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1

Dynamics of trace metals in sediments of a seasonally hypoxic coastal zone in the southeastern Arabian Sea

Mathew Dayana, Gireeshkumar Thundiyil Raju, Shameem Kareekunnan, Furtado Camey Monica, Arya Kanneth Satheesan, Udayakrishnan Pallikkoottathil Balakrishnan, Balachandran Kizhakkepatt Kalathil

Oceanologia

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2022

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No. 64 (4)

735--748

EN

This study examined the effect of water column hypoxia on the distribution and geochemical fractionation of trace metals in the seasonally hypoxic coastal environment in the southeastern Arabian Sea. Water and surface sediments were collected fortnightly from the Alappuzha mud bank between April and August 2016, which covered the pre-upwelling and upwelling seasons. The water column was warm and well-oxygenated during April–May. During June–August, the incidence of cold and hypoxic water indicated strong coastal upwelling prevailed in the entire study domain. The Fe and Mn content in sediments gradually decreased, because of the reductive dissolution and subsequent release of metals under hypoxia. The concentration of metals such as Ni, Zn and V decreased substantially under oxygen deficiency, whereas Cr showed marked enrichment in sediments. Although the geochemical forms of trace metals displayed the dominance of residual fractions (inert), the reactive non-residual metal forms (exchangeable, Fe/Mn-(oxy)hydroxide, and organic matter/sulphide bound) showed considerable variability under hypoxia. The shift from Fe/Mn-(oxy)hydroxide bound to organic matter and sulphide bound was evident during hypoxia. Cr exhibited a strong affinity towards organic matter and sulphide, and Pb and Zn showed relatively high association towards the Fe/Mn-(oxy)hydroxide phase. Even with such a phase shift induced by the hypoxic conditions, the concentrations of these metals remained within the normal background levels, indicating the pristine nature of the mud bank environment.

2

Algal bloom, hypoxia, and mass fish kill events in the backwaters of Puducherry, Southeast coast of India

Mishra Pravakar, Naik Subrat, Babu P. Vipin, Pradhan Umakanta, Begum Mehmuna, Kaviarasan Thanamegam, Vashi Athan, Bandyopadhyay Debasmita, Ezhilarasan Pazhaniyappan, Panda Uma Sankar, Ramana Murthy Mallavarapu Venkata

Oceanologia

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2022

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No. 64 (2)

396--403

EN

The Chunnambar backwater of Puducherry experienced changes in water quality over a period. The most significant impact was the sudden mass fish kill event coincided with the Pseudo-nitzschia bloom. On 25th September 2019, a mass fish kill event was reported, i.e. about a 0.25 metric ton (MT) floating on the water surface. On 29th September 2019, a much larger (∼1 MT) than the earlier incident had occurred. Sampling was carried out to assess the causes thereof. The results indicate that high organic matter and bacterial loads accumulated in the water and sediment due to the closure of the river mouth for an extended period. High ammonia (61.4 µM) and phosphate (6.2 µM) levels attributed to eutrophic conditions in the water column and hypoxemia due to low dissolved oxygen (1.62 mg/L at St.1 and 2.4 mg/L at St.5) and algal bloom were the proximate cause of these sudden fish kills. We recommend periodic dredging to facilitate proper water exchange between the backwater and the sea.

3

Towards high sensitivity and high-resolution PET scanners: imaging-guided proton therapy and total body imaging

Lang Karol

Bio-Algorithms and Med-Systems

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2022

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Vol. 18, no. 1

96--106

EN

Quantitative imaging (i.e., providing not just an image but also the related data) guidance in proton radiation therapy to achieve and monitor the precision of planned radiation energy deposition field in-vivo (a.k.a. proton range verification) is one of the most underinvested aspects of radiation cancer treatment despite that it may dramatically enhance the treatment accuracy and lower the exposure related toxicity improving the entire outcome of cancer therapy. In this article, we briefly describe the effort of the TPPT Consortium (a collaborative effort of groups from the University of Texas and Portugal) on building a time-of-flight positronemission-tomography (PET) scanner to be used in preclinical studies for proton therapy at MD Anderson Proton Center in Houston. We also discuss some related ideas towards improving and expanding the use of PET detectors, including the total body imaging.

