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Photosynthesis parameters are routinely estimated from in vitro measurements of primary production under constant light reaching each incubation bottle, by fitting a photosynthesis‐irradiance function to the measurements. Here we take one such function and integrate it in time for variable light input, similar to natural conditions, to obtain the analytical solution for the vertical profile of daily phytoplankton production in the field. This solution is then fitted to in situ measurements of primary production profiles in the same manner as a photosynthesis‐irradiance function is fitted to in vitro measurements under controlled and constant light conditions to retrieve the photosynthesis‐irradiance parameters. The method is tested on the Hawaii Ocean Time‐series data set. The solution explained 97.88% of the variance in measured normalized production at individual depths. The recovered parameters were then used to model the normalized daily water‐column production. The model explained 99.21% of variance in normalized watercolumn production of the entire data set. The seasonal cycle of the photosynthesis parameters recovered with the analytical solution was further studied for the Hawaii Ocean Time‐series. With respect to the photosynthesis parameter determination, the solution bridges the gap between classical photosynthesis‐irradiance measurements under controlled light conditions and in situ measurements which are made under natural, variable light conditions. It presents a new tool for the estimation of photosynthesis parameters from in situ measurements of primary production. Analytical solution for the profile of phytoplankton production derived from a nonlinear model.Procedure for estimating photosynthesis parameters from in‐situ production profiles established.Photosynthesis parameters estimated from Hawaii Ocean Time‐series in‐situ production profiles.

This paper describes the plant communities of two oligotrophic karstic rivers with a slight anthropogenic influence — the Trebižat and the Lištica — in South Bosnia and Herzegovina, their sinecology, and the relationship between vegetation and plant species and environmental parameters. According to 87 relevés, a total of 26 plant associations, using Braun-Blanquet methods, were found in the rivers and nearby surveyed area. Only nine associations were common to both rivers. Eight associations were recorded for the territory of Bosnia and Herzegovina for the first time. Associations from both rivers differed according to following parameters measured at the sampling site: water temperature, distance from the mouth (river kilometers), river width, water depth, flow, pH and slope. There were no differences in nutrient concentrations among the associations. According to Canonical Correspondence Analysis (CCA), three environmental variables out of the 11 initially considered were retained as being related to plant distribution. The first two axes explained 56.8% and 35.2% of variance of species-environment relationship in the Trebižat and Lištica rivers, respectively. Water depth in the Trebižat River, and pH and river kilometers in the Lištica River were found to be the most influential, while nutrients and other physico-chemical parameters were not significant in either river. Water depth vector was identified as an underlying environmental factor determining distribution of Potamogeton lucensand Myriophyllum verticillatum (Potamion), and Nymphaea alba (Nymphaeion albae). According to in situmeasurements of light intensity, the highest coefficients of light attenuation, radiance and reflection were found at a station with dense populations of Potamogeton lucensand Nuphar luteum (Potametum lucentis). The vegetation and floristic value of the rivers is discussed as a basis for biodiversity conservation programmes and evaluating the state of these ecosystems in the future.

This paper describes the plant communities of two oligotrophic karstic rivers with a slight anthropogenic influence — the Trebižat and the Lištica — in South Bosnia and Herzegovina, their sinecology, and the relationship between vegetation and plant species and environmental parameters. According to 87 relevés, a total of 26 plant associations, using Braun-Blanquet methods, were found in the rivers and nearby surveyed area. Only nine associations were common to both rivers. Eight associations were recorded for the territory of Bosnia and Herzegovina for the first time. Associations from both rivers differed according to following parameters measured at the sampling site: water temperature, distance from the mouth (river kilometers), river width, water depth, flow, pH and slope. There were no differences in nutrient concentrations among the associations. According to Canonical Correspondence Analysis (CCA), three environmental variables out of the 11 initially considered were retained as being related to plant distribution. The first two axes explained 56.8% and 35.2% of variance of species-environment relationship in the Trebižat and Lištica rivers, respectively. Water depth in the Trebižat River, and pH and river kilometers in the Lištica River were found to be the most influential, while nutrients and other physico-chemical parameters were not significant in either river. Water depth vector was identified as an underlying environmental factor determining distribution of Potamogeton lucens and Myriophyllum verticillatum (Potamion), and Nymphaea alba (Nymphaeion albae). According to in situ measurements of light intensity, the highest coefficients of light attenuation, radiance and reflection were found at a station with dense populations of Potamogeton lucens and Nuphar luteum (Potametum lucentis). The vegetation and floristic value of the rivers is discussed as a basis for biodiversity conservation programmes and evaluating the state of these ecosystems in the future.

Abstract: Spatial and temporal variability of pigments was studied from the CZCS satellite data and fromin situ chlorophyll and transparency for the period 1979-1985. The three Adriatic sites, Northern, Middle, and Southern Adriatic are differently influenced by meteorological, hydrological and oceanographic parameters. The differences between seasonalin situ chlorophyll and remotely sensed pigment concentrations (from CZCS satellite data) from the Adriatic are large in winter. Through the correlation analysis, pigments were compared to meteo-oceanographic and hydrological parameters from different Adriatic sites. The PCA (principal component analysis) was applied to the pigment data series and significant components were compared. Different correlations are obtained for warm and cold periods of the year pointing to seasonal differences in the underlying mechanism of pigment variability. The first PC is influenced mainly by temperature. In the warm period more parameters seem to influence the pigment field, than in the cold period. The pigments in the Adriatic are in good correlation to a number of hydrologic and meteo-oceanographic factors.