High Biological Productivity Research Articles

Interannual and Seasonal Variability of CO2 Parameters in the Tropical Atlantic Ocean

This study examined the carbon cycling dynamics in the tropical Atlantic Ocean from 1985 to 2023, focusing on factors influencing the surface partial pressure of CO2 (pCO2), freshwater input, total alkalinity (ALK), total dissolved carbon (TCO2), and pH levels. The time series data revealed significant trends, with average pCO2 concentrations rising from approximately 350 μatm in the early 1990s to over 400 μatm by 2023. The TCO2 levels increased from about 2000 μmol/kg to 2200 μmol/kg, while ALK rose from approximately 2300 μmol/kg to 2500 μmol/kg. This increase highlights the ocean’s role as a carbon sink, particularly in areas with high biological productivity and upwelling where TCO2 also rose. This study employed Empirical Orthogonal Functions (EOFs) to identify variability modes and understand spatial patterns of pCO2. Freshwater dynamics significantly affect TCO2 concentrations, particularly in coastal regions, where pH can shift from 8.2 to 7.9, exacerbating acidification. Rising sea surface temperatures have been linked to elevated pCO2 values. These findings support the need for ongoing monitoring and effective management strategies to mitigate the impacts of climate change and ensure the sustainability of marine resources. This study documented the long-term trends in tropical Atlantic CO2 parameters linked to the North Atlantic Oscillation (NAO) and Atlantic Multidecadal Oscillation (AMO).

Sedimentary organic matter signature hints at the phytoplankton-driven biological carbon pump in the central Arabian Sea

Abstract. The central Arabian Sea, a unique tropical basin, is profoundly impacted by monsoon wind reversal affecting its surface circulation and biogeochemistry. Phytoplankton blooms associated with high biological productivity and particle flux occur in the northern part of the central Arabian Sea due to summer-monsoon-induced open-ocean upwelling and winter convection. The core oxygen minimum zone (OMZ) at intermediate water depths is another important feature of the northern central Arabian Sea and fades southward. In this study, we attempt to interlink how these factors collectively impact phytodetrital export to the sediment. Short sediment core-top (1 cm) samples representing the recent particle flux signatures were analysed from five locations (21 to 11° N; 64° E) in the central Arabian Sea. Previously, we used core-top (0–0.5 cm) samples and observed a trend between diatom frustule abundance and diversity with bulk sedimentary parameters indicating a spatial variability in phytodetrital export to the sediment. To verify this observation further, lipid biomarkers of key phytoplankton groups and a sea surface temperature (SST) proxy have been analysed in addition to diatom frustules. The C37 alkenone-based SST proxy indicated cooler SST (27.6 ± 0.25 °C) in the north (21–15° N) mostly due to upwelling (summer) and convective mixing (winter). Warmer SSTs (+0.4 °C) are measured in the south, which usually remains nutrient-poor. This trend was consistent with satellite-derived average SST values (2017–2020). Lipid biomarker analysis suggests that dinoflagellates were likely to be the highest contributor, as indicated by dinosterol and its degradative product dinostanol, followed by brassicasterol and C37 alkenone, likely representing diatoms and coccolithophores, respectively. The north, which largely experiences periodic phytoplankton blooms and is influenced by the thick OMZ, revealed the highest contents of organic matter, diatom frustules (diversity and abundance), dominated by large, thickly silicified cells (e.g. Coscinodiscus and Rhizosolenia) and phytoplankton lipid biomarkers, as well as lower contents of zooplankton biomarkers (cholesterol and cholestanol). In contrast, relatively smaller chain-forming centric (e.g. Thalassiosira) and pennate (e.g. Pseudo-nitzschia, Nitzschia, Thalassionema) diatom frustules along with lower phytoplankton lipid biomarker contents were found in the south, where zooplankton biomarkers and silicious radiolarians were more abundant. The possible impacts of the OMZ on particle flux related to the phytoplankton community, including zooplankton grazing and other factors, have been discussed.

