Influence of environmental factors on macrofoulant assemblages on moored buoys in the eastern Arabian Sea

Factors governing the distribution of organisms in the pelagic ocean are understudied. In this paper we describe environmental parameters and macrofouling assemblages on 11 buoys deployed in the Arabian Sea for an average duration of 322 days. Macrofoulants on all the mooring components extending from the sea-surface to a depth of 1800–4300 m were documented. Role of temperature, salinity, dissolved oxygen, biological productivity and zooplankton community in governing the macrofoulant distribution are described. Species composition, vertical zonation and wet biomass exhibited significant spatial variations. Lepas anatifera constituted more than 90% of foulant wet biomass on all moorings. Assemblages in the southeastern (SEAS), east-central (ECAS) and northeast (NEAS) regions were distinct. Density of L. anatifera on surface buoys were low in SEAS (0.2±0.09 no./cm2), high in ECAS (0.32±0.11 no./cm2) and moderate in NEAS (0.23±0.04no./cm2). Macrofoulants were observed up to a depth of 75 m in SEAS, 130 m in ECAS and 120 m in NEAS. The depth profile of macrofoulant assemblages on moorings could be related to the prevalent hypoxic condition. Vertical profiles of wet biomass on all moorings exhibited subsurface maxima at depth ranging from 10 to 20 m, consequent to the abundance of L. anatifera in a thermally stable depth of water column, wherein diurnal and semidiurnal temperature variability was minimal. We attribute the observed variation in fouling assemblages to dissolved oxygen levels, salinity and diurnal variability in temperature and salinity.


Introduction
Gaining insight into factors that govern patterns of assemblages is a fundamental objective in ecology. Assemblages are shaped by biotic and abiotic stresses in their respective environments. Mobile and sessile organisms respond differently to the stresses. While the mobile organisms could survive a stressful condition by retreating to a favorable environment, the survival of a sessile organism is determined by tolerance to stresses [1]. The study of sessile assemblages may provide information on the habitat and health of the ecosystem. When compared to terrestrial assemblages, sessile assemblages in marine environments are relatively a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 inaccessible and understudied [2]. Of marine studies, most are of intertidal, subtidal and benthic habitats [3][4][5][6][7][8][9]while sessile assemblages in the pelagic ocean are rarely studied.
Pelagic ecosystems are highly dynamic and are shaped by multiple interrelated scales of biophysical interactions [2]. Crucial environmental variables such as temperature, salinity, light, pH, dissolved oxygen (DO), nutrients, etc. show a strong vertical gradient in the pelagic ocean. Man-made stationary structures in the ocean accumulate sessile assemblages across the vertical gradients in environmental parameters.Assemblages of sessile organisms exhibited notable regional variations and vertical zonation on wind farms [10,11], petroleum platforms [12][13][14][15] moored buoys [16][17][18], test panels [19], undersea cables [20], instrumented platforms on the seabed [21], etc. The factors influencing the distribution of sessile assemblages were identified as the light penetration, temperature, pressure, food and nutrient levels, nature of substratum, duration of immersion, and biology, physiology and dispersal of individual species [19,22].The density of sessile photosynthetic algae in the assemblages is determined by the decay of light levels in the water column, species-specific adaptations [23] and grazing [24]. Invertebrate taxa dominate the sessile assemblages below the photic zone and depend upon exogenous organic material for nutrition [22]. The exogenous organic material for invertebrate taxa in the seabed and seamounts are transported by currents and other physical processes driven by the topographical features [25][26][27]. The influence of large topographical features such as seamounts in altering the environment and increased availability of organic matter in the benthic nepheloid layers [28]plays an important role in the establishment of sessile assemblages in an otherwise hostile condition.But, the man-made stationary structures such as moored buoys and petroleum platforms are much smaller and unlikely to alter the physical environment of the adjacent water column. Consequently, the sessile assemblages on such structures are believed to be dictated by the environmental parameters typical to the pelagic ocean [13,15].
Large-scale spatial patterns of assemblages in the marine environment are primarily driven by abiotic stress [7, [29][30][31][32]. In this study, we have analyzed whether the patterns of macrofoulant assemblages on a network of moored buoys could potentially be explained by spatiotemporal variability of environmental parameters. Eleven moored buoys deployed in an area covering~1×10 6 km 2 in the eastern Arabian Sea (Fig 1) were selected for the study. The Arabian Sea is a tropical ocean basin that exhibits pronounced seasonality in key environmental parameters. In the subsequent sections, we have documented the patterns of macrofoulant assemblages on the moored buoys and analyzed the influence of environmental parameters.

