring, and no expensive installation.
Unfortunately there are many drawbacks with the independent system including; the power supplied by onboard rechargeable batteries is quite minimal and is often not enough to provide a satisfying lighting level also when the solar array is attached to the light becomes large and visible detractor.
With the second system, there is a centralized solar collection array and shared battery bank.
If you consider yourself handy or like to take it to the next level, you can create your own solar powered network through-out your yard.
Because these fixtures are remotely powered they can be placed in dark corners, in trees and other areas where self-contained solar array is not practical. Although the fixtures must be hardwired to a power source this allows for excellent controllability and allows you to use brighter, higher wattage LED products.
Centralized system can run completely off independent solar charged batteries or in winter or darker months the proper low-voltage LED transformer powered by household AC can provide unlimited power. This type of solar powered landscape lighting system requires installation and possibly burying of wires and cables. Although electrical certification and permits are rarely required for these types of installations, care must be taken to prevent unwanted short-circuits, trip hazards etc. The initial monetary outlay may be slightly more, depending how complicated your solar array and battery bank become. The current trend in conservation unfortunately has resulted in many people feeling the need to have a completely dark property every evening.
Criminals hate to be seen but love to target dark properties where they can operate with impunity in the shadows! Accidental falls down dark stairways or people tripping on items and features hidden in dark shadows have been filling our emergency rooms for years. And while motion detected floodlights can be a good idea, care must be taken not to blind the person or create excessive glare to inhibit vision. A properly placed 1 Watt or less LED light can greatly increase visibility of hidden obstacles and reduce accidents around your home and property.
It all began over100 years ago, when electroluminescent phenomenon was first discovered in 1907 by a British experimenter, H.J. After various experimental reports in the 50s, American experimenters Robert Brady and Gary Pittman, working at Texas Instruments in 1961 found that gallium arsenide emitted infrared radiation when electrical current was applied, although this light was not visible to the naked eye is allowed mass adoption of LED for infrared control devices.
The introduction of high brightness blue LEDs, demonstrated by the Nichia Corporation and eventually leading to the 2006 millennium technology prize for Shuji Nakamura, today’s high-tech LED lighting is all based on this research. Most everyone is familiar with it, encapsulated in a; 3mm, 5mm and 10mm, (or smaller) colored plastic, bullet shaped case, these early LED designs are the most commonly recognized LED, their long metal connectors protruding for easy solder connections. This recent LED technology is largely responsible for the possibility of, adoption of LED as a viable alternative to incandescent and mercury-based lighting. The SMD chip itself is created from layers of man-made nano sapphire and gallium crystal layers that are bonded to a ceramic base that can be easily mounted in various package LEDs. Far from being outdated, SMD LED continues to improve in its lumens per watt output, these small, maintenance-free long-lasting solid-state light sources will be around for many years to come. This new LED lighting technology comprises of many small-chips integrated into one large single chip.
COB (Chip on board) LED technology, differs from traditional LED in that instead of individual SMDs soldered to a circuit board and then mounted to a heat sink; the Wafers or “Wafern” are cut into some hundred small chips, with a thickness of only approx.
Before we discuss the many ways in which dolphins communicate, it is first important to get straight exactly what communication is. But communication need not necessarily always be thought of in these complex terms – sometimes messages are much simpler.
Complex multi-cellular organisms like bees (Bee Audio) hey!, flowers and humans rely on communication systems at the cellular level to function properly.
In fact, the ability to communicate is so commonplace for living beings that scientists are convinced that if alien life does exist, it too will have the ability to communicate. Instead of human language, animals possess their own communication systems that allow them to transmit information. Dolphins produce a vast number of signals in a variety of modes which we will discuss here. So let’s start by covering the most obvious form of communication that dolphins use: vocal signals. Scientist have leaned that dolphins are amazing vocal mimics – able to reproduce manmade whistle structures with precise accuracy. Scientists studying bottlenose dolphins have proposed the idea that each individual dolphin produces its own ‘signature whistle’ – a stable unique whistle structure that a dolphin develops during the first year of its life. Unlike whistles, pulsed sounds are brief sounds (called clicks) that occur in rapid succession at regular intervals. Burst pulses occur when dolphins release clicks so rapidly that it is not believe that they are able to gain any sonar information from the returning click echoes. One interesting sound that we’ve discussed on previous episodes of the dolphin pod is the pop-creak sound that has been recorded from the Indo-Pacific dolphins around Mikura Island Japan. Tail slaps (or lob tailing): dolphins often hit the surface of the water with their tail (flukes), producing a very loud booming sound that can transmit great distances in the water.
Jaw claps and jaw pops: dolphins can produce extremely loud sounds by rapidly clamping their jaws together.
Chuffs: dolphins exhale rapidly, and you can often hear the sound of an exhaling dolphin if you happen to by nearby when they break the surface. Breaches: Many cetacean species engage in breaching behavior which includes part of the body or the entire body leaving the water before crashing back into the surface. Bubbles: dolphins often blow bubble streams and bubble clouds in a variety of social situations, and while these are primarily visual signals, the production of a large bubble cloud also produces a distinctive noise that can likely be heard over short distances. Although humans generally tend to think of communication occurring with sound (thanks in part to our reliance on language), much communication happens within the visual modality – both for humans and for dolphins.