Hydrocarbons in waters and bottom sediments of the coastal areas of the Caucasian sector of the Black Sea (2021–2023)

The current level of aliphatic and polycyclic aromatic hydrocarbons was determined in suspended particulate matter of waters (mainly in surface waters) and in upper layer of bottom sediments of coastal areas in the Caucasian sector of the Black Sea of the Russian Federation (September 2021, May and September 2022, March 2023). IR method was used to determine the aliphatic hydrocarbons, and the method of high performance liquid chromatography was employed for PAHs. The average concentration of aliphatic hydrocarbons was ≈20 μg/L and for polycyclic aromatic hydrocarbons ≈130 ng/L in suspended particulate matter in open surface waters of Gelendzhik and Golubaya bays. Their content naturally increased as they approached the coast. Despite the decrease in hydrocarbon concentrations in surface waters in recent years, the Kerch Strait and Novorossiysk remain the most polluted areas as before. Higher concentrations in the waters of the Taman Peninsula may be caused by the seepage of hydrocarbons from the sedimentary layer. Hydrocarbons are accumulated in bottom sediments, that leads to their rising portion in total organic carbon (e.g., aliphatic hydrocarbons up to 14.2 % in the Tuapse region and 13.1 % in the Novorossiysk region). Along with contamination from anthropogenic sources, natural processes also affect the hydrocarbon levels such as high biological productivity of the area and fluid flows from the sediment layer.

Holocene paleolimnological changes in rundvågshetta lakes in the Soya Coast region and their paleoenvironmental significance with glacial isostatic adjustment in East Antarctica

This study investigated Holocene paleolimnological changes inferred from a multi-proxy dataset of C, N, and S elements, biomarkers, and microscopic observations of microalgae and cyanobacteria in sediment cores from two Rundvågshetta lakes (Maruwanminami-ike and Maruwan-oike) in the Soya Coast region of Antarctica, along with sedimentary facies and accelerator mass spectrometry 14C dating. We discuss biological production and sources, the transition from marine to brackish and lacustrine environments in the lakes, paleoenvironmental changes, transition ages, and relative sea level (RSL) falls (or subsidence) from glacial isostatic adjustment (GIA) in the Soya Coast region. The ages of the Maruwanminami-ike (MwS4C-01, length 147 cm) and Maruwan-oike sediment cores (Mw4C-01, length 226 cm) were 1.4 (5.8 cm core depth)–4.9 and 2.3–5.7 cal ker BP, respectively. The local reservoir effects of the Rundvågshetta lakes were very high, possibly because of the influence of dead carbon in the glacially eroded marine sediments and bed rock. The coastal marine environments of Lakes Maruwanminami-ike (4.9–2.6 cal ker BP) and Maruwan-oike (5.7–3.3 cal ker BP) were characterized by low biological production. A transition period marked by a stratified brackish lake environment in Lakes Maruwanminami-ike (2.6–2.4 cal ker BP) and Maruwan-oike (3.3–2.9 cal ker BP) was characterized by stratified conditions with an anoxic layer at the bottom of the photic zone. The freshwater lake environment of Lake Maruwanminami-ike [(65.6–0 cm, 2.4–1.4 (5.8 cm core depth) cal kyr BP)] was characterized by high biological (cyanobacteria and green algae) production, while that of Lake Maruwan-oike (2.9–2.3 cal ker BP) was characterized by low biological production due to the influence of glacial clay. Around 7.2–3.0 cal ka BP in the Holocene was probably a warm period, and progressive glacial retreat with RSL fall occurred during the warm periods in the Soya Coast region. The RSL falls of all raised beaches and isolated basins in the Soya Coast region ranged from 0.36 ± 0.03–4.4 ± 0.5 mm/yr with an average 2.1 ± 0.2 mm/yr (standard deviation, SD). They were similar to GNSS–based GIA–induced uplift with an average of 2.4 ± 1.5 mm/yr (SD) at Soya Coast region.

