Cyanobacteria, li�le-known but common in aquarium 1 All rights reserved: ©José María Cid 2014

Cyanobacteria, li�le-known but common in

aquarium

Text & photos: José María Cid Ruiz

When it was discovered the dis!nc!on between prokaryo!c

cell (cell without nucleus) and eukaryo!c (cell with nucleus), it

was found that the living organisms currently called

"cyanobacteria" were not true algae. Cyanobacteria are in

fact, the only prokaryo�c organisms capable to do oxigénic

photosynthesis1.

Main features of cyanobacteria

Cyanobacteria (badly named "green-blue algae") are unicellular

organisms. They are able to perform photosynthesis and there-

fore synthesize their own food (autotrophs). Like the true algae,

cyanobacteria have chlorophyll and also a set of secondary pig-

ments: phycocyanin, alophycocyanin (blue pigment) and phy-

coerythrin (red pigment). These last pigments, have the func!on

of capturing energy from the light that is then absorbed by the

chlorophyll-a. All of these photosynthe!c compounds are not

enclosed in membranes by way of chloroplasts (as in true algae),

are sca#ered in the protoplasm of the cell. Cyanobacteria have

cell wall surrounded by a mucilaginous layer (viscose) composed

of mucopolysaccharides and pec!nics acids. The protoplasm of

cyanobacteria presents among other organelles: ribosomes, va-

cuoles, granules of poliglucanos and cianoficina.

Different gene!c studies performed with this group have deter-

mined that they are bacteria type Gram-nega!ve.

Many species of cyanobacteria present a mixed metabolism. They, not only are able to ge-

nerate organic compounds through photosynthesis, also can fix atmospheric nitrogen (N2)

dissolved in the water. This last process is performed by cyanobacteria using an enzyme

which breaks the molecule of the gas nitrogen and forms ammonium (NH4+), which is al-

ready directly metabolized as food. Both processes are incompa!ble simultaneously (the

enzyme used in nitrogen fixa!on is inhibited in the presence of oxygen), therefore cyano-

bacteria carry out photosynthesis during the day and fixa!on of nitrogen by night.

Cyanobacteria have played a key role in how life evolved on Earth, given that they belong to

the original group of living organisms, responsible for the massive presence of oxygen in the

Earth's atmosphere.

own

are in

do oxigénic

ed "green-blue algae") are unicellular

able to perform photosynthesis and theheheheheherererererere-----

their own food (autotrophs). Like the trtrtrtrtrtrueueueueueue alglglglglglgaeaeaeaeaeae,

teriririria a a a a a hahahahahave chlorophyll and also a seseseseseset t t t t t ofofofofofof s sececececececonononononondadadadadadaryryry p p p p p pigigigigigig-

s: phyhyhyhyhyhycococococococycycycycycyananananananinininininin, alophycocyanin (blueueueueueue p p p p p pigigigigigigmememememementntntntnt) ) ) ) ) anananananand d d d d d phphphphphphy-y-

coerythrin ( ( ( ( ( (rererererered d d d d d pipipipipipigmgmgmgmgmgmenenenenenent)t). ThThesese e lalastst pigmememememementntntntntnts,s,s,s, h h h h h havavavavavave ththththththe func!on

of capturing e e e e e enenenenenenergrgrgrgrgrgy y y y y y frfrfrfrfrfromomomomomom t t t t t thehehehehe light thahat t t is thehehehehehen n n n n ababababababsorbed by the

lorophyll-a. A A A A A Allllllllll o o o o o of f f f ththththththesesesesesese e e e e e phphphphphphototototototososososososynthe!e!c compounds are not

osed in memembmbmbmbmbmbrarararararanenenenenenes s s s s s bybybybybyby w w w w w wayayayayayay of f f f f f chchchchchchlororoplasts (as in true algae),

a#ereded in the e e e e e prprprototototototopopopopopoplalalalalalasmsmsmsmsmsm o o o o o of f f f f f ththththe cecececececellllllllllll. Cyanobacteria have

surrrrounded b b b b by a a a a a a mumumumumumucicicicicicilalalalalalagigigigigiginononousususususususus l l l l l layayayayayayer ( ( ( ( (viviviviviviscscscscscscososose) composed

ysysysacaccharidideseseseseses andndndndndnd pecececececec!n!n!n!n!n!nicicicicicics acids.s.s.s.s.s. T T T T T Thehehehehehe prototototototoplplplplplplasm of

prpresesenentstststs a a a a amomomomomomongngng othththththther o o o o o orgrgrgrgrgrganelles: ribibibibibososososososomes, va-

of poliglglglglglucucucucucucananananananos andndndndndnd c c c c c cianonononoficficficficficficina.