Body coloration, spots and stripes: many species of dolphins have evolved complicated body markings that communicate information.
Sexual dimorphism: for many dolphin species, there is an obvious difference between the males and females of the same species.

Postures: aside from static visual signals like coloration and body size, dolphins produce a number of visual signals. Bubbles: dolphin often release bubbles from their blowhole when making whistle sounds, although the release of bubbles does not always coincide with the production of whistles. Gestures: dolphins of course do not have arms or hands, and yet they produce a number of subtle movements that could be understood to be meaningful gestures. Synchronous behavior: dolphins have an unusual ability to imitate the behavior of other dolphins, as well as human researchers. Aerial Displays: We’ve already discussed how jumping out of the water created a percussive sound when the dolphin land on the water’s surface, but it also produced an impressive aerial display when the dolphins are airborne. Object Carrying: Some dolphins in Australia have been observed using sponges as foraging tools – not a communicative signal at all, but in the Amazon River, the Boto (or animal river dolphin) has been seen carrying sticks and rocks in its mouth apparently as a visual display meant to wow potential mates.
Perhaps one of the most important modes of signaling in a dolphin’s world is the use of touch. Some people suggest that dolphins are able to share complex 3D images with each other using their echolocation, and often label this something like ‘holographic communication’. There is of course much more that could be said about the ways in which dolphins communication, and I could talk for hours about this subject.
As light travels in a wave, a wavelength is defined as the distance from peak to peak and is measured in nanometers (nm). All wavelengths of ultraviolet light can directly affect the DNA of water inhabitants as well as generate harmful photochemicals 1. This radiation range only makes up 0.5% of all solar radiation, but it can cause the most damage to organisms.
This radiation band is known for causing skin cancer in humans, and can impair photosynthesis in many plants 16. These organisms use carbon dioxide and produce oxygen as a photosynthesis byproduct just as plants do 17.
Collage adapted from drawings and micrographs by Sally Bensusen, NASA EOS Project Science Office. These one-celled plants are responsible for much of the carbon transfer that occurs between the atmosphere and the ocean, a process known as the “biological carbon pump” 17.
90% of infrared radiation is absorbed in the first meter of the water’s surface, and only 1% can reach past two meters in pure water 1. Photosynthesis is a process that requires light energy and optimally occurs in the 400 to 700 nanometer (nm) range 1. Predators would not be able to efficiently hunt prey without light from the sun and prey would not be able to take advantage of dark areas if predators were adapted to dark habitats 1. The equator receives solar radiation at a higher intensity (irradiance) than the norther and southern hemispheres. An relatable way to think about solar irradiance is by looking at the difference between a 20-watt light bulb and a 100-watt light bulb. The distance that radiation has to travel will be at its lowest when the sun is directly overhead.
At greater angles (morning and evening) solar radiation has to pass through more of the atmosphere, which reduces its irradiance.
Both water and land reflect back some of that radiation to warm the atmosphere or other objects in contact with the surface.
While air itself does not absorb infrared radiation, it receives heat from Earth’s surface. As the surface absorbs heat from the sun, it becomes warmer than the surrounding atmosphere. This reflected radiation can be trapped and absorbed by gases in the atmosphere, or re-radiated back to the Earth 25.
These layers are distinguished by their temperatures, densities and often different concentrations of dissolved substances (such as salt or oxygen).
ATP is an energy-bearing molecule that is used in the metabolic reactions of living organisms. In the ocean, significant amounts of photosynthetically active radiation can be detected as deep as 200 m below the surface 29. These particles absorb sunlight and can cause light to be reflected off the particles in water.
It has the perfect amount of energy to excite the electrons needed to start photosynthesis and not damage DNA or break bonds. This energy breaks the bonds in molecules and can destroy DNA and other important structures in organisms 8.
This area is not completely void of ozone, but is instead a patch of atmosphere that possesses a significantly lower level of ozone than normal 27. Too much ultraviolet light can cause irreversible damage to DNA and important photosynthetic structures, while too much infrared light can cause overheating 1.
Not only does this stop oxygen production, but it increases oxygen consumption through plant respiration 1. If radiation from the sun is lower than usual for an extended period of time, photosynthetic production can decrease or be stopped completely. This is particularly important to plants, as the photosynthetic process and plant physiology in general are dependent on sunlight. They open in the presence of sunlight and allow water, carbon dioxide, and oxygen to enter the plant 22. While some plants have specialized proteins that protect them from sunburn, others do not, and intense solar radiation can damage their leaves 32.
This is a complex question to answer as there are different ways to consider and measure light.
Divide the power of the sun by the surface area of a sphere (with a radius equal to the distance between Earth and the sun). Luminance and illuminance attempt to define the brightness and the light projected from a given source.
Different materials, including dissolved and suspended solids, as well as organisms in the water, cause light to scatter in different directions 1.
