in color among Ramicrusta sp. remains uncertain.
Ramicrusta sp. may be affected by its accessibility to light. The alga is purple on the underside of overgrown rubble pieces, while the alga
!"# $%&'()# $'# *+)# ,!(+*# )-.$")/# "!/)# $0# $1)%(%$2'#
%344,)5#6+)#7$'*%&7*!$'#$%#)-.&'"!$'#$0#7+,$%$.,&"*"#
has been correlated with response to light stress 89!)0)%#:;<=>?#2+!7+#@&A#&77$3'*#0$%#*+)#&,($,$%#
change as the chloroplast change (Nugues et al.
BCCD>5# Ramicrusta sp. color may be dependent on the amount of available light for the alga to use.
It is important to study Ramicrusta sp. since it is causing coral death in Lac Bay. A better understanding of the alga’s ecology could lead to control of the alga in the future. This research will determine if there is a difference in color of Ramicrusta sp. among
*+%))#7$%&,#".)7!)"#&'/#)-&@!')"#0&7*$%"#*+&*#@&A#4)#
causing the changes. The main objectives are:
:>#6$# /)*)%@!')# *+)#.)%7)'*#$0# 7$,$'!)"#$0#M.
complanata, M. annularis and P. astreoides that are greater than 80% purple, a gradient between purple and orange, or greater than 80% orange to assess the relationship of Ramicrusta sp. color and species 4)!'(#$1)%(%$2'#!'#*+)#E),/5
B>#F)*)%@!')#!0#7$,$%#7+&'()#!'#Ramicrusta sp.
7&'# 4)# !'/37)/# !'# *+)# E),/# 4A# 7+&'(!'(# )-.$"3%)#
level of sunlight.
=>#F)*)%@!')#!0#7$,$%#7+&'()#$0#Ramicrusta sp.
can be induced in the lab using the watersoluble metabolites of M. complanata metabolites.
Materials and methods
Lac Bay is located on the southwestern side of Bonaire in the Caribbean Sea. The reef crest is along the border of the bay and the open sea, creating a reef barrier between the incoming waves and the shore. Along the reef crest, there are patches of coral growth that stretch inland towards the shores.
In these patches were where the Ramicrusta sp.
overgrowth was most noticeable and where the study was conducted.
To determine if Ramicrusta sp. color was /).)'/)'*# $'# 7$%&,# ".)7!)"?# :=# *%&'")7*"# 2)%)#
conducted and analyzed to determine if the color of Ramicrusta#".5#!"#/!00)%)'*#$'#=#".)7!)"#$0#7$%&,#*+&*#
are being overgrown: M. complanata, M. annularis and P. astreoides (H1>. GPS points were selected 3"!'(#G$$(,)#H&%*+#0$%#*+)#E),/#"3%1)A#$0#*+)#7$,$%"#
of Ramicrusta sp. on the different coral species 8I!(5:>5#6%&'")7*"#+&/#*$#4)#&*#,)&"*#BC#@#,$'(#&'/#
ran southeast towards reef crest from the GPS point.
If the corals had Ramicrusta sp. overgrowth present, the color of the Ramicrusta ".5#2$3,/#4)#7,&""!E)/#
$%&'()# 8JKCL# $%&'()>?# (%&/!)'*# 84)*2))'# KCL#
$%&'()# &'/# KCL# .3%.,)># &'/# .3%.,)# 8JKCL>5# M'#
&'&,A"!"#$0#1&%!&'7)#8MNOPM?#QRC5CS>#2&"#3")/#*$#
7$@.&%)#*+)#.%$.$%*!$'"#$0#7$,$%#&@$'(#*+)#=#7$%&,#
species.
