Chilika Lagoon Research Articles

Length-weight relationships for four mullets from the Chilika lagoon, East coast of India

Current study provides information on Length–weight relationship (LWR) of four fish species of family Mugilidae i.e., Planiliza macrolepis (Smith, 1846), Chelon parsia (Hamilton, 1822), Osteomugil cunnesius (Valenciennes, 1836) and Valamugil speigleri (Bleeker, 1858) from Chilika Lagoon, East coast of India. Samples were collected during monsoon (July 2016), winter (November 2016) and summer (April 2017) seasons from the fisher's boats inside the lagoon while fishing with screen barrier nets (mesh size 18-38 mm) and gill nets (mesh size 34, 38, 46, 62 and 86 mm). The b values were determined from the data set in LWRs as 2.958 for P. macrolepis, 2.952 for O. cunnesius and 2.919 for C. parsia and 2.883 for V. peigleri. In all species, regression values were statistically significant (p < .05).

Structural and metabolic diversity of rhizosphere microbial communities of Phragmites karka in a tropical coastal lagoon

The structural and metabolic diversity of rhizosphere microbial communities of Phragmites karka, a perennial reed, was examined through high-throughput sequencing of 16S rRNA genes, taxonomic-to-metabolic mapping, and the BIOLOG® community level physiological profiling. Rhizosphere sediments were collected from P. karka stands along the shoreline of Chilika Lagoon during the year 2014–2015. At the genus level, bacterial communities were largely composed of Thiobacillus, Methylotenera, Bacillus, Steroidobacter and Escherichia/Shigella whereas Methanomassiliicoccus was one of the most abundant genus in the archaeal communities. In general, rhizosphere communities of samples from the same locations were more similar in their composition than from other sites. Salinity played an important role in driving the community composition along with ‘rhizosphere effect’. Carbon substrate utilization profiles of rhizosphere communities were highly diverse and the highest utilization was recorded in wells containing tween 40 (polymer), D-mannitol (carbohydrates), L-asparagine (amino acids), 4-hydroxybenzoic acid (phenols), putrescine (amines), and D-galacturonic acid (carboxylic acids). Of these, L-asparagine and D-mannitol were preferentially utilized by all rhizosphere communities. Metabolic mapping suggested that rhizosphere microbial communities could play a critical role in maintaining the ecological health of coastal wetlands through cycling of carbon, nitrogen, and sulfur, and degradation of hydrocarbon and xenobiotic compounds. Overall, this study demonstrated a high variability in the community structure and carbon metabolic profiles of rhizosphere communities of P. karka and suggested that nutrient cycling related ecosystem services that are mediated by the rhizosphere microbial communities of reeds must be included in the management and conservation plan of wetlands.

Length-weight relationship of three Cynoglossus species (C. puncticeps , C. lingua and C. lida ) from Chilika lagoon, India

Length-weight relationship of three <i>Cynoglossus</i> species (<i>C. puncticeps</i> ,<i> C. lingua</i> and <i>C. lida</i> ) from Chilika lagoon, India

A Multi-Sensor Approach for Assessing Mangrove Biophysical Characteristics in Coastal Odisha, India

Mangroves around the world play a major role in coastal ecosystem processes by mitigating erosion and serving as a barrier against storm surges. India holds approximately 5% of the world’s mangroves, over half of which are found along its east coast. Situated in the state of Odisha, Chilika Lagoon and Bhitarkanika Wildlife Sanctuary are two wetlands of local importance in need of effective management. This study demonstrated the use of Terra, Landsat, and Sentinel-1 satellite data for spatio-temporal monitoring of mangrove health at these two sites. Several indices, including Normalized Difference Vegetation Index and Enhanced Vegetation Index, were examined to develop biophysical prediction tools and derive a 17-year time-series (from 2000 to 2016) of leaf chlorophyll (CHL), Leaf Area Index (LAI), and Gross Primary Productivity (GPP). The long-term analysis revealed phenological patterns in the biophysical characteristics such as high values during wet season and low values during the dry season. Correlations between biophysical characteristics and meteorological factors revealed a time lag exists in response to precipitation and associated runoff. In contrast, surface temperature did not show any lag in response time. This study also utilized Sentinel-1 radar data for the first time for Odisha mangroves to show seasonal variability in LAI, GPP, and CHL. The results from radar data were consistent with optical sensors and proved useful for capturing the rainy season, where data were limited due to cloud cover. This study revealed the advantages of using a multi-sensor approach for monitoring mangrove health and defining future monitoring protocols.

