The concentration of phytoplankton is often used to assess the ecological status of water bodies; it is determined by the fluorescence intensity of chlorophyll-a, which is located in microalgae cells. Investigators do not usually take into account the effect of the medium on the fluorescence intensity when determining the concentration of phytoplankton. This article describes the use of a fibre-optic spectrometer developed by the authors to identify the relationship between the fluorescence of the chlorophyll-a in phytoplankton cells and under environmental conditions, such as temperature and illumination. A mathematical model is used to calculate the chlorophyll-a concentration based on fluorescence measurements and takes the temperature and amount of light into account. Using the resulting proportionality coefficient can reduce the error in the chlorophyll-a concentration determined using fluorescence methods by a factor of two. In this article the, authors describe the results of applying the method they developed to performance monitoring in the waters of the Gulf of Peter

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol-gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll-a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P. purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed.

In this paper, we review photonic methods and technologies that are promising for monitoring the ocean and atmosphere and have been implemented mainly in recent years at the Institute of Automation and Control Processes, Far Eastern Branch, Russian Academy of Sciences. We present results of lidar studies that have made it possible to understand key features of ocean – atmosphere interaction processes under continent – ocean transition conditions, which determine specific features of the atmospheric aerosol distribution, small gaseous components of the atmosphere and its optical characteristics. We consider methods and tools for combined optical and laser fluorescence monitoring of the ocean surface. Particular attention is paid to results of research on remote methods and tools for real-time laser-induced and laser fluorescence environmental monitoring of the ocean, including specialised fibre-optic probes and mobile underwater robotic systems. We present results of the development and investigation of highly sensitive, noise-proof fibre-optic hydro- and seismic/acoustic sensors for remote monitoring of the ocean and robotic systems for underwater laser protection of marine vessels, hydraulic structures and oceanographic instruments against the negative impact of biofouling.