scholarly journals Contribution of Small Phytoplankton to Primary Production in the Northern Bering and Chukchi Seas

Water ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 235
Author(s):  
Jung-Woo Park ◽  
Yejin Kim ◽  
Kwan-Woo Kim ◽  
Amane Fujiwara ◽  
Hisatomo Waga ◽  
...  
Keyword(s):  
Primary Production ◽  
Primary Productivity ◽  
High Performance ◽  
Environmental Changes ◽  
Chukchi Sea ◽  
Field Measurements ◽  
Northern Bering Sea ◽  
Relative Contribution ◽  
Phytoplankton Communities ◽  
Small Phytoplankton

The northern Bering and Chukchi seas are biologically productive regions but, recently, unprecedented environmental changes have been reported. For investigating the dominant phytoplankton communities and relative contribution of small phytoplankton (<2 µm) to the total primary production in the regions, field measurements mainly for high-performance liquid chromatography (HPLC) and size-specific primary productivity were conducted in the northern Bering and Chukchi seas during summer 2016 (ARA07B) and 2017 (OS040). Diatoms and phaeocystis were dominant phytoplankton communities in 2016 whereas diatoms and Prasinophytes (Type 2) were dominant in 2017 and diatoms were found as major contributors for the small phytoplankton groups. For size-specific primary production, small phytoplankton contributed 38.0% (SD = ±19.9%) in 2016 whereas 25.0% (SD = ±12.8%) in 2017 to the total primary productivity. The small phytoplankton contribution observed in 2016 is comparable to those reported previously in the Chukchi Sea whereas the contribution in 2017 mainly in the northern Bering Sea is considerably lower than those in other arctic regions. Different biochemical compositions were distinct between small and large phytoplankton in this study, which is consistent with previous results. Significantly higher carbon (C) and nitrogen (N) contents per unit of chlorophyll-a, whereas lower C:N ratios were characteristics in small phytoplankton in comparison to large phytoplankton. Given these results, we could conclude that small phytoplankton synthesize nitrogen-rich particulate organic carbon which could be easily regenerated.

scholarly journals Various responses of pine marten morphology and demography to temporal climate changes and primary productivity

2021 ◽  
Author(s):  
Anna Wereszczuk ◽  
Anastasia Fedotova ◽  
Adrian Marciszak ◽  
Marcin Popiołek ◽  
Arsenia Zharova ◽  
...  
Keyword(s):  
Climate Change ◽  
Body Size ◽  
Sex Ratio ◽  
Primary Production ◽  
Primary Productivity ◽  
Environmental Changes ◽  
Time Lag ◽  
Time Lags ◽  
Pine Marten ◽  
Over Time

Abstract Climate and environmental changes affect species’ morphology and ecology; however, the response of a species to changes in abiotic and biotic factors is not always consistent. Here, we tested how the structural body size of the pine marten and its population sex ratio changed over time and alongside climate change. We analysed temporal changes in morphological traits using 11 measurements of pine marten skulls collected between 1903 to 2020, linking them with climatic and primary production variations. We assessed demographic changes by calculating temporal sex ratio changes over 61 years. Skull size, as a proxy of body size, increased in response to warmer and less snowy winters, with a three-year time-lag. However, changes in primary productivity rapidly shaped postorbital constriction regardless of body size changes and without time-lags, potentially demonstrating increased diet diversity in pine marten. According to climate change, the population sex ratio has skewed towards males over time. Our results suggest that climate conditions and primary production affect skull structural size, highlighting the potential various responses of pine marten morphology and ecology in relation to climate change. Recently changing population demographics, as a consequence of these processes, may constitute a threat to marten populations.

Contribution of small phytoplankton to total primary production in the Chukchi Sea

2013 ◽  
Vol 68 ◽  
pp. 43-50 ◽  
Author(s):  
Sang H. Lee ◽  
Mi Sun Yun ◽  
Bo Kyung Kim ◽  
HuiTae Joo ◽  
Sung-Ho Kang ◽  
...  
Keyword(s):  
Primary Production ◽  
Chukchi Sea ◽  
Small Phytoplankton ◽  
Total Primary Production

Spatial variations of small phytoplankton contributions in the Northern Bering Sea and the Southern Chukchi Sea

2019 ◽  
Vol 56 (5) ◽  
pp. 794-810
Author(s):  
Sang Heon Lee ◽  
Jongseong Ryu ◽  
Dabin Lee ◽  
Jung-Woo Park ◽  
Jae-Il Kwon ◽  
...  
Keyword(s):  
Bering Sea ◽  
Chukchi Sea ◽  
Spatial Variations ◽  
Northern Bering Sea ◽  
Small Phytoplankton

scholarly journals N2O dynamics in the western Arctic Ocean during the summer of 2017