4

Hyperbaric Oxygen Therapy in COVID-19 Treatment : Efficacy and Safety

Ubysz Dorota, Giermaziak Wojciech, Ostrowska Aurelia

Polish Hyperbaric Research

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2021

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nr 2(75)

25--40

EN

Introduction: New effective treatments are sought to eliminate COVID-19-related hypoxia. Hyperbaric oxygen therapy is an effective method in the treatment of many diseases accompanied by hypoxia. Aim: The aim of this study was to analyse the literature on the use of hyperbaric oxygen in the treatment of COVID-19 and to evaluate the effectiveness and safety of this method. Materials and methods: Medical databases (Medline and PBL) and websites were reviewed using the terms hyperbaric oxygen and COVID-19. 25 works were qualified for the analysis. Conclusions: The analysed literature shows that hyperbaric oxygen therapy is an effective and safe method of treating patients with COVID-19. Due to the limited amount of scientific evidence assessing the use of HBOT in COVID-19, there is a need for further research to confirm the effectiveness and safety of this method.

PL

Wstęp: Do eliminowania hipoksji związanej z COVID-19 poszukiwane są nowe sposoby skutecznego leczenia. Tlenoteriapia hiperbaryczna jest skuteczną metodą w leczeniu wielu chorób z towarzyszącą hipoksją. Cel: Celem niniejszej pracy było przeanalizowanie literatury dotyczącej zastosowania hiperbarii tlenowej w leczeniu COVID-19 oraz ocena skuteczności i bezpieczeństwa tej metody. Materiały i metody: Dokonano przeglądu medycznych baz danych (Medline i PBL) oraz stron internetowych za pomocą haseł: hiperbaria tlenowa i COVID-19. Do analizy zakwalifikowano 25 prac. Wnioski: Z przeanalizowanej literatury wynika, że tlenoterapia hiperbaryczna jest skuteczną i bezpieczną metodą leczenia pacjentów z COVID-19. Ze względu na ograniczoną liczbę dowodów naukowych oceniających stosowanie HBOT w COVID-19, istnieje potrzeba przeprowadzania dalszych badań potwierdzających skuteczność i bezpieczeństwo tej metody.

5

Positronium as a biomarker of hypoxia

Moskal Paweł, Stępień Ewa Ł.

Bio-Algorithms and Med-Systems

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2021

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Vol. 17, no. 4

311--319

EN

In this review article, we present arguments demonstrating that the advent of high sensitivity total-body PET systems and the invention of the method of positronium imaging, open realistic perspectives for the application of positronium as a biomarker for in-vivo assessment of the degree of hypoxia. Hypoxia is a state or condition, in which the availability of oxygen is not sufficient to support physiological processes in tissue and organs. Positronium is a metastable atom formed from electron and positron which is copiously produced in the intramolecular spaces in the living organisms undergoing positron emission tomography (PET). Properties of positronium, such as e.g., lifetime, depend on the size of intramolecular spaces and the concentration in them of oxygen molecules. Therefore, information on the partial pressure of oxygen (pO2) in the tissue may be derived from the positronium lifetime measurement. The partial pressure of oxygen differs between healthy and cancer tissues in the range from 10 to 50 mmHg. Such differences of pO2 result in the change of ortho-positronium lifetime e.g., in water by about 2–7 ps. Thus, the application of positronium as a biomarker of hypoxia requires the determination of the mean positronium lifetime with the resolution in the order of 2 ps. We argue that such resolution is in principle achievable for organ-wise positronium imaging with the total-body PET systems.

