J. Biodi . & En i on. Sci.
Mu ugesan e al.
REVIEW PAPER OPEN ACCESS
A e iew o he ecological impac s o wa e pollu ion on lakes: F om
dia om assemblages o mig a o y bi d popula ion declines
A unpandiyan Mu ugesan1, Roshy Ann Ma hews1, S. Rajakuma 2,
P ashan hi De i Ma imu hu*1
1Depa men o En i onmen al Science and Managemen , Bha a hidasan Uni e si y, Ti uchi appalli,
Tamil Nadu, India
2Depa men o Ma ine bio echnology, Bha a hidasan Uni e si y, Ti uchi appalli, Tamil Nadu, India
Key wo ds: Wa e quali y, Dia oms, Mig a o y bi ds, Eu ophica ion, We land conse a ion
DOI: h ps://dx.doi.o g/10.12692/jbes/27.3.23-38
[ Published: Sep embe 05, 2025 ]
ABSTRACT
Lakes a e key eshwa e ecosys ems ha main ain he biodi e si y, egula e nu ien cycles, and p o ide
habi a o mig a o y bi ds. Thei ecological well-being is g ea ly impac ed by wa e quali y, which a ec s
he composi ion and p oduc i i y o p ima y p oduce s such as dia oms. Dia oms a e sensi i e bio-
indica o s ha espond spon aneously o he changing physical, chemical, and biological pa ame e s. The
dynamics o hei communi ies ex end h ough ood webs, a ec ing ish, zooplank on, and, e en ually,
mig a o y bi d popula ions. This e iew ou lines he cu en scien i ic unde s anding ega ding he
ela ionships be ween bi d communi ies, dia om ecology, and lake wa e quali y, wi h a ocus on case
s udies om Tamil Nadu and India. I has been demons a ed ha majo wa e quali y s esso s such as
pollu ion, eu ophica ion, salinisa ion, and hyd ological changes, dis u b dia om assemblages, dec ease he
a ailabili y o p ey, and de e io a e i al mig a o y bi d s opo e and b eeding habi a s.
*Co esponding Au ho : P ashan hi De i Ma imu hu p ashan hide [email protected]
*
h ps://o cid.o g/0000-0002-5500-6085
Fi s au ho : A unpandiyan Mu ugesan: h ps://o cid.o g/0000-0002-4281-725X
Co-au ho s:
Roshy Ann Ma hews: h ps://o cid.o g/0000-0003-4718-4014
S. Rajakuma : h ps://o cid.o g/0000-0001-5122-4491
Jou nal o Biodi e si y and En i onmen al Sciences | JBES
ISSN: 2220-6663 (P in ); 2222-3045 (Online)
Websi e: h ps://www.innspub.ne
E-mail con ac : [email p o ec ed]
Vol. 27, Issue: 3, p. 23-38, 2025
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24
Mu ugesan e al.
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INTRODUCTION
Lakes a e c i ical componen s o he global eshwa e
sys em, suppo ing a wide ange o biodi e si y and
p o iding essen ial ecosys em se ices. They se e as
ese oi s o d inking wa e , i iga ion sou ces o
ag icul u e, habi a s o aqua ic o ganisms, and key
si es o nu ien cycling (Kal , 2002; Moss, 2010).
Lakes also ac as sinks o a mosphe ic ca bon and
play a signi ican ole in local clima e egula ion
(T an ik e al., 2009). Thei ecological unc ions
ex end o suppo ing socio-economic ac i i ies such
as ishe ies, ou ism, and cul u al p ac ices (MEA,
2005; Ca pen e e al., 2011).
The ecological heal h o a lake is la gely
de e mined by i s wa e quali y, which e lec s he
physical, chemical, and biological cha ac e is ics o
he aqua ic en i onmen . Wa e quali y is
in luenced by bo h na u al p ocesses (e.g., seasonal
u no e , p ecipi a ion) and an h opogenic
p essu es (e.g., ag icul u al uno , indus ial
discha ge, u ban was e) (We zel, 2001; Smi h and
Schindle , 2009). Deg ada ion o wa e quali y can
lead o eu ophica ion, algal blooms, hypoxia, and
he collapse o aqua ic ood webs (Ca pen e e al.,
1998; Dodds e al., 2009). Assessing wa e quali y
is, he e o e, essen ial o unde s anding ecosys em
in eg i y and o guiding conse a ion and
managemen ac ions (UNEP, 2016; Kuma e al.,
2020).
Role o dia oms as bioindica o s
Dia oms a e mic oscopic, pho osyn he ic algae
ound in nea ly all aqua ic habi a s. Thei silica-
based cell walls ( us ules) p ese e well in
sedimen s, making hem aluable indica o s o
bo h p esen and pas en i onmen al condi ions
(Smoland S oe me , 2010). Due o hei apid
esponse o changes in wa e chemis y—
pa icula ly nu ien s, pH, and conduc i i y—
dia oms a e widely used as bioindica o s in wa e
quali y assessmen (S oe me and Smol, 1999;
Ba a bee e al., 2001). Va ia ions in dia om
assemblages can e lec sub le ecological shi s ha
migh no be de ec ed h ough con en ional
chemical es ing (Kelly e al., 1998). Hence, hey
o e a powe ul ool o long- e m moni o ing and
ecological diagnosis o eshwa e sys ems (Round
e al., 1990; Bennion e al., 2014).