Steady nutrient upwelling around a biological hotspot of the confluence between the quasi-stationary jet and the Oyashio in the western North Pacific

The quasi-stationary jet, a branch of the Kuroshio Extension, transports warm saline water in the mixed water region of the western North Pacific. Around the subarctic front between the quasi-stationary jet and Oyashio and its downstream area is a biologically productive area including small pelagic fishes. However, how nutrient is supplied to the euphotic zone in this region remains elusive, especially into the quasi-stationary jet. Using high-resolution hydrography sections across the jet, we showed that Oyashio water isopycnally intrudes under the jet around 26.5–26.8 σθ and forms nutrient-rich intermediate water. Upwelling associated with ageostrophic secondary circulation across the front, caused by confluence, uplifts the intermediate water. A local nitrate maximum was also identified inside the jet by the hydrographic observation. Upwelling has been suggested as a precondition for nutrient supply from nutrient-rich intermediate water to the jet through water mixing which potentially sustains high biological production in the downstream.

Patagonian dust, Agulhas Current, and Antarctic ice-rafted debris contributions to the South Atlantic Ocean over the past 150,000 years

Disentangling inputs of aeolian dust, ice-rafted debris (IRD), and eroded continental detritus delivered by ocean currents to marine sediments provide important insights into Earth System processes and climate. This study uses Sr-Nd-Pb isotope ratios of the continent-derived (lithogenic) fraction in deep-sea core TN057-6 from the subantarctic Southern Ocean southwest of Africa over the past 150,000 y to identify source regions and quantify their relative contributions and fluxes utilizing a mixing model set in a Bayesian framework. The data are compared with proxies from parallel core Ocean Drilling Program Site 1090 and newly presented data from potential South America aeolian dust source areas (PSAs), allowing for an integrated investigation into atmospheric, oceanic, and cryospheric dynamics. PSA inputs varied on glacial/interglacial timescales, with southern South American sources dominating up to 88% of the lithogenic fraction (mainly Patagonia, which provided up to 68%) during cold periods, while southern African sources were more important during interglacials. During the warmer Marine Isotope Stage (MIS) 3 of the last glacial period, lithogenic fluxes were twice that of colder MIS2 and MIS4 at times, and showed unique isotope ratios best explained by Antarctic-derived IRD, likely from the Weddell Sea. The IRD intrusions contributed up to 41% at times and followed Antarctic millennial warming events that raised temperatures, causing instability of icesheet margins. High IRD was synchronous with increased bioavailable iron, nutrient utilization, high biological productivity, and decreased atmospheric CO2. Overall, TN057-6 sediments record systematic Southern Hemisphere climate shifts and cryospheric changes that impacted biogeochemical cycling on both glacial/interglacial and subglacial timescales.

Phytoremediation of technogenically disturbed soils of coal mines

The use of joint planting of tree species with different life strategies, annual growth rates, but with a complementary reaction to co-growth in reclamation sites makes it possible to more effectively use ecological niches and ensure the formation of species-rich forest communities with higher biological productivity. At each age stage of planting, a certain category of woody plants "works" on carbon accumulation, which generally provides an increased deposition effect compared to single-species plantations. Modern recommendations on forest reclamation are focused on the creation of monocultures that are insufficiently stable, do not create a nature-like structure of plant communities and are not sustainable for a long period of time. Currently, technologies have been developed taking into account the sustainability of forest plantations on landfills.

Unraveling marine phosphogenesis along the Miocene coast of Peru: Origin and sedimentological significance of the Pisco Formation phosphorites

