Potential habitat for chum salmon (Oncorhynchus keta) in the Western Arctic based on a bioenergetics model coupled with a three-dimensional lower trophic ecosystem model

AbstractChum salmon (Oncorhynchus keta) are predominantly located in the Bering Sea during summer and fall. However, several studies have recently reported a different tendency as follows. Observed densities of chum salmon were higher in the vicinity of the Bering Strait and the Chukchi Sea than the eastern Bering Sea in September 2007, and Japanese chum salmon migrated to northern areas in the Bering Sea during summer 2009. The sea surface temperature (SST) in the Arctic marginal seas has increased since the mid-1960s, and especially since 2000. We speculated that the SST increase directly promoted salmon northing from the Bering Sea to the Western Arctic. In this study, we estimated the potential habitat for chum salmon in the Western Arctic using a bioenergetics model coupled with a three-dimensional lower trophic ecosystem model (3-D NEMURO). “Potential habitat” was defined as “an area where chum salmon could grow (i.e., the growth rate was positive)”. In the bioenergetics model, the growth rate of an individual chum salmon was calculated as a function of water temperature, salinity, and prey density, which were obtained from the 3-D NEMURO model results. To evaluate the habitat responses under a global warming scenario, we used the modeled monthly change of water temperature between 2005 (averaged from 2001 to 2010) and 2095 (averaged from 2091 to 2100) under the IPCC SRES-A1B scenario. Our calculations, following the global warming scenario, suggested that the potential habitat for chum salmon would expand to the north due to the increase in water temperature and prey density. In contrast, south of 71°N during summer, the potential habitat would shrink regionally because the water temperature exceeded the optimal condition

CD82/KAI1 Maintains the Dormancy of Long-Term Hematopoietic Stem Cells through Interaction with DARC- Expressing Macrophages

Hematopoiesis is regulated by crosstalk between long-term repopulating hematopoietic stem cells (LT-HSCs) and supporting niche cells in the bone marrow (BM). Here, we examine the role of CD82/ KAI1 in niche-mediated LT-HSC maintenance. We found that CD82/ KAI1 is expressed predominantly on LT-HSCs and rarely on other hematopoietic stem-progenitor cells (HSPCs). In Cd82 +/-/+/- mice, LTHSCs were selectively lost as they exited from quiescence and differentiated. Mechanistically, CD82based TGF-b1/ Smad3 signaling leads to induction of CDK inhibitors and cell-cycle inhibition. The CD82 binding partner DARC/ CD234 is expressed on macrophages and stabilizes CD82 on LT-HSCs, promoting their quiescence. When DARC + BMmacrophages were ablated, the level of surface CD82 on LT-HSCs decreased, leading to cell-cycle entry, proliferation, and differentiation. A similar interaction appears to be relevant for human HSPCs. Thus, CD82 is a functional surface marker of LT-HSCs that maintains quiescence through interaction with DARC-expressing macrophages in the BM stem cell niche.113525Ysciescopu

Bioinformatics services for analyzing massive genomic datasets

The explosive growth of next-generation sequencing data has resulted in ultra-large-scale datasets and ensuing computational problems. In Korea, the amount of genomic data has been increasing rapidly in the recent years. Leveraging these big data requires researchers to use large-scale computational resources and analysis pipelines. A promising solution for addressing this computational challenge is cloud computing, where CPUs, memory, storage, and programs are accessible in the form of virtual machines. Here, we present a cloud computing-based system, Bio-Express, that provides user-friendly, cost-effective analysis of massive genomic datasets. Bio-Express is loaded with predefined multi-omics data analysis pipelines, which are divided into genome, transcriptome, epigenome, and metagenome pipelines. Users can employ predefined pipelines or create a new pipeline for analyzing their own omics data. We also developed several web-based services for facilitating down-stream analysis of genome data. Bio-Express web service is freely available at https://www. bioexpress.re.kr/. ?? 2020, Korea Genome Organization

Relative contributions of external forcing factors to circulation and hydrographic properties in a micro-tidal bay

The dominant external forcing factors influencing estuarine circulation differ among coastal environments. A three-dimensional regional circulation model was developed to estimate external influence indices and relative contributions of external forcing factors such as external oceanic forcing, surface heat flux, wind stress, and river discharge to circulation and hydrographic properties in Tango Bay, Japan. Model results show that in Tango Bay, where the Tsushima Warm Current passes offshore of the bay, under conditions of strong seasonal winds and river discharge, the water temperature and salinity are strongly influenced by surface heat flux and river discharge in the surface layer, respectively, while in the middle and bottom layers both are mainly controlled by open boundary conditions. The estuarine circulation is comparably influenced by all external forcing factors, the strong current, surface heat flux, wind stress, and river discharge. However, the influence degree of each forcing factor varies with temporal variations in external forcing factors as: the influence of open boundary conditions is higher in spring and early summer when the stronger current passes offshore of the bay, that of surface heat flux reflects the absolute value of surface heat flux, that of wind stress is higher in late fall and winter due to strong seasonal winds, and that of river discharge is higher in early spring due to snow-melting and summer and early fall due to flood events. (C) 2017 Elsevier Ltd. All rights reserved

