Jozef M Wiktor

Institue of Oceanology Polish Academy of Sciences Sopot · Marine Ecology

We studied phyto- and protozooplankton community composition based on light microscopy, flow cytometry and photosynthetic pigment data in the Atlantic sector of the Southern Ocean during March 2019 (early austral autumn). Sampling was focused on the area east of the prime meridian in the Kong Håkon VII Hav, including Astrid Ridge, Maud Rise and a s...

Instytut Oceanologii Polskiej Akademii Nauk przechowuje 77500 okazów przyrodniczych z obszarów morskich, gromadzonych od 1985 r., czyli od początku istnienia Pracowni Ekosystemów Arktyki, przekształconej później w Zakład Ekologii Morza. Większość zbiorów stanowi zooplankton (około 36000 okazów) zebrany podczas corocznych rejsów badawczych statku s/...

Macroalgae can directly restrict the growth of various phytoplankton species by releasing allelopathic compounds; therefore, considerable attention should be paid to the allelopathic potential of these organisms against harmful and bloom-forming cyanobacteria. The main aim of this study was to demonstrate for the first time the allelopathic activit...

Macroalgae are the source of many harmful allelopathic compounds, which are synthesized as a defense strategy against competitors and herbivores. Therefore, it can be predicted that certain species reduce aquaculture performance. Herein, the allelopathic ability of 123 different taxa of green, red, and brown algae have been summarized based on lite...

As a contribution to understanding the ecological framework of protistan seasonal succession patterns, we present the weekly-to-monthly (January–October) light microscopy-based study of nano- and microplanktonic protist communities of Adventfjorden waters in 2013. In general, protist dynamics corresponded to the classic paradigm for the Arctic ice-...

Photophysiological and biochemical characteristics were investigated in natural communities of Arctic sea ice algae and phytoplankton, to understand their respective responses towards variable irradiance and nutrient regimes. This study revealed large differences in photosynthetic efficiency and capacity between the two types of algal assemblages....

Phytoplankton blooms in the Arctic Ocean's seasonal sea ice zone are expected to start earlier and occur further north with retreating and thinning sea ice cover. The current study is the first compilation of phytoplankton bloom development and fate in the seasonally variable sea ice zone north of Svalbard from winter to late summer, using short-te...

Coastal waters are among the most productive regions in the Arctic (Leu et al. 2015; Smola et al. 2017; Ardyna et al. 2020). In these areas, a strong coupling exists between the sea and the land, and the shallow depths create a tight pelagic-benthic coupling (McGovern et al. 2020). These regions are also critical breeding and foraging grounds for m...

We present a case study on the impact of effluent from a wastewater lagoon-wetland system on phytoplankton and local primary production near a coastal Arctic community (Cambridge Bay) over spring to fall 2018. Results are also placed within an interannual and regional context for the surrounding Kitikmeot Sea. We find the shallow, relatively fresh...

Assessing the relative importance of sea ice algal-based production is often vital for studies about climate change impacts on Arctic marine ecosystems. Several types of lipid biomarkers and stable isotope ratios are widely used for tracing sea ic-associated (sympagic) vs. pelagic particulate organic matter (POM) in marine food webs. However, there...

Plain Language Summary In the surface ocean, microalgae convert dissolved atmospheric CO2 into organic carbon (OC). As OC sinks in the water column, microbes and zooplankton graze on it. It has been suggested that these organisms reduce the amount of sinking OC stronger in warm waters than in cold waters. We found, however, that the amount of sinki...

The restructuring of planktonic communities toward an increasing share of small individuals is not only expected, but also already observed consequence of warming in the rapidly changing Arctic. Here, we demonstrate a simultaneous study on the nano-, micro- and meso plankton (divided into small and large), and corresponding size fractions of partic...

The European Arctic is rapidly changing where increasing water temperatures and rapid loss of sea ice will likely influence the structure and functioning of the entire ecosystem. This study aimed to describe the taxonomic composition and spatial distribution of early summer (2015–2016) nano- and microplanktonic protists in the Nordic (Norwegian, Gr...

In the Arctic Ocean ice algae constitute a key ecosystem component and the ice algal spring bloom a critical event in the annual production cycle. The bulk of ice algal biomass is usually found in the bottom few cm of the sea ice and dominated by pennate diatoms attached to the ice matrix. Here we report a red tide of the phototrophic ciliate Mesod...

Due to its year-round accessibility and excellent on-site infrastructure, Kongsfjorden and the Ny-Ålesund Research and Monitoring Facility have become established as a primary location to study the impact of environmental change on Arctic coastal ecosystems. Due to its location right at the interface of Arctic and Atlantic oceanic regimes, Kongsfjo...

Several floristic studies on macroalgae of Svalbard have been published, but as access to the archipelago is difficult, these studies are scattered and often only cover single sites and habitats. Kongsfjorden, Isfjorden and Hornsund are the three most comprehensively investigated areas, and most of the species information comes from these three fjo...

