ALBERT

Description: We report two Arctic species of incirrate octopods new to science. One is formally described here as Muusoctopus aegir Golikov, Gudmundsson & Sabirov sp. nov. while the other, Muusoctopus sp. 1, is not formally described due to a limited number of samples (all are immature individuals). These two species differ from each other, and from other Muusoctopus, especially in: 1) absence of stylets (in M. aegir sp. nov.); 2) proportions of mantle and head; 3) funnel organ morphology (W-shaped with medial and marginal limbs of equal length in M. aegir sp. nov., or medial are slightly longer; V V-shaped with medial limbs slightly longer and broader than marginal in Muusoctopus sp. 1); 4) sucker and gill lamellae counts; 5) relative arm length and sucker diameter; and 6) male reproductive system relative size and morphology. Species of Muusoctopus now comprise four of 12 known Arctic cephalopods. Additionally, this study provides: a) new data on the morphology and reproductive biology of M. johnsonianus and M. sibiricus, and a diagnosis of M. sibiricus; b) the equations to estimate mantle length and body mass from beak measurements of M. aegir sp. nov. and M. johnsonianus; c) a cytochrome c oxidase subunit I gene barcode for M. sibiricus; d) new data on the ecology and distribution of all studied species; and e) a data table for the identification of northern North Atlantic and Arctic species of Muusoctopus.

Description: Background: Sponges (phylum Porifera) constantly interact with microbes. They graze on microbes from the water column by filter-feeding and they harbor symbiotic partners within their bodies. In experimental setups, sponges take up symbionts at lower rates compared with seawater microbes. This suggests that sponges have the capacity to differentiate between microbes and preferentially graze in non-symbiotic microbes, although the underlying mechanisms of discrimination are still poorly understood. Genomic studies showed that, compared to other animal groups, sponges present an extended repertoire of immune receptors, in particular NLRs, SRCRs, and GPCRs, and a handful of experiments showed that sponges regulate the expression of these receptors upon encounter with microbial elicitors. We hypothesize that sponges may rely on differential expression of their diverse repertoire of poriferan immune receptors to sense different microbial consortia while filter-feeding. To test this, we characterized the transcriptomic response of two sponge species, Aplysina aerophoba and Dysidea avara, upon incubation with microbial consortia extracted from A. aerophoba in comparison with incubation with seawater microbes. The sponges were sampled after 1 h, 3 h, and 5 h for RNA-Seq differential gene expression analysis. Results: D. avara incubated with A. aerophoba-symbionts regulated the expression of genes related to immunity, ubiquitination, and signaling. Within the set of differentially-expressed immune genes we identified different families of Nucleotide Oligomerization Domain (NOD)-Like Receptors (NLRs). These results represent the first experimental evidence that different types of NLRs are involved in microbial discrimination in a sponge. In contrast, the transcriptomic response of A. aerophoba to its own symbionts involved comparatively fewer genes and lacked genes encoding for immune receptors. Conclusion: Our work suggests that: (i) the transcriptomic response of sponges upon microbial exposure may imply “fine-tuning” of baseline gene expression as a result of their interaction with microbes, (ii) the differential response of sponges to microbial encounters varied between the species, probably due to species-specific characteristics or related to host’s traits, and (iii) immune receptors belonging to different families of NLR-like genes played a role in the differential response to microbes, whether symbionts or food bacteria. The regulation of these receptors in sponges provides further evidence of the potential role of NLRs in invertebrate host-microbe interactions. The study of sponge responses to microbes exemplifies how investigating different animal groups broadens our knowledge of the evolution of immune specificity and symbiosis.

Description: The annual glacier mass balance of Hallstätter Gletscher in Austria is measured since 2006-10-01 with the direct glaciological method in the fixed date system (1st October to 30th September of the following year). The accumulation of snow is measured by determination of the water equivalent in 6 snow pits, the ice ablation is measured with 15 stakes drilled into the ice. Results are the annual net mass balance in kg, the total accumulation and ablation, the glacier area and the portions of the area which are subject to ablation and accumulation, the elevation of the equilibrium line and the specific mass balance in kg/m**2 (= mm w.e.). The accumulation during the winter is determined by the 1st May. The project is funded by the Amt der Oberösterreichischen Landesregierung and the Energie AG. The measurements are carried out by the Institute for Interdisciplinary Mountain Research (http://www.mountainresearch.at/index.php/en/) of the Austrian Academy of Sciences and the company Blue Sky in Gmunden, Austria. New data will be added every year.