Phosphorite deposits form through phosphogenesis, a mechanism of diffusion and concentration of interstitial phosphate in sediments leading to Ca-phosphate mineral precipitation in a favorable sedimentary regime at the seafloor. Stretching along the Peruvian coast, the East Pisco Basin is known to host phosphorite beds of Miocene age. In this study, we investigate the petrographic, mineralogical and chemical composition of the Miocene phosphorite layers of the East Pisco Basin, and discuss the phosphogenetic mechanism(s) and sedimentary dynamics that led to the genesis and accumulation of P-rich deposits. Phosphorite samples were collected from layers overlaying stratigraphic unconformities within the Pisco Formation and subsequently analyzed through multiple methods: optical microscopy, XRD, XRF, SEM-EDS, EPMA, ICP-MS and LA-ICP-MS. Our results indicate that these layers consist of phosphatic clasts and nodules along with dolomite clasts, basement boulders, shark teeth, mollusk molds and vertebrate bone fragments. The P-rich clasts are mainly composed of phosphatic intraclasts and small phosphatic nodules. They occur associated with minor amounts of dolomite clasts coated by Fe-oxyhydroxides and laminites. Clasts and nodules are cemented by both early and late diagenetic cements, such as dolomite, calcite, silica, gypsum/anhydrite and baryte. Our observations suggest that the Pisco phosphorite deposits are transgressive lags laying on ravinement surfaces. They formed just below the sediment-water boundary during the early transgression phases, when the porewaters were enriched in phosphorus due to the abundance of organic-rich sediments and the microbial activity, as typical of upwelling settings. These deposits formed in shallow marine conditions, characterized by high biological productivity and low net sedimentation rates, with suboxic conditions at and beneath the sediment-water interface. The concentration of phosphate-coated clasts was then favored by a sedimentary condensation mechanism of dynamic bypassing. Overall, this study provides new insights into the genesis of phosphorite layers in the East Pisco Basin and highlights the importance of understanding the complex interplay between authigenic and sedimentological processes in the formation of these economically and geologically relevant sedimentary rocks.

Controlling Factors of Organic Matter Enrichment in Marine–Continental Transitional Shale: A Case Study of the Upper Permian Longtan Formation, Northern Guizhou, China

The marine–continental transitional shale of the Upper Permian Longtan Formation in northern Guizhou is an important source rock in the upper Yangtze region of China, and it holds significant potential for the exploration of shale gas. To investigate the correlation between sedimentary conditions and the accumulation of organic matters in marine–continental transitional shale, this paper performed an extensive analysis using organic geochemical testing, organic petrology examination, a cross-section polisher–scanning electron microscope (CP-SEM), and geochemical analysis. The Jinsha and Dafang drilling cores were selected as the research subjects. The results showed that the TOC of the Longtan Formation in the study area was relatively high, and the TOC content of the tidal flat–lagoon environment (average of 8.37%) was significantly higher than that of the delta samples (average of 2.77%). The high content of Al2O3 (average of 17.41% in DC-1, average of 16.53% in JC-1) indicated strong terrigenous detrital input. The proxies indicated that the Longtan Formation shale in northern Guizhou was deposited in a climate that was both warm and humid, with oxic–dysoxic sedimentary water characterized by high biological productivity and a rapid sedimentation rate. The organic-rich shales during the marine and continental transitional phases were affected by various factors, including the paleo-climate, water redox properties, paleo-productivity, sedimentation rate, and other variables, which directly or indirectly impacted the availability, burial, and preservation of organic matter.

Photothermal conditions and upwelling enhance very short-lived brominated halocarbons emissions in the western tropical Pacific Ocean

Sea-to-air emissions of very short-lived brominated halocarbons (VSLBrHs) are known to contribute to 30 % of stratospheric and tropospheric ozone depletion. However, empirical data on their occurrence in open ocean are scarce, which makes it difficult to estimate the significant contribution of open ocean releases to the global budget of halocarbons. This study was conducted in 2022 to explore the spatial variations of VSLBrHs and their controlling factors in the western tropical Pacific Ocean (WTPO). The findings highlighted that high biological productivity and the resulting dissolved organic matter (DOM) as well as upwelling dynamics significantly influenced the distribution and production of VSLBrHs in seawater, with atmospheric levels primarily governed by oceanic emissions. Based on the simultaneous observation of seawater and atmospheric concentrations, the mean sea-to-air fluxes of CH2Br2, CHBr3, CHBrCl2, and CHBr2Cl were estimated to be 1.01, 6.65, 9.31, and 7.25 nmol m−2 d−1, respectively. Sea-to-air fluxes of these gases in the upwelling regions were 9.0, 4.6, 2.9, and 6.8 times those in the non-upwelling regions, respectively. Additionally, in-situ incubation experiments revealed that the enzymatic mediated biosynthesis pathways of VSLBrHs were enhanced under temperature and light-induced stress and in waters rich in humus-like substances. Therefore, we tentatively concluded that abundant photothermal conditions and the existence of upwelling in the WTPO made it a potential hotspot for the emission of VSLBrHs. This study offers critical insights into the environmental dynamics of VSLBrHs emissions and underscores the importance of regional oceanic conditions in influencing atmospheric greenhouse gas compositions.