Measuring geographic distribution of macrofoulants
Patterns of macrofoulants were observed on moorings deployed in the eastern Arabian Sea for a durationof 128 to 477 days (Fig 1 and Table 1).The moorings examinedduring the study comprised of four configurations, namely Met-Ocean buoy (AD02 and AD04), CALVAL, tsunami buoy (TB12) and Ocean Moored buoy for North Indian Ocean (OMNI, moorings AD09, AD10, AD08-A, AD08-B, AD07-A, AD07-B and AD06). Moorings AD08-A and AD08-B were located only 16 km apart and hence are collectively referred as the AD08 in subsequent text. Similarly, AD07-A and AD07-B are collectively referred as AD07 as they were located only 14 km apart. Field permit for the research was granted by the National Institute of Ocean Technology, Chennai, India.
Distribution of macrofoulants on mooring was documented during retrieval of the system using photographic and scrape sampling techniques. Photographs of random quadrat measurements (0.25 x 0.25 m) were taken of all mooring components shallower than 5 m to estimate density of various fouling communities. Scrapes were made upto mooring substratum from all accessible mooring components. Individual organisms were sorted, preserved in 95% ethanol and identified to species level for the dominant fouling barnacle and to family or order for the other macrofoulants. Retrieval procedure of OMNI buoys permitted sampling from all depths and analysis of depth wise distribution of macrofoulants. For other type of moorings, samples from the components up to a depth of about four meters were collected, as rest of the mooring components were not retrieved. Total wet biomass on Conductivity-Temperature (CT) sensors deployed on OMNI buoys was estimated by subtracting the weight after retrieval from thatof a clean sensor. Zooplankton samples in the upper 100 mof the water column were collected by single vertical haul of zooplankton net (mesh size 300μm) near the moorings during OctoberandNovember 2016.

Environmental data
Data on environmental parameters in the mooring locations were documented based on mooring mounted sensors, shipborne measurements during retrieval of the moorings, remote   [33]. Monthly climatology of remotely sensed surface chlorophyll-a concentration over the eastern Arabian Sea was used as a proxy for phytoplankton abundance.The chlorophyll-a data is based on the European Space Agency's Climate Change Initiative (OC-CCIv3) mission [34]. Gridded monthly climatology of ocean surface current data used in the analysis was based on Ocean Surface Current Analysis-Real time (OSCAR), which is an estimate of mean currents in top 30 m of the ocean [35].The bathymetry data wasGridded Global Relief Data, Earth topography two arc-minute (ETOPO2) v2.

Data analysis
Temporal variations in temperature and salinity at different depths in OMNI buoy locations were analyzed based on the hourly dataset collected by the moorings.Summary statistics of the temperature and salinity data were calculated to describe mean conditions, short-term variability and seasonal-scale variability. All statistics presented here are based on quality-controlled data during the period mentioned in Table 1. The average value of salinity and temperature at different depths in the mooring locations were obtained as the mean of the dataset during the entire deployment period. Diurnal variability of salinity and temperature were studied using a proxy called mean daily peak-to-peak variability. The mean daily peakto-peak variability in salinity and temperature was computed as the mean of the difference between daily maximum and minimum.The standard deviation of salinityand temperature timeseries after smoothing out high-frequency variability using a three-day running mean is considered as a proxy to study seasonal scale variability. Higher values for the standard deviation are indicative of large seasonal variations in salinityand temperature.Linear correlations of the summary statistics with density distribution of the most predominant macrofoulant at different depths on the moorings were determined using Pearson correlation. All statistical analysis was performed in MATLAB R2019a.

Distribution of foulants on moored buoys in the eastern Arabian Sea
Mooring components in the top 100 m of the water column were found to be colonized by diverse macrofouling organisms. On the basis of wet biomass, macrofoulant taxa on moorings were composed of 93-97% pedunculate barnacles, 1-3% algae, 1-2% bivalves, 1-2% hydroids and less than 1% other fouling organisms like bryozoans, sessile filter feeder polychaetes, nonsessile mobile organisms such as crab species, predatory polychaetes and echinoderms, etc.