Description: Temperature and salinity reconstructions for two 1000-year high-resolution sedimentary records, located at the boundary between Atlantic and Arctic surface waters on the North Icelandic shelf, are based on transfer functions and oxygen isotopes for planktonic and benthic foraminifera. There is a general increase of Arctic Water indicator species at the transition from the Medieval Warm Period into the Little Ice Age (LIA) and a subsequent return of Atlantic Water indicator species towards the end of the LIA and in the 20th century. The timing of the reconstructed temperature changes, both at the beginning and at the end of the LIA, appears to be slightly different for the different water masses. The earliest temperature change is seen in the bottom and subsurface waters, where a cooling is reconstructed as early as AD 1150-1200 at both locations, whereas previously published diatom-based and alkenone-based sea-surface temperature reconstructions show a change at AD 1300, coinciding with the air temperature shift in the area. Our results show the need of a thorough understanding of the oceanography in the study area, as well as the different living habitat for the biological proxies used for the temperature estimates.

Description: The only low latitude pathway of heat and salt from the Pacific Ocean to the Indian Ocean, known as Indonesian Throughflow (ITF), has been suggested to modulate Global Mean Surface Temperature (GMST) warming through redistribution of surface Pacific Ocean heat. ITF observations are only available since ~1990s, and thus, its multidecadal variability on longer time scales has remained elusive. Here we present a 200 year bimonthly record of geochemical parameters (d18O-Sr/Ca) measured on Cocos (Keeling) corals tracking sea surface temperature (SST; Sr/Ca) and sea surface salinity (SSS; seawater-d18O-d18Osw) in the southeastern tropical Indian Ocean (SETIO). Our results show that SETIO SSS and d18Osw were impacted by ITF transport over the past 60 years, and therefore, reconstructions of Cocos d18Osw hold information on past ITF variability on longer time spans. Over the past 200 years ITF leakage into SETIO is dominated by the interannual climate modes of the Pacific Ocean (El Niño-Southern Oscillation) and Indian Ocean (Indian Ocean Dipole). Pacific decadal climate variability (represented by the Pacific Decadal Oscillation) significantly impacted ITF strength over the past 200 years determining the spatiotemporal SST and SSS advection into the Indian Ocean on multidecadal time scales. A comparison of our SETIO d18Osw record to GMST shows that ITF transport varied in synchrony with global warming rate, being predominantly high/low during GMST warming slowdown/acceleration, respectively. This hints toward an important role for the ITF in global warming rate modulation.

Description: To study shifts in phytoplankton proxies linked to terrigenous inputs and teleconnections, we analyze the composite core MV99 GC41/PC14 from Soledad Basin, Gulf of Ulloa, NW Mexico. We used biogenic opal (% opal), organic carbon (% TOC) and inorganic carbon (% CaCO3) as proxies of productivity; and opal/TOC and CaCO3/TOC ratios as proxies of nutrient uptake and C-export by siliceous and carbonate organisms. We reconstructed terrestrial inputs using grain size Weibull analyses. Grain size analyses show significant amounts of fine fraction (between 0.06 - 6.6 µm) present during the early- to mid-Holocene in agreement to extreme weather on land, with episodes of aeolian and fluvial transport to the sea. The found that ENSO-like variations influence biological C-export producers on a scale of 1.1-1.8 ka, although PDO-related variability is uncertain. We suggest that Holocene drivers for phytoplankton successions are changes in insolation, ITCZ migration, California Current upwelling, nutrient inputs by advection and terrestrial sources.

Description: The open source Video In Situ Snowfall Sensor (VISSS) is a novel instrument for the characterization of particle shape and size in snowfall. The VISSS consists of two cameras with LED backlights and telecentric lenses that allow accurate sizing and combine a large observation volume with relatively high resolution and a design that limits wind disturbance. Here, movies and images of falling precipitation particles are provided for station Ny-Ålesund from July 2022 to December 2023. For further details on the VISSS Sensor see Maahn et al. (2024).

Description: The North American monsoon (NAM), an onshore wind shift occurring between July and September, has evolved in character during the Holocene largely due to changes in Northern Hemisphere insolation. Published paleoproxy and modeling studies suggest that prior to ~8000 cal years BP, the NAM affected a broader region than today, extending westward into the Mojave Desert of California. Holocene proxy SST records from the Gulf of California (GoC) and the adjacent Pacific provide constraints for this changing NAM climatology. Prior to ~8000 cal years BP, lower GoC SSTs would not have fueled northward surges of tropical moisture up the GoC, which presently contribute most of the monsoon precipitation to the western NAM region. During the early Holocene, the North Pacific High was further north and SSTs in the California Current off Baja California were warmer, allowing monsoonal moisture flow from the subtropical Pacific to take a more direct, northwesterly trajectory into an expanded area of the southwestern U.S. west of 114°W. A new upwelling record off southwest Baja California reveals that enhanced upwelling in the California Current beginning at ~7500 cal year BP may have triggered a change in NAM climatology, focusing the geographic expression of NAM in the southwest USA into its modern core region east of ~114°W, in Arizona and New Mexico. Holocene proxy precipitation records from the southwestern U.S. and northwestern Mexico, including lakes, vegetation/pollen, and caves are reviewed and found to be largely supportive of this hypothesis of changing Holocene NAM climatology.