Biogenic Sulfur Gases as Biosignatures on Temperate Sub-Neptune Waterworlds

Theoretical predictions and observational data indicate a class of sub-Neptune exoplanets may have water-rich interiors covered by hydrogen-dominated atmospheres. Provided suitable climate conditions, such planets could host surface liquid oceans. Motivated by recent JWST observations of K2-18 b, we self-consistently model the photochemistry and potential detectability of biogenic sulfur gases in the atmospheres of temperate sub-Neptune waterworlds for the first time. On Earth today, organic sulfur compounds produced by marine biota are rapidly destroyed by photochemical processes before they can accumulate to significant levels. Domagal-Goldman et al. suggest that detectable biogenic sulfur signatures could emerge in Archean-like atmospheres with higher biological production or low UV flux. In this study, we explore biogenic sulfur across a wide range of biological fluxes and stellar UV environments. Critically, the main photochemical sinks are absent on the nightside of tidally locked planets. To address this, we further perform experiments with a 3D general circulation model and a 2D photochemical model (VULCAN 2D) to simulate the global distribution of biogenic gases to investigate their terminator concentrations as seen via transmission spectroscopy. Our models indicate that biogenic sulfur gases can rise to potentially detectable levels on hydrogen-rich water worlds, but only for enhanced global biosulfur flux (≳20 times modern Earth’s flux). We find that it is challenging to identify DMS at 3.4 μm where it strongly overlaps with CH4, whereas it is more plausible to detect DMS and companion byproducts, ethylene (C2H4) and ethane (C2H6), in the mid-infrared between 9 and 13 μm.

Classification of optical water groups in the subarctic pacific and adjacent seas using satellite-derived light absorption spectra of chromophoric dissolved organic matter

The characteristics of the water masses that contribute to high biological production in the subarctic Pacific and adjacent seas (SPA) could change because of recent climate change. This study reports on a method to classify water in the SPA into distinct optical water groups using the light absorption coefficient of chromophoric dissolved organic matter (CDOM), aCDOM(λ), captured using an ocean color satellite. In situ samples obtained from ship surveys between 2006 and 2021 were classified into five optical group numbers (OGN1–OGN5) based on aCDOM parameters in the ultraviolet (UV) region: aCDOM(λ) at 350 nm (aCDOM(350)) and the spectral slopes at 275–295 nm (S275–295) and at 350–400 nm (S350–400). We were also able to identify OGN with a new method using machine learning technique developed in this study that adopted satellite-derived aCDOM(λ) in the visible (VIS) region. The distribution and characteristics of OGN classified using the in situ aCDOM parameters in the UV region supplement the interpretation of the origin and mixing of the water masses classified by temperature and salinity. Relative to in situ samples, the accuracy of the OGN estimation from the ocean color satellites was 83.3%. The satellite-derived OGN were able to distinguish high chlorophyll-a areas where high phytoplankton productivity is expected. In addition, identifying the distribution of OGN from satellites supports improved understanding of the bloom process. This method has potential to help to understand the impact of phenomena from accelerating ocean warming (e.g., sea ice decline, enhancement of stratification and increase in riverine input) on water masses structure and the consequent changes in the phytoplankton productivity in the SPA.

On the Hydrofauna of the First Batabat Water Reservoir

For the first time generalized data on hydrofauna of the First Batabat reservoir are given. In the fauna 6 species of zooplanktonic organisms are revealed, with absolute predominance of large predatory copepod Hemidiaptomus rylovi Charin, 1928. The mean body length of fertilized egg-bearing female crustaceans was 3.6 mm to the furca and 5.1 mm to the tip of the telson. In the ecosystem, Daphnia pulex Leydig, 1860 typically produces its last parthenogenetic generation in September. In the macrozoobenthos of the reservoir, 40 species of macrobenthic organisms were found, with the Heteroptera (9 species) and the Chironomidae family (9 species) predominating in terms of the number of species. According to all its ecological indicators Gammarus lacustris (Sars, 1863) is the dominant bottom organism of the ecosystem. The maximum number of population individuals — 346 spec./m2 and biomass — 2804 g/m2 was calculated in the last decade of June 2017. Being a detritophage with a wide food spectrum, individuals of the higher crayfish have an abundant food base in the reservoir. The first Batabat reservoir located in the high mountainous region of the autonomous republic and having favorable natural and geographical conditions is characterized by high biological productivity.