udies pepepepepeperforororororormed withththththth t t t t t thihihihihihis grou

bacteriaiaiaiaiaia typypypypypype Gram-nega!v

Many species of cyanob

nerate organic com

dissolved in t

which br

read

Cyanobacteria, li�le-known but common in aquarium 2 All rights reserved: ©José María Cid 2014

Cyanobacteria in the aquarium

An organism that is able to survive during the day with a li!le bit

of light and that s"ll feeding at night with nitrogen from the at-

mosphere (nitrogen dissolved in the water), does not seem to

need much addi"onal help to se!le in an aqua"c environment as

it is a freshwater or marine aquarium. They are in fact almost

always present although not detect them at a glance. The pro-

blem comes, when in the aquarium there is a significant imbalan-

ce by excess of energy: chemical (excess of organic carbon, nitra-

tes, phosphates, silicates) or light (excess of luminous radia"on).

In marine aquariums for example, in a natural process of

"maturing", we would observe as some surfaces and especially

the substrate is moderately colonized by a so$ mono-layer of

brownish algae, due to ini"al coloniza"on by diatoms2 (these al-

gae does not present great requirements in terms of the level of

luminous radia"on and take advantage of the silicon available in

the aquarium’s water for its incorpora"on into their cell walls). In

a balanced aquarium, the situa"on would be stabilized in a few

weeks. On the contrary, if the energy sources men"oned above

abound, a second wave of cyanobacteria (and later or simulta-

neously another of filamentous green algae) will be developed.

Cyanobacteria are able to firmly be a!ached to virtually any surfa-

ce inside the aquarium (including living "ssue). There they grow,

are reproduced and produce extracellular polymers from each

single cell to the fixing surface. Over "me, they will form a consis-

tent layer like a microbiological structure ("biofilm"). This structu-

re is the "greenish or brownish film" we are accustomed to

seeing on the substrate, plants or rocks in aquariums with high

levels of pollu"on and unbalanced in its energy balance.

It is not always easy to determine that groups or species cons"tute the "biological pollu"on"

of an aquarium. O$en bacteria, cyanobacteria and "true algae", share the invasion and the

complex tapestry that can cover the sand at the bo!om, the rocks on the substrate, "ssue of

corals and sponges and even colonize the body of fishes like seahorses (Hippocampus spp).

As a general rule, not rigorous, can be considered that the viscous layers of reddish, brownish

or black shades correspond to cyanobacteria (though the same species may have different

appearances under different ligh"ng spectra or nutrients), while arborescent appearance in

greenish layers typically correspond to invasions of filamentous algae, where are frequent

genus Debersia and Bryopsis, which in turn are not easy to differen#ate from cyanobacteria

of the genus Lyngbya.

pro-

cant imbalan-

nic carbon, nitra-

f luminous radia"on).

, in a natural process of

ve as some surfaces and especiallylylylylyly

ately colonized by a so$ mono-layer of

due to ini"al coloniza"on by diatoms2

(t(t(t(t(t(thehehehehehesesesesesesese a a a a a al-l-l-l-l-l-

present great requirements in terms o o o o o of f f f f f ththththththe e e e e e lelelelelelevevevevevevel ofofofofofof

usususususus r radia"on and take advantage o o o o o of f f f f f ththththththe e e e e e sisisisisisililicocococococon n n n n avavavavavavaiaiaiailalalalalalablblblblblble e e e ininin