Some light is able to reach this depth, but it is not enough for photosynthesis to occur 29.
In waters with a high level of turbidity, or suspended solids, light will not reach as far as clear bodies of water. Clear, colorless ice has the same percentage of light transmission as liquid water, which is about 72% 1.
Dissolved oxygen is continuously consumed in metabolic reactions by living organisms in the water, regardless of snow and ice cover. Warm colors are absorbed faster than cool colors(Image courtesy of Kyle Carothers, NOAA-OE). They possess color vision because the visible light spectrum penetrates the surface of water26. With this ability, they can efficiently locate prey as the polarization of light is altered when it bounces off scales 26. This can happen naturally to many types of plants in the wild through a variety of processes, for example, when a strawberry plant lays down runners the resulting baby strawberry plants are clones of the original. With a well designed grow room program you can be self sufficient for cuttings, growing only the highest quality weed from cuttings that you have selected yourself. Although it is possible to take a cutting from a flowering plant we would advise against it. I like London drugs because they take back compact fluorescent bulbs and take back packaging Styrofoam) and are always having specials on energy-efficient lighting. In the table lamp- light, it did resemble a 60 W incandescent almost perfectly, colors were accurately reproduced, people’s skin appeared natural and it was comfortable to read under for extended periods of time. Having passed LM79 and LM80 testing (Energy Star), it is almost certain these LED products will closely live up to their expected lifetimes and offer homeowners great value in reducing electrical utility consumption expenses. However, by lasting up to 50 times longer and using only 20% of the energy, the initial outlay easily recovered.
High amounts of this yellow light can cause stem elongation and lowers the quality of crops.
Spectra mixes can be customized for specific crops, optimizing maximum production without wasting energy outputting nonproductive wavelengths.
At first these LEDs were well under 1 W each, then the next generation utilized 1 W LEDs that were beginning to become more spectrum specific. Long August summer nights produce much redder spectrum, flowering plants tend to respond more to red spectrum because of these biological triggers.
The light produced is in a 360° beam that must be focused and concentrated on the growing area, using metal halide and high-pressure sodium in, reflectors, hoods and other fixtures, further reduce usable light output. New SMD (surface mounted diode) can produce more light from less electricity than any other available technology. They are especially valuable for large trucks and industrial vehicles such as fire trucks and ambulances, and other types of commercial vehicles designed to be in operation 24 hours a day. Although the modern automotive world filled with a variety of light bulb base types, the old standards such as T10-T20 wedge, as well as 1156 and 1157 remaining the most common automotive light bulb.
Universally accepted color patterns allow drivers to quickly identify orientation of surrounding vehicles, and is generally strictly enforced. Because the LEDs use only 10% of their incandescent brothers, they will sometimes falsely trigger lamp failure indicator lights in your automobile interior. LEDs enhance visibility for both driver and other motorists, creating a safer environment on our roads. Champion of energy efficiency, the fact that LED lighting can reduce electrical costs up to 80% has not gone unnoticed. LED replacements for 40 to 60 W incandescent, generate no radiant heat or IR and often run only warm to the touch. Compared to maintaining or upgrading existing HID (high intensity discharge) for roadway and public places, LEDs are becoming more and more attractive. A quick visual inspection of the product reveals RGB SMD (red green and blue multichip, surface mounted diode) mounted on white flexible circuit board.
Black-medium quality can be found in some strip, and finally premium white flexable circuit board.
There are four distinct color changing patterns and we quickly found the slow fade through multi-colors setting. Which could come in handy for your submarine, but also means it can be installed directly in pools and fountains and other water features, with no fear of water ingress.
The NASA space agency has been experimenting with LED grow lights for decades now, LEDs are considered a necessity to colonizing life on other planets.
Years later the research has matured dramatically, we now know there are five bands in the visible and non-visible light spectrum that affect plant growth to various degrees. Check for product reviews and testimonials to see what customers think of particular products and the types of success they’re having with different crops.
LED lamps and luminaries are now becoming commonplace because of their energy-saving, long lifespan, non-toxicity and many other fantastic benefits of using LED lighting for landscaping and home use. There are many types available ranging from the common solar lanterns right up to off grid Streetlights. LED requires very little current and voltage therefore quite thin wire may be used to install low-voltage LEDs throughout the project.
Make your house or property much less a target for thieves with a properly conceived LED lighting plan.
Round, using an electrified probe on a chunk of silicon carbide crystal,  produced the first visible shafts of light, however Russian scientists credibly reported the first creation of LED in 1927. Quickly propelled into mass adoption in handheld devices such as calculators, wristwatches, and digital displays of all types but until around 1995, were not considered bright enough for any replacement of traditional lighting.