Mig a o y bi ds and hei dependence on
aqua ic ood webs
Mig a o y bi ds, especially wa e owl and wade s, ely
hea ily on heal hy we land and lake ecosys ems
du ing b eeding, s opo e , and win e ing phases o
hei li e cycle (Kea , 2005; New on, 2008). These
bi ds eed on a ange o aqua ic o ganisms such as
insec s, mollusks, c us aceans, and ish—many o
which a e pa o ood webs d i en by p ima y
p oduc i i y om o ganisms like dia oms (G een and
Elmbe g, 2014; Baldassa e, 2014). Dis up ion in
hese ood webs, due o declining wa e quali y o
habi a deg ada ion, can esul in al e ed mig a ion
pa e ns, educed su i al a es, and o e all
popula ion decline (Da idson, 2014; Finlayson e al.,
2017). Thus, lake ecosys ems o m a i al ecological
linkage be ween aqua ic p ima y p oduce s and
highe ophic le els including bi ds (Welle , 1999;
We lands In e na ional, 2021).This e iew aims o
syn hesize he cu en unde s anding o how lake
wa e quali y a ec s dia om communi ies and how
hese changes cascade h ough he ood web o
in luence mig a o y bi d popula ions. The e iew is
s uc u ed in o sec ions ha p og essi ely build on
he in e ac ions be ween wa e quali y, dia oms, and
mig a o y bi ds, ollowed by an analysis o
conse a ion implica ions and u u e esea ch
di ec ions.
Lake wa e quali y pa ame e s
Unde s anding lake wa e quali y is undamen al o
assessing ecosys em heal h and biodi e si y
dynamics. Va ious physical, chemical, and biological
pa ame e s in luence he p oduc i i y, nu ien
cycling, species composi ion, and o e all ecological
balance o eshwa e sys ems (We zel, 2001; APHA,
2017). These pa ame e s no only a ec p ima y
p oduce s like dia oms bu also shape he a ailabili y
o ood and habi a o highe ophic le els, including
mig a o y bi ds (Ka hick e al., 2013; Sa a anan e
al., 2022).
In India, se e al s udies ha e highligh ed how wa e
quali y de e io a ion—d i en by nu ien en ichmen ,
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Mu ugesan e al.
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indus ial pollu ion, and u ban was e—has al e ed
ecological unc ions o lakes and we lands
(Ramak ishnan e al., 2006; Gup a and Bha , 2014).
Speci ically in Tamil Nadu, in es iga ions o
Pallika anai Ma sh, Pulica Lake, and Vedan hangal
Bi d Sanc ua y ha e e ealed how changes in pH,
dissol ed oxygen, and nu ien le els a ec plank on
communi ies, ish popula ions, and ul ima ely
wa e bi d abundance (Naga ajan and Thiyagesan,
1996; Sa a anan e al., 2022; Ramachand an e al.,
2020). These s udies unde sco e he
in e connec edness o wa e quali y pa ame e s wi h
ecological heal h and conse a ion ou comes.
In luence o physical, chemical and biological
pa ame e s on plank on communi y
Tempe a u e
Tempe a u e plays a cen al ole in egula ing lake
s a i ica ion, dissol ed oxygen solubili y, and
biological me abolism. I in luences he g ow h and
ep oduc ion o dia oms, wi h ce ain species
p e e ing colde o wa me condi ions (Reynolds,
2006; We zel, 2001). Seasonal changes in
empe a u e can lead o he mal s a i ica ion,
a ec ing e ical mixing o nu ien s and oxygen
dis ibu ion, which in u n impac s aqua ic li e (Kal ,
2002). S udies om Indian lakes, such as Lok ak and
Vembanad, demons a e ha seasonal empe a u e
shi s signi ican ly al e phy oplank on and
zooplank on dynamics (Ramak ishnan e al., 2006;
Jyo hibabu e al., 2010).
In Tamil Nadu, seasonal luc ua ions in wa e
empe a u e a Pulica Lake ha e been shown o
in luence ish popula ions and wa e bi d abundance
(Ramachand an e al., 2020).
Tu bidi y
Tu bidi y e e s o he cloudiness o wa e caused by
suspended solids like sil , o ganic ma e , and
plank on. High u bidi y can educe ligh pene a ion,
limi ing pho osyn hesis by dia oms and o he
au o ophs (Ki k, 2011). I may also clog ish gills and
a ec isual p eda o s like bi ds ha ely on clea
wa e s o o age (Da ies-Colley and Smi h, 2001). In
Indian we lands, ag icul u al uno and u ban
e luen s a e majo con ibu o s o u bidi y (Khan
and Ansa i, 2005). Resea ch on Pallika anai Ma sh,
Tamil Nadu, has epo ed ha high u bidi y le els
deg ade aqua ic p oduc i i y and educe o aging
e iciency o wading bi ds (Sa a anan e al., 2022).