( Table 2). The semi-submerged buoys of all eleven moorings were nearly identical (S1-S3 Figs). Fouling was observed to be concentrated around the rubber fender fixed at the waterline and on the ridges of the corners. Mean density of the most predominant macrofoulant Lepasanatifera on fender and edges of surface buoy of moorings are given in Fig 2A (corresponding to depth 0.5 m). In the southeastern Arabian Sea (SEAS), density of L. anatiferawas observed to be very low (0.2±0.09no./cm 2 ) on surface buoys (Fig 2A and S1 Table). Buoys deployed for more than 420 days in the SEAS (S1B and S1D Fig) had only low to moderate fouling. The moorings Table 2. Macrofoulants observed on moorings and the zooplankton groups collected from vicinity of the moorings. Zooplankton samples were collected only from selected stations for moorings located less than 30 nautical miles apart from one another.  The vertical distribution of fouling organisms colonizing the buoy and its mooring system were investigatedbased on data from OMNI buoys. The algal communities were observed on all moorings in the depths from 0 to 75 m. The dominant macrofoulant species colonizing subsurface mooring components were pedunculate barnacles, hydroids, polychaetes, oysters, etc. The density and wet biomass of the macrofoulants varied with depth. The Macrofoulants were noticeable up to a depth of 75 m in the SEAS, 130 m for the ECAS and 120 m for the NEAS. The pedunculate barnacle, L. anatifera was dominant from 0 to 50m (Fig 2). Besides, a few specimens of L. anatifera were observed even at 75m depth on moorings in the ECAS and NEAS.At 75 to 130 m depth, the moorings in the ECAS and NEAS were mainly colonized by pedunculate barnacles Conchodermahunteri and Octolasmiswarwickii, and their maximum density was observed around 100m depth.The analysis of vertical profiles of wet biomass on all moorings revealed subsurface maxima in the depth range 10 to 20 m (Fig 2B), which coincided with high barnacle abundance (Figs 2A and 3). Consequently, the vertical profile of foulant wet biomass was nearly identical to the vertical distribution of L. anatifera (Fig 3). The analysis in S1 Appendix suggests that the distribution of macrofoulant assemblages documented herein were not significantly affected by the factors like dissimilarities in deployment duration, antifouling measures and retrieval procedures among moorings.

Environmental control on spatial variability of fouling communities
Macrofoulant assemblages on eleven moored buoys retrieved from the open ocean waters of the Arabian Sea revealed the existence of distinct regional patterns. Ecological and oceanographic factors might explain the observed distributions. Herein, the possible influences of various ecological and oceanographic factors in governing the regional patterns were investigated.
Biological productivity. Several studies have reported increased growth of organisms in various trophic levels, aided by the upwelling driven availability of nutrients, phytoplankton and detritus [29,[36][37][38][39][40]. We used remotely sensed and in situ chlorophyll-a data (Figs 4 and 5A) as proxies for phytoplankton abundance. Remote sensing gives an average value for chlorophyll-a in the top 25 meters [41]. High concentration of chlorophyll-awas observed in the NEAS (Fig 4A-4L). But, the chlorophyll-a concentration was perennially low in the ECAS. Moderately high chlorophyll-a concentration was observed in the vicinity of SEAS moorings during July to October. Vertical profile of chlorophyll-a in upper 200mof water column based on CTD casts in the vicinity of moorings (Fig 5A) was also consistent with the monthly climatology data (Fig 4A-4L).Relatively low concentration of chlorophyll-a observed in the ECAS in comparison to SEAS and NEAS suggests that ECAS was least productive region. However, the moorings in the least productive area within the study region had the highest density of macrofoulants (Figs 2 and 3). Hence, it is apparent that factors other than biological productivity also contribute significantly to the spatial variability of macrofoulant wet biomasson moorings. Previous studies suggest that pelagic production constitutes the dominant basal resource fueling sessile suspension-feeding organisms on artificial reefs [24].The role of changes in concentration of planktonic food in determining the vertical distribution of filter feeders on the mooring has to be further examined. Zooplankton community analysis. The zooplankton samples were collected during the mooring retrieval. The density of zooplankton was higher in NEAS (~5000 no./m 3 ) in comparison to ECAS and SEAS (~2000 no./m 3 ) (S4 Fig). Copepods were the dominant taxain all zooplankton sampling locations but they did not account for the fouling. Among the fouling  (Table 2). ECAS and NEAS also recorded the presence of Poecilasmatidae nauplii. Zooplankton samples from all stations lacked larval forms of acorn barnacles, substantiating the absence of adult acorn barnacles from the moorings. The absence of acorn barnacles could be attributed to the offshore location of the stations [42][43][44]. Although Mytilidae and Ostreidae were observed on moorings, the zooplankton community lacked bivalve larvae, except for bivalve veliger in ECAS. The absence of bivalve larvae could be attributed to seasonality of reproduction exhibited by the species.