Other processes (Zohnenschmelz or Czochralski process) are required and then it is pulled or grown into crystals up to 20 cm wide with a length of up to 2 m! 5mil LED, with its inherent heat management problems to today’s High-output MCCOB LED technology . The solid plastic package of DIP LED can be designed to focus its light instead of an external reflector used in incandescent and fluorescent, the plastic can act as a lens. SMD chips allowed manufacturers to automate production, improve quality control and offer a product that features; better heat dispersion, high lumen output (high lumen flux ) and longer overall life (low optical decay) than its predecessor the DIP LED . Quite simply, communication is the transmission of information .  This is a broad definition that covers all of the many ways that the word ‘communication’ is used, not just in terms of living organisms. A large bull moose, for example, grows enormous antlers that convey a relatively straight forward message: I’m big and strong – don’t mess with me!
Communication occurs between your brain and your muscles through tiny electrical currents flowing through your nerves.
What’s more, scientists think that intelligent life, if there is any in the universe, will probably have developed mass communication abilities similar to that of humans, likely involving radio waves. In a previous episode of The Dolphin Pod , we discussed what the difference is between language and communication, so I won’t go into detail here.
The different channels or modes include: vocal signals, non-vocal auditory signals, visual signals and tactile signals.
Dolphins produce whistles during social situations, when separated from friends, when excited, when happy and when panicked. Dolphins appear to be able to produce their own signature whistle quite reliably, but also the signature whistle of their friends.  Isolated or lost dolphins appear to frantically produce signature whistles, apparently calling out to their friends. Clicks can be released as high as 200 a second and still likely yield information for echolocation – but clicks released over that rate, and extending as rapidly as 2000 clicks per second – are thought to be communication signals, not echolocation signals. It sounds like a pop followed by what can be described as a bouncing ping-pong ball, and is often heard during aggressive chase encounters. This behavior bangs their teeth together, producing an acoustic signal that transmits large distances.
Dolphins may also exhale rapidly through their blowhole as a communicative signal, producing a loud sound called a ‘chuff’ – a chuff is another signal thought to denote aggression.
Some Breaches produce loud sounds (sometimes called percussive sounds) with many low frequencies that travel long distances. For example, Atlantic spotted dolphins slowly develop spots as they age, with adult dolphins being covered in mottled spot patterns – this quickly conveys information about a dolphin’s age. In general for most species, males are larger and bulkier, although specific body parts for species often differ between males and females, for example longer rostrums, darker colors, etc. They can signal other dolphins with body postures – for example, by forming their body into an S-shape posture they convey anger or aggression. Bubbles appear to be an extra communicative signal, and can take a variety of forms: bubble streams, bubble clouds, and bubble rings. For example, a dolphin shaking its head back and forth rapidly, an open jaw, or dipping its head during a frontal approach is often a sign of aggressions. In the wild it is thought that mirroring the behavior of your dolphin friends is a signal to other dolphins that the you are in a close relationship with your partners. These displays can be viewed both from above and below the water, and may be used to convey information about the direction of travel, location of food or general excitement levels. Males will collect objects and often swim out of the water holding the rocks or sticks in the air before slowly sinking back into the water. A few colleagues of ours from Japan have tested the idea that dolphins may poop directly in the path of human swimmers and other dolphins as a kind of warning signal. Dolphins have skin that is quite sensitive to even the lightest touch – much like the skins of human beings. During aggressive encounters, dolphins can body slam each other, butt heads and ram each other with their rostrums.
At present, there is no evidence that a dolphin’s echolocation ability is able to transmit anything like an image to other dolphins, so this suggestions is purely fanciful at this point. But the information presented here should serve as a brief overview – enough to whet your appetite. Although we at DCP are happy to present information to the public in the form of our podcasts and web pages, the information we provide (like any online info) is not a strong source to be cited in a research paper (especially for an undergrad or graduate paper). This radiant energy is necessary for the metabolism of the environment and its inhabitants 1. However, most of this short-wave radiation is absorbed by stratospheric gases (ozone), and very little reaches the surface 9.
UV-A is also called blacklight, and is known for its ability to cause fluorescence in some materials 37. Much of the ocean life below the surface depends on phytoplankton, consuming them directly or indirectly 17. Infrared radiation is readily absorbed by water and carbon dioxide molecules and converted to heat energy 10.
Human eyes are adapted to the visible spectrum, though some other species can see ultraviolet light in addition to colors 26. Most plants reflect green wavelengths while absorbing the rest of the visible light spectrum. The process ensures that more oxygen is produced than is used up by organisms in the surrounding environment. Both produce visible light in the same wavelengths, but the brightness and intensity are very different.
This is why the annual net solar irradiance is greater over the equator than over the northern and southern latitudes. As cloud cover increases, the angle of the sun becomes less important when measuring irradiance. The heat is then transferred by conduction (contact) from the warmer Earth to the cooler atmosphere 24.
The different water strata are separated by steep temperature gradients known as thermoclines 1. Denatured enzymes no longer speed up chemical reactions and instead slow down photosynthesis. The more particles present in the water, the less photosynthetically active radiation that will be received by plants and phytoplankton. When plants and other photoautotrophs attempt to use UV-A (320-400 nm) for photosynthesis, electron transport efficiency is decreased, which in turn decreases the rate of photosynthesis 6.
The greater the angle of the sun, the more ozone that sunlight must pass through to reach the surface 9. This occurs because the angle of the sun does not significantly fluctuate over the equator.