T anspa ency
Measu ed using a Secchi disk, anspa ency indica es
he dep h o which ligh can pene a e wa e . I is a
di ec measu e o he wa e ’s op ical cla i y. High
anspa ency a o s he g ow h o ben hic and pelagic
dia oms by enabling be e ligh a ailabili y, while
educed anspa ency o en signals eu ophica ion o
pollu ion (Ca lson, 1977; Moss, 2010). In India,
anspa ency has been a eliable indica o o ophic
s a us in u ban lakes such as Hussain Saga (Kuma
e al., 2010). In Tamil Nadu, educed anspa ency in
Vedan hangal and Pulica lakes has been linked o
nu ien en ichmen and algal blooms, a ec ing he
ca ying capaci y o mig a o y bi ds (Naga ajan and
Thiyagesan, 1996; Ramachand an e al., 2020).
pH
The pH o lake wa e a ec s nu ien a ailabili y,
me al solubili y, and he su i al o aqua ic o ganisms
(We zel, 2001; Kal , 2002). Dia oms a e pa icula ly
sensi i e o pH luc ua ions; di e en axa h i e
unde acidic, neu al, o alkaline condi ions
(Ba a bee e al., 2010). Ex eme pH alues can
dis up cellula p ocesses and lead o shi s in
communi y composi ion. Indian s udies, such as
hose om Lok ak Lake and Dal Lake, demons a e
ha pH luc ua ions signi ican ly in luence
phy oplank on di e si y (Ramak ishnan e al., 2006;
Ra he and Khan, 2013). In Tamil Nadu, a ia ions in
pH in Pulica Lake ha e been linked o changes in ish
popula ions and wa e bi d o aging e iciency
(Ramachand an e al., 2020).
Dissol ed oxygen (DO)
Dissol ed oxygen is i al o ae obic aqua ic li e. I is
eplenished h ough di usion om he a mosphe e
and pho osyn hesis by algae, including dia oms
(We zel, 2001). Low DO le els (hypoxia) o en esul
om o ganic pollu ion and eu ophica ion, causing
ish kills and he collapse o ae obic mic obial ac i i y
(Dodds e al., 2009). This has cascading e ec s on
bi d ood sou ces such as ish and in e eb a es
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(Da idson, 2014). In Indian lakes, hypoxic condi ions
ha e been epo ed in Hussain Saga and Vembanad,
leading o biodi e si y decline (Kuma e al., 2010;
Jyo hibabu e al., 2010). In Tamil Nadu, DO
luc ua ions in Pallika anai Ma sh and Vedan hangal
Bi d Sanc ua y ha e been linked o seasonal bi d
abundance (Sa a anan e al., 2022; Naga ajan and
Thiyagesan, 1996).
Nu ien s (Ni ogen and Phospho us)
Ni ogen (N) and phospho us (P) a e essen ial o
p ima y p oduc i i y bu also d i e eu ophica ion
when p esen in excess (Smi h and Schindle , 2009).
Nu ien en ichmen o en leads o shi s in algal
communi ies— eplacing bene icial dia oms wi h
nuisance o oxic cyanobac e ia (Ca pen e e al.,
1998). This al e s he ood base o in e eb a es and
ish, ul ima ely a ec ing mig a o y bi ds (G een and
Elmbe g, 2014). In India, high nu ien loading has
been eco ded in lakes like Lok ak, Chilika, and
Hussain Saga (Ramak ishnan e al., 2006; Pa naik
e al., 2007). In Tamil Nadu, Pulica Lake and
Pallika anai Ma sh ace nu ien -d i en
eu ophica ion om ag icul u e and sewage,
h ea ening biodi e si y (Ramachand an e al., 2020;
Sa a anan e al., 2022).
Salini y
Salini y in luences osmo egula ion in aqua ic
o ganisms and shapes species composi ion in
eshwa e lakes (Hamme , 1986). Dia oms exhibi
a ying ole ance o salini y; some a e es ic ed o
eshwa e , while o he s h i e in b ackish
en i onmen s (Smoland S oe me , 2010).
Inc eased saliniza ion due o clima e change,
seawa e in usion, o human ac i i ies can s ess
eshwa e axa and modi y ophic in e ac ions
(Williams, 2001). In Indian we lands like Sambha
Lake and Pulica Lake, ising salini y has been shown
o educe eshwa e biodi e si y and a ec mig a o y
bi d popula ions (Naga ajan andThiyagesan, 1996;
Ramachand an e al., 2020).
Conduc i i y
Conduc i i y measu es he wa e ’s abili y o conduc
elec ici y, which co ela es wi h ion concen a ion
(e.g., Na⁺, Cl⁻, SO₄²⁻). I p o ides a gene al indica o
o wa e mine aliza ion and an h opogenic inpu s
(APHA, 2017). Ele a ed conduc i i y o en e lec s
pollu ion o land-use change and in luences dia om
assemblages and habi a quali y (Ka hick e al.,
2013). S udies om Indian we lands, including
Chilika and Pallika anai, e eal ha conduc i i y is
s ongly linked o u ban e luen s and ag icul u al
uno (Pa naik e al., 2007; Sa a anan e al., 2022).
In Tamil Nadu, seasonal a ia ions in conduc i i y a
Vedan hangal and Pulica lakes ha e been epo ed
due o impac plank on communi ies and wa e bi d
o aging g ounds (Naga ajan and Thiyagesan, 1996;
Ramachand an e al., 2020).
