NUISANCE ALGAE:
Everything You Need to Know to ID it and
keep it from being problematic in your reef
tank!!
In this article I’ll describe the most common types of algae growth we frequently
encounter in our reefing experiences. For each of the types of algae and “algaelike” growth listed below, I’ll provide a physical description; give suggestions for
the best means of control, and list animals that will readily prey on it. I’ll also
include some general helpful facts that may help reef keeper’s gain the upper edge.
This article will include information on:
Hair Algae
Bryopsis
Bubble Algae
Diatoms
Cyanobacteria (cyano)
Dinoflagellates
Even though cyanobacteria and dinoflagellates aren‘t truly a species of algae
from the plant kingdom, they do look similar to some types of algae growth and
are often a common nuisance for reefers just the same as the many types of “true
algae“ from the plant kingdom. Since the treatment and physical description is so
similar to nuisance algae, I’ll include them in this article as well.
I can’t emphasize it enough that breaking the nutrient cycle is the key to
winning the battle against nearly every species of nuisance algae. We often institute
the use of a cleanup crew (CUC) consisting of various hermits, snails, fish, and
crabs to eat the algae, however, this is only a portion of the solution to nuisance
algae growth. A CUC can quickly remove any algae presence by eating it,
however, that doesn’t break the life cycle of the algae. As the CUC eats the algae it
uses some of the nutrients for its own nutritional needs and metabolic processes,
however, much of the algae simply passes through the digestive tract of the animal
and is then expelled as waste. This waste consists of dissolved organic material
(DOM) and particulate organic material (POM) which then provides the fuel for
further algae growth. This can be very frustrating and an ongoing problem until the
cycle is broken by removing the key component we have control over - the organic
nutrients. In future articles I’ll describe the most common means of nutrient
management, but for now I’ll remain focused on the specific types of algae and
what conditions (as well as specific nutrients) cause the algae to become
problematic.
There are also many products on the market that we can dose into our tanks
to directly kill various types of algae. Algaecides are chemicals that directly kill
algae. I don’t recommend any sort of algaecides even if the product claims to be
“reef safe”. An important aspect to consider when dosing an algaecide is that once
the algae dies it will decompose. That decomposition releases the same nutrients
that fueled the growth in the first place. Once the algaecide is exhausted or
removed by skimming or carbon use, the nutrients released from the dead algae
will fuel the growth of algae in the future and will likely negatively impact the
health of our corals. There may be occasional success stories of various products
effectively managing algae growth, but in this article I’ll not suggest the use of
algaecides nor will I attempt to further describe their potential actions and possible
negative consequences.
Now let’s get down to the details and discuss the specific types of algae.
HAIR ALGAE
Physical description: There are many species of algae with great similarities
that we often term “hair algae”. For
simplicity, the “hair algae” referred to in
this article is best described as green or
brown tuft-like growths of algae most
commonly found growing on the
rockwork. With species variation, the color
of the algae can vary from green, brown,
or sometimes red, however, the common
hair algae we encounter are a dark shade of
green.
Best means of control: Limiting nutrients such as nitrate and phosphate
should be the primary focus of attention when trying to manage hair algae growth.
Manual removal is also important with this type of algae because of the large
volume that can grow. If nutrients are
properly lowered the algae will starve. The
dead and decomposing algae will merely
re-introduce more organic nutrients back
into the water column and fuel further
growth of algae. Good flow throughout
the tank will also aid in winning the battle
against hair algae. The growth pattern and
structure of hair algae allows it to trap
detritus which will decompose and further
fuel its growth. Often hair algae will first arise in areas of the tank which receive a
low amount of flow. These are the most common areas where detritus is allowed to
settle.
Animals that consume hair algae: Most tangs, rabbitfish, blennies,
various hermits, snails, mitherix crabs, and most urchins.
