Enzymatic activity in the surface microlayer and subsurface water in the harbour channel

Enzymatic biodegradation of high molecular weight polymers in the sediment–water interface in the coastal river estuary

“…In our study, we documented considerable seasonal variation in the level of enzymatic activity in the SWI of the studied estuary in Ustka. This finding supports the results of earlier studies carried out on the surface microlayer and subsurface water of this estuary (Perliński et al, ) and other aquatic environments (Allison et al, ; Bhaskar & Bhosle, ; Kalwasińska & Brzezińska, ; Misic et al, ). As a rule, all tested enzymes of the SWI showed their maximum hydrolytic activity during the vegetation period, whereas minimum in the winter season.…”

“…Cellulolytic bacteria synthesizing cellulosomes in the SWI of the studied estuary accounted for only about 5% of the total number of heterotrophic bacteria (Perliński, ), and this may be the reason why so low activity of cellulase was recorded in this boundary water level. In the earlier studies carried out in the coastal Słupia River estuary (Perliński et al, ), the enrichment factor of enzymatic activity (EF SML/SSW ) in the surface microlayer (SML) and subsurface water varied within the range of 1.2–3.2. Similar values of the EF SML/SWI factor (1.5–4.2) of enzymatic activity were recorded in the surface microlayer and the water–sediments interface of this estuary.…”

“…The main sources of these organic compounds in the water bodies are living and dead phytoplankton, zooplankton, benthos, and detritus (Grossi, Massias, Stora, & Bertrand, ). Apart from the sources mentioned above, lipids in the SWI of the coastal river estuary in Ustka may originate from polluted Słupia River and anthropogenic pollution due to intensive exploitation for tourism and commercial purposes of the studied estuary (Perliński et al, ). All these sources may accumulate large quantities of lipids (76.32–386.62 μg·dm −3 ) in the SWI of the studied estuary (Table ) and consequently induce high lipase activity observed in our study.…”

“…The enzymatic activity rates were expressed in terms of maximum velocity of hydrolysis (Vmax; Caruso, ). All details on the methods used to determine the activity level of the studied enzymes were given in the study by Perliński, Mudryk, and Antonowicz ().…”

Spatio-temporal variation in number and production of neustonic and planktonic bacteria inhabiting polluted estuarine harbour channel

“…Although the SML as a very dynamic structure is frequently disrupted by rain and wind of speed greater than 5-6 m s −1 (Engel and Galgani 2016; Sun et al 2018), the results of stirred tank experiments suggest that microlayers can self-reconstruct their original structure in less than a minute (Cunliffe et al 2013). The surface microlayer is generally enriched in both dissolved and particulate organic matter by physical processes including diffusion, convection, advection, adhesion to rising bubble, upwelling of sub-surface water and particle deposition from air (Kurata et al 2016;Perliński et al 2017). Compared to subsurface waters, the surface microlayer can be enriched up to10 2 -10 3 times in molecular and dissolved organic matter consisting mainly of proteins, carbohydrates, lipids, nucleic acids, chitin, pectin and cellulose (Perliński et al Communicated by Govarthanan Muthusamy.…”