The opposing hemisphere (tilted away from the sun) would have shorter sunrises and sunsets, as well as shorter periods of daylight 15.
Although the daily values do not appear to change, the level of solar radiation received at the poles will slowly shift throughout the year. The majority of UV-C, most of UV-B and about half of UV-A are absorbed by oxygen and ozone in the ozone layer.
While the cause of gap is sometimes a subject of debate, studies have shown that ozone is destroyed when it reacts with chlorine, nitrogen, hydrogen, or bromine 27.
The decrease in infrared light will also cool the shaded surface or body of water, which in turns cools the surrounding air. Plants that are not adapted to full or intense sunlight, such as hostas or rhododendrons, can develop heat stress. There is radiance (projected power) and visible light, which can be measured as luminance (brightness) or illuminance (incident light). About 26% of the sun’s energy is reflected or scattered back into space by clouds and particulates in the atmosphere 34. If snow and ice prevent photosynthesis, plant respiration will contribute to the oxygen depletion instead of restoring dissolved oxygen levels. Many fish are also equipped with UV vision, giving them an opportunity to see animals that are transparent in visible light 26. Mantis shrimp may also use this ability for mating, as the male’s paddles change color with a different polarized orientation 30. Because of this natural ability the cloning of plants is separate from the controversy and ethical debate that surrounds the cloning of animals. While they may be taken from your plant while flowering, the clone itself must revert to the ‘vegging’ stage and the hormonal shift required will slow down growth as the plant gets ‘confusing’ signals.
Although all new smoke will taste the same as the last (given the same nutes); as it is genetically identical. This bulb works well in lamps where the bulb itself is not visible, but the fixture (or lamp) is designed to reflect light from a standard lightbulb. These familiar orange high-pressure sodium lamps have high electrical efficiencies, and long operating life and a wide spectrum of light which is suitable for many plant species. Solid-state lighting, using LEDs represents a fundamentally different technology from the gaseous discharge type lamps currently used in horticulture and has more advantages than the traditional forms of HID lighting.
Many claims were made; professional horticulturists reported only limited success with these early models. Stadium type setups for these type of light bulbs are often needed to keep plants equal distance from light source. HID operate at high temperatures and can damage crops, can provide excessive UV spectrum as well as unwanted yellow, green spectrum and unwanted IR (infrared).
LED used for general lighting is rapidly growing in popularity, due in part to “new” high-quality LEDs that are gradually becoming less expensive. Ultra smooth transitions through thousands of colors (we did however notice a slight (very minor) hickup when the pattern begins to re-loop).
Get to know your crop, do some research on what lighting requirements best suit your targeted harvest, You may want to include UV or IR to your production.

These (included) batteries are often a very poor quality; they can usually easily be replaced with a higher quality rechargeable for noticeably improved performance. These crystal extrudes are now called “wafern” and must go through a further crucial doping procedure in which the wafer in are bombarded with ions from foreign atoms in sophisticated accelerator chambers. These tiny small and hardly visible pieces of semiconductor crystal are bonded directly to the aluminum substrate (with a proprietary bonding procedure) allowing for optimum heat dissipation, and solderless fabrication. Modern technology is based on communication protocols that allow printers to communicate with computers, web browsers to communicate with web servers, GPS systems to communicate with satellites, etc. Ants for example share large amounts of information with other members of the colony through chemical trails and pheromones.
Communicating these kinds of simple messages is not restricted to the animal kingdom however. Cells in your body communicate information with other cells by releasing and receiving various proteins, and a breakdown in these communication channels leads to devastating problems like cancer and diabetes. The governments of the world are so sure of this idea that they have funded the multimillion dollar SETI project (Search for Extra Terrestrial Intelligence), which has spent 24 hours a day for the past few decades listening to the background noise of space with giant radiotelescopes hoping to hear something that resembles a communication signal from alien life forms. In brief, human language is a system of combining small meaningful elements into larger elements, forming phonemes, words and sentences that allow humans to convey infinitely complex amounts of information. As we have already discussed, these signals occur in many forms: a moose’s antlers signal that it is big and dangerous, changing the behavior of smaller moose – possibly discouraging them from entering into a fight. It is unlikely that dolphins transmit olfactory signals – those are signals that involve the sense of smell.
Pure tones can take the form of whistles (Whistle), chirps (Chirp), screams (Wilhelm Scream) sorry – screams (Scream) and other continuous sounds that you are likely familiar with.
Different whistles are produced in different situations, and scientists have been attempting to catalog and categorize whistles from study populations for some time. The jury is still out on the exact nature of the signature whistle however – some scientists believe that the whistles may not be all that stable – changing over time throughout a dolphin’s life. Dolphins of many species release bursts pulses when they are excited or angry, and burst pulses are thought to convey information about a dolphin’s emotional state.
Some scientists have described a similar pop sounds for other species as well – here is an example. For a human, screaming is a vocal sound, whereas clapping your hands together is a non-vocal sound.
Tail slaps may mean many things in many situations – for example, a signal that it is time to leave the area.