Valuing the carbon sequestration regulation service by seagrass ecosystems of Palk Bay and Chilika, India

The regulatory ecosystem services in terms of carbon sequestration and storage by Indian seagrass ecosystems were coupled with their monetary values in the context of climate change mitigation in the seagrass meadows of Palk Bay and Chilika Lagoon, two major seagrass ecosystems of India. The results showed that the meadows acted as a net sink of atmospheric CO2; however, they may also act as a minor source of CO2 to the atmosphere depending on the degree of anthropogenic influence. The mean ecosystem productivity ranged between 6.31 and 11.9 kg C ha−1d−1, which is equivalent to the capture of 8.44 and 15.9 Mg CO2 ha−1 year−1. This captured carbon was apportioned primarily in sediments (129 Mg Corg ha−1 in top 1 m soil), which was much higher than the carbon stored as above and below ground biomass (0.20–0.96 Mg Corg ha−1 and 0.30–2.90 Mg Corg ha−1, respectively). The economic valuation of regulatory ecosystem services in the form of C sequestration by an estimated 51,700 ha of total seagrass cover in India was largely dependent on the sequestration rates and the average social cost of carbon. The estimated values ranged between $ 1.02 million and $ 3.65 million per year. In addition, monetary values of the stored carbon in live biomass of Indian seagrass systems ranged between $ 0.45 million and $ 3.89 million, whereas, in the top 1 m soil it ranged between $ 109 million and $ 146 million. Detailed evaluations of various ecosystem functions considering the importance of the local variables may provide a better monetary estimate of these regulatory services.

Fisher communities in transition: understanding change from a livelihood perspective in Chilika Lagoon, India

The sustainable livelihood framework is a widely used approach to analyze changes in rural livelihoods, especially in resource dependent communities. The framework emphasizes that given a certain situation where the livelihood context, resources and institutions remain favourable, livelihood strategies carried out by people could possibly lead to two different outcomes. One, the results of livelihood strategies will produce sustainable outcomes providing affected households respite from the impacts of livelihood loss. Two, there is a possibility that resulting outcomes may not be sufficient to reverse livelihood crisis and may not necessarily result in sustainable livelihood because of the complexities, uncertainties and multilevel drivers associated with it. This paper aims to evaluate both these possibilities through use of empirical data to clarify factors and conditions that may impede sustainable livelihood outcomes despite well planned strategies. It highlights that availability of more resources (or capitals) do not necessarily contribute to more robust livelihood strategies or outcomes. Using the case of small scale fishery-based livelihood system of Chilika Lagoon, Bay of Bengal in the East coast of India, this paper suggests that the relationship between livelihood shocks and stresses, capitals, institutions and livelihood strategies is circular and not linear.Extensive household and village level survey data are used to examine the processes of social-ecological change in Chilika from a livelihood perspective. It describes how through changes in context, resources and institutions, fishers in Chilika responded to the livelihood crisis, and how various strategies were used. It further examines the extent to which the outcomes of the strategies contributed to making fisher livelihoods sustainable. Conclusions drawn suggest that the outcomes of the livelihood crisis and responses from Chilika fishers have resulted in higher levels of their disconnection from the Lagoon and their marginalization. The multiplicity of ways through which fishers in Chilika perceive their livelihood suggest that livelihood in resource dependent communities, such as Chilika small-scale fisheries, is multidimensional and far more complex and dynamic than often perceived. Further innovations in approaches and tools will help better understand livelihood challenges and make related outcomes sustainable.

Two faces of shrimp aquaculture: commonising vs. decommonising effects of a wicked driver

Much coastal fisheries literature supports the idea that shrimp aquaculture has the potential to cause considerable social and environmental destruction. The aim of the paper is to highlight the two faces of shrimp aquaculture as a wicked driver, emphasizing its potential role in activating systematic conversion of lagoon –based fisheries commons to non-commons and vice versa. We use the cases of aquaculture-led privatisation in Chilika Lagoon, located in the Bay of Bengal area of India, and collective action surrounding shrimp aquaculture in Northwestern Sri Lanka. For both studies, data are collected through mixed research methods, including semi-directive interviews, focus group discussions, and participant observations. Our analysis shows clear evidence that shrimp aquaculture can potentially contribute to either making commons or losing commons depending on the context and influences of multi-level drivers. Aquaculture-led factors contributing to the process of losing commons in Chilika are: large-scale, individually owned aquaculture operations; encroachment of customary fishery commons; loss of commons rights (access and entitlements); breakdown of commons institutions; policy changes; caste politics and resource conflicts; ecological disturbances; change in fishing practices. In Sri Lanka, aquaculture related factors contributing to making commons are: coordinating discharge; built-in incentive for stewardship; multi-level commons institutions; collective decision-making; bottom-up management approach; mixed commons regime; and small-scale operations.