6

Pulmonary barotrauma during hypoxia in a diver while underwater

Kierznikowicz Brunon, Wolański Władysław, Olszański Romuald

Polish Hyperbaric Research

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2020

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nr 2(71)

45--50

EN

The article describes a diver performing a dive at small depths in a dry suit, breathing from a single-stage apparatus placed on his back. As a result of training deficiencies, the diver began breathing from inside the suit, which led to hypoxia and subsequent uncontrolled ascent. Upon returning to the surface, the diver developed neurological symptoms based on which a diagnosis of pulmonary barotrauma was made. The diver was successfully treated with therapeutic recompression-decompression.

PL

W artykule opisano nurka wykonującego nurkowanie na małej głębokości w skafandrze suchym, oddychającego z jednostopniowego automatu umieszczonego na plecach. Na skutek brakow w wyszkoleniu nurek zaczął oddychać z wnętrza skafandra, co doprowadziło do hipoksji a następnie niekontrolowanego wynurzenia. Po powrocie na powierzchnię u nurka wystąpiły objawy neurologiczne na podstawie ktorych rozpoznano uraz ciśnieniowy płuc. Nurek był z powodzeniem leczony rekompresją – dekompresją leczniczą.

7

Diver poisoning with contaminated compresses air

Olszański Romuald, Mamet-Ossowska Elżbieta

Polish Hyperbaric Research

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2020

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nr 2(71)

51--54

EN

The paper describes the case of a military diver who suffered from a complicated poisoning caused by hydrocarbons contained in his breathing air. The hydrocarbons came from a malfunctioning compressor which was used to fill the diving cylinders; the compressor sucked in the exhaust gases of its own motor. Exhaust gas poisoning was further complicated by hypoxia and hypercapnia as the diver spat out the mouthpiece and started to breathe from inside the suit. This resulted in a loss of consciousness. The diver was extracted to the surface and was given oxygen to breathe. The course of treatment was successful. On the same day, symptoms of exhaust gas poisoning occurred in several divers using cylinders filled with the same compressor.

PL

W pracy opisano przypadek nurka wojskowego u ktorego wystąpiło powikłane zatrucie węglowodorami zawartymi w powietrzu oddechowym. Pochodziły one z nieprawidłowo działającej sprężarki ktorą ładowano butle nurkowe; sprężarka zasysała gazy spalinowe napędzającego ją silnika. Zatrucie spalinami było dodatkowo powikłane hipoksją i hiperkapnią gdyż nurek wypluł ustnik i zaczął oddychać z wnętrza skafandra. Doszło do utraty przytomności. Nurka wydobyto na powierzchnię, podano tlen do oddychania. Przebieg leczenia pomyślny. W tym samym dniu objawy zatrucia gazami spalinowymi wystąpiły u kilku nurkow korzystających z butli napełnianych tym samym kompresorem.

8

Numerical analysis of the temperature impact to the oxygen distribution in the biological tissue

Jasiński Marek

Journal of Applied Mathematics and Computational Mechanics

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2020

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Vol. 19, nr 3

17--28

EN

The aim of the study was to analyze changes in tissue oxygen distribution resulting from temperature changes by the use of the Krogh cylinder model with Michaelis-Menten kinetics. A Hill model was also used to describe the oxyhemoglobin dissociation curve. In particular, variable values of parameters of dissociation curve and blood velocity in capillary were considered. Mathematical description was based on two separate equations for radial and axial directions. An additional task related to determination of the temperature, tissue thermal damage and perfusion was also solved. At the stage of numerical realization, the finite difference method was used.

9

Wypadki spowodowane różnicą ciśnień powietrza wewnątrz aparatu nurkowego i wody otaczającej nurka

Dolatkowski A.

Polish Hyperbaric Research

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2018

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nr 3(64)

45--54

PL

W pracy opisano 4 nieszczęśliwe wypadki wywołane różnicą ciśnienia wewnątrz i na zewnątrz skafandra nurka. Wyjaśniano zagadnienia związane ze ściśnięciem nurka, chorobą kesonową, zbyt szybkim wynurzeniem na powierzchnię a także niedotlenieniem w rezultacie wyczerpania się tlenu w aparacie nurkowym. Analizowano przy tym mechanizm urazów u nurków i zasugerowano metody profilaktyki tych nieszczęśliwych wypadków.

