Research Article A New Trophic State Index for Lagoonsdownloads.hindawi.com/archive/2014/152473.pdf · 2019-07-31 · Research Article A New Trophic State Index for Lagoons MukeshGupta

Research ArticleA New Trophic State Index for Lagoons

Mukesh Gupta12

1 Earth Sciences and Hydrology Division Marine and Earth Sciences Group Remote Sensing Applications andImage Processing Area Space Applications Centre Indian Space Research Organization Ahmedabad Gujarat 380 015 India

2 Centre for Earth Observation Science Department of Environment and Geography Clayton H Riddell Faculty of EnvironmentEarth and Resources University of Manitoba 463 Wallace Building Winnipeg MB Canada R3T 2N2

Correspondence should be addressed to Mukesh Gupta guptmyahoocom

Received 27 December 2013 Revised 27 January 2014 Accepted 28 January 2014 Published 9 March 2014

Academic Editor Wen-Cheng Liu

Copyright copy 2014 Mukesh Gupta This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This paper proposes a new nitrogen-based trophic state index (TSI) for the estimation of status of eutrophication in a lagoonsystem Nitrite-nitrogen (NO

2-N) is preferable because of its greater abundance in Chilika lagoon and its relation to other criteria

of trophic state for example chlorophyll-a (Chl-a) and Secchi disk depth (SDD)Nitrite is preferable over nitrate because the formerdecreases the fluorescence and affects photosynthesis thereby controlling primary productionThis paper also computes TSI usingChl-a and SDD The three parameters account for the biological chemical and physical characteristics of the lagoon It will bepossible to estimate the TSI of freshwater and brackish water lagoons and other water bodies using the new expressions taking intoconsideration the spatial and temporal variability in the dataset Depending on the data availability alternative TSI (Chl-a) and TSI(SDD) can account for the biological and physical contributions to eutrophication The estimated TSI can account for Chl-a andNO2-N up to 32218mgmminus3 and 6199 120583g Lminus1 respectively The TSI based on these three parameters can serve as a complimentary

and predictive tool for lagoon management and field programs to monitor the health of a lagoon

1 Introduction

It is much easier to convey to the public the status and natureof a lagoon through an index which provides the scientificaccord of eutrophication and character of the lagoon Themonitoring of water quality especially in the inland waterbodies aquifers lakes reservoirs and lagoons is importantas it helps with the management of the eutrophication andproductivity of the water body Carlson [1] made earlyattempts to define an index termed trophic state index (TSI)which could tell about the trophic status and nature ofthe lakes Based on this trophic index further classificationof eutrophication of a lake into oligotrophic mesotrophicand eutrophic was possible Because of water pollution andcontamination of inland and coastal water bodies it hasbecome important to develop methods to determine suchindex of eutrophication of coastal lagoons that provides betterspatial and temporal coverage

Carlson [1] presented the trophic condition on a 0ndash100scale however the author reported three different TSI valuesthat is total phosphorus (TP) chlorophyll-a (Chl-a) and

Secchi disk transparency depth (SDD) [2] To eliminate thisconfusion Osgood [3] suggested using differences in theindices to assess the water quality in lakes The basis ofthe development of an index of trophic state depends onthe characteristic features and peculiarity of eutrophicationDifferent from Carlsonrsquos and othersrsquo approaches OrsquoBoyleet al [4] have recently suggested pH- and dissolved oxygen-based index of status of eutrophication Chalar et al [5]report a completely different TSI based on benthic inverte-brates which is little dependent on environment variablesThe variability and dominance of specific eutrophicationparameters in different lakes hold the key to using a suitableindex because different lakes may have different sources ofnutrients depth and size So far there is no universallyapplicable trophic index reported which could adequatelypredict the productive character of a coastal lagoon

However many trophic scales water quality indices andmeasures of an assessment of water quality and trophic statusof lakes estuaries and marine coastal areas are abundant inthe literature For example Vollenweider et al [6] proposed anew trophic index (TRIX) based onChl-119886 oxygen saturation

Hindawi Publishing CorporationJournal of EcosystemsVolume 2014 Article ID 152473 8 pageshttpdxdoiorg1011552014152473

2 Journal of Ecosystems

15 15A 14

13

12 16 11 10

9A 9

8A 8

7A 7

19

19A 20

21

22 23

17 1A

1 2A

2 3A

3 4

18

20A

5

Bay of Bengal

India

ArabianSea Bay of Bengal

10∘N

20∘N

10∘N

20∘N

70∘E 80∘E 90∘E

70∘E 80∘E 90∘E

IRS-ID LISS-III (FCC)May 21 2002

Chilika lagoon

85∘15998400E 85∘30998400E

19∘30998400N

19∘45998400NDred

ged ch

annel

Figure 1 A map of Chilika lagoon at Odisha coast IndiaThe background satellite imagery is IRS-1D LISS-III (FCCmdashfalse color composite)of May 21 2002