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jang-Mu Heo ◽  
Seong-Su Kim ◽  
Sung-Ho Kang ◽  
Eun Jin Yang ◽  
Ki-Tae Park ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Environmental Changes ◽  
Chukchi Sea ◽  
Hot Spot ◽  
Open Water ◽  
Northern Region ◽  
The Arctic ◽  
Western Arctic Ocean ◽  
Deep Layers ◽  
Western Arctic

AbstractThe western Arctic Ocean (WAO) has experienced increased heat transport into the region, sea-ice reduction, and changes to the WAO nitrous oxide (N2O) cycles from greenhouse gases. We investigated WAO N2O dynamics through an intensive and precise N2O survey during the open-water season of summer 2017. The effects of physical processes (i.e., solubility and advection) were dominant in both the surface (0–50 m) and deep layers (200–2200 m) of the northern Chukchi Sea with an under-saturation of N2O. By contrast, both the surface layer (0–50 m) of the southern Chukchi Sea and the intermediate (50–200 m) layer of the northern Chukchi Sea were significantly influenced by biogeochemically derived N2O production (i.e., through nitrification), with N2O over-saturation. During summer 2017, the southern region acted as a source of atmospheric N2O (mean: + 2.3 ± 2.7 μmol N2O m−2 day−1), whereas the northern region acted as a sink (mean − 1.3 ± 1.5 μmol N2O m−2 day−1). If Arctic environmental changes continue to accelerate and consequently drive the productivity of the Arctic Ocean, the WAO may become a N2O “hot spot”, and therefore, a key region requiring continued observations to both understand N2O dynamics and possibly predict their future changes.

scholarly journals Transposable Elements and Teleost Migratory Behaviour

2021 ◽  
Vol 22 (2) ◽  
pp. 602
Author(s):  
Elisa Carotti ◽  
Federica Carducci ◽  
Adriana Canapa ◽  
Marco Barucca ◽  
Samuele Greco ◽  
...  
Keyword(s):  
Transposable Elements ◽  
Environmental Changes ◽  
Chromosomal Rearrangements ◽  
Quantitative Difference ◽  
Regulatory Elements ◽  
Phylogenetic Position ◽  
Migratory Behaviour ◽  
Relative Contribution ◽  
Migratory Routes ◽  
Eukaryotic Genomes

Transposable elements (TEs) represent a considerable fraction of eukaryotic genomes, thereby contributing to genome size, chromosomal rearrangements, and to the generation of new coding genes or regulatory elements. An increasing number of works have reported a link between the genomic abundance of TEs and the adaptation to specific environmental conditions. Diadromy represents a fascinating feature of fish, protagonists of migratory routes between marine and freshwater for reproduction. In this work, we investigated the genomes of 24 fish species, including 15 teleosts with a migratory behaviour. The expected higher relative abundance of DNA transposons in ray-finned fish compared with the other fish groups was not confirmed by the analysis of the dataset considered. The relative contribution of different TE types in migratory ray-finned species did not show clear differences between oceanodromous and potamodromous fish. On the contrary, a remarkable relationship between migratory behaviour and the quantitative difference reported for short interspersed nuclear (retro)elements (SINEs) emerged from the comparison between anadromous and catadromous species, independently from their phylogenetic position. This aspect is likely due to the substantial environmental changes faced by diadromous species during their migratory routes.

Responses of CO2 Exchange and Primary Production of the Ecosystem Components to Environmental Changes in a Mountain Peatland

Ecosystems ◽  
2009 ◽  
Vol 12 (4) ◽  
pp. 590-603 ◽  
Author(s):  
D. O. Otieno ◽  
M. Wartinger ◽  
A. Nishiwaki ◽  
M. Z. Hussain ◽  
J. Muhr ◽  
...  
Keyword(s):  
Primary Production ◽  
Environmental Changes ◽  
Co2 Exchange

Seagrass Ecosystems of Andaman and Nicobar Islands: Status and Future Perspective

2020 ◽  
Vol 7 (4) ◽  
pp. 169-174
Author(s):  
Chatragadda Ramesh ◽  
Raju Mohanraju
Keyword(s):  
Water Quality ◽  
Primary Production ◽  
Environmental Changes ◽  
Future Perspective ◽  
Marine Biodiversity ◽  
Seagrass Beds ◽  
Seagrass Meadows ◽  
Seagrass Ecosystem ◽  
Seagrass Ecosystems ◽  
Nicobar Islands

Seagrasses are unique marine flowering plants that play an important ecological role by yielding primary production and carbon sequestration to the marine environment. Seagrass ecosystems are rich in organic matter, supporting the growth of bio-medically important epi and endophytic microorganisms and harbor rich marine biodiversity. They are an essential food source for endangered Andaman state animal Dugongs. Seagrasses are very sensitive to water quality changes, and therefore they serve as ecological bio-indicators for environmental changes. The benthic components in and around the seagrass beds support a significant food chain for other Micro and organisms apart from fishery resources. The epiphytic bacterial communities of the leaf blades support the sustenance against the diseases. Recent reports have shown that the loss of seagrass beds in tropical and temperate regions emphasizes the depletion of these resources, and proper management of seagrass is urgent. The decline of seagrass will impact primary production, biodiversity, and adjacent ecosystems, such as reefs. Therefore, restoring the seagrass meadows could be possible with effective implementing management programs, including seagrass meadows in marine protected areas, restoration projects, seagrass transplantation, implementation of legislative rules, monitoring coastal water quality and human activities in the coastal zone. Lacunas on the seagrass ecosystem management in Andaman & Nicobar Islands are addressed.

