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101.
Recent studies in the western North Pacific reported a declining standing stock biomass of anchovy (Engraulis japonicus) in the Yellow Sea and a climate-driven southward shift of anchovy catch in Korean waters. We investigated the effects of a warming ocean on the latitudinal shift of anchovy catch by developing and applying individual-based models (IBMs) based on a regional ocean circulation model and an IPCC climate change scenario. Despite the greater uncertainty, our two IBMs projected that, by the 2030s, the strengthened Tsushima warm current in the Korea Strait and the East Sea, driven by global warming, and the subsequent confinement of the relatively cold water masses within the Yellow Sea will decrease larval anchovy biomass in the Yellow Sea, but will increase it in the Korea Strait and the East Sea. The decreasing trend of anchovy biomass in the Yellow Sea was reproduced by our models, but further validation and enhancement of the models is required together with extended ichthyoplankton surveys to understand and reliably project range shifts of anchovy and the impacts such range shifts will have on the marine ecosystems and fisheries in the region. 相似文献
102.
Despite rapidly growing interest in the effects of ocean acidification on marine animals, the ability of deep-sea animals to acclimate or adapt to reduced pH conditions has received little attention. Deep-sea species are generally thought to be less tolerant of environmental variation than shallow-living species because they inhabit relatively stable conditions for nearly all environmental parameters. To explore whether deep-sea hermit crabs (Pagurus tanneri) can acclimate to ocean acidification over several weeks, we compared behavioral “boldness,” measured as time taken to re-emerge from shells after a simulated predatory attack by a toy octopus, under ambient (pH ~7.6) and expected future (pH ~7.1) conditions. The boldness measure for crab behavioral responses did not differ between different pH treatments, suggesting that future deep-sea acidification would not influence anti-predatory behavior. However, we did not examine the effects of olfactory cues released by predators that may affect hermit crab behavior and could be influenced by changes in the ocean carbonate system driven by increasing CO2 levels. 相似文献
103.
Extending the conversation on socially engaged geographic visualization: representing spatial inequality in Buffalo,New York 总被引:1,自引:1,他引:0
This paper is situated at the intersections among GIS and geovisualization, critical social theory, and urban studies. It presents an analysis of housing segregation and unequal food and transportation access in Buffalo, New York. We demonstrate how the representation and examination of this socially complex multi-scalar issue benefits from deliberate, reflexive conversation between different critical social-spatial epistemologies. We begin with a relatively simple GIS analysis of spatial segregation and arrive through critical iteration at a more qualitatively nuanced cartogram which moves beyond representations of fixed space to reveal a much more relational situation—a case of “time-space expansion” in which the travel time needed to meet a basic daily need is much greater for the poor and people of color than it is for whiter, more affluent populations. We conclude by infusing this narrative with additional considerations from social theory to show how even a limited visualization such as ours might better critically engage broader social and discursive processes in and across urban space. 相似文献
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106.
Abu Affan Joon-Baek Lee Jun -Teck Kim Young -Chan Choi Jong -Man Kim Jung -Goo Myoung 《Ocean Science Journal》2007,42(2):117-127
The dynamics of phytoplankton abundance with seasonal variation in physicochemical conditions were investigated monthly at
10 stations around the Chagwi-do off the west coast of Jeju Island, Korea, including inshore, middle shore, and offshore in
the marine ranching area from September 2004 to November 2005. Water temperature varied from 12.1 to 28.9°C (average 18.8°C),
and salinity from 28.9 to 34.9 psu (average 33.7 psu). The chlorophyll a concentration was 0.02-2.05 μg L1 (average 0.70 μg L1), and the maximum concentration occurred in the bottom layer in April. A total of 294 phytoplankton species belonging to
10 families was identified: 182 Bacillariophyceae, 52 Dinophyceae, 9 Chlorophyceae, 12 Cryptophyceae, 6 Chrysophyceae, 4 Dictyophyceae,
13 Euglenophyceae, 6 Prymnesiophyceae, 5 Prasinophyceae, and 5 Raphidophyceae. The standing crop was 2.21-48.69x104 cells L1 (average 9.23x 104 cells L1), and the maximum occurred in the bottom layer in April. Diatoms were most abundant throughout the year, followed by dinoflagellates
and phytoflagellates. A phytoplankton bloom occurred twice: once in spring, peaking in April, and once in autumn, peaking
in November. The spring bloom was represented by fourChaetoceros species andSkeletonema costatum; each contributed 10–20% of the total phytoplankton abundance. The autumn bloom comprised dinoflagellates, diatoms, and phytoflagellates,
of which dinoflagellates were predominant.Gymnodinium conicum, Prorocentrum micans, andP. triestinum each contributed over 10% of the total phytoplankton abundance. 相似文献
107.