P esence o algae
Algae, including dia oms, o m he base o he aqua ic
ood web and a e widely ecognized as eliable
indica o s o wa e quali y and ophic s a us
(Reynolds, 2006; Smoland S oe me , 2010). Thei
abundance, species di e si y, and communi y
composi ion e lec nu ien le els and ecological
balance in aqua ic sys ems. A balanced algal
popula ion suppo s heal hy ood chains, while
excessi e g ow h, pa icula ly cyanobac e ial blooms,
indica es nu ien en ichmen and can p oduce oxins
ha m ul o aqua ic auna and humans (Pae land
O en, 2013; Saha and Paul, 2020). In Indian
eshwa e ecosys ems, phy oplank on composi ion
has been di ec ly linked o eu ophica ion and
seasonal changes (Kaushik and Saksena, 1995; Singh
and Singh, 2006). S udies om Tamil Nadu lakes
ha e epo ed seasonal a ia ion in phy oplank on,
especially dia oms and cyanobac e ia, as e ec i e
bioindica o s o wa e quali y (A i oli and Mohan aj,
2013; Mu ugan and San hanam, 2011).
Mic obial ac i i y
Mic obial communi ies play a cen al ole in
decomposi ion o o ganic ma e , nu ien cycling,
and sus aining ene gy low in aqua ic sys ems
(We zel, 2001). Shi s in mic obial abundance and
di e si y p o ide ea ly wa nings o de e io a ing
wa e quali y. Ele a ed o ganic loads o en enhance
mic obial espi a ion, leading o deple ion o
dissol ed oxygen and c ea ing s ess o ish and
in e eb a es (Jindal and Sha ma, 2011). In India,
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mic obial ac i i y has been shown o inc ease
signi ican ly in sewage- ed and pollu ed wa e bodies,
accele a ing oxygen deple ion (Reddy and Rao, 1986).
In Tamil Nadu lakes, mic obial communi ies such as
he e o ophic bac e ia ha e been ound o co ela e
s ongly wi h nu ien en ichmen and o ganic
pollu ion (Sen hilkuma and Si akuma , 2018). Such
mic obial esponses highligh hei signi icance as
bioindica o s o an h opogenic s ess in eshwa e
ecosys ems.
Eu ophica ion and i s e ec s
Eu ophica ion is he p ocess o nu ien en ichmen ,
p ima ily wi h ni ogen and phospho us, leading o
excessi e algal g ow h and loss o ecological balance
in aqua ic ecosys ems (We zel, 2001; Smi h e al.,
1999). While i may ini ially enhance p ima y
p oduc i i y, ch onic eu ophica ion dis up s lake
ecology in mul iple ways.
One o he mos p ominen impac s is he decline in
dia om di e si y, as as -g owing g een algae and
cyanobac e ia domina e unde high nu ien
condi ions (Reynolds, 2006; Saha and Paul, 2020).
This dominance o cyanobac e ia and g een algae,
which a e less pala able o e en oxic o
g aze se en ually allow dia oms o lose hei
dominance. This shi can lowe he e iciency o
ene gy ans e o zooplank on and in e eb a es.
This u he educes he nu i ional quali y o p ey
a ailable o bi ds (Pae land O en, 2013; Jeppesen e
al., 2020).
The excessi e o ganic ma e p oduced leads o
oxygen deple ion, pa icula ly in bo om wa e s,
due o mic obial decomposi ion o algal biomass
(Ca pen e e al., 1998; Jindal and Sha ma, 2011)
as a esul o mic obial espi a ion which consumes
la ge amoun s o dissol ed oxygen, leading o
hypoxic o anoxic condi ions. This p ocess o en
igge s ish kills o inc eased mo ali y a es,
educing p ey a ailabili y o pisci o ous bi dsand
insec i o ous bi ds (Schindle , 2001; Kaushik and
Saksena, 1995). Bi d species such as e ns, gulls,
and g ebes may abandon deg aded si es o su e
ep oduc i e ailu e (Diaz and Rosenbe g, 2008;
Rabalais e al., 2014).
Eu ophica ion also causes habi a deg ada ion,
making lakes unsui able o o aging and nes ing o
mig a o y wa e bi ds (A i oli and Mohan aj, 2013).
The eme gence o ha m ul algal blooms (HABs),
domina ed by oxin-p oducing cyanobac e ia, poses
di ec heal h h ea s o ish, bi ds, and e en humans
(Pae land O en, 2013). Long- e m eu ophica ion
al e s species composi ion and ood web dynamics,
unde mining he abili y o lakes o sus ain biodi e si y,
wi h se e e consequences o sensi i e g oups such as
mig a o y wa e bi ds ha depend on s able, nu ien -
balanced ecosys ems (Mu ugan and San hanam, 2011;
Sen hilkuma and Si akuma , 2018).