EN

This paper describes 4 unfortunate accidents caused by the difference in pressure inside and outside the diver's suit. The issues relate to diver crushing, caisson disease, too fast an ascent to the surface and hypoxia as a result of exhaustion of oxygen in the diving apparatus are explained. The mechanism of the diving injuries was analysed and methods of prevention of such incidents were suggested.

10

The structure of macrozoobenthic communities as an environmental status indicator in the Gulf of Gdańsk (the Outer Puck Bay)

Warzocha J., Gromisz S., Wodzinowski T., Szymanek L.

Oceanologia

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2018

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No. 60 (4)

553--559

EN

An attempt is made to use long-term (1979-2014) macrobenthos data series to derive insights on changes in abiotic conditions and on potential effects of long-term macrobenthos variability on food availability for fish and wintering waterfowl. The data were collected from a small embayment, protected as a NATURA 2000 area, functioning as a fishing ground important for the local community and as a site of diverse commercial developments. The analysis showed a drastic reduction of the macrobenthos abundance and biomass, which could have been related to oxygen deficiency; on the other hand, recolonisation processes have also been observed.

11

Temperature controlled dual hypoxic chamber design for in vitro ischemia experiments

Bagó M., Horváthy D. B., Simon M., Marschall B., Pinto A., Kuten O., Polsek D., Hornyák I., Nehrer S., Lacza Z.

Biocybernetics and Biomedical Engineering

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2018

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Vol. 38, no. 3

498--503

EN

In vitro ischemia models are designed to study various aspects of hypo-perfusion, focusing on the consequences of acute events under body temperature. Cold ischemia is less investigated even though the beneficial effects of cooling is expected. The aim of the present work was to develop a device modeling cold and warm ischemia in vitro. Oxygen-glucose deprivation was applied with continuous nitrogen flow and glucose-free cell culture media to mimic ischemia. The temperature in both chambers were independently set between 4 and 37 °C. Samples were placed inside for the ischemic period, followed by a reperfusion stage under standard cell culture conditions. We tested rat calvaria bone pieces undergoing 1, 7, 12 and 24 h of ischemia at 4 and 37 °C. After 24 h of reperfusion, cell number was measured with a tetrazolium cell viability assay. One hour of warm ischemia paradoxically increased the post-reperfusion cell count, while cold-ischemia had an opposite effect. After 7 h of warm ischemia the cells were already unable to recover, while under cold ischemia 60% of the cells were still functioning. After 12 h of cold ischemia 50% of the cells were still be able to recover, while at 24 h even the low temperature was unable to keep the cells alive. The markedly different effect of warm and cold ischemia suggests that this newly designed systemis capable of reliable and reproducible modeling of ischemic conditions. Moreover, it also enables deeper investigations in the pathophysiology of cold ischemia at cellular and tissue level.

12

Strategie odżywcze komórek nowotworowych – przegląd wybranych typów nowotworów z uwzględnieniem zmian w poziomie i wzorze ekspresji transporterów glukozy

Gajek K., Wiatrak B., Ślęzak A., Ussowicz M.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2017

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Vol. 23, nr 2

133--146

PL

Zaburzona równowaga pomiędzy proliferacją a dojrzewaniem i różnicowaniem komórek nowotworowych powoduje szybki wzrost guza, prowadząc do zwiększenia zapotrzebowania na składniki odżywcze, m.in. glukozę i tlen. Pierwszą odpowiedzią komórek nowotworowych na niewystarczającą ilość składników odżywczych jest zmiana metabolizmu na beztlenowy (efekt Warburga). Glukoza niezbędna do przeprowadzenia tego procesu dostarczana jest za pomocą transporterów – najczęściej białek GLUT1 i SGLT1. Zmiana poziomu i wzoru ekspresji transporterów glukozy w komórkach nowotworowych w porównaniu z komórkami odpowiednich tkanek prawidłowych świadczy o adaptacji, do której doszło w obrębie guza. Dotychczasowe badania pozwoliły ustalić, w których rodzajach nowotworów dochodzi do zmian w ekspresji białek GLUT1 i SGLT1 oraz pokazały, że zmiany te mogą mieć bezpośredni związek z zaawansowaniem choroby i rokowaniem dla pacjentów. Niniejsza praca ma charakter przeglądowy i stanowi zestawienie zmian w poziomie ekspresji transporterów glukozy w niektórych typach nowotworów. Określenie poziomu ekspresji tych białek w komórkach nowotworowych może mieć kluczowe znaczenie dla spersonalizowanej terapii przeciwnowotworowej.

