136
"
«
'
,
.
_
,
on the other
the
…
“types, grow in gOOd'light iri situations devoid of plant life and give
the! same benefits as the
although ona less‘er Jscale‘.
TheyÏare especially useful in marine en-“Vironments because of». the
“usual lack of higherplant life. They also form an
part
of
the diet of mariÿ fishes. Algae must, however, be kept in check and '
,,
limited to a useful function only. ln freshwater environments, strong
_
algal growth“ can smother plants, which die as a result of blocked leaf
»por€s and poor light. Similarlÿ, gravels are grown over and become
"
-
Small light-dependent organisms called Zooxanthellae are present
_
-
inside many marine filter feeders, and their well—being, and thus that
‘
of-‘their hosts, depends on their living in properly-‘iliuminated
Ï
_
surr0ùndings… This fact is well illustrated by the observation that in
'
dim lighting the host creatures lose their natural colouration and.
become pale, often acquiring algal growth, a condition which is a
sure sign of ill health. Light has
influence in all natural
‘
«systems because of the inclusion in these environments of light‘
'
dependent organisms. Theré—fore the remarksÏ—made elsewhere onthis
'subject (p.16) and the methods of application recommendedm—ust
…
be pai*ticularlynoted.
>
,,
—
Ï
There are a_ feW techniques coïnmolyused by aqüarists in natural
?
systems which help to keep the level of toxic materials below that
which the available nitrify'ing bacteria can deal with.
might be conSidered ‘cheating’ by some, but, anything î"WhlCh im.
pfoves the inhabitants’ way of
and as long as:th€ reason
_
,
for their use is understood and they are not detrimental they must
'
‘
surely be used. In many ehvif‘0nmehts the aquarist
changes part of the water to reduce the toxic Content.
added should be mature and“ similar in Character to
'
being replaced. Mechanical—filters may also be used, either temporar-,
…
Ÿily or permanently td remove'swiihg—debñs, Which may f never
Settle as a result of turbulence—f."«‘Pe‘riodic‘sipho‘ningto remove mulm
.
and large pieces'of u—nèaten
cleaning
front glass
.
for good visibility are’
ÿTïhe uséof…a columnof
“air bubbles to .indüc‘e wlate’r movement
»”,
thermal stratication
the
1nfact ;
to some extent
sk1mmer1nbreak
…
ing up toxic wastes (see p. 45).
:?
r
‘
=
’
‘
The problem of uric ac}idiiS*Oe1nstance1n wh1ch thé]…hiarié
has an
thefreshwaterofiçä;f Freshwater
.}filshes exerete large quant1t1esofur1nebecausethe1rbod1eshavea
"
«
'
,
.
_
,
on the other
the
…
“types, grow in gOOd'light iri situations devoid of plant life and give
the! same benefits as the
although ona less‘er Jscale‘.
TheyÏare especially useful in marine en-“Vironments because of». the
“usual lack of higherplant life. They also form an
part
of
the diet of mariÿ fishes. Algae must, however, be kept in check and '
,,
limited to a useful function only. ln freshwater environments, strong
_
algal growth“ can smother plants, which die as a result of blocked leaf
»por€s and poor light. Similarlÿ, gravels are grown over and become
"
-
Small light-dependent organisms called Zooxanthellae are present
_
-
inside many marine filter feeders, and their well—being, and thus that
‘
of-‘their hosts, depends on their living in properly-‘iliuminated
Ï
_
surr0ùndings… This fact is well illustrated by the observation that in
'
dim lighting the host creatures lose their natural colouration and.
become pale, often acquiring algal growth, a condition which is a
sure sign of ill health. Light has
influence in all natural
‘
«systems because of the inclusion in these environments of light‘
'
dependent organisms. Theré—fore the remarksÏ—made elsewhere onthis
'subject (p.16) and the methods of application recommendedm—ust
…
be pai*ticularlynoted.
>
,,
—
Ï
There are a_ feW techniques coïnmolyused by aqüarists in natural
?
systems which help to keep the level of toxic materials below that
which the available nitrify'ing bacteria can deal with.
might be conSidered ‘cheating’ by some, but, anything î"WhlCh im.
pfoves the inhabitants’ way of
and as long as:th€ reason
_
,
for their use is understood and they are not detrimental they must
'
‘
surely be used. In many ehvif‘0nmehts the aquarist
changes part of the water to reduce the toxic Content.
added should be mature and“ similar in Character to
'
being replaced. Mechanical—filters may also be used, either temporar-,
…
Ÿily or permanently td remove'swiihg—debñs, Which may f never
Settle as a result of turbulence—f."«‘Pe‘riodic‘sipho‘ningto remove mulm
.
and large pieces'of u—nèaten
cleaning
front glass
.
for good visibility are’
ÿTïhe uséof…a columnof
“air bubbles to .indüc‘e wlate’r movement
»”,
thermal stratication
the
1nfact ;
to some extent
sk1mmer1nbreak
…
ing up toxic wastes (see p. 45).
:?
r
‘
=
’
‘
The problem of uric ac}idiiS*Oe1nstance1n wh1ch thé]…hiarié
has an
thefreshwaterofiçä;f Freshwater
.}filshes exerete large quant1t1esofur1nebecausethe1rbod1eshavea