Trait response of three Baltic Sea spring dinoflagellates to temperature, salinity, and light gradients

Climate change is driving Baltic Sea shifts, with predictions for decrease in salinity and increase in temperature and light limitation. Understanding the responses of the spring phytoplankton community to these shifts is essential to assess potential changes in the Baltic Sea biogeochemical cycles and functioning. In this study we use a high-throughput well-plate setup to experimentally define growth and the light acquisition traits over gradients of salinity, temperature and irradiance for three dinoflagellates commonly occurring during spring in the Baltic Sea, Apocalathium malmogiense, Gymnodinium corollarium and Heterocapsa arctica subsp. frigida. By analysing the response of cell volume, growth, and light-acquisition traits to temperature and salinity gradients, we showed that each of the three dinoflagellates have their own niches and preferences and are affected differently by small changes in salinity and temperature. A. malmogiense has a more generalist strategy, its growth being less affected by temperature, salinity, and light gradients in comparison to the other tested dinoflagellates, with G. corollarium growth being more sensitive to higher light intensities. On the other hand, G. corollarium light acquisition traits seem to be less sensitive to changes in temperature and salinity than those of A. malmogiense and H. arctica subsp. frigida. We contextualized our experimental findings using data collected on ships-of-opportunity between 1993-2011 over natural temperature and salinity gradients in the Baltic Sea. The Apocalathium complex and H. arctica subsp. frigida were mostly found in temperatures<10°C and salinities 4-10 ‰, matching the temperature and salinity gradients used in our experiments. Our results illustrate that trait information can complement phytoplankton monitoring observations, providing powerful tools to answer questions related to species’ capacity to adapt and compete under a changing environment

Bioimpedance method for monitoring venous ulcers: Clinical proof-of-concept study

Evaluation of wound status is typically based on means which require the removal of dressings. These procedures are often also subjective and prone to inter-observer bias. To overcome aforementioned issues a bioimpedance measurement-based method and measurement system has been developed to evaluate the state of wound healing. The measurement system incorporated a purpose-built bioimpedance device, a measurement software and a screen-printed electrode array. The feasibility and the performance of the system and method were assessed in an open non-randomized follow-up study of seven venous ulcers. Healing of ulcers was monitored until the complete re-epithelialization was achieved. The duration of follow-up was from 19 to 106 days (mean 55.8 +/- 25.2 days). A variable designated as the Wound Status Index (WSI), derived from the bioimpedance data, was used for describing the state of wound healing. The wound surface area was measured using acetate tracing for the reference. A strong correlation was found between the WSI and the acetate tracing data, r(93) = 0.84, p < 0.001. The results indicate that the bioimpedance measurement-based method is a promising quantitative tool for the evaluation of the status of venous ulcers

First application of IFCB high-frequency imaging-in-flow cytometry to investigate bloom-forming filamentous cyanobacteria in the Baltic Sea

Cyanobacteria are an important part of phytoplankton communities, however, they are also known for forming massive blooms with potentially deleterious effects on recreational use, human and animal health, and ecosystem functioning. Emerging high-frequency imaging flow cytometry applications, such as Imaging FlowCytobot (IFCB), are crucial in furthering our understanding of the factors driving bloom dynamics, since these applications provide community composition information at frequencies impossible to attain using conventional monitoring methods. However, the proof of applicability of automated imaging applications for studying dynamics of filamentous cyanobacteria is still scarce. In this study we present the first results of IFCB applied to a Baltic Sea cyanobacterial bloom community using a continuous flow-through setup. Our main aim was to demonstrate the pros and cons of the IFCB in identifying filamentous cyanobacterial taxa and in estimating their biomass. Selected environmental parameters (water temperature, wind speed and salinity) were included, in order to demonstrate the dynamics of the system the cyanobacteria occur in and the possibilities for analyzing high-frequency phytoplankton observations against changes in the environment. In order to compare the IFCB results with conventional monitoring methods, filamentous cyanobacteria were enumerated from water samples using light microscopical analysis. Two common bloom forming filamentous cyanobacteria in the Baltic Sea, Aphanizomenon flosaquae and Dolichospermum spp. dominated the bloom, followed by an increase in Oscillatoriales abundance. The IFCB results compared well with the results of the light microscopical analysis, especially in the case of Dolichospermum. Aphanizomenon biomass varied slightly between the methods and the Oscillatoriales results deviated the most. Bloom formation was initiated as water temperature increased to over 15°C and terminated as the wind speed increased, dispersing the bloom. Community shifts were closely related to movements of the water mass. We demonstrate how using a high-frequency imaging flow cytometry application can help understand the development of cyanobacteria summer blooms

Kuormitustaajuuden ja -aallonmuodon vaikutus entsymaattisen biopolttokennon autotehoon

Tässä diplomityössä tutkittiin, kuinka kuormituksen taajuuden ja pulssinleveyden vaihtelu vaikuttaa entsymaattisen biopolttokennon lähtötehoon ja lähtötehon heikkenemisnopeuteen. Tutkittu taajuusalue oli välillä 5 mHz - 1 MHz. Kuormituspulssin muodon vaikutus lähtötehoon ja sen heikkenemiseen havaittiin vähäiseksi. Valtaosan tästä vaikutuksesta todettiin johtuvan kennon sisäisen resistanssin ja kuormitusvastuksen vaihtelun yhteisvaikutuksesta koejärjestelyssä. Lähtötehon havaittiin pysyvän vakiona yli 1 Hz taajuuksilla. Tätä alemmilla taajuuksilla teho laski hieman. Kokeissa käytettiin yksinkertaisia biopolttokennoja, joitten katodi oli suljettu. Entsyymin konsentraatio anodilla oli alhainen. Kokeissa käytettiin enimmillään neljää identtistä kennoa samanaikaisesti. Vertailun vuoksi kokeet toistettiin myös ilman entsyymiä

M/S Silja Serenade (Helsinki-Stockholm) pCO2 data 2018-2020

This data set contains the partial pressure of carbon dioxide (CO2) present in seawater together with temperature, salinity and other necessary auxiliary information measured on a voluntary observing ship, M/S Silja Serenade between April 2018 and April 2020. During this period, M/S Silja Serenade operated daily on a route Helsinki-Mariehamn-Stockholm in the Baltic Sea. During the ice season of 2018-2019, the flow-through system was set offline and no measurements were taken. The measurement setup of seawater CO2 (SuperCO2, Sunburst Sensors) consists of two showerhead equilibrators where the CO2 is equilibrated between the continuous water stream and the overlaying gas which is directed to an infrared gas analyzer (LI-840A, LI-COR), which measures the molar fraction of CO2. The measured molar fraction of CO2 has been corrected for the sensor drift by using four reference gases, which are measured every four hours. The calculation of the partial pressure of CO2 is based on these drift corrected molar fractions. The flow-through system is part of the Alg@line network of Finnish Environment Institute and the pCO2 measurement is governed by Finnish Meteorological Institute. This measurement has been supported by the BONUS INTEGRAL project, the JERICO research infrastructure and Finnish Marine Research Infrastructure and the SEASINK Finnish Academy project. The metadata (see dataset comments) contains information about the data quality control and assurance, including an information about the flagging system used