Dia oms as ecological indica o s
Biology and ecology o dia oms
Dia oms a e unicellula , pho osyn he ic algae
belonging o he class Bacilla iophyceae. They a e
cha ac e ized by in ica ely pa e ned, silica-based
cell walls called us ules, which make hem bo h
ecologically signi ican and axonomically iden i iable
unde a mic oscope (Round e al., 1990; Smoland
S oe me , 2010). Dia oms occu in a wide ange o
aqua ic habi a s— om p is ine moun ain s eams o
nu ien - ich lakes—and can be ound in plank onic
( ee- loa ing) and ben hic (a ached o su aces)
o ms (We zel, 2001; Saha and Paul, 2020).
Ecologically, dia oms a e p ima y p oduce s,
o ming he ounda ion o aqua ic ood webs. They
exhibi apid ep oduc ion unde a o able
condi ions, allowing hem o espond quickly o
en i onmen al changes (S oe me andSmol, 1999;
Reynolds, 2006). Thei sensi i i y o speci ic
en i onmen al pa ame e s such as nu ien le els,
salini y, empe a u e, and pH makes hem eliable
indica o s o ecological shi s (Ramak ishnan and
Kuma , 2018; A i oli and Mohan aj, 2013;
Mu ugan and San hanam, 2011).
Sensi i i y o wa e quali y changes
Dia oms a e widely ecognized as one o he mos
esponsi e g oups o mic oo ganisms o changes in
wa e quali y (Smoland S oe me , 2010; We zel,
2001). Di e en species ha e dis inc ecological
ole ances and op ima, which allow o ine-scale
de ec ion o al e a ions in en i onmen al
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condi ions (S oe me and Smol, 1999;
Ramak ishnan and Kuma , 2018). Fo example,
Eu ophic condi ions known as high nu ien le els
a o species like Cyclo ella meneghiniana and
Ni zschia palea (Reynolds, 2006; Saha and Paul,
2020). Howe e , oligo ophic en i onmen s which
a e low nu ien condi ionssuppo species such as
F agila ia c o onensis o Achnan hes spp. (Round
e al., 1990; Singh and Singh, 2006) and acidic
wa e s p omo e acid- ole an dia oms like
Tabella ia enes a a, while alkaline wa e s a o
Na icula and Gomphonema species (Ba a bee e
al., 2010; A i oli and Mohan aj, 2013).
Since dia oms ha e sho gene a ion imes, hey can
apidly colonize new habi a s o shi in composi ion
in esponse o s esso s, o e ing a eal- ime
assessmen o lake heal h (Mu ugan and San hanam,
2011; Sen hilkuma and Si akuma , 2018).
Dia om indices and bioassessmen
Dia oms a e ex ensi ely used in bioassessmen
p o ocols due o hei sensi i i y, di e si y, and
pe sis ence in he sedimen s (Smoland S oe me ,
2010; We zel, 2001). Quan i a i e dia om indices
ha e been de eloped o assess he ophic s a us,
o ganic pollu ion, and acidi ica ion o eshwa e
sys ems (S oe me andSmol, 1999; Ramak ishnan
and Kuma , 2018). Some o he widely used indices
include:
1. T ophic Dia om Index (TDI): Assesses nu ien
en ichmen in i e s and lakes (Kelly and Whi on,
1995; Saha and Paul, 2020).
2. Paleoecological Dia om Index: Recons uc s
his o ical wa e quali y using ossil dia oms om
sedimen co es (Ba a bee e al., 2010; Singh and
Singh, 2006).
3. Speci ic Pollu ion Sensi i i y Index (IPS): Sco es
dia oms based on hei ole ance o o ganic
pollu ion (Cos e, 1982; A i oli and Mohan aj,
2013).
These indices a e ins umen al in egula o y
moni o ing amewo ks such as he Eu opean Union
Wa e F amewo k Di ec i e (WFD) and can in o m
conse a ion and managemen ac ions (Kelly e al.,
1998; Mu ugan and San hanam, 2011).
Dia oms as a link be ween wa e quali y and bi d
ecology
Dia oms o m he base o many eshwa e ood webs
whe e hei heal h di ec ly in luences he a ailabili y o
esou ces o in e eb a es and ish—c i ical p ey o
mig a o y bi ds. A decline in dia om di e si y o
p oduc i i y can dis up ophic pa hways, educing
biomass a highe le els (S oe me andSmol, 1999;
Ba a bee e al., 2010). This can also a ec he iming
and quali y o ood du ing bi d mig a ion pe iods
(Jeppesen e al., 2011; Kuma e al., 2019), lead o
habi a unsui abili y, causing changes in bi d
dis ibu ion o decline in popula ions (Mukhe jee and
Bo ad, 2001; A i oli and Mohan aj, 2013).Thus,
moni o ing dia om communi ies p o ides no only a
measu e o wa e quali y bu also an indi ec indica o o
bi d habi a quali y and sus ainabili y (Soininen, 2007;
Mu ugan and San hanam, 2011).
Lakes and we lands se e as complex ecological
ne wo ks whe e ene gy and nu ien s a e ans e ed
ac oss mul iple ophic le els o ming ophic linkages
be ween dia oms and mig a o ybi ds. Dia oms, as
p ima y p oduce s, o m he base o his aqua ic ood
web. Though bi ds do no di ec ly consume dia oms, he
ophic in luence o dia oms cascades h ough
in e eb a es and ish o shape ood a ailabili y and
habi a condi ions o mig a o y bi d species (Reynolds,
2006; Jeppesen e al., 2010). Unde s anding hese
linkages is c i ical o assessing how changes in lake
wa e quali y can impac bi d popula ions (Mukhe jee
and Bo ad, 2001; A i oli and Mohan aj, 2013).