Most of the biofouling taxa on mooring components, viz. barnacles, bivalves, bryozoans, polychaetes, hydrozoans etc. have a planktonic larval stage in their life cycle [45]. However, the fouling community is not a replica of the zooplankton community. The variations between biofoulants and zooplankton communities could be due to the dispersal capability of larval forms, which are susceptible to competition, predation, mortality and advection by ocean currents [46] (Fig 4). Besides, the zooplankton distributions reported here are based on point samples of larvae from organisms which live for months to years.
Salinity. The eastern Arabian Sea is part of a highly saline tropical ocean [47]. Seasonally reversing monsoon currents in the north Indian Ocean [48]advect low-saline water from the Bay of Bengal into the SEAS during the period from November to April. Consequently, salinity in the SEAS rapidly decreases during November to April (Fig 6B-6G). Vertical profile of salinity based on CTD casts (Fig 5B) also suggests that salinity in upper 200min theSEASwas lower than that of ECAS and NEAS. Fig 7A-7C showcertain summary statistics of temporal  (Fig 7A). The mean salinity in the SEAS was about 1 PSU lower than that of ECAS and NEAS (Fig 7A). On average, daily variations in salinity, determined as mean daily peak-to-peak variability in salinity, was less than 0.4 PSU in the eastern Arabian Sea, with highest daily variations recorded in the SEAS and lowest in the ECAS (Fig 7B). Salinity in the SEAS mooring locations showed large seasonal variations as evident from the high standard deviation of salinity (Fig 7C). The large seasonal scale salinity variations in the SEAS were a consequence of changes in circulation patterns (Fig 4A-4L and Fig 5A-5L). Fig 8A-8C shows scatter plot of density of L. anatifera on CT sensors in the depth range 5 to 75 m versus different statistics of salinity. The density of L. anatifera showed a significant positive correlation (R = 0.45, p = 0.011) with mean salinity. The significant positive correlation suggests that density of L. anatifera could increase with increase in mean salinity. Significant negative correlation (R = -0.495, p = 0.004) was observed between the mean daily peakto-peak variability in salinity and density of L. anatifera (Fig 8B). Seasonal variability of salinity did not show any significant correlation with density of L. anatifera (Fig 8C) in the eastern Arabian Sea.Hence, it is apparent that the prevailing low-saline conditions and strong diurnal variability of salinity contributedsignificantly to the lowdensity of L. anatifera on moorings in the SEAS. Influence of environmental factors on macrofoulant assemblages on moored buoys in the eastern Arabian Sea Temperature. Temperature plays a vital role in regulating respiration, feeding and breeding of marine organisms [49,50]. Tolerance of marine organisms to ambient temperature showed marked variations across species [51,52]. Recruitment of larvae on substrates were also influenced by temperature [53][54][55]. Hence, temperature could potentially regulate species composition and vertical zonation of macrofoulants on moorings. The most predominant macrofoulant on the mooring, L. anatifera is usually found in tropical oceans having Influence of environmental factors on macrofoulant assemblages on moored buoys in the eastern Arabian Sea temperature >18˚C. Laboratory experiments suggests that L. anatifera could reproduce in temperatures ranging from 15 to 30˚C, with 19 to 27˚C being the most optimal breeding temperature [56].