e aquauauauauauaririririririumumumumumum’s’s’s’s’s’s water for its incorpopopopopoporararararara"o"o"o"o"o"on n n n n n inininininintotototototo t t t t t theheheheheheiriririririr c c c c c celelelelelell l l l l l walls)s)s)s)s)s). In

a balalancncncncncncedededededed a a a a a aququququququarararararariuiuiuiuiuium, the situa"on wowowowowowoululululululd d d bebebebebebe s s s s s statatatatatabibibibibibililililililized in a few

weeks. O O O O O On n n n n ththththththe e e e e e cocococococontntntntntntrararararararyryryryryry, if the enenergrgrgy sosososososoururururururcececes s s s s men"oned above

abound, a sesesesesesecocococococondndndndndndnd w w w w w wavavavavavave ofofofofofof cyanobabactcteria (and later or simulta-

neously ananototototototheheheheheher r r r r r ofofofofofof fi fi fi fi fi filalalalalalamememememementouououououous s s s s s greeeen algae) will be developed.

anobacacteria arararararare abababababablelelelelele to o o o o o firfirfirfirfirfirmlmlmlmlmlmly y y y y y bebe a!a!a!a!a!a!achchchchchched to virtually any surfa-

ide e the aquauauauauauariumumumumumum (ininininininclclududududududinining lililililivivivivivivingngngngngng " "ssueueueueueue).).).).).). T T T T T There they grow,

ododucuced andndndndndnd prorororororodududucececececece extxtxtxtxtxtrarararararacellular p p p p p pololololololymymymymymymerererererers s s from each

to thehe fi fi fi fixixixixixixingngngngngng sururururururfacecece. OvOverererererer " " "me, they will form a

e a microbobobobobobiolololololological ststststststrurururururucturururururure ("biofilm") Th

ish or b b b b b brownwnwnwnwnwnish filmlmlmlmlmlm" " " " " wewewewewewe are acc

bstrate,e,e,e,e,e, plalalalalalants or rocks in aq

and ununununununbabababababalanced in

It is not always

of an aqua

comp

Cyanobacteria, li�le-known but common in aquarium 3 All rights reserved: ©José María Cid 2014

Also, in presence of silicon in excess, a tapestry of diatoms (true

algae) may be cons!tuted and replace and "bury" a first coloniza!-

on of cyanobacteria. Some!mes the scenario is complicated furt-

her, when together with cyanobacteria and diatoms, is confirmed

under the microscope the massive presence in the water of the

aquarium of pelagic algae (dinoflagellates). The la�er are more

difficult to control than the groups men!oned before, given that

not required for survival or nitrogen or phosphorus. They survive

simply with the calcium carbonate from seawater.

How to control its massive expansion in the aquarium?

The first ques!on would be: how to control the "what"?. As we saw

in the previous sec!on is not always easy to know what we're dea-

ling and frequently the invasive biofilm not always corresponds to

a single group of organisms. When set up plans to deal with a mas-

sive coloniza!on, we should know whether we face a "plant" a

"bacteria", a "dinoflagellate" or several of them simultaneously. A

good way to start the diagnosis is to inves!gate which is the source

of uncontrolled energy. For example, if we find high levels of silica-

tes (levels ≥ 0.2 mg / are able to trigger massive coloniza!on) we

may suspect that we are facing with a coloniza!on of diatoms. Al-

though in this case, it should be measured not only the level of

silicates in the aquarium’s water but also measure the same para-

meter in the freshwater used. This recommenda!on is because the

diatoms incorporate very quickly the silicon available in the aqua-

rium water and some!mes the level of silicates in the aquarium is

not alarming but the fresh water used to replenish the evaporated

water or the sea salts used to make marine water present meaning-

ful levels of silicates

Let's see now, some ac!ons to control this type of "pests" in aquarium :

Eliminate zones prone to be colonized changing its condi!ons. It is generally observed that the

areas of the aquarium with void or weak stream of water show accumula!on of detritus and

are the anchor points of coloniza!on, especially if those areas are exposed to strong light. Ge-

nerate moderate water flows in every corner where usually accumulate organic debris will

hinder the establishment of the first colonies in these vulnerable areas.