Dia oms as p ima y p oduce splay an impo an ole in
ood web dynamics, whe e heycon ibu e signi ican ly
o p ima y p oduc i i y in lakes. Th ough
pho osyn hesis, hey con e sunligh in o biomass and
oxygen, o ming a majo pa o he phy oplank on and
pe iphy on communi y. Thei p oduc ion suppo s he
die o Zooplank on like copepods and o i e s, Mac o-
in e eb a es o e.g., insec la ae, mollusks and
amphipods and also o small ish and ish la ae ha
g aze on in e eb a es o plank on. These lowe ophic
o ganisms a e essen ial ood esou ces o mig a o y
wa e bi ds, such as ducks, sho ebi ds, and he ons
(Reynolds, 2006; Jeppesen e al., 2010; A i oli and
Mohan aj, 2013).
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Ene gy ans e o bi ds is wi nessed especially in
mig a o y bi d popula ions. Based on hei eeding
p e e ences mig a o y bi ds a e ca ego ized as
Plank i o es,such as some ducks, ha consume
zooplank on suppo ed by dia om blooms; In e i o es
ha eed on in e eb a es ha ely on ben hic
dia oms(e.g., sandpipe s, s o ks) and pisci o es ha
depend on ish ha a e indi ec ly sus ained by dia om-
based p ima y p oduc ion(e.g., pelicans, co mo an s).
Dis up ions a he dia om le el, due o pollu ion,
eu ophica ion, o salini y changes, can he e o e educe
p ey abundance and quali y, diminishing bi d o aging
success (Mukhe jee and Bo ad, 2001; Ramachand an
and Rajkuma , 2018).
Dia oms no only suppo ood webs bu also
con ibu e o habi a s uc u ing whe e ben hic
dia oms o m bio ilms on subme ged su aces,
suppo ing in e eb a e communi ies in mud la s
and shallow wa e zones—c i ical eeding a eas o
wading bi ds.This c i ically de e mines he
o aging beha io and habi a sui abili y o
mig a o y bi ds as hey selec eeding and s opo e
si es based on p ey a ailabili y, which is a unc ion
o unde lying p oduc i i y and wa e quali y.The
pe iphy ic dia oms in luence mac ophy e g ow h,
which p o ides shel e and b eeding g ounds o
aqua ic o ganisms and nes ing a eas o
bi ds.When dia om-based p oduc i i y is high and
s able, hese si es suppo highe bi d abundance,
di e si y, and ep oduc i e success (Waise and
Roba s, 2004; Kuma e al., 2019; Mu ugan and
San hanam, 2011).
Abo e all heseasonal dynamics and mig a ion iming
play a signi ican ole as he seasonal a ia ion in dia om
p oduc i i y also in luences he iming o bi d a i al
and depa u e a we lands, hei body condi ion and a
ese es needed o long-dis ance ligh and he
ep oduc i e eadiness in species ha nes nea lakes.
Fo ins ance, p e-mig a o y s aging bi ds ely on
nu ien - ich o aging g ounds o accumula e ene gy. A
collapse in dia om popula ions du ing c i ical mig a o y
windows which can happen due o he mal s ess o
nu ien imbalance o en delaying mig a ion o educing
su i al a es (Smoland S oe me , 2010; Balachand an,
2006; Samikannu e al., 2020).
Feedback loops be ween bi ds and lake
ecosys ems
Mig a o y bi ds also con ibu e o nu ien cycling in
lakes h ough exc e ion o guano, en iching shallow
zones wi h ni ogen and phospho us, Bio u ba ion om
o aging, in luencing sedimen mixing and dia om
esuspension and Seed dispe sal and habi a
enginee ing, which a ec s aqua ic plan –dia om
in e ac ions. This c ea es eedback loops, whe e bi d
ac i i y can in luence he composi ion and p oduc i i y
o dia oms, and ice e sa, making he ela ionship
be ween dia oms and bi ds mu ually in e dependen
and dynamic (Pos e al., 1998; Hahn e al., 2007;
Ramachand an e al., 2017).
In luence o lake deg ada ion on mig a o y bi d
popula ions, conse a ion implica ions and
managemen s a egies
Lakes and associa ed we lands a e c ucial s opo e ,
win e ing, and b eeding si es o millions o
mig a o y bi ds wo ldwide. Howe e , deg ada ion o
hese habi a s, especially due o declining wa e
quali y, poses se ious h ea s o bi d popula ions. As
dia oms play a majo ole in sus aining lake habi a s
o mig a o y bi ds, any nega i e impac will lead o
ophic dis up ion (Finlayson e al., 2018; Ramsa
Con en ion Sec e a ia , 2021). When dia om
communi ies a e deg aded, he zooplank on and
mac oin e eb a e popula ions decline and su i al
o ish la ae d ops due o ood sho age. Bi ds
exhibi changes in eeding pa e ns, si e ideli y, o
mig a e longe dis ances o ind sui able habi a s
whe e some species may su e popula ion declines
o al e ed mig a o y pa hways.