Different statistics of temperature evolution in the eastern Arabian Sea were analyzed to study the influence of temperature on biofouling. Vertical profile of temperature based on mean data during the mooring deployment period (Fig 7D) and CTD casts during October 2016 ( Fig 9A) revealed a warm mixed layerhaving minimal variation of temperature with depth. A significant fraction of the biofoulants observed on the mooring was concentrated withinthis warm layer in top 50 m (Fig 3). Also, majority of L. anatifera observed on moorings were in the water column having mean temperature in the range of 28 to 29.5˚C (Fig 8D). But density of L. anatifera exhibited insignificant correlation with mean temperature (Fig 8D), apparently due to the nearly identical mean temperature values throughout the eastern Arabian Sea (Fig 7D). Previous studies have shown that diurnal temperature fluctuations can influence community structure in marine environments [57,58]. Diurnal temperature variability in the eastern Arabian Sea was studied based on mean daily peak-to-peak variability in temperature (Fig 7E). In all mooring locations, average daily variations in temperature was only about 0.5˚C at depth 15 to 20 m, while much larger daily temperature variations were observed in other depths of the water column.The larger values of mean daily peak-to-peak variability in Influence of environmental factors on macrofoulant assemblages on moored buoys in the eastern Arabian Sea temperature in the water column deeper than 20 m was due to internal tides having diurnal and semidiurnal periodicities [59,60]. High frequency temperature variability was most pronounced in the SEAS moorings ( Fig 7E). Temperature data close to sea surface also had diurnal and semidiurnal oscillations (Fig 7E). The high-frequency temperature variability penetrating up to a depth of 10 m from the sea surface was driven by factors such as turbulence, air-sea fluxes and diurnal solar heating [61]. In the eastern Arabian Sea moorings, L. anatifera was observed in the water column that recorded mean daily peak-to-peak variability of temperature less than 1.5˚C (Fig 8E). Significant negative correlation (R = -0.549, p = 0.001) was observed between density of L. anatifera and mean daily peak-to-peak variability in temperature ( Fig 8E). Hence, it is plausible that relatively stable temperature in water column in the depth range 15 to 20 m could have promoted increased growth of L. anatifera, leading to the formation of subsurface maxima (Fig 2).Standard deviation of temperature time series after smoothing out high frequency variability using a three-day running mean (Fig 7F) is considered as a proxy to study seasonal scale variability of temperature. Relatively higher standard deviations of temperature were observed in the water column deeper than 20m in the SEAS pointing to the large seasonal variability of temperature in the region compared to both NEAS https://doi.org/10.1371/journal.pone.0223560.g008 Influence of environmental factors on macrofoulant assemblages on moored buoys in the eastern Arabian Sea and ECAS. But, density of L. anatiferadid not show any significant correlation with seasonal variability of temperature ( Fig 8F).

Dissolved oxygen
Availability of DO in the marine environment is a crucial factor that regulates metabolic and biogeochemical processes. The near-surface layer of the ocean is replete with DO. But, the subsurface depths has a much lower concentration of DO, wherein oxygen advected from surface layer is consumed by respiration, decay of sinking organic matter etc. [63]. The depleted level of DO in water depth ranging from 10 to 1300 m with a concentration less than 0.5 ml l -1 is called mid-depth Oxygen Minimum Zone (OMZ) [64]. The Arabian Sea with its closed northern boundary encompasses the second-most intense OMZ of all tropical oceans [62].
Profiles of DO in the vicinity of moored buoys based on CTD casts are plotted in Fig 9B. The concentration of DO in the near-surface layer was~3 ml l -1 at all mooring locations. The thickness of the well-mixed oxygen-repletenear-surface layer was observed to be highest in the ECAS (~65 m) and lowest in the SEAS (~30m) (Fig 9B). DO depleted rapidly in oxycline located below near-surface layer at all mooring locations. DO in the NEAS and ECAS decreased to microxic levels (<0.1 ml l -1 , [65])at~140mdepth. But in the SEAS, DO first decreased to hypoxic levels (<0.2 ml l -1 ) at~70mand then increased with depth from 140m ( Fig 9B). The higher concentrationof DO in intermediate depths in the SEASwas driven by advection of DO from southern hemisphere [66,67]. The oxycline was very shallow and had strong vertical gradientin the SEAS (Fig 9), which indicates prevalence of strong upwelling in the region.Time seriesin-situ measurement of DO in the SEAS also revealed the occurrence of pronounced seasonality associated with upwelling [68].Macrofoulants with limited or no motility may be exposed to physiological stress associated with episodes of hypoxia. Seasonal occurrence of hypoxia could devastate marine environment [69][70][71]. Hence, the varying levels of oxygen stress can be instrumental in shaping composition and vertical zonation of macrofoulants on moorings. Hypoxic conditions in the SEAS at a shallow depth of 75 m could be a significant contributor for the absence of macrofoulants below 75 m on moorings.
