Endless Blue – Week 32 – Sense Despite Darkness   5 comments


Senses Despite Darkness

While life may have genesised from the water, it could not have begun there if not for the light bathing the world of Elqua from its sun.  Without that energy, the most basic link in the food chain — namely photosynthesis — could not metabolize, and sans a method of creating food the earliest phytoplankton colonies would have died from starvation.  Sans light, the smallest creatures of the oceans could not survive long enough to evolve into the immense and varied ecosystem of today.

In order for life to flourish, light had to be available for it.  On land light is plentiful, and even the most passive of biological constructs can soak in its bounty.  However, water is much less forgiving medium for transmission of light than air is, and some unique situations developed from the water’s special qualities of reflection, refraction, and absorption.

Layers of Water

Just as there are vertical zones in the bodies of water on Elqua — colloquially known as the Shore, the Shoals, and the Shelf — there are also horizontal layers.  These layers are defined by the amount of light that can penetrate the depths.

The uppermost layer of the ocean is where almost 75% of all photosynthetic life on the planet exists.  Named the euphotic layer, it reaches about 300 feet from the sunbathed surface of the water.  By definition, the Shore is always in the euphotic layer.

Below this layer of life is the disphotic layer, it stretches downward to about 3,000 feet deep, and is dimly lit.  Animals can easily survive here, but it is rare for any botanical life to survive due to the inadequate amount of light to complete photosynthesis.  The Shoals reach from the disphotic layer up through the euphotic layer to the surface of the water.

Finally is the aphotic layer, where no light penetrates at all, and this layer accounts for a stunning 90% of the entire ocean area of Elqua.  The Shelf includes all three photic layers, the euphotic, disphotic, and aphotic layers.

Elqua’s zones and layers intersect in a step pattern:

The Euphotic Shore The Euphotic Shoals The Euphotic Shelf
The Disphotic Shoals The Disphotic Shelf
Elqua’s Sea Floor The Aphotic Shelf
The layers of Elqua's ocean and the absorption of light spectra.

Color absorption roughly to scale; water depth is not.

That is a lot of water for light to shine through to reach the life living at the bottom of the sea.  But before the light can even start its journey through liquid, it has its first obstacle to overcome: reflection.

The water’s surface has a property called albedo, which effectively reflects a varying amount of the light shining down onto it back into the atmosphere, affecting the planet’s weather and climate.  The shape of the water’s surface determines how much sunlight can penetrate through its surface into the depths below.  Rough waters reflect less light while calm seas reflect more.  It is the rolling tidal motion of waves that results in the wavy light effect that can be seen in shallow costal waters — the wavering bands of light that dance along with the rise and fall of the waves.

Once the albedo barrier is pierced, light then has to penetrate through the optically more dense medium of water.  It is here that the individual portions of light — the eight colors of visible light — begin a process of attrition.  As light penetrates lower and lower depths of the oceans, the more difficult it becomes for white light to filter through the water.  Called refraction, it is the natural tendency of water to break up light into its component colors, which are thereby absorbed by particulate matter and the blue wavelengths are bounced off water molecules’ own intrinsic though subtle shade of blue.

Colors with shorter wavelengths – greens, blues, and violets – are able to penetrate deeper into the water than those with long wavelengths.  While eventually all color fades to darkness at the aphotic layer, the various colors can reach different depths.  Under the best of conditions (i.e., clearest water, sun directly overhead, etc.), red is the first color absorbed by the fluid surroundings; at a mere 15 feet red looks at best as a muddy sienna or burnt umber.  Orange is faded at 25′, while yellow peters out at around 45 feet down.  Violet is absorbed at nearly 100 feet, followed by green at 135′.  Blue, curiously enough, is not absorbed until significantly deeper — at about 300 feet.  This anomaly in the pattern is due to water’s inherent blue tint, which scatters the blue wavelengths of light instead of absorbing them.

Note that these distances are measured from the surface of the water directly to the colored object.  The distance from that object that an observer views from is cumulative for determining what color wavelengths can be discerned.  Thus:

Object’s distance from surface + object’s distance from observer = total distance of color absorption.

For example, a Mer gazes at a goldfish from ten feet away from him, and they are both ten feet below the surface of the waves.  The light from the sun penetrates the water’s albedo and travels 10′ to bounce off the goldfish and then travels an additional 10′ to reach the Mer’s eyes.  That’s a total of 20′, which is coming close to orange’s maximum absorption point.  The goldfish’s color would appear muddy and bland in the surrounding blue.  Had the goldfish been green, however, its coloration would still have maintained its vividness to a point where the distances between the Mer, the “greenfish”, and the surface of the ocean equaled approximately 135 feet.