This ophic dis up ion can be especially ha m ul in
egions whe e lakes se e as c i ical mig a o y lyways o
b eeding g ounds, such as Ramsa we lands o
anscon inen al bi d ou es (e.g., Cen al Asian Flyway,
Eas Asia–Aus alasia Flyway) (Da idson, 2014;
Balachand an, 2006; Samikannu e al., 2020).
The e o e, changes in ophic dynamics, habi a
s uc u e, and ood web s abili y esul ing om
pollu ion, eu ophica ion, o saliniza ion can
signi ican ly al e bi d beha io , o aging success, and
su i al as shown in Table 1.
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Table 1. E idence om case s udies linking dia oms and mig a o y bi ds
Region
Key s esso s
Ecological Impac
on dia oms / Food
web
Consequences o
mig a o y bi ds
Re e ences
Chilika Lake, Odisha, India
Sedimen a ion,
eu ophica ion
Algal blooms;
educed ish
popula ion
Decline in pisci o ous
bi ds (pelicans and
co mo an s)
Balachand a e al.,
2020; Sunda and
Sub amanya, 2010.
Keoladeo Na ional pa k,
Bha a hpu , India
Wa e di e sion,
pollu ion, we land
d ying
Habi a loss;
educed p ey
a ailabili y
Decline in mig a o y
wa e owl; Sibe ian
c ane (G us
leucoge anus)
Vijayan, 1991;
Bi dLi e
In e na ional, 2020
Danube del a and Lake,
Eu ope
Eu ophica ion,
indus ial
discha ges
Shi om dia oms
o Cyanobac e ia
dominance
Reduced ood esou ce
o ben hic- eeding
bi ds (snipes and
sandpipe s)
Ibelings, 2016;
Donohue e al.,
2019
G ea Lakes egion, No h
Ame ica
Nu ien imbalance,
habi a al e a ion
Loss o dia om-
based p oduc i i y;
decline in
in e eb a es
Mig a o y ducks and
sho ebi ds impac ed
du ing sp ing/ all
mig a ions
Smi h e al., 2015;
Schindle , 2019
O he impac s
Some cyanobac e ia p oduce neu o oxins o
hepa o oxins ha can accumula e in aqua ic
o ganisms and pose di ec oxic e ec s o heal h isks
o bi ds. Documen ed bi d die-o s due o cyano oxins
ha e occu ed in se e al we lands globally (Me cal e
al., 2012; Bu o d e al., 2020). Sub-le hal e ec s
include impai ed na iga ion, ep oduc ion, o
immuni y (Ca michael, 2001; Mille e al., 2010).
Deg aded wa e quali y o en coincides wi h inc eased
sedimen a ion and ege a ion o e g ow h.
Loss o mud la s and shallow eeding a eas a e c i ical
o wade s (Ma e al., 2010; Sunda and Sub amanya,
2010) and enc oachmen o in asi e species lead o
al e ing nes ing habi a s (Sha ma e al., 2016).
Pollu ion and wa e abs ac ion al e hyd ological
egimes, a ec ing he a ailabili y and iming o
sui able o aging habi a s. Ea ly d ying o we lands
limi s esou ce a ailabili y du ing mig a ion windows
(Vijayan, 1991; Pa naik e al., 2021). Inc eased
salini y excludes eshwa e species, educing p ey
di e si y (Zhang e al., 2019).
Clima e-induced changes—such as inc eased
empe a u es, al e ed p ecipi a ion pa e ns, and
saliniza ion—a ec bo h dia om communi ies and
mig a o y bi d beha io (IPCC, 2022; Smoland
Douglas, 2007). Howe e , clima e-media ed
in e ac ions ac oss ophic le els a e poo ly
unde s ood (Ad ian e al., 2009; Hassan e al., 2021 –
Indian we lands; Bo h e al., 2009; Pea ce-Higgins
and G een, 2014; Thacke ay e al., 2016).
Conse a ion conce ns
Deg aded lake sys ems no only h ea en indi idual
species bu also dis up en i e mig a o y lyways.
Lakes se e as s epping s ones ac oss con inen s o
millions o bi ds. The deg ada ion o one o mo e o
hese c i ical si es can ha e cascading consequences
ac oss he en i e mig a ion ne wo k, especially o
species al eady acing clima e and land-use p essu es
(Bi dLi e In e na ional, 2020; Ha is e al., 2019).
Gi en he c i ical ole o lake ecosys ems in
suppo ing biodi e si y—pa icula ly p ima y
p oduce s like dia oms and mig a o y bi ds a highe
ophic le els—i is impe a i e o adop in eg a ed
conse a ion and managemen app oaches. The
deg ada ion o wa e quali y and i s cascading
ecological impac s necessi a e mul i-p onged
s a egies combining es o a ion, moni o ing, policy,
and communi y pa icipa ion (Jeppesen e al., 2020;
Kuma e al., 2022; Ramsa Con en ion Sec e a ia ,
2021). Consequences in beha io al and
demog aphical changes mus be add essed. Bi ds
expe iencing habi a deg ada ion may ex end
mig a o y ou es in sea ch o sui able al e na i es
(New on, 2008). They delay mig a ion o show poo
body condi ion due o educed ood (Da idson and
S oud, 2016). Popula ion a es su e due o declines
in b eeding success as a esul o inadequa e
nou ishmen (Finlayson e al., 2018).Cumula i ely,
hese s esso s can lead o popula ion declines, loss o
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Mu ugesan e al.