To determine if Ramicrusta sp. color was affected by light, 12 pieces of rubble overgrown with Ramicrusta sp. were chosen from a rubble patch. All rubble pieces had to have an orange
*$."!/)# &'/# .3%.,)# 3'/)%"!/)5# T!-# %&'/$@# %344,)#
.!)7)"# 2)%)# "),)7*)/# &'/# /)"!('&*)/# *$# 4)# U!..)/#
.3%.,)#"!/)#3.#8I!(5#B>5#6+)#%)@&!'!'(#%344,)#2)%)#
placed orange side up. The rubble pieces were zip tied to scuba weights to prevent movement of rubble 8I!(5#B>5#V344,)#.!)7)"#2)%)#.,&7)/#$'#&#"&'/#.&*7+#
')&%#*+)#%))0#&'/#%)@&!')/#!'#*+)#E),/#0$%#B#2))W"5#
Each week the rubble was visited to inspect for 7$,$%#7+&'()5#X*#2&"#+A.$*+)"!Y)/#*+&*#!0#*+)#U!..)/#
rubble does not change, then the color change is not
&00)7*)/#4A#7+&'(!'(#"3',!(+*#)-.$"3%)5
6$# E'/# $3*# !0# Ramicrusta sp. was affected by M. complanata metabolites (H=># .,&"*!7# 4&("# 2)%)#
placed over the M. complanata for 2 hours as to collect the metabolites in the water surrounding the M. complanata colony. Twelve pieces of rubble with Ramicrusta sp. overgrowth were collected and separated into three groups. One group was
!@@)%")/#!'#(,&""#4$2,"#E,,)/#2!*+#2&*)%#7$,,)7*)/#
from M. complanata with no dilution. The other group was immersed in a 50% dilution of the collected water. The remaining group was immersed in regular seawater collected at the same site. Bowls 2)%)#E,,)/#2!*+#&#@!'!@3@#$0#DCC#@Z#$0#")&2&*)%?#
covered and maintained in the lab for 10 d.
All data was collected over 5 wk period from early October through early November 2010. To analyze Ramicrusta sp. color on coral species, ANOVA was used to compare the differences in
*+)#@)&'"5#X0#*+)#MNOPM#2&"#"!('!E7&'*?#63W)A["#
\ZTF# *)"*# 2&"# 3")/# *$# /)*)%@!')# *+)# ".)7!E7#
differences of the means between each coral species.
! Fig. 1#X@&()#$0#"*3/A#"!*)#&'/#:=#*%&'")7*"#$'#Z&7#
]&A?#]$'&!%)#8G$$(,)#H&%*+#BC:C>
<D
To analyze Ramicrusta sp. color change to sunlight
!"#$%&'!()(*+$,*)-.!/(*,*!%*(+)%(&%!/(*$(/!*!'0-1!(
*2!(3)'-)14!($5(*2!(0!)1%(6!*+!!1(7-##!/()1/(1$1, 7-##!/('&66.!(#-!4!%8(92!()1).:%-%($5(*2!(0!)1%($5(
Ramicrusta sp. color change in the presence of M.
complanata metabolites used an ANOVA. If the
;<=>;(*!%*(+)%(%-?1-@4)1*A(9&B!:C%(DEFG(*!%*(+)%(
#!'5$'0!/( *$( /!*!'0-1!( *2!( %#!4-@4( /-55!'!14!%( -1(
the means between metabolites concentrations.
Results
Field observations
;(*$*).($5(HIJ(4$').(4$.$1-!%(+!'!($6%!'3!/8(=5(*2!(
total colonies observed 546 were M. complanata, KI( M. annularisA( )1/( ILK( P. astreoides. Purple Ramicrusta sp. overgrowth was observed most on M.
complanata(4$.$1-!%(MHN8OPQA(+2!'!)%(?')/-!1*()1/(
$')1?!($3!'?'$+*2()**'-6&*!/(5$'($1.:(K8RP(MS-?8(IQ8(
There were a few cases of orange alga overgrowth on M. complanata, but it was commonly observed on dead or bleaching M. complanata colonies and alga growth had completely overgrown the colony.
=5( *2!( KI( M. annularis colonies observed 86.0% had orange Ramicrusta sp. overgrowth, )1/( $1.:( T8IP( +!'!( $6%!'3!/( *$( 2)3!( #&'#.!( ).?)(
$3!'?'$+*2( MS-?8( IQ8( Ramicrusta sp. overgrowth normally occurred in the crevasses located at the top of the colony. Purple Ramicrusta sp. growth on M.
annularis was commonly observed in the shade of the colony at the base or in the crevasses. No M.
annularis colonies were observed to be completely overgrown.