Breaching may occur for a variety of reasons – possibly it is a method of removing remoras or other parasites, but more than likely it is a communicative signal.
Many color patterns – like counter-shading and the distinctive black and white markings of orcas – are likely used for camouflage or to help when hunting prey species.
Sometimes these signals evolve as a means of competition between males – larger males are larger because they need to fend off competition from other males.
Some scientists speculate that this S posture is in fact an imitation of the S shaped posture assumed by sharks – something that also conveys aggressions for sharks. Male alliances in Shark Bay Australia can synchronize their movements  perfectly, breaking the surface and taking a breath at exactly the same time, and executing turns and twists underwater with perfect precision. These object carrying displays may signal to the females that she has a hunky, strong male on her hands that is worth mating with.
Dolphins are know to rub their bodies up against each other, but also to engage in intricate rubbing behaviors using the pectoral fins.
They also smack each other with their powerful flukes, and have even been observed leaping out of the water each other and slamming into each other while airborne. However, it has been shown that a dolphin who is positioned close to their friend can overhear the click echoes that are produced by their friend who may be echolocating on an object. For more information, have a look around the Dolphin Communication Project website, and listen to previous episodes of the Dolphin Pod where we cover some of these topics in more detail. The three relevant bands, or ranges, along the solar radiation spectrum are ultraviolet, visible (PAR), and infrared. Due to this extra energy, shorter wavelengths tend to cause more harm than longer wavelengths 16.
UV-B will reach greater depths in saline water than in freshwater and can reach as deep as 20m below the surface of the ocean 1,9. UV-A and UV-B radiation inhibit photosynthetic production, thus reducing carbon dioxide intake and oxygen output.
Phytoplankton also contribute to “marine snow” – the dead, organic material that falls to the ocean floor as fuel for deep sea organisms.
The longer wavelengths cause heat by exciting electrons in the substances that absorb them. As visible light reaches Earth, a surface will absorb or reflect different wavelengths, producing a visible color. However, even underwater when only blue light is available, photosynthesis can still occur.
In addition, shade plants respond to lower levels of PAR while sun plants harvest PAR more efficiently at higher light levels 7.
If photosynthesis does not produce enough dissolved oxygen underwater, it can create anoxic conditions where fish and other organisms cannot live 1. This intense radiation contributes to the arid climates, and the thinner air means more UV radiation reaches the surface at these altitudes.
Air itself is a poor conductor of heat, so convection, or the rise and fall of warm and cool air, warms the rest of the atmosphere not in contact with the surface 31. Without the greenhouse effect, the Earth’s average surface temperature would be about-18°C instead of the current +18°C 25.
This heat is then transferred to greater depths through movement from wind and convection 1. Even with convection and wind, it is difficult for most of the sun’s heat to cross these barriers.
Photoautotrophs use sunlight, six carbon dioxide molecules, and twelve water molecules to produce one molecule of glucose, six oxygen molecules, and six water molecules.
As heat increases kinetic energy (causing reactants to bump into one another more often), a higher temperature can speed up chemical reactions in addition to initiating the process 11. Thus temperature is an important factor in photosynthetic production, both in activating and maintaining the process. This layer is primarily found in the stratosphere, between 10 and 50 km above Earth’s surface. While most living cells have adapted and can repair simple damage, increased exposure to UV radiation can cause cells to mutate beyond repair, or to die 16.
These conditions can cause dissolved oxygen levels in the water to plummet, potentially causing a fish kill 20.
On cold, sunless days, stomata close because not enough energy from the sun is being received to continue photosynthesis 23.
Many plants, including shade plants, are susceptible to leaf scorch, where parts of the plant die due to excessive water loss through transpiration 33.
Lumens can only be measured over the photosynthetically active radiation band, or the range of visible light. The amount of sunlight reflected depends on the sun’s angle, wavelength, and weather conditions. In most rivers and streams, light will reach the riverbed, and photosynthesis can occur throughout the water column. Aquatic plants in the littoral zone can grow on the lake bed and still receive enough light for photosynthesis 19.
Almost no light is focused out of the top of the bulb, and is not a good choice for recessed fixtures or cans. These Opto electronic SSL solid-state lighting devices feature high radiant efficiency, long lifetime cool admitting temperature, relatively narrow spectrum emission, short switching time, and contain no mercury or other hazardous contaminants. LED grow lights produce minimal heat, therefore adding unnoticeable temperature differences and electricity consumption from LED grow lights is far less than their traditional counterparts. There is definitely a wide range of quality, with the cheapest plastic ones available, right up to stainless steel housings that are quite expensive. There are many low-voltage LEDs choose from, starting from about 0.3 watts to 3 W- 12 V DC.
