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Page 210. 10 Light and temperature demands of marine benthic microalgae and seaweeds in polar regions Iván Gómez, Angela Wulff, Michael Y. Roleda, Pirjo Huovinen, Ulf Karsten, María Liliana Quartino, Ken Dunton and ...
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When the name Entomoneis annagodhei Al-Handal & Mucko was published (Al Handal et al. 2020), an error was made in giving the name of the species. The species is named after the late Professor Dr An...
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We investigated the ultrastructure of Achnanthes delicatissima Simonsen in materials collected from the Swedish Baltic coast. Valve structure differs markedly from that of Achnanthes sensu lato, particularly in the absence of cribrate... more
We investigated the ultrastructure of Achnanthes delicatissima Simonsen in materials collected from the Swedish Baltic coast. Valve structure differs markedly from that of Achnanthes sensu lato, particularly in the absence of cribrate areolae which separates Achnanthes from all other members of the family Achnanthaceae. Comparing this species with those recently described achnanthoid genera, such as Scalariella Riaux-Gobin & Witkowski and Madinithidium Witkowski, Desrosiers & Riaux-Gobin revealed morphological differences that warrant the erection of a new genus, Navithidium. Owing to the small size of the frustules, it is difficult to identify Navithidium delicatissima in light microscopy due to similarities with some closely related taxa like Achnanthidium pseudochamaepinnularia (which is here transferred to Navithidium). A comparison with related genera is provided and discussed.
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In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead... more
In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead release acidic water containing nutrients and contaminants back to the marine environment. In the current study, scrubber washwater was tested on a Baltic Sea microplankton community. A significant increase in chlorophyll a, particulate organic phosphorus (POP), carbon (POC) and nitrogen (PON) were observed when the community was exposed to 10% scrubber washwater for 13 days as compared to the control. A laboratory experiment with the filamentous cyanobacteria Nodularia spumigena and the chain-forming diatom Melosira cf. arctica showed negative responses in photosynthetic activity (EC10 = 8.6% for N. spumigena) and increased primary productivity (EC10 = 5.5% for M. cf. arctica), implying species-specific responses to scrubber washwater discharge.
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Research Interests: Carbon Dioxide, Photosynthesis, Biology, Phytoplankton, Sea Ice, and 15 moreSea surface temperature, Global Warming, Biological Sciences, Global change, Ocean acidification, Laboratory experiment, Diatom, Species Composition, Physiological Response, Photosynthetic Pigment, Polar Biology, Growth rate, Quantum Yield, Elevated Temperature, and Navicula
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Research Interests: Biology and Cyanobacteria
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Research Interests: Environmental Science, Oceanography, Photosynthesis, Microalgae, Earth and Environmental Sciences, and 15 moreSouthern Ocean, Production economics, Assemblage, Temperature, Benthic Diatoms, King George Island, Diatom, Sediment, Ice, Macroalgae, Primary Production, Sedimentation, Oxygen Flux, Biovolume, and Shading
The diatom genus Fallacia includes species having a conopeum which is a perforated thin sheath of silica lying along the apical axis on the external valve face and a hyaline lateral area in the internal valve face. In surveying the... more
The diatom genus Fallacia includes species having a conopeum which is a perforated thin sheath of silica lying along the apical axis on the external valve face and a hyaline lateral area in the internal valve face. In surveying the benthic diatoms of Basra, a new small brackish water species, Fallacia fawensis was found associated with fine-grained substrata on the western bank of Shatt Al–Arab River, Southern Iraq. This epipelic species is described based on light and scanning electron microscopy and characterized by having a porous conopeum covering the area between raphe sterna and mantle, narrow elongated marginal striae, and a structure similar to lateral hyaline areas in the valve internal side. The terminal raphe endings on the external valve face, below valve apex, the raphe sternum inner margins come close to each other, blocking raphe canal but leaving a lacuna-like thin groove for connection with the deflected upper part of the open raphe canal. These features separated t...
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ABSTRACT Synedropsis abuflosensis sp. nov. is the third species of the genus recorded from a sub-tropical brackish water habitat as opposed to a polar distribution. This species is differentiated from others in the genus by having a... more
ABSTRACT Synedropsis abuflosensis sp. nov. is the third species of the genus recorded from a sub-tropical brackish water habitat as opposed to a polar distribution. This species is differentiated from others in the genus by having a different number of slits in the apical slit field at opposite ends of the valve (i.e., 4 at the end possessing a rimoportula versus 5 at the end lacking a rimoportula), an apically oriented rimoportula and 3-4 non-porous cingular bands. Its habitat is different than that of all known Synedropsis Hasle, Medlin & Syvertsen species as it is either benthic or epiphytic in algal mats rather than planktonic or associated with sea ice. The new species was found in waters with a conductivity of 7.1 µS cm-1 (salinity 3.3 psu) and a temperature of 33 °C. Morphological characters of the new species are described based on light and scanning electron microscopy observations. A comparison of S. abuflosensis sp. nov. with morphologically similar species is provided.