Hoi-Soo Jung Young-Tak Ko Sang-Bum Chi Jai-Woon Moon 《Marine Georesources & Geotechnology》2001,19(3):167-180
Seafloor morphology and ferromanganese nodule occurrence were studied using a multibeam side scan sonar (SeaBeam, 2000) and a deep-sea camera system in the Korea Deep-sea Environmental Study (KODES) area, northeast equatorial Pacific. Seafloor morphology and nodule abundance are highly variable even in this small study area. The NNE-SSW oriented hills are parallel and about 100-200 m high. Valleys are very flat-floored, while hilltops are rugged with depressions of tens of meters. Cliffs to about 100 m bound the valleys and the hills. The study area can be classified into three types based both on nodule occurrence and seafloor morphology, mostly G- and B-types and some M-type. G-type is characterized by high nodule abundance, ubiquitous bioturbation, and flat seafloor morphology, while B-type is characterized by irregular-shaped nodules, variable nodule abundance, occurrence of giant nodules and sediment lumps, rugged bottom morphology with depressions, and white calcareous surface sediments. Medium nodule abundance and a generally flat seafloor characterize M-type. G-type occurs mostly in the valley regions, while B-type is on the hilltop areas. M-type is located between the hilltop and the valley. Tectonic movement of the Pacific plate resulted in the elongated abyssal hills and cliffs. The rugged morphology on hilltops resulted from erosion and redistribution of surface siliceous sediments on hilltops by bottom currents, outcropping of underlying calcareous sediments, and dissolution of the carbonate sediments by corrosive bottom water undersaturated with CaCO 3 . Sediment eroded from the hills, which is relatively young and organic-rich, is deposited in the valleys, and diagenetic metal supply to manganese nodules in the valley area is more active than on the hills. We suggest that tectonic movement ultimately constrains morphology, surface sediment facies, bottom currents and sediment redistribution, bioturbation, thickness of the sedimentary layer, and other conditions, which are all interrelated and control nodule occurrence. The best potential area for mining in the study area is the G-type valley zones with about 3-4 km width and NNW-SSE orientation. 相似文献
108.
Numerical flow analysis of single-stage ducted marine propulsor 总被引:1,自引:0,他引:1
The present work has solved 3D incompressible RANS equations on a rotating, non-orthogonal multi-blocked grid to efficiently analyze a ducted marine propulsor with rotor–stator interaction. To handle the interface boundary between a rotor and a stator, the sliding multi-block technique using the cubic spline interpolation and the bilinear interpolation was applied. To validate the present code, the flow of a single stage turbine flow was simulated. Time averaged pressure coefficients were compared with experiments and good agreements were obtained. After the code validation, the flowfield around a single-stage ducted marine propulsor having a single stage of rotor and stator was successfully simulated and the hydrodynamic performance coefficients were computed. 相似文献
109.
The geochemical and mineralogical characteristics of pre-Holocene core sediments from Haenam Bay, southwest coast of Korea,
were examined for post-depositional diagenetic changes and used to assess the provenance of fine-grained sediments in the
region. The geochemical and mineralogical compositions of the sediments vary very little with core depth (Holocene to pre-Holocene
age), except for the upper part of the pre-Holocene sedimentary layer. In this case, smectite and chlorite are depleted, presumably
due to intensive subaerial weathering and low pH conditions. Highly mobile elements (Ca, Mg, Na and K) were likely removed
with the breakdown of labile minerals, such as carbonate minerals, feldspar, and clay minerals, during subaerial exposure
of this layer, resulting in low weathering indices. In particular, the low smectite content (<5%) and low V/Al ratio (<13)
suggest that the Holocene and pre-Holocene sediments along the southwestern coast of Korea did not originate from mainland
China but rather mostly from the Korean Peninsula. This aspect has been a subject of debate since the mid-1970s. 相似文献
110.
The geochemical and mineralogical characteristics of pre-Holocene core sediments from Haenam Bay, southwest coast of Korea, were examined for post-depositional diagenetic changes and used to assess the provenance of fine-grained sediments in the region. The geochemical and mineralogical compositions of the sediments vary very little with core depth (Holocene to pre-Holocene age), except for the upper part of the pre-Holocene sedimentary layer. In this case, smectite and chlorite are depleted, presumably due to intensive subaerial weathering and low pH conditions. Highly mobile elements (Ca, Mg, Na and K) were likely removed with the breakdown of labile minerals, such as carbonate minerals, feldspar, and clay minerals, during subaerial exposure of this layer, resulting in low weathering indices. In particular, the low smectite content (<5%) and low V/Al ratio (<13) suggest that the Holocene and pre-Holocene sediments along the southwestern coast of Korea did not originate from mainland China but rather mostly from the Korean Peninsula. This aspect has been a subject of debate since the mid-1970s. 相似文献