If pests are developed usually in an aquarium that has an efficient filtra%on system, we should

stake out a reduc!on in the number of specimens maintained (biomass) and / or in the quan!-

!es of supplied food and see if the tank is stabilized at lower energe!c levels.

at

survive

on in the aquarium?

e: how to control the "what"?. As we sawawawawawaw

on is not always easy to know what we'rererererere d d d d d deaeaeaeaeaeaea------

tly the invasive biofilm not always corrrrrrrrrrrresesesesesespopopopopopondndndndndnds s s s s totototototo

upupupupupup of organisms. When set up plansnsnsnsnsns t t t t t to o o o o o dedededededealalalalalal witititititith h a a mamamamamamas-s-s-s-s-

oloniziziziziziza!a!a!a!a!a!onononononon, we should know wheththththththerererererer w w w w w we e e e e e fafafafafafacececececece a a a a a " "plplplplplplanananananant"t"t"t"t"t" a

"bacteria"a"a"a"a"a", a a a a a a "d"d"d"d"d"dininininininofloflofloflofloflagagagagagagellate" or severalalalal o o o o of f f ththththththemememememem s s s simimimimimimulululululultatatatatataneously. A

good way t t t t t to o o o o o ststststststarararararart t t t t t ththththththe e e e e e didididididiagagagagagagnosis isis t to o inves!s!s!s!s!s!gagagagagagatetetetetete w w w w w which is the source

of uncontrolleleleleleled d d d d d enenenenenenererererererergygygygygygy. . . . FoFoFoFoFoFor r r r r r exexexexexample, i if f we fi fi fi fi fi findndndndndnd high levels of silica-

(levels ≥ 0.0.0.2 2 2 2 2 2 mgmgmgmgmgmg / / / / / / arererererere a a ablblblblblble totototototo t t t t triggerer massive coloniza!on) we

suspecect t thatatatatatat we e e e e e arararararare e e e e e fafafafafafacicicicingngngngngng withththththth a a a a a a coloniza!on of diatoms. Al-

in ththis case,e,e,e,e,e, it shshshshshshououououououldld bebebebebebe m m m m meaeaeaeaeaeaeaeasusurered d d d d d nonononononot only the level of

n ththe aquauaririririririumumumumumum’s’s w w w w w watatatatataterererererer b b b b but alslslslslslso o o o o o mememememeasururure e e e e e e ththththththe same para-

he f frereshwateteteteteter ususususususededed. ThThThThThThis r r r r r rececececececommendndndndndnda!a!a!a!a!a!onononononon i i i i i is s s s s s because th

rporate veveveveveveryryryryryry quiuiuiuiuiuickly t t t t t thehehehehehe sililililililicicicicicicon available in the aq

some!m!m!m!m!m!mes t t t t t thehehe levelelelelelel o o o o o of sililililililicacacacacacates in the a

he freshshshshshsh watatatatatater used totototototo replenish

ts used d d d d d to m m m m m make marine w

Let's see now, some ac!ons

Eliminate zones pron

areas of the aqu

are the an

nera

Cyanobacteria, li�le-known but common in aquarium 4 All rights reserved: ©José María Cid 2014

Few measures are more effec"ve in the control of "biological

pollu"on" of the aquarium, as a maintenance protocol that in-

cludes frequent par"al renewals of water. In marine aquariums

is recommended renewals of wáter between 15 and 20%

weekly, which in the case of freshwater aquariums can be bet-

ween 30 and 50%, depending on the level of biomass maintai-

ned.

If you have no inten"on of cleaning mechanical filters two or

three "mes a week, do not put . The opposite is just accumulate

organic detritus in an area of high flow of well oxygenated wa-

ter and thus enhance the nitrifica"on at maximum level. The

same basic argument, serves to recommend make the greatest

possible effort in acquiring the best "skimmer" and the best an"-

phosphates resines.