Each of these systems relies on a structured communication protocol that allows these computer devices to receive and understand instructions. Bees are known to communicate complicated information about the location of flower patches by engaging in an intricate ‘dance’ that lets other bees know the distance and direction of tasty nectar-rich flowers. Flowers too communicate –many species of flowers demonstrate this ability when we take a special photograph using ultraviolet photography equipment. After many years of study, scientists now think that some animals may possess small parts of this system within their own communication systems that allow them to generate some basic forms of human language-like communication, but nearly everyone agrees that only humans are able to learn and use language to the complicated extent that we know as ‘language’. Bees transmit signals that tell other bees where flower patches are, influencing their behavior by encouraging them to fly out and have a look. Dolphins’ sense of smell is likely extremely restricted or entirely vanished, and their ability to smell underwater is probably non-existent.
Scientists refer to these as ‘frequently modulated sounds’, which means that the pitch of the sound changes with time – rising and falling. This is an extremely complicated process, and much has been written about how various species develop and use whistle communication. And it may be, like the orca, that these signature whistles are simply variations of shared whistles within a group.
Echolocation clicks are used for sonar purposes (check out our episode on echolocation for more information ), and generally a dolphin will make a click and then wait for the echoes from that click to return before producing the next click. Some scientist have found a very specific burst signal produced by bottlenose dolphins that appears to be a ‘play’ signal – indicating to other dolphins that ‘it’s time to for games, so I’m not really being aggressive’. But jaw clapping also occurs during play – the difference between real aggression and play aggression is often very subtle, just like in the case of humans. Breaching may produce sounds that convey information about emotional or motivations states, or the sound produced may tell distant friends about a dolphin’s position and the direction it is moving. However, some of the markings also help species to quickly tell the difference between animals belonging to the same or different species.
Male Amazon river dolphins accumulate scars all over their body which turns their skin bright pink, making it easier to pick out males from females.  Male narwhals usually have a single long tusk – unlike females who rarely develop a tusk.
This synchronous swimming displays constitute a strong visual signals to anyone who is watching. Some have speculated that impressive aerial displays may also occur during contents – where individuals try to out-do each other. Dolphins will rub their fins into the fins of other dolphins, engaging in a behavior that looks a lot like holding hands. With sensitive skin, these kinds of aggressive contacts surely must hurt, and these are clearly aggressive signals. So please use the information here as a jumping-off point for further research, and track down and cite peer-reviewed articles wherever possible. At the surface, solar energy can be absorbed directly from the sun, called direct radiation, or from light that has been scattered as it enters the atmosphere, called indirect radiation 1.
Likewise, the longer the wavelength, the longer it will take to complete a cycle, which produces a lower frequency 1. The more energy a wavelength has, the easier it is to disrupt the molecule that absorbs it. Visible light falls within the range of 400-700 nm, and infrared light contains wavelengths from 700 nm to over 1 mm 1.
When ultraviolet radiation reduces photosynthetic production of phytoplankton, it negatively affects the world carbon cycle and the marine food chain 16.
In other words, as solar irradiance (intensity) increases, sun plants experience higher rates of photosynthesis. Photosynthesis also consumes carbon dioxide, thus lowering carbon dioxide levels in air and water 1.
While heat is slowly transferred throughout the water column, it often does not reach all the way to the bottom.
Instead, the lowest strata of water will remain near 4°C, while the surface water temperature will fluctuate both diurnally (daily) and seasonally 1. This reaction reduces carbon dioxide levels in the air or water while producing glucose for ATP. As long as a photosynthesizing organism, on land or underwater, has enough of these molecules, it can produce glucose and oxygen.
This is why there are different optimal temperatures for photosynthesis for different organisms 1. If the photosynthetic production is limited, the dissolved oxygen level in the water will decrease 13.
The insufficient energy does not excite electrons in molecules enough to be used for photosynthesis. Cloud cover, air pollution and the hole in the ozone layer all alter the amount of solar radiation that can reach the surface.
In the Northern Hemisphere, the radiation increases as the year progresses until it peaks around June or July. Regardless of its cause, the hole in the ozone layer allows more UV radiation to reach Earth. This means that in warmer water, less dissolved oxygen is available for aquatic organisms 21. Too much intense sunlight can also halt the production of photosynthesis, as stomata will close on sunny, hot and dry days to prevent water loss 23.
In addition to slowing or halting photosynthesis, heat stress and leaf scorch can make plants more susceptible to disease or insect infestations.
Sunlight is usually defined in radiance units, as only half of the solar radiation that reaches Earth is visible light, but all of the radiation provides energy. Ozone absorbs ultraviolet radiation, while carbon dioxide and water vapor can absorb infrared radiation 34. However, in particularly deep, algae-covered or turbid lakes, light may not be able to reach certain depths. If a body of water is covered in ice and snow for a long period of time, its entire metabolism can be stunted. However, many of the organisms that live at or below this depth still have functioning eyes.