This demonstrates the benefit of portable sources of light beneath the waves.  Bioluminescence is a poor but unfortunately the sole viable source of light generation under the sea.  Shedding light barely greater than a lit candle, it can barely illuminate the immediate area with its weak radiance.  Stronger light sources can be achieved through alchemy, and these light sources make discerning colors much more practical, and the distance light travels would use these alchemical lamps as the starting point to measure color absorption instead of the surface of the water, effectively exposing color to layers of the oceans that cannot normally be appreciated.

With vision such an integral sense for exploring one’s environment, other methods of “sight” evolved to fulfill the role of the primary sense.  Such established methods like infravision still exist in Elqua, though in this case infravision is severely truncated due to the light- and heat-absorption properties of water, and so is only useful on the surface and in Shore areas where light is barely refracted.

Dive deep enough, all color eventually disappears, leaving most creatures in the dark without any wavelength of light to stimulate their optic receptors, save for the ultraviolet.  Water is perplexingly transparent to ultraviolet rays, which can reach down to almost the aphotic layer.  What this signifies is that even though these depths would appear as an almost inky blackness to our eyes, there is still enough light to see with eyes that can peer into the ultraviolet range.  Perhaps the most successful adaption to deal with this depth-blindness was the evolution of ultravision.


The Kraken’s innate camouflage abilities, while formidable, would make it difficult to find others of their own kind if they did not possess a form of vision that enables them to spot each other despite their best disguise.  This sense — known as “ultravision” — works on the principle that while camouflage tends to be uncanny in the visible spectrum, the chemicals used to duplicate the natural coloring of the surroundings do not share the same make-up as the surroundings.  While skin tone can be recreated in a painting, the pigments used in both complexion and paint are not the same compounds, expressing different properties when exposed to the proper stimuli.  In this case, light.

When exposed to a special light source, these chameleonic pigments fluoresce whereas the natural coloring of the surrounds remain unlit, making detection as easy as looking in the right direction.  However, ultravision is a passive medium. meaning it is dependent on an outside source to function correctly.  Ultravision would be a useless quirk of vision without special illumination, and such sources are immediately detectable by those that have ultravision as if it was a normal light source of the same size.

It wasn’t until the historically antagonistic Chelon and Lumulus both realized the Kraken Occupation was a greater risk to their survival that either one of them were to each other.  The despite that propelled the Shellback Wars to wage over and over had to be put aside for the greater continuation of piscean life.  Only the Chelon’s mastery of mystic might and the Lumulus’ expertise at smithing metal could come together to form the ultimate tool for freedom — ultraviolet enchanted dearthsteel.

Unguis/Nautilus Abilities

Ultraviolet – An item with this quality gives off the kind of ultraviolet light that enables ultravision to work.  The magical bonus equivalent bestowed on the item by the enchantment varies according to the intensity of light shed: from +1 for a glow of a candle to +5 for the pure amount from full sunlight.  Further, an item’s size also limits how bright a glow the item can cast.  Tiny items such as daggers can only shed the weak +1/candlelight equivalent amount of ultraviolet light, with the capacity increasing by +1 for every size type larger an item from there.

Unguis/Nautilus Bonus
Illumination Level
Illumination Range
Unguis/Nautilus Size


Candlelight 5 ft. (Shadowy) Dagger, bracer, buckler


Lamp 10 ft. Short Sword, helmet, cestus


Dancing lights 20 ft. Longsword, half-spear, shield


Lantern 30 ft. Spear, quarterstaff, large shield


Sunlight 60 ft. Polearm, Lance, double weapon *, tower shield

* — Except quarterstaves.

Ultraviolet Burst — Upon a successful hit on (for an unguis) or hit by (for a nautilus) a target capable of camouflage, the striking/struck item releases a massive momentary burst of ultraviolet light that overstimulates the pigment producing cells and temporarily stuns them for 1d6 rounds.  In order for an item to be enchanted with ultraviolet burst it must already possess the ultraviolet ability before it can be given ultraviolet burst.  It is a +1 bonus equivalent ability.

