Karoliina Annika Koho

Geological Survey of Finland | GTK

Foraminifera are unicellular eukaryotes that are an integral part of benthic fauna in many marine ecosystems, including the deep sea, with direct impacts on benthic biogeochemical cycles. In these systems, different foraminiferal species are known to have a distinct vertical distribution, i.e., microhabitat preference, which is tightly linked to th...

Metabarcoding analyses of bacterial and eukaryotic communities have been proposed as efficient tools for environmental impact assessment. It has been unclear, however, to which extent these analyses can provide similar or differing information on the ecological status of the environment. Here, we used 16S and 18S rRNA gene metabarcoding to compare...

For full access visit: https://sites.utu.fi/bre/towards-a-green-future-of-the-baltic-sea/ Baltic Rim Economies, BRE1/2021

Molybdenum (Mo) and uranium (U) contents in sedimentary archives are often used to reconstruct past changes in seafloor oxygenation. However, their sequestration processes are as yet poorly constrained in low-salinity coastal waters, which often suffer from anthropogenic eutrophication but only mild oxygen depletion. Due to the consequent lack of r...

Coastal sediments play a fundamental role in processing anthropogenic trace metal inputs. Previous studies have shown that terrestrialorganic matter (OM) is a significant vector for trace metal transport across the land-to-sea continuum, but little is known about the fate of land-derived metal-OM complexes in coastal sediments. Here, we use a compr...

Benthic foraminifera are known to play an important role in marine carbon and nitrogen cycles. Here, we report an enrichment of sulphur cycle-associated bacteria inside intertidal benthic foraminifera (Ammonia sp. (T6), Haynesina sp. (S16) and Elphidium sp. (S5)), using a metabarcoding approach targeting the 16S rRNA and aprA-genes. the most abunda...

Supplementary Material of the article "Metabarcoding Insights Into the Trophic Behavior and Identity of Intertidal Benthic Foraminifera" https://doi.org/10.3389/fmicb.2019.01169

Foraminifera are ubiquitous marine protists with an important role in the benthic carbon cycle. However, morphological observations often fail to resolve their exact taxonomic placement and there is a lack of field studies on their particular trophic preferences. Here, we propose the application of metabarcoding as a tool for the elucidation of the...

Metabarcoding is a method that combines high-throughput DNA sequencing and DNA based identification. Previously, this method has been successfully used to target spatial variation of eukaryote communities in marine sediments, however, the temporal changes in these communities remain understudied. Here, we follow the temporal changes of the eukaryot...

Research of the past few decades has revealed a great variability of metabolisms (e.g. adaptation to different microhabitats, feeding strategies, symbiosis, survival to stressful conditions) among benthic foraminiferal species. This metabolic variety is reflected in the cell by a great diversity of organelles, cellular organization and organelle as...

Assimilation, sequestration and maintenance of foreign chloroplasts inside an organism is termed “chloroplast sequestration” or “kleptoplasty”. This phenomenon is known in certain benthic foraminifera, in which such kleptoplasts can be found both intact and functional, but with different retention times depending on foraminiferal species. In the pr...

The ultrastructure of the living foraminiferan, Ammonia sp. (phylotype unknown), collected from surficial and deeper, subsurface (anoxic) sediments from the Dutch Wadden Sea, was examined to provide information on the physiology of the foraminiferal cell and its adaptive strategies to low oxygen conditions. The observed changes in cell ultrastructu...

The Mn / Ca of calcium carbonate tests of living (rose-Bengal-stained) benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata) were determined in relation to pore water manganese (Mn) concentrations for the first time along a bottom water oxygen gradient across the continent...

The Mn / Ca of carbonate tests of living (rose Bengal stained) benthic foraminifera (Elphidium batialis, Uvigerina spp., Bolivina spissa, Nonionellina labradorica and Chilostomellina fimbriata) were determined in relation to pore water manganese (Mn) concentrations for the first time along a bottom water oxygen gradient across the continental slope...

The Mn/Ca of carbonate tests of living deep-sea foraminifera (Hoeglundina elegans, Bulimina aculeata, Uvigerina peregrina and Melonis barleeanus) were determined together with pore water manganese along a bottom water oxygen gradient across the lower boundary of the Arabian Sea Oxygen Minimum Zone. Although Mn has long been considered an indicator...

On March 11th, 2011 the Mw 9.0 2011 Tohoku-Oki earthquake resulted in a tsunami which caused major devastation in coastal areas. Along the Japanese NE coast, tsunami waves reached maximum run-ups of 40 m, and travelled kilometers inland. Whereas devastation was clearly visible on land, underwater impact is much more difficult to assess. Here, we re...

Live (Rose-Bengal stained) deep-sea foraminiferal faunas have been studied at five stations between 500-2000-m depth along the NE Japanese margin (western Pacific) to understand how complex environmental conditions (e.g., oxygen depletion, organic matter) control their structure (i.e., diversity, standing stocks, and microhabitats). All stations ar...