In cases where sound is a concern, LEDs provide none of the humming of HID transformers, and have about the same DB as a average computer. These signals occur in different channels: for example, visual signals, auditory signals, chemical signals, etc. The whistles and other vocal calls of orca have received considerable attention, and scientists have discovered that family groups appear to reliably produce distinct categories of whistles and other calls that are stable across time, and that appear to be taught to new members of the group. Regardless of the details, it is clear that whistles form an important basis from which much acoustic communication takes place between individuals. Echolocation is not a form of communication, but rather a method of ‘seeing’ the world through sound. Burst pulses can be extremely loud, and dolphins may use them during aggressive encounters – possibly to hurt the ‘ears’ of other dolphins. Some dolphins and whales also slap their tails as a means of hunting fish – stunning the fish with a powerful blow. Some species of dolphin like Risso’s dolphin, accumulate scars and bite marks after a lifetime of fighting with other animals, and the amount of scarring seen may indicate to others that the animal is either a veteran fighter, or low on the totem pole.
This may be a signal to other males about the size and power of the individual sporting the biggest, manliest tusk. During aggressive encounters, dolphins will also flare out their pec fins in an attempt to make themselves look larger, and open up their jaws – a threat signal. When groups of dolphins are stressed or threatened, they often group together and synchronize their behavior – perhaps to display solidarity and group cohesion.
They will also rub the bodies of their friends, moving their fins rapidly over the face, flank or genital region, producing what is likely to be a pleasurable sensation.
This is not necessarily a form of communication – unless of course dolphins purposely echolocate on objects because they know that their friend will be receiving the click echoes.
Ultraviolet light (which has the highest energy) can cause damage to DNA and other important cellular structures 16. Infrared light is reflected more than UV or visible light due to its longer wavelengths 10. The leaves of sun plants are small and thick, with special cells allowing for these higher rates 20. On these days solar radiation still reaches Earth’s surface, simply with a lower irradiance.
As the warmed air rises, cooler air sinks to the surface, where it continues in the convection process. In addition, turbidity can cause significant damage to water habitats by absorbing infrared radiation and increasing water temperature above normal levels. If the increase in UV radiation becomes excessive, it can be harmful to both terrestrial and aqueous habitats 27. Too much infrared light can also cause the enzymes used in photosynthesis to denature, which can slow or halt the photosynthetic process 11. The energy that reaches Earth is measured as solar irradiance (energy per second over a square meter). In direct sunlight, when the sun is at its zenith (directly overhead), measured lux could be as high as 130,000 40.
These calls are so distinct that researchers are able to distinguish different family groups just by listening to their calls. It should be noted however that there are a number of dolphin species which do not in fact produce any whistles whatsoever. By listening to the information coming back in the click echoes, dolphins can get a mental image of objects in their environment. Burst pulse sounds are often seen in social situation where males are herding female dolphins, where burst pulses are directed at the genital region of the fleeing females. Spinner dolphins produce dramatic spinning leaps which also produce loud sounds upon re-entry – given that many of these leaps are performed at night, these may be leaps whose primary purpose is the generation of noise.
For the harbor porpoise, the female is actually larger than the male – but for the sperm whale, males are as much as three times larger than the females. We have witnessed an interesting behavior in Japan where a dolphin adopts a vertical position in the water, and slowly sinks to the sea floor without moving its body at all – the precise meaning of this position and behavior unknown.
Sometimes dolphins will seek out rubs by positioning their bodies under the fin of their friend.
In this case, it may be something like communication – there is not yet any evidence that this is the case, although scientists are actively researching this area to learn just how dolphins use their echolocation in the wild. This reflection allows infrared radiation to transfer heat between the surface, water and the air. Under these conditions, humans can become sunburned without realizing the effects until it is too late. However, some of this light is reflected off of snow or other bright ground surfaces, so only 48% is available to be absorbed by land or water 36.
They have also been observed when a mother emits a loud burst pulses directed at a misbehaving calf. Flipper slaps: just like they would do with their tails, dolphins slap their flippers (that is, their pectoral fins) to sound.
Scientist have just begun to classify the subtle differences between types of breaching behavior, and are beginning to understand how small changes in the structure of the breach may in fact communicate vastly different information in various situations.
These differences between the sexes signal vital information that individual use to determine how to approach social situations. Researchers have observed a behavior where dolphins will rest their fin on the back of their friend, holding it in place for hours at a time – likely a signal to other dolphins of their friendship. This is because UV-A decreases the efficiency of electron transport which in turn decreases photosynthetic production.
At the beginning of the year, levels are high and then slowly drop to their lowest point around June. On an overcast day, incident light may only reach 1000 lux, and at twilight it may be 10 lux 40. Of the radiation that reaches the surface, approximately half is visible light and half is infrared light 1. Different kinds of burst pulse sounds used during aggressive encounters have been given names like ‘squawks’ and ‘barks’ – these click trains are often produced so rapidly that to the human ear, they sound like a continuous sounds, but in reality that are a series of tightly packed clicks. Most all of the tactile behavior I mention here is thought to be a sign of friendly, affiliative contact. The greater the angle of the sun, the lower the lux will be, as the lumens are spread out over a greater area. It’s not always easy to tell the difference between a burst pulse and an echolocation click train, and scientists are just now learning about how dolphins use burst pulses in social situations.
In cloudy weather, up to 70% of solar radiation can be absorbed or scattered by the atmosphere 35. Instead, organisms that permanently reside in the profundal zone (such as bacteria) rely on falling organic matter from higher zones 19.

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