EN

Due to imbalance between proliferation, differentiation and maturation, cancer cells grow rapidly and require elevated levels of oxygen and glucose. The main strategy of cancer cells is to prevent starvation is the anaerobic adaptation of cellular metabolism known as the Warburg’s effect. Increased glucose uptake is maintained by alterating the level and the pattern of glucose transporters expression, mainly GLUT1 and SGLT1. In many cancer types, these proteins are present despite their absence in healthy tissue. Previous researches revealed cancer types in which GLUT1 and SGLT1 expression are altered. There is a strong direct correlation between their expression pattern, cancer stage and prognosis for the patient. This review provides an overview of changes in the level of glucose transporters expression in some cancer types. Determination of glucose transporters expression levels in cancer cells could be crucial for personalized cancer treatment.

13

Nutrient turnover at the hypoxic boundary: flux measurements and model representation for the bottom water environment of the Gulf of Riga, Baltic Sea

Eglite E., Lavrinovič A., Müller-Karulis B., Aigars J., Poikane R.

Oceanologia

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2014

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No. 56 (4)

711--735

EN

Experimental studies of intact sediment cores from the Gulf of Riga, Baltic Sea, were conducted to estimate the response of sediment nutrient fluxes to various near-bottom water oxygen conditions. The experiment was performed in the laboratory using a batch-mode assay type system on the sediment cores held at 4°C and oxygen concentrations maintained at 1, 2, 3, 4 and 5 mg l-1. The results from the experiment were subsequently used to optimise the fit of the sediment denitrification sub-model of the Gulf of Riga basin. Sediment-water fluxes of phosphate were low and directed out of the sediments under all treatments, demonstrating a general decreasing tendency with increasing near-bottom water oxygen concentration. The sediment-water fluxes of ammonium and nitrate+nitrite demonstrated opposing trends: ammonium fluxes decreased whereas nitrate+nitrite fluxes increased with rising near-bottom water oxygen concentration. The modelled fluxes agreed well with the measured ones, with correlation coefficients of 0.75, 0.63 and 0.88 for ammonium, nitrate+nitrite and phosphate fluxes respectively. The denitrification rate in sediments was simulated at oxygen concentrations from -2 to 10 mg l-1. At oxygen concentrations <2 mg l-1 the modelled denitrification was sustained by nitrate transport from water overlying the sediments. With increasing oxygen concentrations the simulated denitrification switched from the process fuelled by nitrates originating from the overlying water (Dw) to one sustained by nitrates originating from the coupled sedimentary nitrification – denitrification (Dn). Dn reached its maximum at an oxygen concentration of 5 mg l-1.

14

Czynnik wzrostu śródbłonka naczyń (VEGF) jako marker progresji choroby nowowotworowej - przegląd doniesień

Flak B., Wawrzyniec K., Kwiatek S., Kawczyk-Krupka A., Czuba Z., Sieroń-Stołtny K., Sieroń A.