For further reading on “hair algae” check out the following links:
http://www.reefkeeping.com/issues/2008-07/nftt/index.php
http://www.saltyzoo.com/HairAlgae.html
http://algaecontrolguides.blogspot.com/2009/07/hair-algae-how-to-control-hairalgae.html
http://hubpages.com/hub/Hair-Algae
BRYOPSIS
Physical description: Grows in dark green patches on the rockwork
or substrate and has distinctive fern-like
fronds resembling a feather. Bryopsis is
often confused with hair algae, but the
feather-like leaves are the distinguishing
factor.
Best means of control:
Bryopsis is a battle that you’ll remember if
you ever encounter it. Although similar to
and often confused with hair algae,
bryopsis can grow in lower nutrient
conditions than hair algae, is eaten bar far
less herbivores, and can reproduce very
easily. Again, organic nutrient management (particularly limiting nitrate and
phosphate) should be the first approach. Coincidently, bryopsis is also particularly
irritated and its growth is discouraged when there are elevated magnesium levels
with the use of Kent Marine Tech-M. Often raising the magnesium levels between
1500-1700 PPM using Tech-M will prevent the growth of this nuisance. I don’t
believe it’s fully understood why bryopsis is so sensitive to elevated magnesium
levels with the use of Tech - M, but it is a well known tool in managing this pest. It
should be noted that the elevation of magnesium levels through other means
besides the use of Tech-M has been found to be ineffective in the battle with
bryopsis by many reefers.
Similar to the management of hair algae, manual removal of bryopsis is
helpful so that the dying algae doesn’t release nutrients as it decomposes.
However, be mindful that this algae spreads easily through asexual reproduction. It
can re-grow from tiny bits and pieces that are
spread throughout the tank as you’re pulling it
out.
As with hair algae, the growth pattern
and structure of bryopsis allows it to trap
detritus to further fuel its growth, therefore,
high flow throughout the tank to keep the
rockwork and the sandbed free of detritus is
important.
Animals that will eat bryopsis: It’s
important to note that fish and herbivorous
inverts are far more reluctant to eat bryopsis in comparison to hair algae. As for
fish, tangs from the zebrasoma family and naso tangs have been known to
occasionally consume bryopsis. Other inverts that may consume the bryopsis are
pincushion urchins, emerald mitherix crabs, and the common sea lettuce
nudibranch.
Below are a few links for further reading about bryopsis:
http://fish.suite101.com/article.cfm/bryopsis_a_common_pest_in_aquaria
http://www.melevsreef.com/id/bryopsis.html
http://www.tropicalfishtanklover.com/bryopsis-algae-problem-in-saltwateraquariums-a-solution-that-actually-works/
http://reefcentral.com/forums/showthread.php?t=1113109&highlight=bryopsis
BUBBLE ALGAE (Valonia, Dictyosphaeria, Ventricaria,
and Colpomenia)
Physical characteristics: Bubble
algae looks exactly like it sounds - little
green bubbles. Unfortunately, the little
green bubbles aren’t as pleasant as they
may sound. Bubble algae comes in the
form of clumps of green bubbles or
single sporadic bubbles which pop up in
various areas throughout the tank (the
growth characteristics, density of
bubbles, and reproductive characteristics
are based on the specific species of
bubble algae). The outer skin is commonly very tough and difficult for any animal
to puncture; therefore, finding animals that can and will eat bubble algae is quite
difficult. The bubble algae can range in size from as small as 50 microns all the
way up to a few inches in diameter.
Best means of control: Controlling bubble algae can be quite difficult,
frustrating, and take several months or years for complete eradication. Similar to
bryopsis, a good approach to preventing an infestation of bubble algae is proper
QT of everything that goes into your tank. Once one tiny bubble is present in your
tank, it can be less than a few weeks before you see them everywhere. Once the
bubbles are everywhere it’s going to take some elbow grease and persistence to
keep this nuisance under control. When introducing new rock, substrate, or
anything else the bubble algae can hitch a ride on, it’s possible for spores or tiny
bubble algae to make their way into your tank without you even knowing it. The
spores and smallest bubbles aren’t visible to the naked eye. Even more frustrating,
many species of bubble algae are able remain dormant and essentially undetectable
for a great length of time.