Late Pleistocene-Holocene sea level and climate changes in the Gulf of Saros: Evidence from seismostratigraphic record and sediment core data

A detailed record of sea level changes and climate oscillations in the Gulf of Saros during the late Pleistocene to the Holocene is provided by high-resolution seismic reflection profiles and analysis of a sediment core. The seismic stratigraphy reveals the formation of four main depositional units bounded by prominent reflection surfaces, reflecting high sea level variations. The Last Glacial Maximum period in the gulf is associated with the lowstand sea level, forming the deepest marine terrace at −148 m. The increasing sea level due to post-glacial warming was accompanied by the deposition of transgressive units characterized by coastal onlaps together with local channel-fills. This transgressive phase was modulated by three brief still-stands sea levels at 17 cal ka BP, 14.6 cal ka BP and 13.6 cal ka BP, producing the younger marine terraces in the gulf at −135 m, −112 m and −90 m, respectively. A comparison of their depths with the global sea level curve reveals elevation differences with decreasing subsidence rates from the older to younger ages, implying tectonic subsidence along the gulf floor.The close correlation of multi-proxy data from core SAG-22 in the gulf with the northern Aegean and Anatolia data strongly indicates that the timings of the past climate events generally agree with the global and regional climate patterns. The warm climate around the gulf during the late phase of Bølling/Allerød (13.3–12.6 cal ka BP) is represented by high marine biological productivity and improved ventilation in the deeper water due to subsequent transgression. Permafrost formation in the catchment area during the following cold and dry Younger Dryas period (12.6–11.7 cal ka BP) resulted in reduced soil erosion and sediment input to the gulf. Noticeable warming during the Early Holocene between 11.2 cal ka BP and 9.4 cal ka BP is recorded by the multi-proxy data of the core when the enhanced marine biological productivity occurred above the poorly oxygenated deep water column. The climatic deterioration to a cooler and drier phase during the Early to Middle Holocene transition (9.4–7.8 cal ka BP) resulted in intense physical weathering and erosion, causing the highest sedimentation in the gulf. The later period of the Holocene is associated with the formation of two discrete sapropels at 7.8 cal ka BP and 5.4 cal ka BP that were accompanied by warm and wet climates around the gulf.

Использование биологических рабочих агентов для снижения углеродного следа

Introduction. Chemical compounds related to greenhouse gases (CO2, CH4, N2O, some fluorinated F-gases), capturing the energy of the Sun and absorbing infrared radiation, create a greenhouse effect above the Earth’s surface. In order to assess the impact of humanity on the climate system, the carbon footprint indicator is used, which takes into account greenhouse gas emissions from anthropogenic human activities. This indicator is used to estimate direct emissions from technological processes that can be controlled and from indirect emissions that occur during the product lifecycle. One of the promising areas for reducing greenhouse gases can be considered the use of biological working agents. The purpose of the research. Conducting an assessment of the possibilities of using biological working agents to reduce the carbon footprint in mining enterprises. Methodology. The research was conducted on the basis of analyses of literary data from Russian and foreign sources, specific preventive and compensatory initiatives for the absorption of greenhouse gases from the atmosphere based on the participation of biological working agents were considered. Results and discussion. As a result of the research, various technologies for reducing the carbon footprint using biological working agents were considered. Dependences of the carbon footprint on changes in the natural gas content of coal seams for coalmines were obtained. The carbon footprint was calculated when obtaining energy resources for the extraction of 1 ton of coal using various types of fuels, during the burning of rock dumps. It is proposed to use biological working agents to reduce the carbon footprint using various technologies to reduce direct and indirect emissions, as well as to recycle greenhouse gases to obtain alternative energy. The results of the study of the applicability of biological working agents in mining enterprises in order to reduce the carbon footprint are shown. Conclusions. 1. Research has been conducted on the use of various technologies to reduce the carbon footprint using biological working agents in relation to mining enterprises. 2. It has been determined that biological working agents, when used in mining enterprises, can reduce the carbon footprint from direct greenhouse gas emissions by many times, as well as deposit carbon for many years by extracting CO2 and other gases directly from the air, growing trees and plants with high biological productivity capable of sequestering carbon dioxide. 3. It has been found, that biological working agents are able to process CO2 to produce various useful products, as well as utilize greenhouse gases to produce alternative energy.