Acta Bio-Optica et Informatica Medica. Inżynieria Biomedyczna

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2013

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Vol. 19, nr 4

205--209

PL

Angiogeneza zwana również neowaskularyzacją jest wieloetapowym procesem tworzenia nowych naczyń krwionośnych w miejscu już istniejących, regulowanym przez czynniki pobudzające (proangiogenne) oraz hamujące (antyangiogenne). Nowotworzenie naczyń zachodzi w procesach fizjologicznych oraz w stanach patologicznych organizmu. W wyniku zaburzenia równowagi między czynnikami proangiogennymi, aktywującymi proces tworzenia nowych naczyń a czynnikami hamującymi (antyangiogennymi) dochodzi do przewagi aktywacji czynników angiogennych oraz nadmiernej angiogenezy, co sprzyja rozwojowi guza nowotworowego. W wyniku niedotlenienia (hipoksji) tkanki dochodzi do aktywacji czynników angiogennych, w tym przede wszystkim czynnika odgrywającego kluczową rolę w progresji nowotworowej – VEGF (ang. Vascular Endothelial Growth Factor). VEGF jest białkiem uważanym za główny czynnik odpowiedzialny za proces angiogenezy oraz wzrost przepuszczalności naczyń krwionośnych; nazywany jest również czynnikiem przepuszczalności naczyniowej. Najważniejszym czynnikiem indukującym proces angiogenezy oraz wydzielanie czynnika VEGF przez komórki nowotworowe jest niedotlenienie (hipoksja) panujące w mikrośrodowisku guza. VEGF jest złym czynnikiem prognostycznym odpowiadającym za progresję oraz aktywację tworzenia przerzutów wielu guzów litych. Zmniejszenie wydzielania czynnika VEGF ma istotne znaczenie w zahamowaniu procesu angiogenezy, a także potencjału metastatycznego komórek nowotworowych, które wcześniej nie uległy zniszczeniu na drodze apoptozy lub nekrozy.

EN

Angiogenesis, also called neovascularization is a multistep process of forming new blood vessels and it is regulated by stimulating factors (proangiogenic) and inhibitors (anti-angiogenenic). Neovascularization occurs in physiological processes and in pathological states of the organism. As a result of an imbalance between proangiogenic factors activating the process of creating new blood vessels and inhibitors (anti-angiogenic) comes to lead the activation of angiogenic factors and excessive angiogenesis, which promotes tumor growth. As a result of hypoxia an activation of tissue angiogenic factors occurs, including, in particular, the key factor in tumor progression - VEGF (Vascular Endothelial Growth Factor). VEGF is a protein considered to be the main factor responsible for process of angiogenesis and an increased vascular permeability’ It is also known as a vascular permeability factor. The most important factor that induces angiogenesis and VEGF secretion by cancer cells is hypoxia in the tumor microenvironment. VEGF is a poor prognostic factor responsible for the progression and metastasis activation of many solid tumors. Decreased levels of VEGF is important in the inhibition of angiogenesis and metastatic potential of tumor cells that have not been destroyed by apoptosis or necrosis.

15

Phosphate exchange across the sediment–water interface under oxic and hypoxic/anoxic conditions in the southern Baltic Sea

Łukawska-Matuszewska K., Burska D.

Oceanological and Hydrobiological Studies

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2011

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Vol. 40, No.2

57-71

EN

Benthic fluxes of phosphate and phosphorus distribution in sediments from the southern Baltic Sea were investigated in spring and autumn in 2005 and 2007–2010. Strong spatial variability of phosphate fluxes was observed across the sediment–water interface. The highest values of phosphate flux from sediment (up to 37 μmol m-2 h-1), resulting from the high mineralization rate of organic matter and rapid phosphorus turnover due to macrofaunal activity and hydrodynamic conditions, were observed in the shallow area at depths ranging from 50 to 69 m. The rate of phosphate exchange in the transportation and accumulation bottom area with the water depth .72 m was several times lower (2.12 – 6.22 μmol m-2 h-1). In continuously hypoxic or anoxic sediments, phosphorus was preserved in the refractory organic form, and sediments were depleted of redox-dependent phosphorus forms. In shallow area with well oxygenated near-bottom water, phosphorus was present mainly in the calcium-bound form.