Phytoplankton phenology is a key driver of biological and chemical processes in marine ecosystems because it directly affects cycling of nutrients, the strength of the biological carbon pump, and energy transfer to higher tropic levels. However, phytoplankton time-series from the Arctic are scant, thus limiting our ability to link phytoplankton phe...

Meltwater discharge from tidewater glaciers impacts the adjacent marine environment. Due to the global warming, tidewater glaciers are retreating and will eventually terminate on land. Yet, the mechanisms through which meltwater runoff and subglacial discharge from tidewater glaciers influence marine primary production remain poorly understood, as...

The northern coast of Svalbard contains high-arctic fjords, such as Rijpfjorden (80°N 22°30'E). This area has experienced higher sea and air temperatures and less sea ice in recent years, and models predict increasing temperatures in this region. Part of the West Spitsbergen Current (WSC), which transports relatively warm Atlantic water along the c...

We investigated the spatial variability of qualitative and quantitative planktonic protist community structure in the Nordic Seas in relation to the environmental factors. Our study was conducted in the summers of 2015 and 2016 during cruises of the Institute of Oceanology PAS to the Norwegian and Greenland Seas. The samples were collected using Ni...

We investigated the spatial variability of qualitative and quantitative planktonic protist community structure in the Nordic Seas in relation to the environmental factors. Our study was conducted in the summers of 2015 and 2016 during cruises of the Institute of Oceanology PAS to the Norwegian and Greenland Seas. The samples were collected using Ni...

We present phytoplankton and nutrient observations from a period of ten years within five biological ‘hotspots’ in the Bering and Chukchi Seas, as identified by the Distributed Biological Observatory (DBO). Nitrate (NO3⁻) and total and size-fractionated (< and >5 µm) chlorophyll a (Chl a) concentrations, and rates of carbon (ρC, ‘primary productivi...

We investigated the size and trophic structure of the annual planktonic protist community structure in the ice-free Adventfjorden in relation to environmental factors. Our high-resolution (weekly to monthly) study was conducted in a period of high inter-annual variability in Atlantic water advection to the fjord (January 2012 - October 2013). A hi...

We investigated the size and trophic structure of the annual planktonic protist community structure in the ice-free Adventfjorden in relation to environmental factors. Our high-resolution (weekly to monthly) study was conducted in a period of high inter-annual variability in Atlantic water advection to the fjord (January 2012 - October 2013). The s...

We investigated the spatial variability of qualitative and quantitative planktonic protist community structure in the Nordic Seas in relation to the environmental factors. Our study was conducted in the summers of 2015 and 2016 during cruises of the Institute of Oceanology PAS to the Norwegian and Greenland Seas. The samples were collected using Ni...

Sea ice not only shapes the global climate but is also an important background for a complicated ecosystem that is closely related to the littoral benthic ecosystem. This similarity is the reason why this formation is usually referred to as an “inverted bottom.” In the deep central part of the Arctic Basin (which is 47% of its overall surface area)...

The aim of the research was to try to obtain of the biogas on a laboratory scale from marine algae biomass and water plant biomass. The research was conducted in 2016 year and samples were taken from the Polish coast of the Baltic Sea. In laboratory work, algae and plant species were first identified. The next, in order to subject them to methane f...

Hornsund and Kongsfjorden are two similar-sized Arctic fjords on the West coast of Spitsbergen. They are influenced by cold coastal Arctic water (Hornsund) and warmer Atlantic water (Kongsfjorden). Environmental conditions affect the timing, quantity, spatial distribution (horizontal and vertical) of spring and summer blooms of protists as well as...

During the Norwegian young sea ICE expedition (N-ICE2015) from January to June 2015 the pack ice in the Arctic Ocean north of Svalbard was studied during four drifts between 83° and 80° N. This pack ice consisted of a mix of second-year, first-year and young ice. The physical properties and ice algal community composition was investigated in the th...

The identification of macroalgal beds is a crucial component for the description of fjord ecosystems. Direct, biological sampling is still the most popular investigation technique but acoustic methods are becoming increasingly recognized as a very efficient tool for the assessment of benthic communities. In 2007 we carried out the first acoustic su...

Two high latitude fjords of Spitsbergen (Hornsund 77°N and Kongsfjorden 79°N) are regarded as being highly productive (70g and 50gCm⁻²year⁻¹) and having organic-rich sediments. Hornsund has more organic matter in its sediments (8%), nearly half of it of terrestrial origin, while most of that in Kongsfjorden (5%) comes from fresh, marine sources (mi...

We report the identification of a range of C25 highly branched isoprenoid (HBI) alkenes and certain sterols in filtered phytoplankton samples obtained from western Svalbard (Arctic) and near South Georgia (South Atlantic, sub-Antarctic) in 2016 and 2014, respectively. The C25 HBIs contained 3–5 double bonds and had structures identified previously...