mineral total nitrogen and phosphorus for coastal marinewaters TRIX is scaled from 0 to 10 which covers a wide rangeof trophic conditions Analogously a turbidity index (TRBIX)serves as a complimentary water quality index TRIX andanalogous other indices are most useful for saline coastalmarine waters but are not well suited for a brackish waterlagoon Padisak et al [7] have developed an assemblage index119876 to assess ecological status of lake types established by theWater Framework Directive (WFD)119876 varies from 0 to 5 andprovides a 5-grade qualification as required by WFD But 119876is primarily a phytoplankton assemblage index that neglectswater quality parameters OSPAR OsloParis convention (forthe Protection of the Marine Environment of the North-EastAtlantic) has adopted COMPP (Comprehensive Procedure)for the identification of eutrophication status of OSPARMaritime Area [8] Although OSPAR COMPP provides aholistic procedure for trophic state assessment it does notset any thresholds for the trophic status indicator variables(eg Chl-a water clarity etc) and there are no differentialweightings across indicators Bricker et al [9] have suggestedan analogous integrated methodology for the Assessmentof Estuarine Trophic Status (ASSETS) for eutrophicationstatus of estuaries and coastal areas [9] It considers awhole suite of nutrients and water quality parameters for adetailed assessment but suffers from lengthy and computa-tion demanding procedure for trophic assessment Howeverit has a limitation to only estuaries and coastal waters Anindex that is easy to implement a first-hand approach fora quicker assessment of trophic status of a brackish waterlagoon is still a requirement

The most common estimates of TSI have their basis onvarious in situ water quality data collected in the lake [1] Thespatial and temporal changes that occur in the lake constrain

these estimates Wezernak et al [10] reported a methodusing Chl-a and SDD as parameters for the determinationof TSI Thiemann and Kaufmann [11] determined TSI basedon Chl-a estimated using field spectrometer data for lakes inGermany Walker Jr [12] suggested a TSI based on depletionof dissolved oxygen from in situmeasurements as a measureof status of water quality of lakes Analogous to Carlsonrsquos[1] trophic indices Kratzer and Brezonik [13] estimatedTSI for total nitrogen based on in situ measurements forvarious lakes in Florida USA Nitrite-nitrogen (NO

2-N) is an

important element in a lagoon system because it is present inplant tissues compost manure soil food fertilizer mineralwater and yellow substances Literature on a TSI primarilybased on nitrogen (nitrite or nitrate or ammonia) is rareThis paper does not use ammonia to compute TSI as itnitrifies into nitrite by bacterial oxidation [4] This paperpresents a new detailed model of TSI based on NO

2-N with

intercomparison to TSI based on Chl-a and SDD for Chilikalagoonrsquos eutrophication status

2 Study Area and Sampling Data

The study area lies between 19∘281015840ndash19∘541015840N and 85∘051015840ndash85∘381015840E in the coastal regions of the state of Odisha India(Figure 1) Eastern Ghats hills surround the eastern andwestern margins of the lagoon There are 52 small rivuletsin the north that drain fresh water into the lagoon mainrivers being Daya and Bhargavi Rivers the distributaries ofMahanadi River [14] The Bay of Bengal seawater enters thelagoon through a mouth midway along the east coast lengthof the lagoon

Chilika lagoon situated on the east coast of India in thestate of Odisha is the second largest brackish water lagoon

Journal of Ecosystems 3

in the world [15] Ramsar Convention designated it as aWetland of International Importance since 1 October 1981The pear-shaped lagoon sprawls about 64 km in length NE-SW and about 5ndash18 km in width from S-N covering an area of1165ndash906 km2 during themonsoon and summer respectivelyChilika lagoon is a shallow water body with the deepest pointof sim3m in the southern end and the shallowest point of sim60 cm in the northern end It opens in the Bay of Bengalthrough an artificially opened mouth approximately 200mwideThis new artificialmouthwas opened in 2007 by cuttingand dredging the sand spit to increase the eutrophicationand protect wild life habitat which were declining due todecreasing salinity after the closure of northern opening intothe Bay of Bengal [14 16]

Water sample data collection campaign occurred during2001ndash2003 at 27 different locations evenly distributed in thelagoon to cover the entire lagoon area (Figure 1) Stations 1515A 14 13 12 16 11 10 and 17 in the southern sector werecomparatively deeper Stations in the central sector were 11A 2 2A 8A 9 9A 20A and 21The northern sector stations3 3A 4 7 7A 8 19 19A and 20 were shallow characterizedby very high suspended sediment concentration The sampleanalysis that is filtering weighing and so forth assisted inretrieving Chl-a NO

2-N and SDD values The samples were

filtered through GFC Whatman filter paper for the analysisof Chl-a NO

2-N data were analyzed according to themethod

described by Strickland and Parsons [17] Generally Chilikalagoon has lower values of nitrite except during monsoonwhen there are higher nitrite values resulting from releaseby decomposed freshwater weeds into the water column [18]Table 1 provides the range and general statistics of Chl-aNO2-N and SDD