16

Uraz ciśnieniowy płuc w przebiegu hipoksji u płetwonurka pod wodą

Olszański R., Siermontowski P., Dąbrowiecki Z.

Polish Hyperbaric Research

|

2010

|

nr 3(32)

67-70

PL

W artykule opisano przypadek nieprawidłowego zachowania nurka pod wodą, które doprowadziło do niedotlenienia i hiperkapni z następową utratą przytomności podczas nurkowania powietrznego, płytkowodnego, w skafandrze suchym, powikłanego urazem ciśnieniowym płuc.

EN

The article discusses the case of an improper diver’s underwater behaviour which led to hypoxia and hypercapnia, with a following loss of consciousness during air diving in shallow water and in a dry diving suit, and consequent pulmonary barotrauma.

17

The effect of hypoxia and anoxia on osmotic concentrations of Corophium volutator (Pallas) from the Gulf of Gdańsk

Dobrzycka-Krahel A., Szaniawska A.

Oceanological and Hydrobiological Studies

|

2005

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Vol. 34, No.1

99--109

EN

The aim of the investigations was to determine the effect of hypoxia and anoxia on the osmoregulation of Corophium volutator. The experiments were performed at salinities of 3.0, 6.6,15.0, and 25.0 PSU in conditions of hypoxia (saturation = 30% O2) and anoxia at a constant temperature of 10°C. Control experiments in aerated water were conducted simultaneously. Hypoxia (saturation = 30% O2) had no statistically significant effect on the osmoregulation of C. volutator after either 6 h or 48 h. However, after 6 h it did lower the osmotic concentration slightly. After 6 h anoxia had no effect on osmoregulation, but no subsequent effects of this factor (after 24 and 48 h) were detectable due to high animal mortality. Anoxia also had no effect on osmoregulation after 24 h at salinities of 15.0 and 25.0 PSU or 48 h at 15.0 PSU.

18

Seasonal and annual changes in the macrozoobenthic populations of the Gulf of Gdańsk with respect to hypoxia and hydrogen sulphide

Janas U., Wocial J., Szaniawska A.

Oceanologia

|

2004

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No. 46 (1)

85-102

EN

This study was designed to investigate seasonal and annual changes in the benthic macrofauna in relation to changes in hydrogen sulphide concentration in the sediment and the oxygen content in the water column. Data were collected over a three-year period from 1994 to 1997. The benthic macrofauna inhabiting the sediments of the Gulf of Gdansk, in which H2S is permanently present, consists mostly of species with a high tolerance to oxygen deficiency and the presence of H2S. These species are: Macoma balthica, Harmothoe sarsi, Nereis diversicolor, Saduria entomon and Halicryptus spinulosus, as well as Pontoporeia femorata and Corophium volutator, which are more sensitive to these factors. In 1996-1997 a decline in the abundance of almost all benthic species, and especially of the bivalve M. balthica at all the stations was observed in comparison to 1994-1995.

19

Monitoring of the cardiac activity of the Baltic isopod Saduria entomon exposed to hypoxia, using non-invasive, computer-aided techniques

Miąc J.

Oceanological Studies

|

2001

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Vol. 30, No. 3-4

115-124

EN

The repertoires of physiological responses which invertebrates possess play a major role in determining their distribution and survival potential. In the present study the effect of severe hypoxia on the heart rate of S. entomon has been investigated. Saduria entomon are often exposed to extended periods of severe hypoxia and anoxia in their natural habitats. The animals were exposed to conditions of a reduced level of oxygen ( 10% O2 saturation) for 24 hours. The experiment confirms that the pattern of their heart rate changed considerably with time and experimental condition. Under hypoxic condition a steady, regular heart rate was observed and the variability of beat rate decreased in comparison with normoxic one. The mean heart rate of the unburied animals in normoxia was higher than that of the buried S.entomon with considerably lower inter-individual variability. The mean heart rate of animals in hypoxic conditions was similar for all individuals (41.66 ą 2.03 (mean ą SD)), but not significantly different in normoxic conditions (Student t-test, p 0.05).