Management of the pest through the ligh"ng, if it is of cyano-

bacteria, a useful thought is remember that "invasive" species is

not a plant and that it may even prefer coloniza"on zones that

are not the most intensely lit. However, it is demonstrated its

affinity for the orange-red region of the spectrum, ie the longer

wavelengths of the visible spectrum. This should lead us to take

two decisions: First, we should use lamps which radiated energy

is focused more towards the "blue" spectrum (λ between 450

and 300 nm), which would match lamps characterised by an co-

lor temperatures of 8000 to 10000 K for marine aquariums. In

freshwater aquariums, not opt for lamps below 6000 K. Secon-

dly, not delay in excess the replacement of the lamps with new

ones, given that in some technologies (fluorescent especially),

the old lamps show its radiated spectrum shi*s towards the

"red".

In all types of pests, a good op"on is always the physical elimina"on of the colonies, whenever

we keep in mind that "remove" isn't the same than " to move". We must catch and remove qui-

ckly outside the aquarium, great por"ons of invasive tapestry. We must therefore, not simply

shake it and transport it to the circula"ng water column, because in this case we only make that

empowerment the capability of the “pest” for invading new areas of the aquarium

In the case of an invasion of pelagic algae (dinoflagellates), where the dras"c reduc"on of nitra-

tes and phosphates, as already referred, does not resolve the problem, the use of UV-C lamps

and ozonators are preferable op"ons.

In the case of benthic algae, most algaecides are using as ac"ve principles, copper or potassium

permanganate.

The use of an"bio"cs in the case of cyanobacteria, is known that it can be effec"ve (due to its

condi"on of gram-nega"ve bacteria), but carries the danger that a dose not enough high, could

lead to develop an strain resistant to the an"bio"cs used. On the other hand, have to take into

account, that the recommendable an"bio"cs are broad-spectrum and therefore also eliminated

the nitrifying bacteria beds (Nitrosomonas and Nitrobacter) in our aquarium.

own bubububut

ers two or

is just accumulate

f well oxygenated wa-

on at maximum level. The

to recommend make the greatest

ing the best "skimmer" and the best anananananan""""""-

.

ntntntntntnt of the pest through the ligh"ngngngngngng, ifififififif i i i i i it t t t t t isisisisisis o o o o o of f cycycycycycyanananananano-o-o-o-o-o-

ia, a ususususususefefefefefefulululululul thought is remember t t t t t thahahahahahat t t "i"i"i"i"i"invnvnvnvnvnvasasasasasasivivivivivive"e"e"e"e"e" s s s s s spepepepepepecicicicicicieseseseseses is

not a planananananant t t t t t anananananand d d d d d ththththththatatatatatat i i i i i it t t may even prefer cocococococololololololoninininininizazazazazaza"o"o"o"o"o"on n n n n n zozozozozozonenenenenenes that

are not the momomomomomostststststst i i i i i intntntntntntenenenenenenseseseseseselylylylylyly lit. Howewevever, it isisisisisis d d d d d dememememememononononononstrated its

affinity for thehehehehehe orarararararangngngngngngngeeeeee-rererererered d d d d d rerererereregigigigigigion of the e spectrum, ie the longer

velengths ofof t t t t t thehehehehehe v visisisisisisibibibibibiblelelelelele s s s spepepepepepectctctctctctrurururururum. ThThis should lead us to take

decisionons: Firsrsrsrsrsrst, w w w w w we shshshshshshououououououldldldldldld u u u u u use lamamamamamampspspspspsps which radiated energy

ed m more towawawawawawardrdrdrdrdrds s s s ththththththe e e e e e "b"b"b"b"b"blulululululue"e"e"e"e" s s s s s s s s s spepepepepepectrurururum m m m m m ((((((λ between 450

nmnm),),), which w w w w w wouldldldldldld matatatatatatchchchchchch l l l l l lamamamamamps c c c c c chahahahahahararacterisisisisisisisedededededed by an co-

urureses of 80000000000000 totototototo 1 1 1000000000000000000000000 K K K K K K f f f f f foror marine aqaqaqaqaqaquauauauauauaririririririums. In

ariums, nonononononot opopopopopopt for lalalalalalamps s s s s s bebebebebebelow 6000 K. Seco

excess thehehehehehe repepepepepeplacemememememementntntntntnt of ththththththe lamps wi