3 Materials and Methods

The use of many variables responsible for the eutrophicationof lagoon may question the selection of two-three variablesfor determining the trophic state of the lagoon However theevaluation of only a few variables is the basis of the need fora TSI that can provide the trophic status of the lagoon andto avoid the large computations involving multiparameterstatistical analysis to arrive at an indicator of trophic state ofthe lagoon A TSI should have its basis on only a few variablesthat one can easily measure and analyze with optimum effort

In the present analysis Chl-a NO2-N and SDD have

been chosen as the potential candidates for estimating a TSIwhich can cover a substantial range of concentrations of eachof the three parameters and is applicable to any brackishwaterlake lagoon inland water body and reservoir One can easilymeasure and understand the SDD because it is dependenton direct human vision SDD and Chl-a are representativesof the optical scattering and absorption in the lagoon watersThe underwater light availability in the lagoon controls thegeneral growthhealth of the microorganisms biomass floraand fauna Nitrogen is one of the major nutrient componentsof the food chain of a lagoon rather to say it lies at the baseof food web and provides food for all living organisms in alagoon

Table 1The range and general statistics of in situ data used inModelA computation for TSI

Parameter Minimum Maximum Mean Standard deviationSDD (cm) 10 200 56 32Chl-a (mgmminus3) 009 4853 492 557NO2-N (120583g Lminus1) 008 365 062 068

31 Reasons for ChoosingNitrite for TSI Estimation NO2-N is

preferable for TSI estimation because of its greater abundancein a trophic system and its relation to the other criteria oftrophic state such as Chl-a and SDD The presence of nitritein biomass rich water decreases fluorescence thus affectingthe Chl-a and photosynthesis [19] and thereby regulatingprimary production of the lagoon A Chl-a based trophicindex is likely to underestimate the trophic state of the lagoonin the presence of nitrite A nitrite-based index can overcomethis problem Nitrate is not preferable though it is morestable than nitrite because nitrate does not have any influenceon the Chl-a thus it does not affect the fluorescence andphotosynthesis [19] Secondly SDD-based TSI is likely to beconfused with water quality index however the nutrient-based index should serve as a better indicator of the trophicstatus in a lagoon Finally the computed TSI values undergoa validation at each station in the lagoon to check if thecomputed TSI values are consistent with the observations inthe lagoon

32 Model A This model computes a TSI based on theCarlsonrsquos model [1] The relationship among three param-eters that is Chl-a NO

2-N and SDD is nonlinear and is

computed as follows (no transformation of the data valuesinto logarithmic and so forth was performed only thenontransformed actual data values have been used)

1

SDD= 14479 + 07763NO

2-N (119899 = 60 1198772 = 07753)

1

SDD= 0216 + 08771Chl-119886 (119899 = 60 1198772 = 07761)

(1)

where 119899 sample points constitute the data for regression1198772 is the coefficient of determination The model computes

corresponding TSI values for Chl-a NO2-N and SDDThese

are as follows

TSI (SDD) = 10 [6 + ln (1SDD)ln 2]

TSI (NO2-N) = 10 [6 +

ln (14479 + 07763NO2-N)

ln 2]

TSI (Chl-119886) = 10 [6 + ln (02160 + 08771Chl-119886)ln 2

]

(2)

Themodel underestimates the computed values of Chl-a andNO2-N in the absence of upper limits of the SDD


33 Model B This model is a slight modification of Model ADefining the maximum limit of SDD and computing the TSIfor Chl-119886 andNO

2-N from the empirical equations construct

this model

119887119886= SDDmax (3)

It is safe to consider SDDmax as 200 cm for Chilika lagoon Letus consider

TSI (SDD) = 10 [119886 + ln (1SDD)ln 119887] (4)

Solving (1) and (4) we get 119886 = 15475 and 119887 = 15650

TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (5)

TSI (NO2-N)

= 10 [15475 +ln (14479 + 07763NO

2-N)

ln 1565]

(6)

TSI (Chl-119886)

= 10 [15475 +ln (02160 + 08771Chl-119886)

ln 1565]

(7)

34 Model C This model is a slight modification of Model BAn improved nonlinear relationship among Chl-a NO

2-N

and SDD is obtained for a limited range of each parameter asfollows1

SDD= 1135 + 06926NO

2-N (119899 = 61 1198772 = 08455)

(8)

1

SDD= 10907 + 01334Chl-119886 (119899 = 60 1198772 = 08487)

(9)

009 le Chl-119886 le 2000 25 le SDD le 120 (10)

One can compute TSI (SDD) using the formula given in (5)

TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (11)

Substituting (8) and (9) into (11) respectively we get TSI(NO2-N) and TSI (Chl-a)

TSI (NO2-N) = 10 [15475 +

ln (1135 + 06926NO2-N)

ln 1565]

TSI (Chl-119886) = 10 [15475 + ln (10907 + 01334Chl-119886)ln 1565

]

(12)

4 Results and Discussion

A large amount of data collected over three-year span duringmonsoon summer and postmonsoon provides a basis of theresults in this study Thus the data contain large variabilityrequired for formulating an ameliorated TSI for a brackishwater lagoon

0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x

TSI (SDD)TSI (NO2-N)