Although highly debatable, a frequently suggested method to manage this
frustrating nuisance is simply removing as many as possible with a forceps (while
keeping them in tact) and popping the
ones that are unable to be removed
undamaged. It’s also important to remove
any of the remaining tissue and skin of
the bubbles that were merely popped
since it will only decompose and release
more nutrients. The rationale behind the
logic of popping any that are unable to be
removed intact is that although there is
potential for these bubbles to release
spores for further reproduction, they
would have eventually grown large enough and released the spores anyway.
Removal of the bubbles intact is best; however, if unable to remove them intact,
it’s still best to remove then one way or another. It’s also commonly mentioned that
many of the smaller juvenile bubble algae have not yet developed any spores for
reproduction. This makes popping the tiny bubbles more reassuring since they are
often the most difficult to remove intact.
Animals that will eat bubble algae: This is a short and subjective list.
The various species of bubble algae are a type of algae that are simply not
palatable to many animals that will often devour other types of algae. Bubble algae
is also tough to break open due to its thick and strong outer layer as well as it’s
spherical or egg-like shape further increasing the difficulty for some animals to be
able to penetrate it. Some tangs and rabbitfish have been mentioned to eat bubble
algae; however, there is no one species of fish that are strongly indicated for
eradicating this nuisance. One animal that is often indicated to eat bubble algae is
the emerald mitherix crab. Many reefers who have battled bubble algae indicate
that sometimes the mitherix crabs will pick at the bubble algae and sometimes they
will ignore it all together just as most fish do. Most often, mitherix crabs will
occasionally eat the very small bubble algae (1-2 mm in size) which haven’t yet
developed the characteristic thick layers of skin. Several urchins have been
reported to graze on some types of bubble algae, however, as any other reef
herbivore, an urchin will be more interested in eating nearly any other algae first including coralline algae.
Further information on bubble algae: The four most common species
of bubble algae a reefer will encounter are: Valonia, Dictyosphaeria, Ventricaria,
and Colpomenia. Unfortunately, they will all grow in very low nutrient
environments. Bubble algae can even thrive in tanks with very low nutrient levels.
Unfortunately, a little drop in nitrate and phosphate won’t eradicate this pest like it
may for hair algae. Another frustrating aspect of the bubble algae is that they need
little to no light to thrive. The bubbles will grow and thrive in almost entirely unlit
areas.
Some reefers advocate for a method of siphoning out the contents of the
bubble if you’re unable to remove them without popping them. This entails a piece
of rigid airline with a pointed end and length of common airline attached to create
a siphon to suck out the contents of the bubble. If the infestation is minimal and the
bubbles are large then this method may be beneficial, however, most often once
the reefer becomes annoyed with the growth of bubble algae, the volume of
“bubbles” is often overwhelming and unrealistic to implement this method of
siphoning for all them.
Links for further reading:
http://reefkeeping.com/issues/2002-02/hcj/feature/index.php
http://reefkeeping.co.uk/blog/pests/bubble-algae/
DIATOMS
Physical Characteristics: Diatoms are a type of algae that are seen with
nearly every initial start up and cycle of a saltwater fish tank. They are a brownish
or dark yellow growth that will cover
the rocks, glass, and sandbed. It’s
sometimes described as appearing to
have a powder-like appearance. On a
microscopic level, diatoms consist of
tiny layers of shells composed of
silica. Although a common nuisance
in a reef aquarium, they are a very
basic life form and a necessary food
for the survival of many species of
micro and macro fauna. Diatoms are
one of the most abundant and basic
life forms found throughout the worlds lakes and oceans.
Best means of control: As any other type of algae, diatoms will require
nitrate and phosphate for their growth; therefore, limiting those two nutrients is
important as always. A characteristic attributed to diatoms is that they require
silicate or silicic acid to build the physical structure of their body. This means a
good way to limit diatomaceous growth in your tank is to limit the silicate
available to them. Silicate and silicic acid can be found in tap water, some
synthetic salt mixes, and questionably some of the substrate we add to our tanks.