Development of a unique integrated bioreactor for simultaneous desalination and bioenergy and biohydrogen production

In the wastewater treatment challenge, it is really essential to develop integrated systems in reducing greenhouse gases, producing green energy and achieving sustainable development. In this regard, an integrated electro-biomembrane reactor was developed and performed in this study for simultaneous biohydrogen (bioH2) production from energetic poplar leaves using dark fermentation (DF) process, conventional H2 production, bioenergy production in the DF process, and saline water desalination in a single system. The results of this study showed that pH was the main controlling parameter in bioH2 production, and the superior production of 40.2 mL/g-biomass was obtained at a pH of 5.5. The maximum current and power density values were 2861.7 mW/m2 and 2819.4 mA/m2 at pH 5.5 under improved conditions. Furthermore, the maximum conventional H2 production was found to be 1341.6 mL using 2 M of KOH solution. Overall, the results further proved that the proposed integrated system can be a sustainable and promising process for industrial applications, considering its high desalination, energy production, and conventional and biological H2 production efficiencies.

New species and new records of aquatic asexual ascomycetes from estuarine beaches of the Brazilian Amazon

ABSTRACT Estuaries are habitats characterised by high biological productivity; however, fungal biodiversity in these ecosystems remains understudied. During an investigation of asexual ascomycetes associated with decaying twigs in the intertidal zone of fluvial beaches on Mosqueiro Island, Pará, Brazil, three new species have been proposed based on their morphological characteristics. These new species are Bactrodesmium amazonicum sp. nov., Craspedodydymum brasiliense sp. nov., and Cancellidium estuarinum sp. nov. Additionally, new records of Cumulospora marina for the Americas and Virgariella caribensis, the second recorded instance in the world, have been reported. The results include descriptions, taxonomic comments, geographic distribution, and illustrations, all contributing to the knowledge of estuarine fungal diversity.

A benthic foraminifera perspective of the Late Miocene-Early Pliocene Biogenic Bloom at ODP Site 1085 (Southeast Atlantic Ocean)

The Late Miocene-Early Pliocene Biogenic Bloom (ca. 9.0–3.5 Ma) was a phase of high marine biological productivity documented globally at multiple ocean sites, related to an increase in nutrient input and/or a significant reorganization of nutrients in the oceans. Here, we studied the Biogenic Bloom at Ocean Drilling Program (ODP) Site 1085 in the Southeast Atlantic Ocean, additionally providing an updated age model based on calcareous nannofossil biostratigraphy. During the event, we identified four intervals characterised by distinct benthic foraminiferal assemblages, suggesting changes in paleoenvironmental/paleoceanographic conditions. The Biogenic Bloom extends from 8.1 to 3.0 Ma at Site 1085, as detected by different proxies such as linear sedimentation rates, carbonate mass accumulation rates, benthic foraminiferal indices and assemblage data. The inferred paleoenvironmental changes allowed us to differentiate four intervals within the Biogenic Bloom. From 8.1 to 5.2 Ma and from 3.8 to 3.0 Ma, the high benthic foraminiferal accumulation rates (BFARs) and the abundance of phytodetritus-exploiting taxa point to highly seasonal phytoplankton blooms. Between 5.2 and 4.8 Ma, we document short-term fluctuations between well‑oxygenated conditions with transient input of phytodetritus and phases of low oxygen eutrophic conditions. Between 4.8 and 3.8 Ma, a decrease in opportunistic species and an increase in eutrophic taxa likely suggest a switch to a higher food supply to the seafloor. Our data shows that the onset of the Biogenic Bloom was synchronous with other global well-dated records and its end appears to align with other Atlantic records. Lastly, our findings support the hypothesis that the Biogenic Bloom was not a single productivity event, but a complex event made up of several short-lived, high-productivity regimes with different driving forces.