Total observed P. astreoides colonies were similar to M. annularis in that orange Ramicrusta sp. overgrowth was observed more frequently. P.
astreoides with orange colored alga overgrowth attributed for 86.5% of the total colonies observed MS-?8(IQ8(=1.:(N8LP($5(*$*).($6%!'3!/(P. astreoides was found to have purple colored overgrowth. Purple and gradient alga overgrowth on P. astreoides was observed in areas with less availability to light.
The majority of purple Ramicrusta sp.
overgrowth occurred on M. complanata, while orange overgrowth occurred on M. annularis and P. asteroides8(;1(;<=>;(*!%*(MU(V(L8LWQ(4$1@'0!/(
*2!'!( +)%( )( %-?1-@4)1*( '!.)*-$1%2-#( 6!*+!!1( 4$').(
species and color of Ramicrusta sp. overgrowth (p <
L8LLNQ8((S&'*2!'0$'!A(9&B!:C%(DEFG(*!%*(-1/-4)*!/(
that the proportion of purple colonies was higher for M. complanata than M. annularis and P. astreoides M#(V(L8LLOQ8
Field experiment
;( @!./( !"#!'-0!1*( +)%( 4$1/&4*!/( -1( E)4( X):( $1(
12 rubble pieces with Ramicrusta sp. overgrowth to determine its '!)4*-$1( *$( .-?2*( !"#$%&'!8( =5( *2!(
6 Ramicrusta sp.( #-!4!%( *2)*( +!'!( 7-##!/( #&'#.!(
side up, 5 showed purple to orange color change.
92!($*2!'(R('&66.!(#-!4!%(*2)*(+!'!(1$1,7-##!/()1/(
remained orange side up showed no color change or other signs of disturbance to light. The results indicate that there is an effect of sunlight on color of Ramicrusta(%#(M#(V(L8LLIHWQ8(
Laboratory experiment
;(.)6$')*$':(!"#!'-0!1*(+)%(4$1/&4*!/(*$(/!*!'0-1!(
if M. complanata metabolites cause color change in 15 pieces of rubble with Ramicrusta sp. In 100%
concentration of the M. complanata water, 2 of the I('&66.!(#-!4!%(%2$+!/(%-?1%($5(4$.$'(42)1?!8(F0)..(
portions of the rubble changed from orange to a light purple color, but not to a deep purple. In the 50%
and 0% concentrations, there were no signs of color change in any of the rubble pieces.
Fig. 2(D2$*$?')#2($5(@!./(!"#!'-0!1*(%!*((S.-##!/(
rubble pieces are on the right side of the weight and 1$1,7-##!/()'!($1(*2!(.!5*(%-/!
0.0 0.2 0.4 0.6 0.8 1.0 1.2
Millepora Montastrea Porites
Proportion of color difference in species
Coral Species
Fig. 3 Proportions of color portrayal of Ramicrusta sp. distributed among Millepora complanata, Montastrea annularis, and Porites astreiodes. Purple bars represent purple Ramicrusta sp. overgrowth, red bars represent gradient color overgrowth, and orange bars represent orange color overgrowth.
Error bars represent standard deviation for each
?'$&#(M#(Y(L8LLNQ
JW
Discussion
An overwhelming majority of Ramicrusta sp.
overgrowing M. complanata was purple, whereas it was orange when overgrowing M. annularis and P. asteroides. There appears to be some type of allelopathic interaction between M. complanata and Ramicrusta sp. Since there was a common observation between most colonies, it may be assumed that M. complanata! "#$! %&'()&*%&+!
Ramicrusta sp. color. Ramicrusta sp. grows on live and dead coral heads, but the morphology is variable between coral species (Pueschel and ,#&-).$!/00123!45%$!$56"$!75#7!Ramicrusta sp. has different interactions when interacting with different coral species. As of yet, there are no similar studies in other locations to assess if the reaction is uniform
#86&+! 9.)! *6.#:$! %&! 675).! #.)#$3! ;(.75).! $(.<)=$!
of Ramicrusta sp.! 6<).+.6"75! *6:6.! 6&! 9.)! *6.#:$!
in other locations would indicate whether this is a localized phenomenon or more generalized.