Since sponges often utilize
silicate to create their skeletal
structure, any rock with dead
or dying sponges can be
releasing silicates as well.
Diatoms are almost always
seen as one of the first life
forms when we start up a reef
tank because of the excessive
nutrients upon start up and
the commonly increased
levels of silicates that may be
leaching from dead or dying sponges.
Properly curing rock and scrubbing it free of any dead or dying sponges will
help limit any silicate that will get leached into the tank from the rock you use.
Diligence in carefully curing and cleaning the rock can make a big difference in the
amount of nutrients the rock will add to fuel the growth of the diatoms. Sometimes
people even use a power washer to clean dead or dying debris from the rock.
Using an RO system with a DI (de-ionization) unit will significantly
decrease (or entirely remove) any silicates that will be introduced through your
water. Coincidently, when a DI cartridge is exhausted, it can leach significant
amounts of silicate back into your RO/DI water. Be sure to watch the TDS of your
RO/DI water to ensure your DI cartridge isn’t exhausted and feeding nutrients
directly into your tank.
There is debate as to whether or not silicate can be leached from various
types of substrate. Most commonly concerning is the use of silica sand used for
sand blasters. This is very fine sand that people sometimes use in reef tanks for
various reasons - aesthetics, filtration, refugiums, etc…. There have been claims
that this silica sand can directly leach silicates as well as the diatoms being able to
directly extract silica from the sands molecular structure. I have no information
supporting that silica sand can or cannot increase silicate levels or increase
diatomaceous growth in a reef tank, but with so many substrates available to us I
find it unnecessary to risk using something that could potentially cause trouble and
increase levels of an unwanted element.
There are also many types of marketed filtration media that can be used to
adsorb silicates from your reef tank which will then limit diatom reproduction.
Animals that will eat Diatoms: Fortunately for us, diatoms are readily
consumed by many types of snails and hermit crabs. Nearly every omnivorous or
herbivorous snail or hermit crab will prey on diatomaceous algae. Obviously snails
can more easily remove the diatoms from the glass, but hermit crabs are very
effective at picking the diatoms from every little crevice in the rockwork. Many
types of urchins will also feed on diatoms.
Links for further reading:
http://www.saltwater-aquarium-online-guide.com/diatoms.html
http://www.saltwater-aquarium-online-guide.com/diatoms.html
http://saltaquarium.about.com/cs/algaecontrol/a/aa091100.htm
http://www.associatedcontent.com/article/937815/diatoms_saltwater_aquairum_ent
husiasts.html?cat=53
CYANOBACTERIA
Physical Characteristics: Cyanobacteria aren’t in the plant kingdom like
the previous types of algae discussed. Cyanobacteria are actually a species of
photosynthetic bacteria and there are actually hundreds of different species of
cyanobacteria.
Cyanobacterial growth often
exhibits as a slimy film or
mat on the sand bed or
rockwork and can range in
color from red, purple,
brown, blue or green. Most
commonly in reef tanks, the
species of cyanobacteria we
encounter will be a reddish
brown in color. Often, in
freshwater tanks, the species
of cyanobacteria commonly
observed will be blue/green
in color. Cyanobacteria may
be sometimes confused with diatoms, however, the major difference between the
two is that the diatoms will grow as a “dusting-like” layer and may grow in areas
of (and may actually grow better in areas of) high flow. Cyanobacteria grows as a
slimy mat that will not tolerate high flow and is often found having a shiny/slimy
look and may also contain what appear like air bubbles coming from within it.
These bubbles can often simply be an accumulation of oxygen which is a
byproduct of the photosynthetic processes the cyanobacteria utilizes.
Best Means of Control: Since cyanobacteria are photosynthetic bacteria,
limiting the light source available to it will directly impact its proliferation.