scholarly journals Satellites reveal an increase in gross primary production in a greenlandic high arctic fen 1992–2008

2010 ◽  
Vol 7 (1) ◽  
pp. 1101-1129 ◽  
Author(s):  
T. Tagesson ◽  
M. Mastepanov ◽  
M. P. Tamstorf ◽  
L. Eklundh ◽  
P. Schubert ◽  
...  
Keyword(s):  
Primary Production ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Gross Primary Production ◽  
Field Measurements ◽  
High Arctic ◽  
Research Area ◽  
Strong Increase ◽  
Co2 Uptake ◽  
Flux Measurements

Abstract. Arctic wetlands play a key role in the terrestrial carbon cycle. Recent studies have shown a greening trend and indicated an increase in CO2 uptake in boreal and sub- to low-arctic areas. Our aim was to combine satellite-based normalized difference vegetation index (NDVI) with ground-based flux measurements of CO2 to investigate a possible greening trend and potential changes in gross primary production (GPP) between 1992 and 2008 in a high arctic fen area. The study took place in Rylekaerene in the Zackenberg Research Area (74°28' N 20°34' W), located in the National park of North Eastern Greenland. We estimated the light use efficiency (ε) for the dominant vegetation types from field measured fractions of photosynthetic active radiation (FAPAR) and ground-based flux measurements of GPP. Measured FAPAR were correlated to satellite-based NDVI. The FAPAR-NDVI relationship in combination with ε was applied to satellite data to model GPP 1992–2008. The model was evaluated against field measured GPP. The model was a useful tool for up-scaling GPP and all basic requirements for the model were well met, e.g., FAPAR was well correlated to NDVI and modeled GPP was well correlated to field measurements. The studied high arctic fen area has experienced a strong increase in GPP between 1992 and 2008. The area has during this period also experienced a substantial increase in local air temperature. Consequently, the observed greening trend is most likely due to ongoing climatic change possibly in combination with CO2 fertilization, due to increasing atmospheric concentrations of CO2.

scholarly journals Distribution of Arctic and Pacific copepods and their habitat in the northern Bering Sea and Chukchi Sea

2015 ◽  
Vol 12 (22) ◽  
pp. 18661-18691 ◽  
Author(s):  
H. Sasaki ◽  
K. Matsuno ◽  
A. Fujiwara ◽  
M. Onuka ◽  
A. Yamaguchi ◽  
...  
Keyword(s):  
Sea Ice ◽  
Water Mass ◽  
High Salinity ◽  
Chukchi Sea ◽  
Bottom Layer ◽  
Sea Ice Extent ◽  
High Salinity Water ◽  
Explanatory Variables ◽  
Northern Bering Sea ◽  
Salinity Water

Abstract. The advection of warm Pacific water and the reduction of sea-ice extent in the western Arctic Ocean may influence the abundance and distribution of copepods, i.e., a key component in food webs. To understand the factors affecting abundance of copepods in the northern Bering Sea and Chukchi Sea, we constructed habitat models explaining the spatial patterns of the large and small Arctic copepods and the Pacific copepods, separately, using generalized additive models. Copepods were sampled by NORPAC net. Vertical profiles of density, temperature and salinity in the seawater were measured using CTD, and concentration of chlorophyll a in seawater was measured with a fluorometer. The timing of sea-ice retreat was determined using the satellite image. To quantify the structure of water masses, the magnitude of pycnocline and averaged density, temperature and salinity in upper and bottom layers were scored along three axes using principal component analysis (PCA). The structures of water masses indexed by the scores of PCAs were selected as explanatory variables in the best models. Large Arctic copepods were abundant in the water mass with high salinity water in bottom layer or with cold/low salinity water in upper layer and cold/high salinity water in bottom layer, and small Arctic copepods were abundant in the water mass with warm/saline water in upper layer and cold/high salinity water in bottom layers, while Pacific copepods were abundant in the water mass with warm/saline in upper layer and cold/high salinity water in bottom layer. All copepod groups were abundant in areas with deeper depth. Although chlorophyll a in upper and bottom layers were selected as explanatory variables in the best models, apparent trends were not observed. All copepod groups were abundant where the sea-ice retreated at earlier timing. Our study might indicate potential positive effects of the reduction of sea-ice extent on the distribution of all groups of copepods in the Arctic Ocean.

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