Length-weight and length-length relationship of Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch &amp; Schneider, 1801) from Chilika lagoon, India

Current study provides basic information on Length–weight relationship (LWR) and length-length relationship (LLR) of three fish species of genus Thryssa (Clupeiformes: Engraulidae) i.e., Thryssa purava (Hamilton, 1822), Thryssa polybranchialis Wongratana, 1983 and Thryssa mystax (Bloch & Schneider, 1801) from Chilika Lagoon, India. Samples were collected during the monsoon (July) and post-monsoon (November) seasons in 2016 and during the pre-monsoon season (May) in 2017, using screen barrier nets (mesh size 8–18 mm) and gill nets (mesh size 14 and 16 mm). The b values were determined from LWRs as 3.026 for Thryssa purava, 3.326 for Thryssa polybranchialis and 3.081 for Thryssa mystax.

The Impact of Tropical Cyclone ‘Phailin’ on the Hydrology of Chilika Lagoon, India

The Impact of Tropical Cyclone ‘Phailin’ on the Hydrology of Chilika Lagoon, India

Characterization of benthic habitat settings in a lagoonal ecosystem using free-living nematodes as proxy

Free-living nematodes are sensitive to most of the disturbances and therefore have ability to reflect direct structural and functional changes in an ecosystem. We studied nematode assemblages of Chilika Lagoon, the largest lagoon of Asia, across spatio-temporal scales in link with environmental variables and evaluated nematode assemblages as a proxy to characterize lagoonal benthic habitat settings. Our results revealed that nematode communities showed significant variation spatially and temporally in terms of mean density (16–854/10 cm2) and mean number of species (7–74). Salinity is the key factor that controls nematode community structure across this lagoon and was strongly supported by statistical analyses. The observed nematode assemblages were further used as a proxy to assign benthic habitats of Chilika into distinct biological, topographical and hydrological settings. This study showed that nematode assemblages could be effectively used for long term ecological monitoring of dynamic sedimentary environment of lagoons globally.

Trace metal concentrations in euryhaline fish species from Chilika lagoon: human health risk assessment

Five trace metals, viz. copper (Cu), chromium (Cr), iron (Fe), mercury (Hg) and zinc (Zn), in three organs (muscle, gills and liver) of four selected fish species (Mugil cephalus, Eleutheronema tetradactylum, Etroplus suratensis and Daysciaena albida) from Chilika lagoon were studied monthly to assess the concentration level and human health risk via consumption. The average and range of metal concentrations (μg g−1) in flesh of the fish species were found to be: Cu (4.15, 3.47–5.03), Cr (0.25, 0.04–0.63), Fe (19.72, 14.51–27.30), Hg (0.07, 0.05–0.08) and Zn (8.09, 4.41–11.36). The metal concentrations measured in the edible muscles of all fish species were found lower as compared to the contents in liver and gill. Analysis of variance revealed a significant difference in trace metal accumulation among the organs (p 0.05), with the exception of Zn accumulation (p < 0.05). The estimated daily intake (EDI) of the trace metals through the consumption of fish as a dietary component varied widely from 0.48 to 21.33% with respect to the corresponding permissible tolerable daily intake (PTDI). The target hazard quotients (THQs) calculated considering these EDIs for individual metals indicated that the Cr and Cu metals dominantly contributed (avg. THQ = 0.198) to represent the hazard index (HI) than other metals (avg. THQ = 0.029). The average HI determined for all the species was <1 (0.484, ranged 0.255–0.605), indicating that these fish species of Chilika are safe for human consumption.