Chl-a (mgm3) Secchi disk depth (cm) NO2-N (120583gL)

TSI (Chl-a)

Figure 2 TSI versus corresponding values of Chl-a NO2-N and

SDD computed using Model A Most Chl-a and NO2-N values are

underestimated which fall below zero Note that the SDD is open-ended

41 Model A Carlsonrsquos index [1] provides a basis forModel Ataking the entire data set into consideration The computedTSI values are underestimated by this model and producenegative numbers for Chl-a and NO

2-N Figure 2 shows a

plot of three TSI computed for Chl-a NO2-N and SDDusing

Model AThe variability in Chl-a andNO2-N does not reflect

in the computed TSI whereas SDD is open-ended Tables1 and 2 provide the corresponding data values Model A isobviously not a good TSI estimator for the Chilika lagoon

42 Model B Here the SDD has a limit of a maximum depthof 200 cm for Chilika lagoon The choice of SDDmax relieson the observational data in the lagoon One can elucidatethe physical significance of this limitation on SDD throughthe penetration of light into the lagoon waters The lightavailability in turn controls the growth of organisms hencethe eutrophication in the lagoon There is a requirement offurthermodifications and regulations to arrive at a reasonableTSI which consider the entire range of concentrations of Chl-a NO

2-N and SDD from the surface to the SDDmax in the

lagoon This model produces substantial negative values ofthe computed Chl-a and NO

2-N thus it is not suitable for

a good TSI (Table 3)Figure 3 shows the results of Model B The computed

TSI clearly elucidates the variability in Chl-a and NO2-N

However Model B also underestimates NO2-N beyond 21 cm

of SDDThis implies that themodel considers only the surfaceconcentration of NO

2-N up to a depth of 21 cm (Table 3)

43 Model C The intersected area among the threecurves corresponding to Chl-a NO

2-N and SDD

provides the most common TSI values in a typical lagoon


Table 2 TSI and corresponding values of Chl-a NO2-N and SDD computed using Model A It is noticeable that this model gives negativenumbers (shown as ldquomdashrdquo dash) which implies the nonapplicability of this model for Chl-a concentrations less than 004mgmminus3 and NO2-Nconcentrations less than 071 120583g Lminus1

TSI SDD computed (cm) NO2-N computed (120583g Lminus1) Chl-a computed (mgmminus3)0 6400 mdash mdash10 3200 mdash mdash20 1600 mdash mdash30 800 mdash mdash40 400 mdash 00450 200 mdash 03260 100 mdash 08970 50 071 20380 25 329 43190 12 844 888100 6 1875 1800

Table 3 TSI and corresponding values of Chl-a NO2-N and SDD computed using Model B It is noticeable that this model gives negativenumbers (shown as ldquomdashrdquo dash) which implies the nonapplicability of this model for NO2-N concentrations less than 013 120583g Lminus1 Model Bshows slight improvement over Model A however the values of computed indices are underestimated in this model

TSI SDD computed (cm) NO2-N computed (120583g Lminus1) Chl-a computed (mgmminus3)0 200 mdash 03210 128 mdash 06520 82 mdash 11530 52 mdash 19440 33 mdash 31750 21 013 51160 14 070 81370 9 128 128680 6 186 202790 4 244 3186100 2 301 5000

(Figure 4) For instance Figure 5 shows the observed TSIvalidatedcomputed using the Model C from the observeddata from the Chilika lagoon [20] Each data point representsa mean value taken over several observations at selectlocations within the lagoon during monsoon postmonsoonand summer periods Note that the data ranges provided inthe Table 1 account for the entire data at all stations to createstatisticsThe observed data cover a large seasonal variabilityfor example monsoon summer and postmonsoon andtemporal variability from 2001 to 2003 The computedTSI values go through a validation at each station in thelagoon The physically observed eutrophication state and thepredicted TSI-based health status are in good agreement

A limited range of Chl-a varying between 009 and2000mgmminus3 and NO

2-N between 041 and 107 120583g Lminus1

enables computation of reasonable values of TSI that cov-ers greater ranges of concentration of Chl-a and NO

2-N

(Figure 4) The high values of Chl-a and NO2-N signify

higher TSI in contrast to high values of transparency signi-fying low TSI The variability in Chl-a and NO

2-N is well

accounted for by the computed TSI (Table 4)The TSI provided in the Model C has many advantages

over previous trophic indices One can increase the scale of

TSI (0 to 100) if the concentrations of observed Chl-a orNO2-N are even higher The used ranges of Chl-a NO

2-

N and SDD provide sufficient information to construct ageneralized TSI which is likely to provide better estimatesof the status of eutrophication in a lagoon These parametersfundamentally account for the availability of organisms(Chl-a) food (nitrogen and phosphorus) and light (SDD)which are typical requirements for a healthy lagoon Inaddition these three parameters provide the biological (Chl-a) chemical (NO