The deeper near-surface DO replete water columnin the ECAS (Fig 9B) hadL. anatifera assemblages up to 75 m depth.C. hunteri and O. warwickii were predominant macrofoulants in the depth range 75 to 130 m on moorings in the NEAS and ECAS. In these regions, the depth range 75 to 130 m coincided with oxycline and thermocline wherein both temperature and DO decreased rapidly with depth (Fig 9A and 9B). The prevalence of strong vertical gradients could regularly cause huge fluctuations in temperature and DO as the water column oscillates due to internal tides. Thus it is apparent that the C. hunteri and O. warwickii thriving in depth 75 to 130 m on moorings in the NEAS and ECAS were better adapted to physiological stress associated with depleted DO and semidiurnal oscillations in DO and temperature.

Conclusion
Macrofoulant assemblages on moored buoys spread across an area of~1×10 6 km 2 in the eastern Arabian Sea exhibited significant spatial variability in terms of species composition, vertical zonation and wet biomass. Our analysis revealed that the observed patterns of macrofoulant assemblages were shaped by various environmental parameters. Biological productivity and zooplankton community distribution in the vicinity of the moorings were observed to have only a limited influence in shaping the macrofoulant assemblages.
A correlation analysis based on temperature and salinity suggests that the most predominant foulant on moorings,L. anatifera was less tolerant to low-saline environments and diurnal variations in both temperature and salinity. But, the mean temperature and seasonal variability in temperature and salinity prevalent in the near-surface waters of the eastern Arabian Sea had only a limited influence on L. anatifera abundance. The results also suggested that the higher density of L. anatifera in the ECAS was aided by the relatively stable near-surfacetemperature and salinity conditions prevalent in this region.
The impact of artificial substratum, foraging and other biotic factors on the macrofouling were not considered in the present study. Previous studies in shallow coastal environments revealed that assemblages on artificial substrates were not identical to that of adjacent natural substrates as they offer atypical surfaces in terms of orientation, depth range and surface [72,73]. Foraging also plays an important role in shaping the assemblages on artificial structures [74]. The influence of these factors in determining the mesoscale patterns of macrofoulant assemblages on artificial structures have to be further investigated.
Broad scale warming observed in the global ocean [75][76][77] as well as interannual warming or cooling events such as El Niño-Southern Oscillation (ENSO) could induce significant impact on marine ecosystems [78]. Ourstudy suggests that the impact of anomalies in ocean temperature or salinity on marine ecosystems could be reflected in the abundance of L. anatifera on artificial structures in the marine environment. Previous studies have shown that certain epifaunal taxa of foulant communities found on the mooring components such as foraminifera, nematoda, polychaeta, etc. are good bioindicators of ocean acidification [79], ocean warming [80] and hypoxic environments [64,81]. Many of the common macrofoulants on moorings are also considered as good bioindicators for anthropogenic impacts [82].These organisms could, potentially act as bioindicators to monitor changes in the pelagic ecosystems, which constitute about 99 percent of earth's biosphere [83]. Moored buoys are distributed in all major oceanic regionsas part of Global Tropical Moored Buoy Array as well as other regional networks enabling real-time in-situ ocean observation [84]. Global distribution of moored buoys, coupled with the availability of high-quality scientific data about its environment make them an ideal platform to monitor the effect of environment on macrofoulant assemblages. Sustained monitoring of mesoscale patterns of macrofoulant assemblages on moored buoys could significantly enhance our understanding of changes in pelagic ecosystem associated with the global changes in climate.
Supporting information S1 Appendix. Potential impact of dissimilar deployment duration, antifouling measures and retrieval procedures of moored buoys on observed spatial patterns of macrofoulant assemblage. (DOCX) S1 Table. Density of L. anatifera on mooring components at different depth levels. The density at depth 0.5 m is based on the quadrat measurements on buoy hull and the density at all other depths are based on the count of L. anatifera on CT sensors at designated depths. Different statistics based on hourly time series measurement of temperature and salinity from sensors mounted on mooring corresponding to entire deployment duration is also given.