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Climate change-induced glacial melt affects benthic ecosystems along the West Antarctic Peninsula, but current understanding of the effects on benthic primary production and respiration is limited. Here we demonstrate with a series of in... more
Climate change-induced glacial melt affects benthic ecosystems along the West Antarctic Peninsula, but current understanding of the effects on benthic primary production and respiration is limited. Here we demonstrate with a series of in situ community metabolism measurements that climate-related glacial melt disturbance shifts benthic communities from net autotrophy to heterotrophy. With little glacial melt disturbance (during cold El Niño spring 2015), clear waters enabled high benthic microalgal production, resulting in net autotrophic benthic communities. In contrast, water column turbidity caused by increased glacial melt run-off (summer 2015 and warm La Niña spring 2016) limited benthic microalgal production and turned the benthic communities net heterotrophic. Ongoing accelerations in glacial melt and run-off may steer shallow Antarctic seafloor ecosystems towards net heterotrophy, altering the metabolic balance of benthic communities and potentially impacting the carbon bala...
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Los distintos escenarios futuros propuestos en el contexto del cambio global predicen una serie de impactos sobre los ecosistemas marinos costeros debido al retroceso glaciario en la Antartida. Estos ecosistemas son complejos y dinamicos... more
Los distintos escenarios futuros propuestos en el contexto del cambio global predicen una serie de impactos sobre los ecosistemas marinos costeros debido al retroceso glaciario en la Antartida. Estos ecosistemas son complejos y dinamicos y presentan una elevada biodiversidad. Caleta Potter es un pequeno fiordo ubicado en la Isla 25 de Mayo que debido a su proximidad a la Base Cientifica Carlini se presenta como un sitio ideal para el estudio de los organismos marinos. Por mas de dos decadas el Instituto Antartico Argentino ha ido desarrollando investigaciones sobre diferentes aspectos ecologicos y fisiologicos sobre las algas marinas bentonicas antarticas. Los estudios iniciales se focalizaron en la distribucion vertical y espacial de la estructura de las comunidades macroalgales. Las primeras observaciones demostraron la presencia de una comunidad conspicua de macroalgas desarrollandose principalmente en las costas rocosas de la parte externa de la Caleta, mientras que en la parte ...
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Stratospheric accumulation of ozone is primarily responsible for absorbing parts of the solar ultraviolet radiation (UVR) before it can reach the marine biosphere. Emission of anthropogenic halogenated volatile substances in the past... more
Stratospheric accumulation of ozone is primarily responsible for absorbing parts of the solar ultraviolet radiation (UVR) before it can reach the marine biosphere. Emission of anthropogenic halogenated volatile substances in the past century haveapart from ...
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In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead... more
In 2020, the global cap of maximum allowable sulphur content in marine fuel will be reduced from the current 3.5% to 0.5%. Another way to reduce the sulphur emissions is to install a seawater scrubber that cleans exhausts but instead release acidic water containing nutrients and contaminants back to the marine environment. In the current study, scrubber washwater was tested on a Baltic Sea microplankton community. A significant increase in chlorophyll a, particulate organic phosphorus (POP), carbon (POC) and nitrogen (PON) were observed when the community was exposed to 10% scrubber washwater for 13 days as compared to the control. A laboratory experiment with the filamentous cyanobacteria Nodularia spumigena and the chain-forming diatom Melosira cf. arctica showed negative responses in photosynthetic activity (EC10 = 8.6% for N. spumigena) and increased primary productivity (EC10 = 5.5% for M. cf. arctica), implying species-specific responses to scrubber washwater discharge.
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Increasing atmospheric CO2 levels are driving changes in the seawater carbonate system, resulting in higher pCO2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to... more
Increasing atmospheric CO2 levels are driving changes in the seawater carbonate system, resulting in higher pCO2 and reduced pH (ocean acidification). Many studies on marine organisms have focused on short-term physiological responses to increased pCO2, and few on slow-growing polar organisms with a relative low adaptation potential. In order to recognize the consequences of climate change in biological systems, acclimation and adaptation to new environments are crucial to address. In this study, physiological responses to long-term acclimation (194 days, approx. 60 asexual generations) of three pCO2 levels (280, 390 and 960 µatm) were investigated in the psychrophilic sea ice diatom Nitzschia lecointei. After 147 days, a small reduction in growth was detected at 960 µatm pCO2. Previous short-term experiments have failed to detect altered growth in N. lecointei at high pCO2, which illustrates the importance of experimental duration in studies of climate change. In addition, carbon metabolism was significantly affected by the long-term treatments, resulting in higher cellular release of dissolved organic carbon (DOC). In turn, the release of labile organic carbon stimulated bacterial productivity in this system. We conclude that long-term acclimation to ocean acidification is important for N. lecointei and that carbon overconsumption and DOC exudation may increase in a high-CO2 world
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When the name Entomoneis annagodhei Al-Handal & Mucko was published (Al Handal et al. 2020), an error was made in giving the name of the species. The species is named after the late Professor Dr An...
