MARTIJANEC-GAMULICA - ANALYSIS OF FINDS FROM 1950

Godine 1950. na tada još neistraženom tumulu Gamulica kod Martijanca ukopan je stup dalekovoda. Tom je prilikom mještanin Martijanca, Martin Štanglin, u tumulu prokopao jamu te otkrio tragove grobne konstrukcije i priloga. Lokalitet je nakon toga obišao prof. Stjepan Vuković, tadašnji kustos Odjela za arheologiju Gradskog muzeja Varaždin, te je pokretne nalaze prikupio, a iskop sanirao. Istraživanje pod vodstvom dr. sc. Zdenka Vinskog kao i detaljna analiza tada prikupljenih arheoloških nalaza, potvrdili su izniman značaj lokaliteta Martijanec-Gamulica, međutim, tom prilikom nisu uzeti u obzir i predmeti koje je 1950. god. prikupio S. Vuković. Dvadeset i sedam keramičkih te jedan brončani predmet čine malu, ali vrijednu skupinu nalaza čija će analiza i konačna objava zaokružiti spoznaje o ukopu u tumulu Gamulica te pridonijeti boljem poznavanju stariježeljeznodobne grupe Martijanec-Kaptol.In 1950, on the then unexcavated tumulus of Gamulica near Martijanec, a transmission line pole was set up. On that occasion Martin Štanglin, a resident of Matrijanec, found a pit in the tumulus which contained traces of a tomb with grave goods. The site was then visited by professor Stjepan Vuković who worked as a curator at the Department of Archaeology of the Varaždin City Museum and who collected movable finds and protected the tomb. Research led by Zdenko Vinski, PhD, as well as a detailed analysis of the finds, confirmed the exceptional status of the Martijanec-Gamulica site. However, the study did not include finds collected in 1950 by S. Vuković. Twenty seven ceramic and one bronze find make up a small but valuable group of finds the analysis of which will unite our knowledge of the tomb inside the Gamulica tumulus and contribute to our understanding of the Iron Age Martijanec-Kaptol group

Influence of nutrient supply on plankton microbiome biodiversity and distribution in a coastal upwelling region.

The ecological and oceanographic processes that drive the response of pelagic ocean microbiomes to environmental changes remain poorly understood, particularly in coastal upwelling ecosystems. Here we show that seasonal and interannual variability in coastal upwelling predicts pelagic ocean microbiome diversity and community structure in the Southern California Current region. Ribosomal RNA gene sequencing, targeting prokaryotic and eukaryotic microbes, from samples collected seasonally during 2014-2020 indicate that nitracline depth is the most robust predictor of spatial microbial community structure and biodiversity in this region. Striking ecological changes occurred due to the transition from a warm anomaly during 2014-2016, characterized by intense stratification, to cooler conditions in 2017-2018, representative of more typical upwelling conditions, with photosynthetic eukaryotes, especially diatoms, changing most strongly. The regional slope of nitracline depth exerts strong control on the relative proportion of highly diverse offshore communities and low biodiversity, but highly productive nearshore communities

Illuminating the Dark Metabolome of Pseudo-nitzschia-microbiome Associations

The exchange of metabolites mediates algal and bacterial interactions that maintain ecosystem function. Yet, while 1000s of metabolites are produced, only a few molecules have been identifiedin these associations. Using the ubiquitous microalgae Pseudo-nitzschia sp., as a model, we employed an untargeted metabolomics strategy to assign structural characteristics to themetabolites that distinguished specific diatom-microbiome associations. We cultured five species of Pseudo-nitzschia, including two species that produced the toxin domoic acid, and examinedtheir microbiomes and metabolomes. A total of 4826 molecular features were detected by tandem mass spectrometry. Only 229 of these could be annotated using available mass spectral libraries,but by applying new in-silico annotation tools, characterization was expanded to 2710 features. The metabolomes of the Pseudo-nitzschia-microbiome associations were distinct and distinguished by structurally diverse nitrogen compounds, ranging from simple amines andamides to cyclic compounds such as imidazoles, pyrrolidines, and lactams. By illuminating the dark metabolomes, this study expands our capacity to discover new chemical targets that facilitatemicrobial partnerships and uncovers the chemical diversity that underpins algae-bacteria interactions

Short-term acidification promotes diverse iron acquisition and conservation mechanisms in upwelling-associated phytoplankton

Coastal upwelling regions are among the most productive marine ecosystems but may be threatened by amplified ocean acidification. Increased acidification is hypothesized to reduce iron bioavailability for phytoplankton thereby expanding iron limitation and impacting primary production. Here we show from community to molecular levels that phytoplankton in an upwelling region respond to short-term acidification exposure with iron uptake pathways and strategies that reduce cellular iron demand. A combined physiological and multi-omics approach was applied to trace metal clean incubations that introduced 1200 ppm CO2 for up to four days. Although variable, molecular-level responses indicate a prioritization of iron uptake pathways that are less hindered by acidification and reductions in iron utilization. Growth, nutrient uptake, and community compositions remained largely unaffected suggesting that these mechanisms may confer short-term resistance to acidification; however, we speculate that cellular iron demand is only temporarily satisfied, and longer-term acidification exposure without increased iron inputs may result in increased iron stress

Diploid genomic architecture of Nitzschia inconspicua, an elite biomass production diatom.

A near-complete diploid nuclear genome and accompanying circular mitochondrial and chloroplast genomes have been assembled from the elite commercial diatom species Nitzschia inconspicua. The 50 Mbp haploid size of the nuclear genome is nearly double that of model diatom Phaeodactylum tricornutum, but 30% smaller than closer relative Fragilariopsis cylindrus. Diploid assembly, which was facilitated by low levels of allelic heterozygosity (2.7%), included 14 candidate chromosome pairs composed of long, syntenic contigs, covering 93% of the total assembly. Telomeric ends were capped with an unusual 12-mer, G-rich, degenerate repeat sequence. Predicted proteins were highly enriched in strain-specific marker domains associated with cell-surface adhesion, biofilm formation, and raphe system gliding motility. Expanded species-specific families of carbonic anhydrases suggest potential enhancement of carbon concentration efficiency, and duplicated glycolysis and fatty acid synthesis pathways across cytosolic and organellar compartments may enhance peak metabolic output, contributing to competitive success over other organisms in mixed cultures. The N. inconspicua genome delivers a robust new reference for future functional and transcriptomic studies to illuminate the physiology of benthic pennate diatoms and harness their unique adaptations to support commercial algae biomass and bioproduct production