The magics needed to permanently enchant ultraviolet abilities seem unable to anchor themselves to xanthellae, so the war ravaged Chelon needed some other source to attach their spells.  Conversely, no Lumulan has shown the ability to coral shape, so they lack the mental discipline to cast the ultraviolet spells into their own metal, dearthsteel.  Through espionage and betrayal, threats and machinations, the Kraken had for the most all of the occupation kept the two shellback races at each other’s throats.  It was finally the Orcans that mediated a cease fire if not peace long enough for the two arts to merge into the last chance the Known World had for freedom.  So unprecedented was the merging of these two quarrelsome factions that the alliance had as much to fear from internal back-stabbing as it ever had from their encephalopodic enslavers.


The aphotic Shelf, where the water is so deep that no light reaches, requires other senses to take up the slack from the now useless sense of vision.  The foremost among these is echolocation.  Most notably expressed by the cetaceans, it is an active system of vocalized “pings” that radiate out through the water and are reflected back when they come in contact with objects.  The reflected sound will sound slightly different in each ear as the soundwaves bounce back to the caller, and it is this stereophonic effect that gives the creature the ability to envision his environment around him in full three dimensional perspective.

The primary organ used in echolocation is the melon.  This is a roughly ovoid shaped organ found in the forehead of such creatures that can located by sound.  It is the melon that gives the Orcans their broad forehead and prominent brow.  The interior of this fatty organ is coated with a waxy oil called parmaceti, which is used in biosonar as both a focusing apparatus for the initial sound and as a receptor for the reflected sound when the consistency of the fatty tissue matches the surrounding environment, aiding in the transfer of sound vibrations to the inner ear.

Since sound travels better in water than through air, this is an effective method of vision.  However, since it requires the possessor to actively create sound pulses, creatures with echolocation can be detected by any creature through a simple passive Listen check with a Difficulty Class of 15.  An interesting side effect of this is that any creature with echolocation themselves can use the pings of active echolocation to determine the distance and direction of the sounds origin.

This curious discovery was frequently used by the Orcan barbarians, whom would spread out to surround an enemy on all sides, then a single warrior (usually the pod alpha) would make a whalesong that all others in the pod used to determine the whereabouts of the pursued prey.  From this, the Orcans learned that their whalesongs need not be the source of soundwaves detected by their melons, and have adapted to using other sources of sound as their “ping”.  This takes a Listen check at a DC of 20 to succeed, with a modifier of +1 for every mile distance the original sound is made.  A failed test cannot be rerolled, but new rolls can be made if the sound lasts for more than a round or is repeated.

Rumor has it that some special Orcans have learned the ability to use echolocation without the need to generate an echo, relying instead on the ambient sounds that fill the oceans constantly.  Most like such stories are tall tales told to magnify the cetacean’s sense of glory, as no Orcan has ever demonstrated the ability.


Currentsense is similar to echolocation, but disparate in two key areas: First, currentsense works on the sense of taste instead of hearing, and Second, the sense needs only a moving trickle of water to operate.  Without some form of currentsense, it is nearly impossible to track a target effectively in a featureless, three dimensional environment.

The most primitive form of currentsense is called bloodtrace.  This is the sense that sharks possess, the ability to detect even the smallest traces of blood in the current from great distances and home in on their origin.  Creatures with bloodtrace gain a +5 circumstance bonus when tracking a bleeding target.

The second form is called tracescent, and it operates like bloodscent, but can detect a greater range of trace compounds dragged along the currents, like recently consumed food or bodily waste.  The +5 circumstance bonus from this method of currentsense extends to any substance that leaves a residue for the currents to carry away.

The final form, true currentsense, can detect its surroundings purely by the eddies it has caused in the current. The character’s sense of touch has become so acute it can feel the lightest eddy or divergent current around him.  Similar to the tremorsense ability many of the eyeless aberrations above the waves exhibit, it allows the character to comprehend its surroundings completely without the benefit of sight.  These individuals are to be treated as if they could normally see in a well-lit area of sunlight, and enjoy the +5 circumstance bonus to tracking regardless if the target is leaving substance traces behind or not.

None of the primitive nor civilized races of the Known World of Elqua possess a form of currentsense, though they may temporarily gain them through magic or employ domesticated animals that themselves have the skill.  Such animals are highly sought after, and packbreeders have been known to be able to improve the currentsense in successive generations of those species.

“Swim fast; swim silent; swim deep.”
— the best advice for swimming closer to the Source

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