Estimation of particulate organic carbon flux produced from eelgrass, Zostera marina L., in a subarctic estuary of Hokkaido, Japan

Akkeshi Lake is a typical subarctic estuary located in Hokkaido, Japan; it is covered with eelgrass, specifically Zostera marina. The oyster Crassostrea gigas is cultured throughout the lake, except for on the intertidal sand flats, where the Manila clam, Ruditapes philippinarum, is cultured near the mouth of the lake. To estimate the particulate organic carbon (POC) flux of various sources, including eelgrass, flowing out from Akkeshi Lake to Akkeshi Bay and to evaluate the role of eelgrass in carbon transport, we developed an ecosystem model that includes phytoplankton, zooplankton, dissolved inorganic matter (DIM), dissolved organic matter (DOM), particulate organic matter (POM), eelgrass, epiphytic algae, oysters and the Manila clam, and separated POM into eight classes according to its sources. Eelgrass and epiphytic algae are the most important sources of POC in Akkeshi Lake, especially in the litterfall season. The total POC inflow/outflow quantities to/from Akkeshi Lake during nine months from April to December was -4648 tons; according to its sources, -4414 tons (outflow) came from eelgrass and epiphytic algae, -551 tons (outflow) from oysters and the Manila clam, 145 tons (inflow) from phytoplankton and zooplankton, 383 tons (inflow) from outside sources (i.e., open sea) and -211 tons (outflow) from the river. The total POC production was approximately 75727 tons, 89% of which was from eelgrass and epiphytic algae; 7% was from oysters and the Manila clam; 3% was from phytoplankton and zooplankton; and 1% was from river

Quantitative estimation of the ecosystem services supporting the growth of Japanese chum salmon

Chum salmon (Oncorhynchus keta) are distributed widely in the subarctic North Pacific. The Japanese stock is maintained by artificial release procedures. Chum salmon, including the Japanese stock, provide important ecosystem services for humans that are related to provisioning, culture and support. These ecosystem services are supported by the supply of prey and habitat that the fish use. We regard the supply of prey and habitat as supporting services for salmon. We developed a procedure to estimate supporting services quantitatively, based on the prey biomass consumed by individual salmon, by coupling a bioenergetics model and a lower trophic level ecosystem model. Using this procedure, we estimated the prey biomass consumed by a cohort of Japanese chum salmon released in a single year. The phytoplankton biomass indirectly consumed by a cohort was also estimated and considered to be the primary production supporting the fish. The Japanese chum salmon cohort was estimated to consume ca. 4.2-4.7 x 10(9) kg wet weight of zooplankton, of which more than half is eaten in the Bering Sea. The Japanese chum salmon cohort is supported by an estimated primary production of 2.0-2.2 x 10(9) kg C, which amounts to 0.17%-0.19% of primary production in the areas and periods through which the fish migrate. We also attempted to calculate the monetary value of supporting services for the growth of Japanese chum salmon

Bioenergetic Model of the Highly Exploited Shark <i>Mustelus schmitti</i> under a Global Warming Context

Bioenergetic models are tools that allow the evaluation of the effect of environmental variables on fish growth. Successful implementation of this approach has been achieved in a few elasmobranch species. Our objective was to develop a bioenergetic model for Mustelus schmitti. The model developed showed a good fit to the field data available and accurately described the growth of this species. The practical example developed in this study provides novel population estimates of prey consumption and daily ration for the species. Results also indicate that this species would be susceptible to the effects of climate change. In the simulated climate change scenarios, the energy budget of M. schmitti was significantly altered, with increased food consumption and impaired growth. While there exists a number of limitations for the model developed in this article, namely its limitation to immature individuals, and its restricted temperature model, it provides an important tool for the management of this and other shark populations under heavy exploitation

Assessment of Heavy Metals Eluted from Materials Utilized in Artificial Reefs Implemented in South Korea

In this study, we aimed to investigate the effect of artificial reefs (ARs) made from concrete, steel, and steel slag on the concentrations of As, Cd, Cr6+, Cu, Hg, Ni, Pb, and Zn in marine ecosystems. We conducted a field investigation of the concentration of heavy metals (HMs) in seawater and marine organisms in the East Sea, South Korea and complemented it with an indoor elution experiment. The concentrations of the eight HMs in the field investigation and elution experiment satisfied the environmental standards. In the elution experiment, elution of Cr6+ from the concrete models was confirmed; however, it may be insignificant in marine ecosystems. These results revealed that the effect of ARs made from concrete, steel, and steel slag on the concentration of HMs in the marine environment was insignificant