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gene ic di e si y, and changes in mig a ion co ido s,
h ea ening he long- e m iabili y o mig a o y
species (Ki by e al., 2008; Ramsa Con en ion
Sec e a ia , 2021). Es ablishing bi d sanc ua ies and
no-dis u bance zones du ing peak mig a ion and
nes ing pe iods. Habi a enhancemen p ojec s such
as he c ea ion o mud la s, shallow pools, and nes ing
islands can imp o e o aging and b eeding
oppo uni ies (Ma e al., 2010; Rahmani, 2012 –
India).
Res o ing wa e quali y is mos equi ed o educe
nu ien load. One o he mos e ec i e measu es o
es o e wa e quali y is limi ing nu ien inpu s,
pa icula ly ni ogen and phospho us, om
ag icul u al uno , sewage, and indus ial was e.
Reducing nu ien loads helps in es o ing dia om
di e si y and minimizing he dominance o ha m ul
algae (Jeppesen e al., 2005; Pae land O en, 2013).
Bu e zones and ege a i e il e s a ound lakes o
ap sedimen s and nu ien s can be planned
(Ca pen e e al., 1998; Wi he s and Ja ie, 2008)
along wi h cons uc ed we lands o e ia y
was ewa e ea men (Vymazal, 2011; Mi sch and
Gosselink, 2015). Regula ions on e ilize use,
especially nea ecologically sensi i e zones can be
manda ed (Smi h and Schindle , 2009).
Main aining na u al hyd ological egimes h ough
en i onmen al low eleases and wa e le el con ol
ensu es habi a a ailabili y du ing c i ical mig a o y
pe iods. Pe iodic lushing o lakes can also help
emo e excess nu ien s and p e en s agna ion (Po
e al., 1997; Bunn and A hing on, 2002). Excessi e
sedimen a ion deg ades ben hic habi a s c ucial o
pe iphy ic dia oms and in e eb a es. Desil a ion
e o s, when well-managed and ecologically
in o med, can help es o e bo h he eeding g ounds
o ben hic- eeding bi ds (Finlayson e al., 2018) as
well as imp o e ligh pene a ion o dia om
pho osyn hesis (Likens, 2010; We zel, 2001).
Conse a ion planning should in eg a e Long-Te m
Dia om Moni o ing P og ams and Sedimen Co e
Analysis. This can be success ul by es ablishing
dia om sampling s a ions a s a egic loca ions in lake
sys ems (Kelly e al., 1998; Dixi e al., 1999), c ea ing
e e ence lib a ies o dia om assemblages om
p is ine and deg aded lakes (Soininen, 2007;
S e enson e al., 2010), including dia om indices
(e.g., TDI, IPS) in na ional wa e quali y moni o ing
p o ocols (Kelly and Whi on, 1995; Pandey e al.,
2014 – India), s udying ossil dia oms in sedimen
co es o e s insigh s in o his o ical ecological
condi ions, helping ack changes due o land use,
pollu ion, o clima e o e decades o cen u ies
(Ba a bee e al., 2001; Smoland S oe me , 2010).
This suppo s adap i e lake managemen based on
long- e m ecological ends (Agniho i and Mish a,
2021 – India).
Technological gaps in dia om moni o ing
T adi ional dia om iden i ica ion is labo -in ensi e
and equi es axonomic expe ise. This limi s
widesp ead adop ion in ou ine moni o ing p og ams
(Round e al., 1990).
P o ec ing mig a o y bi d habi a s equi es
conse ing we land–lake complexes, egula ing
ou ism and de elopmen nea sensi i e zones,
es ablishing sanc ua ies wi h no-dis u bance pe iods,
and unde aking habi a enhancemen h ough
mud la s, shallow pools, and nes ing islands. A
sys ems-based, in eg a ed app oach linking wa e
quali y moni o ing, dia om s udies, and a ian su eys
unde ecosys em-based managemen enhances
esilience and ea ly de ec ion o deg ada ion.
Communi y pa icipa ion h ough capaci y-building,
ci izen science, sus ainable a ming, and eco ou ism
s eng hens conse a ion ou comes while
supplemen ing o mal da ase s. A he policy le el,
en o cing we land laws, expanding Ramsa si e
managemen , and engaging in in e na ional
ag eemen s like he CMS and Cen al Asian Flyway,
alongside egional collabo a ion on dia om
moni o ing, a e essen ial. Howe e , majo esea ch
gaps emain: he absence o in eg a ed long- e m
moni o ing o wa e chemis y, dia oms, and bi d
dynamics; poo unde s anding o dia om–bi d
ophic pa hways ia in e media e consume s; and
he neglec o small o seasonal lakes ha ac as
c i ical mig a o y s opo e s along key lyways. Lack o
In eg a ed Long-Te m Moni o ing Despi e nume ous
sho - e m s udies, in eg a ed, long- e m da ase s
J. Biodi . & En i on. Sci.
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