Salinity and macrophyte drive the biogeography of the sedimentary bacterial communities in a brackish water tropical coastal lagoon

Brackish water coastal lagoons are least understood with respect to the seasonal and temporal variability in their sedimentary bacterial communities. These coastal lagoons are characterized by the steep environmental gradient and provide an excellent model system to decipher the biotic and abiotic factors that determine the bacterial community structure over time and space. Using Illumina sequencing of the 16S rRNA genes from a total of 100 bulk surface sediments, we investigated the sedimentary bacterial communities, their spatiotemporal distribution, and compared them with the rhizosphere sediment communities of a common reed; Phragmites karka and a native seagrass species; Halodule uninervis in Chilika Lagoon. Spatiotemporal patterns in bacterial communities were linked to specific biotic factors (e.g., presence and type of macrophyte) and abiotic factors (e.g., salinity) that drove the community composition. Comparative assessment of communities highlighted bacterial lineages that were responsible for segregating the sediment communities over distinct salinity regimes, seasons, locations, and presence and type of macrophytes. Several bacterial taxa were specific to one of these ecological factors suggesting that species-sorting processes drive specific biogeographical patterns in the bacterial populations. Modeling of proteobacterial lineages against salinity gradient revealed that α- and γ-Proteobacteria increased with salinity, whereas β-Proteobacteria displayed the opposite trend. The wide variety of biogeochemical functions performed by the rhizosphere microbiota of P. karka must be taken into consideration while formulating the management and conservation plan for this reed. Overall, this study provides a comprehensive understanding of the spatiotemporal dynamics and functionality of sedimentary bacterial communities and highlighted the role of biotic and abiotic factors in generating the biogeographical patterns in the bacterial communities of a tropical brackish water coastal lagoon.

Mangrovibacter phragmitis sp. nov., an endophyte isolated from the roots of Phragmites karka.

A facultatively anaerobic, Gram-stain-negative, rod-shaped, nitrogen-fixing, endophytic bacterial strain designated MP23T was isolated from the roots of Phragmites karka growing in Chilika Lagoon, Odisha, India. Strain MP23T was slightly halophilic, and the optimal NaCl concentration and temperature for growth were 1 % and 30 °C, respectively. On the basis of 16S rRNA gene sequence similarities, strain MP23T was affiliated to the family Enterobacteriaceae and most closely related to Mangrovibacter yixingensis KCTC 42181T and Mangrovibacter plantisponsor DSM 19579T with 99.71 % similarity, followed by Salmonella enterica subsp. salamae DSM 9220T (97.22 %), Cronobacter condimenti LMG 26250T (97.14 %) and Salmonella enterica subsp. diarizonae DSM 14847T (97 %). Sequence analysis of 16S rRNA, hsp60, gyrB and rpoB genes showed that strain MP23T formed a phylogenetic cluster with M. yixingensis KCTC 42181T and M. plantisponsor DSM 19579T indicating that it belongs to the genus Mangrovibacter. The major cellular fatty acids were C16 : 0, C18 : 1ω6c and/or C18 : 1ω7c, C16 : 1ω6c and/or C16 : 1ω7c, C14 : 0, C14 : 0 3-OH and/or iso-C16 : 1 I and C17 : 0 cyclo. Polar lipids of strain MP23T consisted of phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine. The DNA G+C content was 50.3 mol%. Based on experimental DNA-DNA hybridization values and average nucleotide identity derived from in silico comparison of whole-genome sequences, strain MP23T could be distinguished from its closest neighbours. We therefore conclude that strain MP23T represents a novel species of the genus Mangrovibacter for which the name Mangrovibacter phragmitis sp. nov. is proposed. The type strain is MP23T (=DSM 100250T=KCTC 42580T).

Sources and Variability of Petroleum Hydrocarbon Residues in Sediments of Chilika Lagoon, East Coast of India.

The spatio-temporal distribution and the controlling factors of petroleum hydrocarbons (PHCs) in sediments of Chilika lagoon was investigated. Samples were collected during three seasons and quantified using UV-fluorescence spectroscopy. Concentrations of PHCs in surface sediments varies from 0.18 to 12.13ppm (mean 3.71 ± 3.94ppm). Compared to the lagoon, the monitoring stations adjacent to jetties with high boating activities tend to have higher PHC concentrations, suggesting that the contribution is likely to be from fossil fuel combustion and accidental seepage. The sediment organic matter (OM) of Chilika ranges from 0.26% to 6.23%. PHC maintains a positive correlation with OM (p < 0.05; f = 0.334), indicating the long term deposition of PHC as sediment OM. However, there is no significant relation between PHC and sediment texture, indicating its negligible control over PHC. The recorded PHC concentrations are below the threshold limit (70ppm) as classified by United States (US) National Academy of Sciences (NAS) and also lower than those reported from similar ecosystems in India and overseas. Since the long term deposition and the bioaccumulation of PHC cannot be avoided, it is essential to monitor these parameters periodically.

Effect of physico-chemical regimes and tropical cyclones on seasonal distribution of chlorophyll-a in the Chilika Lagoon, east coast of India.