2-N) and physical (SDD) grounds for

establishing the trophic state Each of the three TSI obtainedplays a role in biological chemical and physical contributionto the general eutrophication in the lagoon One shouldconsider the necessary abatement of controlling parametersfor inverting the results to achieve the required TSI accordingto a standard For example Chilika Development Authorityopened a new artificial mouth to the Bay of Bengal to increasethe salinity of the lagoon and to control the eutrophication inthe lagoon [16]

44 Comparison with Other Indices Several different indiceshaving their basis on various eutrophication parameters areavailable in the literature since Carlson [1] (see Introduction)


0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)


SDD computed using Model B Some NO2-N values are underesti-

mated which fall below zero The SDD has a limit of 200 cm

0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)


SDD computed using Model C None of parameters is underesti-mated

Obtained TSI ranges are in comparison with that of a recentstudy by OrsquoBoyle et al [4] who used pH and dissolved oxygenas indicators of eutrophication in estuaries Their studyprovides a range of 356ndash698 120583g Lminus1 of Chl-119886 correspondingto trophic index value range of 124ndash997 respectively In thispaper 009ndash4853mgmminus3 of in situChl-a values correspondsto TSI values between 0 and 100 This shows that the TSI inthis study covers a large range of Chl-a values that are not

0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)

Figure 5 TSI validatedcomputed using observed values of Chl-aNO2-N and SDD in Chilika lagoon The displayed data for Chl-a

NO2-N and SDD are mean values of each at select locations in the

lagoon during monsoon postmonsoon and summer periods

addressed in previous studies Yang et al [2] reported TSIvalues ranging between 0 and 100 for Chl-a concentrationsbetween 1705 and 26454 120583g Lminus1 and SDD between 12 and257 cm compared to the ones in this paper (Table 1) Obvi-ously previous studies either lack the ability to cover a largerange of Chl-a or do not consider a nitrogen-based TSI

45 Spatial and Temporal Variability within the LagoonHaving discussed the three models it is now imperativeto advert to the spatial and temporal variability of Chl-a NO

2-N and SDD within the lagoon This is important

for examination of computed TSI for different seasons andlocations in the lagoon to assist in relevant managementplans The lagoon divides into three sectors spatially thatis northern southern and central sectors and temporallythe lagoon experiences three different seasons during a yearthat is monsoon (JulyndashOctober) postmonsoon (NovemberndashMarch) and summer (AprilndashJune) The mean Chl-a con-centration is highest (833mgmminus3) in the central sectorduring summer The mean NO

2-N concentration is highest

(1598 120583g Lminus1) in the central sector duringmonsoonThe SDDis generally the lowest in the northern sector in any givenseason that is the water is clearer in the southern sectorin all seasons The proposed TSI accounts for the expectedconcentrations of Chl-a and NO

2-N and the SDD for any

season covering all sectors of the lagoon

5 Conclusions

This study offers new Chl-a NO2-N and SDD based TSI

expressions for the estimation of status of eutrophication ina lagoon system analogous to Carlsonrsquos index Nitrogen being


Table 4 TSI and corresponding values of Chl-a NO2-N and SDD computed using Model C It is noticeable that this model covers largeranges of NO2-N between 013 and 6199 120583g Lminus1 and Chl-a between 100 and 32218mgmminus3 Model C shows significant improvement overModel A and Model B

TSI SDD computed (cm) NO2-N computed (120583g Lminus1) Chl-a computed (mgmminus3)0 200 mdash mdash10 128 mdash mdash20 82 013 10030 52 113 61940 33 269 143150 21 514 270160 14 897 468970 9 1496 780180 6 2434 1267090 4 3902 20291100 2 6199 32218

the fourth most abundant element found in the organisms issuitable for computing TSI of the lagoon Nitrite is preferablebecause it decreases the fluorescence affecting the underwaterphotosynthesis and thereby controls primary productivity ofChilika lagoon Nitrite is short-lived and readily converts intonitrate that does not affect fluorescencephotosynthesis [19]NO2-N is preferable to TP because of its close relationship

with other trophic state criteria such as Chl-a and SDD Onecan compute TSI using Chl-a NO

2-N and SDD each of

which alone is capable of providing an estimate of trophicstatus of the lagoon The three parameters account forthe biological chemical and physical characteristics of thelagoon It will be possible to estimate the TSI of freshwaterand brackish water lagoons and other water bodies usingthe new expressions taking into consideration the spatialand temporal variability in the dataset TSI (SDD) providesfirst-hand information about the trophic state of the lagoonDepending on the requirement and data availability one canuse alternative TSI (Chl-a) and TSI (NO

2-N) to account for

the biological and chemical contributions to eutrophicationstatus The estimated TSI can account for Chl-a and NO

2-N

up to 32218mgmminus3 and 6199 120583g Lminus1 respectively The TSIbased on these three parameters serves as a complimentaryindex to assess nitrite levels and thereby primary productivityand as a predictive tool for lagoon management and prior toconducting field programs to monitor the health of a lagoon

Conflict of Interests

The author declares that there is no conflict of interestsregarding the publication of this paper

Acknowledgments

The author is thankful to Dr Shailesh R Nayak of SpaceApplications Centre (Indian Space Research Organization)(now at Ministry of Earth Sciences Government of IndiaNew Delhi) Ahmedabad India for funding support andnecessary data Thanks are also due to the personnel from