Considering our reef tanks inhabitants also require light, there needs to be focus on
several means of management to properly control cyanobacteria in a reef tank.
Although a 2-3 day “lights out” period can disrupt the life cycle of cayno and give
you a head start at beating it, the focus should be directed on limiting the nutrients
it requires to grow. Also, in regards to light,
keep in mind that as the aquariums bulbs age
there can be a spectral shift in the light from
the blue wavelengths towards the red end of
the spectral wavelength and this type of light
is more conducive of photosynthesis for all
algae and other photosynthetic animals.
It’s my understanding that
cyanobacteria utilize organic molecules such
as ammonia, nitrate, phosphate, and nitrogen
gas as well as a carbon molecule (commonly
from carbon dioxide or from other carbon
sources we might dose into our tank such as
vodka, vinegar, or sugar) to create energy and
building blocks for reproduction. The
specific organic molecule required is a
detailed process determined by the specific
type of bacteria and process occurring
(aerobic or anaerobic). That being said,
proper nutrient management (nitrate, phosphate, ammonia, ammonium, etc…) will
be the key factor in winning the battle with cyanobacteria.
Another ally we can use to aid in our battle against cyano is a high rate of
water flow in our tank. While cyanobacteria are able to use photosynthesis to fix
nitrogen gas and a carbon molecule (from carbon dioxide) to produce energy and
support metabolic processes, it can also create cells that are efficient at fixing
nitrogen and carbon in an anaerobic environment. Most species of cyanobacteria
form a dense gelatinous mat which will then create an anaerobic region (area
lacking oxygen) underneath it which the bacteria uses to more efficiently convert
organic nutrients into energy for further reproduction. By creating an area of high
flow we then limit the bacteria’s ability to create this thick mat which will then
allow the bacterial growth to become efficient and diverse in its growth and
reproduction.
Interestingly enough, it’s thought that ancient cyanobacterial growth is
responsible for the creation of a large portion of the oxygen in the earth’s
atmosphere. The diversity of cyanobacteria is tremendous and its origins are
ancient. The fact that it can generate energy and building blocks through aerobic
and anaerobic processes makes it a formidable foe and hardy life form in a nutrient
rich reef tank.
Animals that will consume cyanobacteria: Most animals that live
within a sand bed are well suited for consumption of cyanobacteria. There is a
spectacularly long list of micro and macro fauna that will live within a sand bed
and consume cyanobacteria. If we are intending to specifically add animals that
will consume this nuisance, and keep its growth in check, than nearly all
omnivorous snails or hermits will be well suited. There are also a number of
animals that will live within a sand bed and continually keep it stirred as they
forage for food. Even if they don’t directly feed on the cyano, their activity within
the sand bed will continually disrupt the cyano's attempts at creating a gelatinous
anaerobic layer. For that purpose, animals like sand-sifting gobies, nassarius snails,
and fighting conchs work spectacularly.
Below is a list of resources for further learning. The first link has a superb amount
of attached articles which go into great detail on the taxonomy, metabolic
processes, and history of cyanobacteria (I give it an A+).
http://www.experiencefestival.com/cyanobacteria
http://hubpages.com/hub/Cyanobacteria
http://netclub.athiel.com/cyano/cyanos2.htm
Dinoflagellates
Physical description: Dinoflagellates (dinos) can be a significant menace
and can be extremely difficult to
manage. Many reefers have admitted
defeat and completely taken down tanks
due to dinoflagellate infestation. There
are literally hundreds of species of
dinos; some of which are photosynthetic
and others not. Dinoflagellates are
actually a flagellate species of plankton.
The huge diversity of dinos makes it
difficult to describe them in general terms. The most commonly seen species of
dinos in reef aquaria often exhibit as a mat of stringy slime with a significant
amount of bubbles coming from it. It is often brown in color but some species will
be green, yellow, or rust colored. They often exhibit physical characteristics similar
to cyanobacteria, other types of bacterial overgrowth, or diatoms.