A comprehensive analysis on spatiotemporal variation in physico-chemical variables and their control on chlorophyll-a during 2013-14 was carried out in the Chilika Lagoon. Spatiotemporal variation in physico-chemical regimes significantly controlled the phytoplankton biomass of the lagoon. Further, precipitation-induced river/terrestrial freshwater influx and marine influence controlled the physico-chemical regimes of the Chilika Lagoon, such as nutrients (NH4+, NO3-, NO2-, PO43- and Si(OH)4), temperature, salinity, total suspended matter and dissolved oxygen. This study revealed significant effects of tropical cyclones Phailin (2013) and Hudhud (2014) on physico-chemical regimes and in turn the phytoplankton biomass of the lagoon. Although both cyclones Phailin (2013) and Hudhud (2014) were intense, Phailin (2013) had a greater impact on the Chilika Lagoon due to the proximity of its landfall. Heavy precipitation caused an influx of nutrient-rich freshwater, both during each cyclone's passage, through rainfall, and after, through increased river flow and terrestrial run-off. The increase in nutrients, carried by the run-off, promoted phytoplankton growth, albeit in lag phase. In general, phytoplankton growth was controlled by nitrogenous nutrients. However, the addition of SiO4 through terrigenous run-off fuelled preferential growth of diatoms. The salinity pattern (which can be considered a proxy for fresh and marine water influx) indicated injection of freshwater nutrients into the northern, southern and central sectors of the lagoon through riverine/terrestrial freshwater run-off; marine influx was restricted to the mouth of the lagoon. Present and past magnitudes of salinity and chlorophyll-a were also compared to better understand the pattern of variability. A significant change in salinity pattern was noticed after the opening of an artificial inlet, because of the resulting higher influx of marine water. The overall phytoplankton biomass (using chlorophyll-a concentration as a proxy) remained consistent in the lagoon pre- and post-restoration. Due to the wide range of salinity and temperature tolerance, diatoms remained dominant in both pre- and post-restoration periods, but the overall phytoplankton diversity increased after the artificial inlet was dredged.

Alongshore Sediment Transport Near Tidal Inlets of Chilika Lagoon; East Coast of India

ABSTRACTChilika, a lagoon along the east coast of India, is undergoing transformation due to frequent shoreline change near inlet(s). Shoreline change near inlet includes change in position and shape of inlet, inlet channel length, and spit growth/erosion. These variable features of lagoon inlet(s) critically depend on alongshore sediment transport (LST) and discharge (water and sediment) from the lagoon to the sea. The LST and the processes responsible for sand spit growth/erosion, considered as important attributes of inlet stability, are the subject matter of the present investigation and hence the study assumes importance. The study includes integration of observational and modeling framework. Observations include nearshore wave, bathymetry, beach profile, shoreline and sediment grain size of spits while numerical modeling includes simulation of the wave using MIKE 21 Spectral Wave model and LST simulation using LITtoral DRIFT. The results indicate that the predominant wave directions as S and SSE, which induces round the year south to north alongshore transport with significant seasonal variation in magnitude. The estimated LST closely matches with previous studies near Chilika inlet and for other locations along the Odisha coast. Besides temporal variability, the study reveals spatial variability in alongshore transport near Chilika inlet and considers it as one of the important attributes along with northward spit growth for inlet migration/closure/opening.

Spatio-temporal variability and the impact of Phailin on water quality of Chilika lagoon

Chilika, Asia's largest brackish water lagoon was studied for 4 years (2011–2015) to understand the variability of water quality and the impact of a very severe cyclone storm “Phailin” (Category-5). During the study period environmental variables exhibited a significant variation among sectors, seasons, and years (p<0.05, n=1440). Correlation matrix showed the major source of phosphate in Chilika were from in situ processes whereas, nitrate and silicate were from the riverine influx. Principal component analysis revealed that the biological factor and riverine flux mostly controlled the water quality. The overall ‘water quality Index’ indicated that the ecological health of the Chilika lagoon was “Good”. The Phailin had a notable impact on water quality as substantiated by the trends of several parameters. The decrease in nitrate and phosphate after Phailin was attributed to dilution by low nutrient freshwater flux from major rivers whereas, the significant increase in reactive silicate was attributed to mixing of silicate enriched fresh water. Post Phailin increase in dissolved oxygen and chlorophyll-a was attributed to wind-induced mixing and resuspension of benthic chlorophyll respectively. A substantial change of nutrient stoichiometry and decrease in photic depth after Phailin resulted a pull down of primary productivity in the Chilika lagoon.