Understanding the oceanographic dynamics of the Isla Chañaral baleen whale feeding ground, (Humboldt Archipelago, Northern Chile) to extend habitat protection

Off Northern Chile, baleen whales use the area around Isla Chañaral as a feeding ground where they forage on euphausiids. Isla Chañaral is part of the highly productive Humboldt Archipelago (∼ 28°S-29°S) within the Humboldt Current System (HCS). In this study, we seek to understand the sub-mesoscale spatial distribution of fin and blue whales and their prey around Isla Chañaral using systematic and opportunistic visual sighting data of whales and systematic acoustic backscatter data of zooplankton from an Acoustic Zooplankton and Fish Profiler (AZFP); and to examine the oceanographic dynamics of the wider Humboldt Archipelago area with remote-sensing oceanographic data. We completed a total of 512.6 km of survey effort over 20 days in 2018 and 318.3 km over 16 days in 2019 collecting systematic whale sighting and backscatter data. A total of 42 fin whales, 0 blue whales and 66 unidentified whales were sighted in 2018, and 7 fin whales, 3 blue whales and 12 unidentified whales were sighted in 2019. Observed spatial distribution of backscatter and whales was strongly associated with a bathymetric feature, i.e., the submarine canyon that curves around Isla Chañaral. Generalized Additive Models showed that fin whale presence was associated with high levels of backscatter and shallow depths similar to those of the canyon. We found that long-term average geostrophic currents form a recirculation system between 28°S and 31°S that can transport nutrient-rich upwelled surface waters back towards the Humboldt Archipelago and contribute to high biological productivity in this area. However, in summer 2019 geostrophic flow occurred away from the coast and a warm low-productivity spring explained low backscatter and whale sightings around Isla Chañaral. The unique oceanographic features of Isla Chañaral and the Humboldt Archipelago that contribute to high concentrations of Endangered baleen whales and their prey justify the extension of the Isla Chañaral Marine Reserve to include the canyon between the mainland and the island, and the implementation of a Multiple Use Marine Protected Area for the entire Humboldt Archipelago area that explicitly protects this critical feature.

Analysis of multiyear seasonal spatial-temporal chlorophyll-a concentration dynamics in the coastal zone of north-western of the Sea of Japan

The coastal zone and shelf of the north-western of the Sea of Japan have high biological productivity. The vegetation of microalgae is realized due to insolation, nutrient input with river runoff and as a result of seasonal vertical mixing of water masses. Also, the productivity activity relates to the type of marine landscape. Phytoplankton assemblages are first-order food resources for zooplankton and the second for nekton (fish, mammals), and they also serve as a source of biological minerals from the decayed of their dead cell products, which as suspended particles (detritus) provide food for pelagic bacteria and bottom biocenoses. The vertical subdivision of the landscape - neritho-pelagial (coastal zone) of the studied part of the sea reflects a wide biological diversity represented by bottom communities of living organisms. The research objective of this article studied to analyze the spatial and temporal dynamics of chlorophyll-a concentration in phytoplankton in different landscape-bionomic areas in the north- western of the Sea of Japan for each season from 2003 to 2022’s. The article is used the landscape-bionomic and space monitoring data approaches. The known system of units of global zoning of ecoregions (sea basins) describes the natural features of the sea. The fundamental unit of regional zoning is coastal morphostructures or marine landscape which builds ecological conditions for hydrobionts. Space monitoring from the Aqua satellite, NASA, covers the upper layers of water at a wide resolution. Water surface temperature and chlorophyll-a concentration for 20 years (2003-2022's) are compared on the basis of satellite data. Practical significance: the paper discloses the links between landscape-bionomic areas and seasonal multiyear dynamics of temperature and phytoplankton productivity in the north- western of the Sea of Japan. The comprehensive approach will serve as a necessity for the rational use of aquatic biological resources. Moreover, satellite data can be applied to the construction of long-term forecasts of climate variability in the region.