Preliminary optical classification of lakes and coastal waters in Estonia and south Finland

Reinart, Anu; Herlevi, Antti; Arst, Helgi; Sipelgas, Liis

doi:10.1016/s1385-1101(03)00019-4

Cited by 58 publications

(63 citation statements)

References 15 publications

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“…One of the first methods, based on K d , was created by Jerlov (1976), which proposed a scale from 1 to 9 types for coastal waters. As this method was created mainly to analyze oceanic waters, normally poor in organic matter; it is not uncommon that coastal basins display attenuation values exceeding up to eight times those of the most turbid Jerlov's class, type 9 (Reinart et al, 2003). Morel and Prieur (1977) elaborated an optical classification based on the reflectance spectra R(λ), separating the so-called case 1 and case 2 waters.…”

Section: Optical Properties and Classificationsmentioning

confidence: 99%

“…Another optical classification applicable mainly to inland waters was proposed by Kirk (1980), distinguishing waters on their prevalent absorption components. With the aim to focus on case 2 waters and to consider the high diversity existing among them, an alternative classification was proposed by Reinart et al (2003), planned for lakes, but suitable for all coastal waters in small and shallow bays, influenced by river contributions and affected by sediments suspension, i.e. all kind of basins comparable to lakes.…”

Section: Optical Properties and Classificationsmentioning

confidence: 99%

“…Based on the features described by Prieur and Sathyendranath (1981), two patterns were recognized: 1) in almost all stations CDOM strongly absorbed light, with reduced contribution of phytoplankton, but 2) in few cases the scattering, ascribable mainly to particulate matter (Gordon and Morel, 1983;Morel and Prieur, 1977), prevailed on the absorption of photons. To apply the optical classification of Reinart et al (2003), based both on AOPs and on OASs contents, once calculated the average R and K d in the visible spectrum, we obtained Secchi depth for each sampling station, by the approximation of Shifrin (1988). It was surprising to discover that all the five optical classes were present in the lagoon, giving rise to a consistent spatial heterogeneity, not detected by classical optical methods.…”

Section: Optical Propertiesmentioning

confidence: 99%

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Optical characterization of coastal lagoons in Tunisia: Ecological assessment to underpin conservation

Nourisson

Scapini

Massi

et al. 2013

Ecological Informatics

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Ghar El Melh is a shallow lagoon (average depth of 0.8 m) that has undergone a eutrophication process due to growing human pressures. To obtain a global frame of the ecosystem functioning, an optical and an ecological classification were used in parallel. Downwelling and upwelling spectral irradiances were measured in situ in 22 sampling stations across the water body; then Apparent Optical Properties (AOPs), namely reflectance R(λ) and vertical attenuation coefficient K d (λ) were calculated for each wavelength of visible spectrum, furnishing typical spectra from turbid waters, rich in dissolved and suspended matter. From water samples of the same stations the concentrations of OASs (Optically Active Substances), i.e. Chromophoric Dissolved Organic Matter (CDOM), Non-Algal Particulate (NAP) and Phytoplankton, were assessed. The use of an optical classification for water bodies rich in TSM and CDOM, integrating AOPs and OASs, highlighted a great spatial heterogeneity, well overlapping with hydrology and human impacts patterns. A modified version of the Ecological Evaluation Index (EEI), considering the macrophyte distribution (based on a visual assessment of macrophyte coverage, without quantitative sampling) was then used, highlighting an intermediate ecological condition, despite high water turbidities. The integrated use of both systems thus furnished a complete characterization, rapidly detecting the most impacted sectors and the possible primary causes. The method might be applied as a monitoring procedure in other Mediterranean coastal lagoons, with the aim to adopt a common conservation strategy for these important transitional water bodies.