Live (Rose Bengal stained) benthic foraminifera from the Murray Ridge, within and below the northern Arabian Sea oxygen minimum zone (OMZ), were studied in order to determine the relationship between faunal composition, bottom water oxygenation (BWO), pore water chemistry and organic matter (organic carbon and phytopigment) distribution. A series o...

Live (Rose Bengal stained) benthic foraminifera from the Murray Ridge, within and below the northern Arabian Sea Oxygen Minimum Zone (OMZ), were studied in order to determine the relationship between faunal composition, bottom-water oxygenation (BWO), pore-water chemistry and organic matter (organic carbon and phytopigment) distribution. A series o...

Burial of organic matter (OM) plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism remains enigmatic. Here we report biochemical quality,...

Burial of organic matter (OM) plays an important role in marine sediments, linking the short-term, biological carbon cycle with the long-term, geological subsurface cycle. It is well established that low-oxygen conditions promote organic carbon burial in marine sediments. However, the mechanism remains enigmatic. Here we report biochemical quality,...

The intermediate waters off Hachinohe (northeastern Japan) signify one of the lowest oxygen (O2) concentrations in the open ocean around Japanese islands today, indicating below 40μM O2 between 800 to 1200m water depths due to high seasonal primary productivity at the sea surface. To investigate biogeochemical microenvironments, especially to unrav...

The Arabian Sea Oxygen Minimum Zone (OMZ) is sustained by high surface water productivity and relatively weak mid-depth water column ventilation. High primary productivity drives high respiration rates in the water column, causing severe oxygen depletion between ±150-1400 m water depths, with the oxygen concentrations falling below 2 μM in the core...

Benthic foraminifera, single-celled eukaryotes, constitute a significant part of the living community in low-oxygen or even oxygen-depleted marine environments. Although the diversity is typically low and the dominance high, selected species appears to thrive in such “hostile” environments. In this chapter, the spatial distribution of modern benthi...

(15)NO(3)(-) isotope labelling experiments were performed to investigate foraminiferal nitrate uptake strategies and the role of pseudopodial networks in nitrate uptake. Globobulimina turgida were placed below the nitrate penetration depth in homogenized sediment cores incubated in artificial seawater containing (15)NO(3)(-) . A nylon net prevented...

In a laboratory experiment, we examined the prolonged survival and behaviour of the benthic foraminiferan Globobulimina turgida under 3 simulated natural conditions: oxygenated with added nitrate, anoxic with added nitrate, and anoxic. The survival rates, adenosine triphosphate (ATP) reserve and intracellular nitrate pool of G. turgida were measure...

Based on morphological and molecular characteristics, we describe a new genus and species of monothalamous agglutinated foraminifera, Capsammina patelliformis, that occurs mainly at bathyal (1000-3400m) water depths in the Nazare Canyon off Portugal. The test is strongly flattened, up to 500µm or more in maximum dimension, and 30-80µm thick. It lac...

Based on morphological and molecular characteristics, we describe a new genus and species of monothalamous agglutinated foraminifera, Capsamminapatelliformis, that occurs mainly at bathyal (1000-3400m) water depths in the Nazaré Canyon off Portugal. The test is strongly flattened, up to 500µm or more in maximum dimension, and 30-80µm thick. It lack...

Rose Bengal stained benthic foraminifera were studied from 11 cores collected along two depth transects off southern Portugal: one in the Lisbon–Setúbal Canyon and the other along the canyon edge. The total standing stocks and distribution of foraminifera were investigated in relation to sediment and pore water geochemistry. Nitrate was used as a r...

Live benthic foraminifera were collected from the Portuguese continental margin from 900 m water depth. Under controlled laboratory conditions, Thalassiosira pseudonana, was used to create an artificial diatom bloom. Two different diatom loads, high (240 μg C/cm2) and low (80 μg C/cm2) load, were fed to benthos. The response of the benthic foramini...

Living (rose Bengal stained) benthic foraminifera were investigated from thirteen stations ranging from 146–4976 m water depth in the Nazaré Canyon, located on the Western Iberian continental margin. The total standing stocks (TSS), species assemblages and in-sediment distributions are compared between stations located on the highly disturbed axis...

Abundance of metazoan meiofauna and foraminifera, and biomass and community structure of nematodes, were investigated in the benthic zone along the Nazaré Canyon and adjacent continental slope in relation to concentration of organic matter and its suitability as a food source for the meiobenthos. The Nazaré canyon sediments were richer in organic c...

Submarine canyons are dynamic sedimentary environments influenced by sediment transport, erosion and deposition. Gravity flows can scour and erode the canyon floor, thus redistributing sediment to distal locations. In addition, submarine canyons can act as sedimentary traps where sediment transported laterally across the continental shelf and slope...