some tetetetetetechnonononononologies (flufluflufluflufluorescent

ts radiaiaiaiaiaiated d d d d d spectrum shi*s

InInInInInIn all typeseseseseses o o o o of f f f f pepepepestststs,s,s, a a a a a g g g g g gooooooooood d d d op"on is always the ph

we keeeep p ininininininininin m minininind d d d thththatatatatat "remove" isn't the same

ckly outsisidede t thehehehe aquarium, great por"o

shake it and transport it to the cir

empowerment the capability

In the case of an in

tes and phosph

and ozon

In

Cyanobacteria, li�le-known but common in aquarium 5 All rights reserved: ©José María Cid 2014

Erythromycin and Tetracycline are the most frequently used

an!bio!cs in these cases. It is obtained good results by provi-

ding a single dose of 200mg /40l and proceed two days post to

change at least 50% of the aquarium water. Others alterna!ve

treatments described in the literature using hydrogen peroxide

(3%) at a dose of 40g / 50l.

In general it’s observed that cyanobacteria have a behavior in

the aquarium, which could be described as a "vital hysteresis"

in rela!on to the source of energy (food) that made them ap-

pear, in the sense that a once well established, even if the

"s!mulus" disappears (the food source is eliminated almost

completely ), they will remain alive and even their colony may

grow. Against this background somewhat disturbing a final

conclusion seems we are able to extract: in terms of cyanobac-

teria, "be$er safe than sorry".©

For more informa�on or to contact the author : www.aqua�cnotes.com

Notes:

Note1: Oxygenic photosynthesis is the most widespread type of photosynt-

hesis in nature. In this modality water acts as the primary electron donor,

releasing oxygen (O2). There are other photosynthe!c organisms among

bacteria and archaebacteria but develop other types of photosynthesis, in

which the electron donor compound could be an sulfide or hydrogen ins-

tead of water.

Note2: Some authors (Stock & Ward, 1989) found that bacteria are really

the first se"lers of the substrate followed rapidly by the appearance of a

mono-layer of diatoms. Coloniza#on culminates with the appearance of

filamentous green algae a"ached to the framework of bacteria, cyanobac-

teria and diatoms.

Works cited

Welsh,DT (1994), “Microbial Mats: structure, development..”, NATO Series G,E. Sciences VOl 35

Nielsen LP et al (1994), “Denitrifica#on, nitrifica#on, and nitrogen assimila#on in photosynthe#c micro-

bial mats”, LJP Caume"e (eds)

Gamble S. (2002), “Algae Curse: a new view”, F.A.M.A magazine 2002-07

sis"

them ap-

even if the

liminated almost

nd even their colony may

somewhat disturbing a final

able to extract: in terms of cyanobac-

n sosososososorry".©

orma�on or to cocococococontntntntntntacacacacacact t t t t t ththththththe e e e auauauauauauththththththorororororor : www.aqua�a�a�cnoteseseseseses.c.c.c.c.c.comomomomomom

hotosynthehesis is t t t t t the m m m m m mosososososost t t t t t wiwiwiwiwiwidedededededespspspspspsprerererereread typypypypypype e e e e e of photosynt-

modalality wateteteteteter r r r r r actstststststs as ththththththe e prprprprprprimarararararary y y y y y y y y elelelectronononononon d d d d d dononor,

herere are other p p p p p phototototototosyntntntntntnthehehehehehe!c!c!c!c!c!c o organisisisisisismsmsmsmsmsms a among

bubut develop p p p p p otheheheheheher tytytypepepepepepes s s s s s of p p p p p phohohohohohotosynthehehehehehesisisisisisis,s,s,s,s,s, in

pounund d cocococoulululululd d d d d d be a a a a a an sulfilfilfidededededede or hyhyhyhyhyhydrogen ins-

rd, 1989) fofofofofofound d d d d d that bacteteteteteriririririria a a a a a arararararare really

owed rapapapapapapididididididly b b b b b by y y y the appearance of

lminateseseseseses witititititith h the appearan

ameweweweweweworork k of bacte

obial Mats: structure, developme

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