Distribution and sources of carbon, nitrogen, phosphorus and biogenic silica in the sediments of Chilika lagoon

The present study investigated the spatial and vertical distribution of organic carbon (OC), total nitrogen (TN), total phosphorus (TP) and biogenic silica (BSi) in the sedimentary environments of Asia’s largest brackish water lagoon. Surface and core sediments were collected from various locations of the Chilika lagoon and were analysed for grain-size distribution and major elements in order to understand their distribution and sources. Sand is the dominant fraction followed by silt + clay. Primary production within the lagoon, terrestrial input from river discharge and anthropogenic activities in the vicinity of the lagoon control the distribution of OC, TN, TP and BSi in the surface as well as in the core sediments. Low C/N ratios in the surface sediments (3.49–3.41) and cores (4–11.86) suggest that phytoplankton and macroalgae may be major contributors of organic matter (OM) in the lagoon. BSi is mainly associated with the mud fraction. Core C5 from Balugaon region shows the highest concentration of OC ranging from 0.58–2.34%, especially in the upper 30 cm, due to direct discharge of large amounts of untreated sewage into the lagoon. The study highlights that Chilika is a dynamic ecosystem with a large contribution of OM by autochthonous sources with some input from anthropogenic sources as well.

Multiple Spatial Scale Analysis Provide an Understanding of Benthic Macro-Invertebrate Community Structure Across a Lagoonal Ecosystem

Chilika, the largest coastal lagoon of Asia, represents a complex transitional zone between terrestrial and marine ecosystems. In this study benthic macro-invertebrate community structure was elucidated based on multiple spatial scales approach (station-wise, sector-wise and region-wise) across Chilika from June 2013 to February 2015 (temporal scale), encompassing 23 pre-selected stations in link with measurement of abiotic parameters. Sixty two macro-invertebrate species representing seven macrofaunal groups were encountered, of which gastropods were the most abundant in terms of density (~96%) and species composition (~43%), and crustaceans were the least. The structure of the macrofaunal community (in terms of abundance) showed significant differences across spatial (station-wise, sector-wise and region-wise), and temporal scales (month-wise). While macro-invertebrate species composition revealed heterogeneity both station-wise and month-wise but it was found to be homogenous within the sector-wise and region-wise scales. BIO-ENV analysis indicated that salinity together with sediment nature were major abiotic variables associated with observed macro-invertebrate patterns. The results together demonstrated that macro-invertebrate communities are adapted to prevailing environmental conditions of Chilika lagoon; homogeneous and heterogeneous distribution and diversity patterns across multiple spatial scales revealed assemblages distinct to this ecosystem. The multiple scales approach could prove to be useful for ecological monitoring of lagoons.

Differential Impact of Anniversary-Severe Cyclones on the Water Quality of a Tropical Coastal Lagoon

Mapping spatio-temporal dynamics of suspended load in a lagoon before-during-after a cyclone is crucial for monitoring sudden nutrient enrichment and associated processes such as algal blooms and siltation. However, not all cyclones produce similar impact on a coastal lagoon, some trigger algal blooms after passage while others just increase the overall turbidity. Asia’s largest brackish water lagoon, Chilika Lagoon, India was hit by two anniversary-severe cyclones Phailin (12 October 2013) and Hudhud (12 October 2014) recently. Their impacts were analysed with respect to physical, biological and meteorological factors which favour or restrict a phytoplankton bloom after the passage of a storm. Moderate-resolution imaging spectroradiometer surface reflectance data were used to examine the spatio-temporal variability in total suspended sediment (TSS) and chlorophyll-a (Chl-a) concentration pre- and post-cyclone. Comparative results revealed that Phailin was associated with higher rainfall, wind speed and surface runoff compared with Hudhud. These factors contributed to higher TSS concentration in all sectors of the lagoon post-Phailin compared with post-Hudhud. Extreme TSS, limited light, high rainfall and runoff and increased flushing rate post-Phailin restricted the likelihood of a phytoplankton bloom in the lagoon, a commonly reported phenomenon after the passage of a cyclone. In contrast, sufficient light availability due to lower TSS, low runoff and flushing and stable wind supported a phytoplankton bloom post-Hudhud. The observed differential impacts were linked to the individual cyclone’s characteristics such as differences in landfall locations, wind speed, trajectory after the landfall, differences in rainfall rate and surface runoff and speed of passage.