Dinoflagellates are notorious for releasing toxins that can be lethal to snails
and other inverts that might consume them. Because dinos are so similar to other
species of “nuisance growths” we see in our reef tanks, one telling factor, though a
detrimental occurrence, is to observe the reaction of snails as they consume the
growth. If the animals become very slow moving, lethargic and die then it’s pretty
telling that you’re likely dealing with dinos. Snails and hermits will not react
negatively when they consume other similar looking growth like cyano or diatoms.
Best means of control: Looking for animals that will safely consume dinos
is not a good plan of treatment. I’m not aware of any species of animals that will
consume dinos and not die or become significantly ill afterwards.
As with any other type of nuisance algae or algae-like growth a great means
of treatment is limiting the nutrients that will fuel their growth. Decreasing nitrate,
phosphate, and other organic
nutrients will be a very
helpful aid in limiting the
proliferation of dinos.
Raising pH may also
be helpful in battling dinos.
I’m not aware that there has
been a definite identification
of the types of dinos we
encounter in reef aquariums,
therefore looking at the
specific physiology and
metabolic processes can only
be discussed in general terms
and our attempt at targeting specific species metabolic processes is still limited at
this point. It has been noted by several aquarists battling dinos that an elevation of
pH above 8.4 can be helpful in decreasing their proliferation rates. One thought in
regards to this process is that an elevated pH is often commonly related to a
lowered carbon dioxide level in the reef tank (carbon dioxide will drive pH down).
Coincidently it may not be the elevated pH that limits the growth of dinos, but it
may be the coincidental decrease in carbon dioxide (resulting in a higher pH) that
limit’s the growth of dinos. The dinos are dependent on a carbon source for
proliferation (commonly extracted from a carbon dioxide molecule). Not
commonly thought of as an organic nutrient, but a carbon dioxide molecule can be
broken down by many species of bacteria and other organisms to utilize the carbon
molecule in their metabolic processes. In general, limiting carbon dioxide in a reef
tank can be beneficial for many reasons.
Increasing the use of ozone injection, adding more phosphate absorbing
media, and increasing amounts of GAC (granular
activated carbon) can be very helpful in several
ways. Ozone can break down the toxins produced
by the dinos and GAC can adsorb the toxins as
well as adsorb the molecules that the toxins are
broken down into. In addition, ozone injection,
use of GAC, and use of phosphate binders can
limit the available organic nutrients available to
the dinos.
Mechanical removal can be a helpful means of
managing dinos. Many people will siphon dinos
off the sand bed or remove and scrub the rockwork that they’re growing on.
Manual removal of dinos is a means of nutrient export and a method of directly
removing the animal and the toxins it produces. Manual removal is only a simple
method of growth limitation and the true cure needs to come from limiting the
nutrients that are driving their growth.
Since dinoflagellates are photosynthetic, limiting the photoperiod can be
helpful as this limits their ability to create energy and their ability to utilize
nutrients through photosynthesis. Although this single intervention will not cure
the problem, it will be an asset in helping you win that battle as you implement
other interventions.
Animals that will consume dinoflagellates: I’m unaware of any
literature indicating any specific animals that will readily consume dinoflagellates
and not become ill or die after consumption.
Further information on dinoflagellates can be found in the links below:
http://www.reefkeeping.com/issues/2006-11/rhf/index.php#1
http://reefkeeping.com/issues/2005-05/eb/index.php
http://www.reefs.org/library/article/t_crail.html
http://www.geo.ucalgary.ca/~macrae/palynology/dinoflagellates/dinoflagellates.ht
ml
I hope this information was helpful. If you have further questions please don’t
hesitate to start a discussion thread and we‘ll all do our best to clarify and discuss
the topic further. All of the information written in this article was supported by the
articles I linked to below each topic. There are many views and opinions on
various reefkeeping topics and my intentions were to provide only facts supported
by literature written by respectable authors.
Written 8/2/10
Author: Jeremy Linzmaier