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Section: Optical Properties and Classificationsmentioning

confidence: 99%

Section: Optical Properties and Classificationsmentioning

confidence: 99%

Section: Optical Propertiesmentioning

confidence: 99%

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Optical characterization of coastal lagoons in Tunisia: Ecological assessment to underpin conservation

Nourisson

Scapini

Massi

et al. 2013

Ecological Informatics

View full text Add to dashboard Cite

show abstract

“…Summer chlorophyll-a concentrations in the surface layer were 4.8 ±1.3 µg dm -3 , turbidity was 6.5 ±1.8 NTU, and the true colour of the water was 4.8 ±1.5 mg Pt dm -3 . Very little colouring of water (ultraoligohumic lakes) makes the optical properties of these lake waters primarily determined by phytoplankton, as evidenced from the product K d •z SD in the range of 1.9-2.7 (Koenings and Edmundson 1991;Reinart et al 2003;Borowiak 2011). In the case of Lake Szurpiły, for which this parameter is 1.5, a greater impact on the distribution of underwater light field is exerted by nonphytoplankton particles.…”

Section: Discussionmentioning

confidence: 99%

Comparative studies of underwater light regimes in lakes of the East-Suwałki Lakeland

Borowiak

2016

Limnological Review

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Secchi disc transparency and optical properties of water, based on measurements for downward irradiance using an underwater radiometer PER-700, were studied in 23 lakes of the Suwałki Landscape Park (SLP) in 2013. Measurements of optically significant constituents of water were also performed (YSI EXO-2) and analysed. Data on water transparency from published studies were used to assess long-term changes in the optical conditions in the deepest water body in Poland -Lake Hańcza. In terms of the optical characteristics of the water, the analysed SLP lakes can essentially be divided into two distinct groups representing different optical lake types. These are optical categories of lakes most common in Poland, namely types II and IIIb. Regional equations describing the relationships between the attenuation coefficient for downward irradiance as well as optically significant constituents of water were developed. The optical properties of the SLP lakes are mainly affected by suspended solids, mostly phytoplankton. Interannual fluctuations in Sechi disc transparency, as well as the attenuation coefficient for downward irradiance and other apparent optical properties of mid-summer water calculated from it, are determined by the spring thermal conditions and intensity of phytoplankton blooms during this period. Application of the attenuation coefficient for downward irradiance as a criterion for the assessment of the trophic status of the SLP lakes indicates that these are generally eutrophic lakes. The largest and deepest lakes of the park, however, are mesotrophic. Lake Hańcza is currently in the stage of α-mesotrophy.

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“…Various components, such as Chl a concentration, reflectances and Secchi depths can be used as clustering properties (e.g. Reinart et al 2003). Clustering based on reflectance spectra, combined with salinity or temperature, has led to good classification results in various oceanic areas.…”

Section: Introductionmentioning

confidence: 99%

Spectra of a shallow sea—unmixing for class identification and monitoring of coastal waters

et al. 2011

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Ocean colour-based monitoring of water masses is a promising alternative to monitoring concentrations in heterogeneous coastal seas. Fuzzy methods, such as spectral unmixing, are especially well suited for recognition of water masses from their remote sensing reflectances. However, such models have not yet been applied for water classification and monitoring. In this study, a fully constrained endmember model with simulated endmembers was developed for water class identification in the shallow Wadden Sea and adjacent German Bight. Its performance was examined on in situ measured reflectances and on MERIS satellite data. Water classification by means of unmixing reflectance spectra proved to be successful. When the endmember model was applied to MERIS data, it was able to visualise well-known spatial, tidal, seasonal, and wind-related variations in optical properties in the heterogeneous Wadden Sea. Analyses show that the method is insensitive to small changes in endmembers. Therefore, it can be applied in similar coastal areas. For use in open ocean situations or coastal or inland waters with other specific inherent optical properties, re-simulation of the endmember spectra with local optical properties is required. However, such an adaptation requires only a limited number of local in situ measurements.

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Preliminary optical classification of lakes and coastal waters in Estonia and south Finland

Cited by 58 publications

References 15 publications

Optical characterization of coastal lagoons in Tunisia: Ecological assessment to underpin conservation

Optical characterization of coastal lagoons in Tunisia: Ecological assessment to underpin conservation

Comparative studies of underwater light regimes in lakes of the East-Suwałki Lakeland

Spectra of a shallow sea—unmixing for class identification and monitoring of coastal waters

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