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Research Interests: Biology and Cyanobacteria
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(Rhodophyta) tetraspores exposed to ultraviolet radiation
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We investigated the ultrastructure of Achnanthes delicatissima Simonsen in materials collected from the Swedish Baltic coast. Valve structure differs markedly from that of Achnanthes sensu lato, particularly in the absence of cribrate... more
We investigated the ultrastructure of Achnanthes delicatissima Simonsen in materials collected from the Swedish Baltic coast. Valve structure differs markedly from that of Achnanthes sensu lato, particularly in the absence of cribrate areolae which separates Achnanthes from all other members of the family Achnanthaceae. Comparing this species with those recently described achnanthoid genera, such as Scalariella Riaux-Gobin & Witkowski and Madinithidium Witkowski, Desrosiers & Riaux-Gobin revealed morphological differences that warrant the erection of a new genus, Navithidium. Owing to the small size of the frustules, it is difficult to identify Navithidium delicatissima in light microscopy due to similarities with some closely related taxa like Achnanthidium pseudochamaepinnularia (which is here transferred to Navithidium). A comparison with related genera is provided and discussed.
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Temperature and CO2 levels are projected to increase in the future, with consequences for carbon and nutrient cycling in brackish environments, such as the Baltic Sea. Moreover, filamentous cyanobacteria are predicted to be favored over... more
Temperature and CO2 levels are projected to increase in the future, with consequences for carbon and nutrient cycling in brackish environments, such as the Baltic Sea. Moreover, filamentous cyanobacteria are predicted to be favored over other phytoplankton groups under these conditions. Under a 12-day outdoor experiment, we examined the effect on a natural phytoplankton spring bloom community of elevated temperature (from 1°C to 4°C) and elevated pCO2 (from 390 to 970 μatm). No effects of elevated pCO2 or temperature were observed on phytoplankton biovolumes, but a significantly higher photosystem II activity was observed at elevated temperature after 9 days. In addition, three species of diazotrophic filamentous cyanobacteria were inoculated to test their competitive capacity under spring bloom conditions. The toxic cyanobacterium Nodularia spumigena exhibited an average specific growth rate of 0.10 d−1 by the end of the experiment, indicating potential prevalence even during winte...
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Continuous observations of Antarctic benthic diatoms are necessary to detect changes in species composition and biodiversity that may result from environmental changes. The present work provides a systematic list of benthic diatoms from... more
Continuous observations of Antarctic benthic diatoms are necessary to detect changes in species composition and biodiversity that may result from environmental changes. The present work provides a systematic list of benthic diatoms from Potter Cove (62.03°S 58.35°W) collected during summer 2015. The new findings are compared with observations made 12 years ago (summer 2003). In total, 80 taxa were found, similar to that encountered earlier, but 17 species (21% of the total species number) were not observed in 2003, and 26 species (31%) of those reported in 2003 did not appear in 2015. The dominant species in 2003 and 2015 was the large epipelic and cosmopolitan Gyrosigma fasciola. Most of the species either newly observed in the present study, or absent in the present study but observed previously, occurred either rarely or very rarely. Gyrosigma arcuatum and Pleurosigma diversestriatum were newly observed in 2015 and not previously reported from polar regions. This study provides s...
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Research Interests: Geography, Oceanography, Climate Change, Medicine, Multidisciplinary, and 4 moreArctic, Coral Reef, Frontier, and Coral
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Anthropogenic activities, such as construction work, dredging, and different kinds of recreation activities, can alter sediment loading in shallow coastal areas. The effect of increased load of fine sediment on the microbenthos (benthic... more
Anthropogenic activities, such as construction work, dredging, and different kinds of recreation activities, can alter sediment loading in shallow coastal areas. The effect of increased load of fine sediment on the microbenthos (benthic microalgae, bacteria, and meiofauna) was studied in two experhnents using undisturbed cores of a sandy sedi- ment from a microtidal bay on the Swedish west coast. In each experiment, a total of 24 cores were incubated in an outdoor flow-through set-up. Twelve cores were treated with a 2.5-mm thick layer of autoclaved fine-grained, (silt) carbon- rich surface sediment. In the first experiment, estimates of the impact were based on measurements of chlorophyll a, biomass of microalgae, bacteria, and meiofauna, and bacterial production. The main purpose of the second experiment was to study the effect on sediment oxygen profiles using microselasors. Within a week, after being covered by fine sediment, benthic microalgae (particularly diatoms) had migrate...
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Clean version of longterm data, i.e. without N