Regional Research Laboratory Bhubaneswar India for exe-cuting the field campaigns and support

References

[1] R E Carlson ldquoA trophic state index for lakesrdquo Limnology andOceanography vol 22 no 2 pp 361ndash369 1977

[2] J Yang X Yu L Liu W Zhang and P Guo ldquoAlgae communityand trophic state of subtropical reservoirs in southeast FujianChinardquo Environmental Science and Pollution Research vol 19no 5 pp 1432ndash1442 2012

[3] R A Osgood ldquoUsing differences among Carlsonrsquos trophic stateindex values in regional water quality assessmentrdquo Journal of theAmerican Water Resources Association vol 18 no 1 pp 67ndash741982

[4] S OrsquoBoyle G McDermott T Noklegaard and R Wilkes ldquoAsimple index of trophic status in estuaries and coastal bays basedon measurements of pH and dissolved oxygenrdquo Estuaries andCoasts vol 36 no 1 pp 158ndash173 2013

[5] G Chalar R Arocena J P Pacheco and D Fabian ldquoTrophicassessment of streams in Uruguay a Trophic State Index forBenthic Invertebrates (TSI-BI)rdquo Ecological Indicators vol 11 no2 pp 362ndash369 2011

[6] R AVollenweider F Giovanardi GMontanari andA RinaldildquoCharacterization of the trophic conditions of marine coastalwaters with special reference to the NW Adriatic Sea proposalfor a trophic scale turbidity and generalized water qualityindexrdquo Environmetrics vol 9 no 3 pp 329ndash357 1998

[7] J Padisak G Borics I Grigorszky and E Soroczki-Pinter ldquoUseof phytoplankton assemblages for monitoring ecological statusof lakes within the water framework directive the assemblageindexrdquo Hydrobiologia vol 553 no 1 pp 1ndash14 2006

[8] OSPAR Commission OSPAR Integrated Report 2003 onthe Eutrophication Status of the OSPAR Maritime AreaBased Upon the First Application of the ComprehensiveProcedure OSPAR Commission London UK 2003httpwwwosparorgdocumentsdbasepublicationsp00189p00189 eutrophication20status20report202003pdf

[9] S B Bricker J G Ferreira andT Simas ldquoAn integratedmethod-ology for assessment of estuarine trophic statusrdquo EcologicalModelling vol 169 no 1 pp 39ndash60 2003


[10] C T Wezernak F J Tanis and C A Bajza ldquoTrophic stateanalysis of inland lakesrdquo Remote Sensing of Environment vol5 no 2 pp 147ndash165 1976

[11] S Thiemann and H Kaufmann ldquoDetermination of chlorophyllcontent and trophic state of lakes using field spectrometerand IRS-1C satellite data in the Mecklenburg Lake DistrictGermanyrdquo Remote Sensing of Environment vol 73 no 2 pp227ndash235 2000

[12] WWWalker Jr ldquoUse of hypolimnetic oxygen depletion rate asa trophic state index for lakesrdquo Water Resources Research vol15 no 6 pp 1463ndash1470 1979

[13] C R Kratzer and P L Brezonik ldquoA Carlson-type trophic stateindex for nitrogen in Florida lakesrdquo Journal of the AmericanWater Resources Association vol 17 no 4 pp 713ndash715 1981

[14] U S Panda P K Mohanty and R N Samal ldquoImpact of tidalinlet and its geomorphological changes on lagoon environmenta numerical model studyrdquo Estuarine Coastal and Shelf Sciencevol 116 pp 29ndash40 2012

[15] S Pattanaik ldquoConservation of environment and protection ofmarginalized fishing communities of lake Chilika in OrissaIndiardquo Journal of Human Ecology vol 22 no 4 pp 291ndash3022007

[16] A S Rajawat M Gupta B C Acharya and S Nayak ldquoImpactof new mouth opening on morphology and water quality ofthe Chilika Lagoonmdasha study based on Resourcesat-1 LISS-IIIand AWiFS and IRS-1D LISS-III datardquo International Journal ofRemote Sensing vol 28 no 5 pp 905ndash923 2007

[17] J D Strickland and T R Parsons A Practical Handbook ofSeawater Analysis Bulletin 167 Fisheries Research Board ofCanada 1972

[18] S Brahma U C Panda K Bhatta and B K Sahu ldquoSpatialvariation in hydrological characteristics of Chilikamdasha coastallagoon of Indiardquo Indian Journal of Science and Technology vol1 no 4 pp 1ndash7 2008

[19] E Kessler and W G Zumft ldquoEffect of nitrite and nitrate onchlorophyll fluorescence in green algaerdquo Planta vol 111 no 1pp 41ndash46 1973

[20] S Panigrahi B C Acharya R C Panigrahy B K Nayak KBanarjee and S K Sarkar ldquoAnthropogenic impact on waterquality of Chilika lagoon RAMSAR site a statistical approachrdquoWetlands Ecology and Management vol 15 no 2 pp 113ndash1262007