Acoustic imaging of seabed morphology and benthic habitats is a fast-developing tool for investigating large areas of underwater environment. Even though single- and multi-beam echosounders have been widely used for this purpose for many years, there is still much to discover, especially in terms of processing water column echoes to detect macroalg...

The Arctic icescape is rapidly transforming from a thicker multiyear ice cover to a thinner and largely seasonal first-year ice cover with significant consequences for Arctic primary production. One critical challenge is to understand how productivity will change within the next decades. Recent studies have reported extensive phytoplankton blooms b...

For the first time at Svalbard, a colonial form of the tube-dwelling diatom Gyrosigma eximium was found in summer 2010 in the tidal flats on Spitsbergen at 78°N. The colonies take the form of conical, green structures that are 1–2cm high and are associated with other diatom taxa and cyanobacteria (Oscillatoriaceae). The diatom colonies were associa...

As in other Arctic regions, the dinoflagellate community of West Spitsbergen waters is represented by numerous naked forms of the genera Gymnodinium and Gyrodinium. Previous protist studies have included many unidentified species due to difficulties related to taxonomic identification and an insufficient number of illustrated taxonomic keys. Conseq...

Phytoflagellates <10 μm substantially contribute to the abundance, biomass and primary production in polar waters, but information on the distribution of specific groups is scarce. We applied Catalysed Reporter Deposition-Fluorescence in situ Hybridisation (CARD-FISH) to investigate the distribution of total phytoflagellates and of eight specific g...

This paper presents the first comprehensive insight into the structure of planktonic communities, from nanoprotists to mesozooplankton in the waters north of Svalbard during the dark Arctic winter. Our investigations were carried out in two contrasting locations comparing a shallow fjord, Rijpfjorden, and a deep ice-covered region, Sofiadjupet, in...

Seagrass meadows are ranked amongst the most productive ecosystems on Earth, providing high-value ecosystem services in coastal areas. Yet, seagrass habitats are declining worldwide at an unprecedented rate as a consequence of both anthropogenic and natural pressures, which suggests an inefficient management. Seagrasses are widespread along Europea...

We performed genetic analyses of three Baltic eelgrass (Zostera marina) populations in Puck Bay (PB), Cudema Bay (CB) and Greifswalder Bodden (GB). The aim of this study was to identify the eelgrass population genetically closest to that from the PB, which could potentially serve as a reservoir for the restoration of the underwater meadows in this...

We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other...

We performed genetic analyses of three Baltic eelgrass (Zostera marina) populations in Puck Bay (PB), Cudema Bay (CB) and Greifswalder Bodden (GB). The aim of this study was to identify the eelgrass population genetically closest to that from the PB, which could potentially serve as a reservoir for the restoration of the underwater meadows in this...

We report the first observation of large red cyanobacterial mats in the southern Baltic Sea. The mats (up to 2.5 m in diameter) were observed by SCUBA divers at 7.7 m depth on loamy sediments in the Gulf of Gdańsk in mid-November 2013. The main structure of the mat was formed by cyanobacteria Spirulina subsalsa Oersted ex Gomont; a number of other...

The ISME Journal: Multidisciplinary Journal of Microbial Ecology is the official Journal of the International Society for Microbial Ecology, publishing high-quality, original research papers, short communications, commentary articles and reviews in the rapidly expanding and diverse discipline of microbial ecology.

We investigated the spatial and inter-annual variations in planktonic protist community taxonomic composition with respect to size and trophic structure in the West Spitsbergen waters during the 2007, 2009 and 2010 summers. The protist communities were studied along a longitudinal transect from Kongsfjorden through the shelf to open sea waters. Our...

Changes in hydrological conditions of West Spitsbergen Current (WSC), strongly triggered by global warming, generate rapid changes in marine Arctic ecosystem. Spectacular warming of WSC, observed in the last decade, causes high glacier-melt and freshwater discharge, which in consequence creates strong temperature, salinity and water transparency gr...

We investigated the spatial and inter-annual variations in planktonic protist community taxonomic composition with respect to size and trophic structure in the West Spitsbergen waters during the 2007, 2009 and 2010 summers. The protist communities were studied along a longitudinal transect from Kongsfjorden through the shelf to open sea waters. Our...

During two consecutive cruises to the Eastern Central Arctic in late summer 2012, we observed floating algal aggregates in the melt-water layer below and between melting ice floes of first-year pack ice. The macroscopic (1-15 cm in diameter) aggregates had a mucous consistency and were dominated by typical ice-associated pennate diatoms embedded wi...

Sea ice, a characteristic feature of polar waters, is home to diverse microbial communities. Sea-ice picoeukaryotes (unicellular eukaryotes with cell size <3 μm) have received little attention compared with diatoms that dominate the spring bloom in Arctic first-year sea ice. Here, we investigated the abundance of all picoeukaryotes, and of 11 group...