>)$(:7$! ?.68! 75)! 9):-! )@A).%8)&7! $(AA6.7)-!
the hypothesis that Ramicrusta sp. is affected by
%7$! :%+57! )@A6$(.)3! B7! %$! A6$$%C:)! 6&)! .(CC:)! A%)*)!
did not show color change due to the movement of sand that may have shaded it from the sunlight.
D6&)! 6?! 75)! &6&E'%AA)-! .(CC:)! A%)*)$! *5#&+)-!
color, which shows the color change was likely due to sunlight. It is unknown how Ramicrusta sp. changes color, but it is known that some algae species have the ability to adjust the capacity for harvesting sunlight through chloroplast movement FG(::).!)7!#:3!/00H23!I:$6!-(.%&+!#**:%8#7%6&!76!:%+57!
intensity changes, many algae regulate the size of lightharvesting pigments through changes in gene )@A.)$$%6&! FG(::).! )7! #:3! /00H23! Ramicrusta sp.
*6(:-!*6&7.6:!A%+8)&7!)@A.)$$%6&!-)A)&-%&+!6&!75)!
#86(&7!6?!#**)$$%C:)!:%+57!#<#%:#C:)3!J=!)@A#&-%&+!
their chloroplasts in decrease light environments, the alga could absorb more light. When the alga is )@A6$)-! 76! #! $(&:%7! )&<%.6&8)&7K! 75)! *5:6.6A:#$7$!
contract so as not to absorb too much light and cause 7%$$()!-#8#+)3! B&!75)!:#C6.#76.=!)@A).%8)&7K!75)!
100% M. complanata )@A6$)-! "#7).! .)$(:7)-! %&!
some color change. M. complanata metabolites are concentrationdependent when reacting with other :%<)! 7%$$()! F>6L#$! )7! #:3! /00/2! #&-! ?(&*7%6&! 86.)!
)?9*%)&7:=! "5)&! 75)=! #.)! 86.)! *6&*)&7.#7)-3! 45%$!
could also mean the 50% dilution had too much water present and the M. complanata metabolites were too diluted to cause a reaction with the alga.
Several Ramicrusta sp. rubble pieces had to be thrown out since there were equipment problems with the aerators and some of the water became 5=A6@%*3! I:756(+5! 75).)! "#$! &6! )??)*7! 6&! *6:6.!
in dilutions it appears that color change may be
#77.%C(7)-!76!9.)!*6.#:!8)7#C6:%7)$3!I!:#.+).!<#.%)7=!
of dilutions may have led to a better understanding of how metabolites effect color change in Ramicrusta
sp. There is a large difference in the proportion of M. complanata with purple Ramicrusta sp.
overgrowth when compared to M. annularis and P.
astreoides3!!B&!#--%7%6&K!A.):%8%&#.=!)@A).%8)&7$!%&!
75)!9):-!#&-!:#C!$56"!75#7!75)!*6:6.!6?!Ramicrusta responds to sunlight and water soluble metabolites of M. complanata indicating that perhaps the purple color is a stress response of Ramicrusta sp. under 75)!%&'()&*)!6?!%&$(?9*%)&7!$(&:%+57!6.!#::):6A#75%*!
competition for space with M. complanata. This is an important aspect of the ecological and chemical ecology of Ramicrusta sp.
Acknowledgements
I would like to thank Dr. Rita Peachey for her advising throughout the process, the CIEE staff for their logistical help and organization, STINAPA for letting me conduct my study in Lac Bay, my fellow CIEE classmates, and a special thank you to my research partner AnnaRose Adams.
References
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-)! :#! P67).#! [O! F/00/2! P#:*%(8E! -)A)&-)&7!
$86675!8($*:)!)@*%7#76.=!)??)*7!):%*%7)-!C=!75)!
venom of the hydrocoral Millepora complanata.
46@%*6&!R0QMMMEMUT