Submit your manuscripts athttpwwwhindawicom

Forestry ResearchInternational Journal of

Hindawi Publishing Corporationhttpwwwhindawicom Volume 2014

Environmental and Public Health

Journal of



EcosystemsJournal of


MeteorologyAdvances in

EcologyInternational Journal of


Marine BiologyJournal of


Hindawi Publishing Corporationhttpwwwhindawicom

Applied ampEnvironmentalSoil Science

Volume 2014

Advances in


Environmental Chemistry

Atmospheric SciencesInternational Journal of



Waste ManagementJournal of

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International Journal of

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Geological ResearchJournal of

EarthquakesJournal of


BiodiversityInternational Journal of


ScientificaHindawi Publishing Corporationhttpwwwhindawicom Volume 2014

OceanographyInternational Journal of


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Journal of Computational Environmental SciencesHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


ClimatologyJournal of


15 15A 14

13

12 16 11 10

9A 9

8A 8

7A 7

19

19A 20

21

22 23

17 1A

1 2A

2 3A

3 4

18

20A

5

Bay of Bengal

India

ArabianSea Bay of Bengal

10∘N

20∘N

10∘N

20∘N

70∘E 80∘E 90∘E

70∘E 80∘E 90∘E

IRS-ID LISS-III (FCC)May 21 2002

Chilika lagoon

85∘15998400E 85∘30998400E

19∘30998400N

19∘45998400NDred

ged ch

annel

Figure 1 A map of Chilika lagoon at Odisha coast IndiaThe background satellite imagery is IRS-1D LISS-III (FCCmdashfalse color composite)of May 21 2002

mineral total nitrogen and phosphorus for coastal marinewaters TRIX is scaled from 0 to 10 which covers a wide rangeof trophic conditions Analogously a turbidity index (TRBIX)serves as a complimentary water quality index TRIX andanalogous other indices are most useful for saline coastalmarine waters but are not well suited for a brackish waterlagoon Padisak et al [7] have developed an assemblage index119876 to assess ecological status of lake types established by theWater Framework Directive (WFD)119876 varies from 0 to 5 andprovides a 5-grade qualification as required by WFD But 119876is primarily a phytoplankton assemblage index that neglectswater quality parameters OSPAR OsloParis convention (forthe Protection of the Marine Environment of the North-EastAtlantic) has adopted COMPP (Comprehensive Procedure)for the identification of eutrophication status of OSPARMaritime Area [8] Although OSPAR COMPP provides aholistic procedure for trophic state assessment it does notset any thresholds for the trophic status indicator variables(eg Chl-a water clarity etc) and there are no differentialweightings across indicators Bricker et al [9] have suggestedan analogous integrated methodology for the Assessmentof Estuarine Trophic Status (ASSETS) for eutrophicationstatus of estuaries and coastal areas [9] It considers awhole suite of nutrients and water quality parameters for adetailed assessment but suffers from lengthy and computa-tion demanding procedure for trophic assessment Howeverit has a limitation to only estuaries and coastal waters Anindex that is easy to implement a first-hand approach fora quicker assessment of trophic status of a brackish waterlagoon is still a requirement

The most common estimates of TSI have their basis onvarious in situ water quality data collected in the lake [1] Thespatial and temporal changes that occur in the lake constrain

these estimates Wezernak et al [10] reported a methodusing Chl-a and SDD as parameters for the determinationof TSI Thiemann and Kaufmann [11] determined TSI basedon Chl-a estimated using field spectrometer data for lakes inGermany Walker Jr [12] suggested a TSI based on depletionof dissolved oxygen from in situmeasurements as a measureof status of water quality of lakes Analogous to Carlsonrsquos[1] trophic indices Kratzer and Brezonik [13] estimatedTSI for total nitrogen based on in situ measurements forvarious lakes in Florida USA Nitrite-nitrogen (NO

2-N) is an

important element in a lagoon system because it is present inplant tissues compost manure soil food fertilizer mineralwater and yellow substances Literature on a TSI primarilybased on nitrogen (nitrite or nitrate or ammonia) is rareThis paper does not use ammonia to compute TSI as itnitrifies into nitrite by bacterial oxidation [4] This paperpresents a new detailed model of TSI based on NO

2-N with

intercomparison to TSI based on Chl-a and SDD for Chilikalagoonrsquos eutrophication status

2 Study Area and Sampling Data

The study area lies between 19∘281015840ndash19∘541015840N and 85∘051015840ndash85∘381015840E in the coastal regions of the state of Odisha India(Figure 1) Eastern Ghats hills surround the eastern andwestern margins of the lagoon There are 52 small rivuletsin the north that drain fresh water into the lagoon mainrivers being Daya and Bhargavi Rivers the distributaries ofMahanadi River [14] The Bay of Bengal seawater enters thelagoon through a mouth midway along the east coast lengthof the lagoon

Chilika lagoon situated on the east coast of India in thestate of Odisha is the second largest brackish water lagoon



















1

SDD= 14479 + 07763NO

2-N (119899 = 60 1198772 = 07753)

1

SDD= 0216 + 08771Chl-119886 (119899 = 60 1198772 = 07761)

(1)



are as follows

TSI (SDD) = 10 [6 + ln (1SDD)ln 2]

TSI (NO2-N) = 10 [6 +

ln (14479 + 07763NO2-N)

ln 2]

TSI (Chl-119886) = 10 [6 + ln (02160 + 08771Chl-119886)ln 2

]

(2)





this model

119887119886= SDDmax (3)


TSI (SDD) = 10 [119886 + ln (1SDD)ln 119887] (4)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (5)

TSI (NO2-N)

= 10 [15475 +ln (14479 + 07763NO

2-N)

ln 1565]

(6)

TSI (Chl-119886)

= 10 [15475 +ln (02160 + 08771Chl-119886)

ln 1565]

(7)


2-N


SDD= 1135 + 06926NO

2-N (119899 = 61 1198772 = 08455)

(8)

1

SDD= 10907 + 01334Chl-119886 (119899 = 60 1198772 = 08487)

(9)

009 le Chl-119886 le 2000 25 le SDD le 120 (10)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (11)


TSI (NO2-N) = 10 [15475 +

ln (1135 + 06926NO2-N)

ln 1565]

TSI (Chl-119886) = 10 [15475 + ln (10907 + 01334Chl-119886)ln 1565

]

(12)



0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)



















2-N and SDD











2-N



2-N is well




2-






0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)












5 Conclusions








2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics
































1

SDD= 14479 + 07763NO

2-N (119899 = 60 1198772 = 07753)

1

SDD= 0216 + 08771Chl-119886 (119899 = 60 1198772 = 07761)

(1)



are as follows

TSI (SDD) = 10 [6 + ln (1SDD)ln 2]

TSI (NO2-N) = 10 [6 +

ln (14479 + 07763NO2-N)

ln 2]

TSI (Chl-119886) = 10 [6 + ln (02160 + 08771Chl-119886)ln 2

]

(2)





this model

119887119886= SDDmax (3)


TSI (SDD) = 10 [119886 + ln (1SDD)ln 119887] (4)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (5)

TSI (NO2-N)

= 10 [15475 +ln (14479 + 07763NO

2-N)

ln 1565]

(6)

TSI (Chl-119886)

= 10 [15475 +ln (02160 + 08771Chl-119886)

ln 1565]

(7)


2-N


SDD= 1135 + 06926NO

2-N (119899 = 61 1198772 = 08455)

(8)

1

SDD= 10907 + 01334Chl-119886 (119899 = 60 1198772 = 08487)

(9)

009 le Chl-119886 le 2000 25 le SDD le 120 (10)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (11)


TSI (NO2-N) = 10 [15475 +

ln (1135 + 06926NO2-N)

ln 1565]

TSI (Chl-119886) = 10 [15475 + ln (10907 + 01334Chl-119886)ln 1565

]

(12)



0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)



















2-N and SDD











2-N



2-N is well




2-






0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)












5 Conclusions








2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics

















this model

119887119886= SDDmax (3)


TSI (SDD) = 10 [119886 + ln (1SDD)ln 119887] (4)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (5)

TSI (NO2-N)

= 10 [15475 +ln (14479 + 07763NO

2-N)

ln 1565]

(6)

TSI (Chl-119886)

= 10 [15475 +ln (02160 + 08771Chl-119886)

ln 1565]

(7)


2-N


SDD= 1135 + 06926NO

2-N (119899 = 61 1198772 = 08455)

(8)

1

SDD= 10907 + 01334Chl-119886 (119899 = 60 1198772 = 08487)

(9)

009 le Chl-119886 le 2000 25 le SDD le 120 (10)


TSI (SDD) = 10 [15475 + ln (1SDD)ln 1565

] (11)


TSI (NO2-N) = 10 [15475 +

ln (1135 + 06926NO2-N)

ln 1565]

TSI (Chl-119886) = 10 [15475 + ln (10907 + 01334Chl-119886)ln 1565

]

(12)



0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)



















2-N and SDD











2-N



2-N is well




2-






0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)












5 Conclusions








2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics























2-N



2-N is well




2-






0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)












5 Conclusions








2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics















0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 50 100 150 200 250 300 350

0

20

40

60

80

100

120

Trop

hic s

tate

inde

x



TSI (Chl-a)




0 10 20 30 40 50 60 70 80 90 100

20

30

40

50

60

70


Trop

hic s

tate

inde

x


TSI (Chl-a)












5 Conclusions








2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics



















2-N and SDD each of


2-N) to account for


2-N




Acknowledgments



References


























Journal of












Volume 2014

Advances in









Geophysics






























Journal of












Volume 2014

Advances in









Geophysics


















Journal of












Volume 2014

Advances in









Geophysics














Documents

Research Article A New Trophic State Index for Lagoonsdownloads.hindawi.com/archive/2014/152473.pdf · 2019-07-31 · Research Article A New Trophic State Index for Lagoons MukeshGupta