Global warming is affecting the composition, structure, and function of marine ecosystems. The increase in hypoxic regions due to stratification a major environmental problem worldwide. Off southern coast Korea, hypoxia occurs frequently summer, area water affected gradually expanding. In this study, we investigated effects on eggs copepods order Calanoida. Data distribution abundance benthic sediments were collected from 17 stations, using piston core sampler (64 mm internal diameter, 50 cm...

Hypoxia is a global concern, affecting marine ecosystems. In this study, we investigated the effect of low Oxygen concentration on egg hatching rate Acartia erythraea in Gamak Bay, where hypoxia frequently occurs summer. Three situ experiments were conducted June and August 2013 July 2014. Environmental parameters, including water temperature, salinity, dissolved (DO) concentration, pH, measured during experiments. Hypoxic conditions had significant negative impact A. eggs; was positively...

To understand the effects of variable water masses in northeastern East China Sea (Korea South Sea), planktonic copepods were seasonally sampled. Out a total 106 copepod species, 85 oceanic warm-water and number species varied summer, autumn, spring, winter. The study area was divided into two or three regions according to degree influence masses. Canthocalanus pauper, Clausocalanus furcatus, Oithona plumifera, Oncaea venella, venusta, Paracalanus aculeatus showed positive correlation with...

The calanoid copepod Acartia ohtsukai predominates the estuarine and coastal waters of East Asia during summer. Its occurrence characteristics confer it with good potential as live prey for fish larvae through mass culture. To investigate effect temperature salinity combinations on its egg production rate (EPR), hatching success (HS), mortality rate, experiments were undertaken repeated three times five temperatures (10, 15, 20, 25, 30°C) seven salinities 27, 30, 33 psu). EPR HS highest at...

The recent accelerated ocean acidification and global warming caused by increased atmospheric carbon dioxide may have an impact on the physiology ecology of marine animals. This study was conducted to determine egg production rate (EPR) hatching success (EHS) Acartia ohtsukai in response combined effects increase temperature a lower pH. Acartiaohtsukai with fresh surface seawater were collected northwestern Yeoja Bay Korea September 2017. pH conditions applied included two different levels...

Abstract Acartia erythraea, a copepod species commonly found in the summer, was sampled weekly using conical net, Gamak Bay (southern Korea) from 19 July to 14 November 2013. Egg production rate (EPR) and hatching success (HS) were estimated during study period, for egg types with distinct surface morphologies, i.e. smooth or spiny. EPR ranged 1.0 25.0 eggs female−1 day−1 mean of 12.0 day−1. The weight-specific growth (WSGR) 0.01 0.19 value 0.09 Of these, all until August, whereas spiny...

The short-term variation in the abundance of Acartia copepods eutrophic Gamak Bay South Korea was investigated with weekly measurements from October 2007 to September 2008. During this period, four species ( A. erythraea , A . ohtsukai omorii and sinjiensis ) were recorded as showing seasonally different peak abundance. high autumn, whereas that winter spring. In summer, ohtsukai, coexisted at significantly related water temperature salinity. Results response curves salinity suggest...

Abstract Research to understand the distribution and density of jellyfish is actively being conducted using training ships, but this hindered by high cost manpower limitations irradiation area. Unmanned aerial vehicles (UAVs or drones), however, provide cost-effective means for assessing marine animal populations. Therefore, we tested application UAVs in estimating probed altitude-dependent suitability these devices. We analyzed images obtained a drone as well manual counting used ImageJ...

선박평형수를 통한 외래종 확산을 방지하기 위해 국제해사기구(IMO)에서는 2004년 선박평형수관리협약을 채택하였다. 이 협약에 따르면 앞으로 대부분의 선박들은 선박평형수 처리시스템을 통해서 해양 생물을 사멸 또는 제거시킨 후 배출해야 하며, 이는 플랑크톤의 생사판별방법을 통하여 이루어진다. 본 연구에서는 국제적으로 처리후 생사판별법으로 널리 사용되고 있는 fluorescein diacetate assay (FDA) 염색방법의 제한성과 이의 대안으로 Neutral red (NR) 염색방법사용 가능성을 살펴보고자 하였다. FDA 염색법은 플랑크톤 염색에 되어서 현재 가장 사용되는 방법임에도 불구하고 Ditylum brightwellii 을 제외한 모든 식물플랑크톤 대해서 낮은 염색 효율(전체 평균 효율 <50%)을 보였으며, 식물플랑크톤이 갖는 고유한 형광(적색)에 간섭을 많이 받는 것으로 나타났다. 또한 FDA는 형광파장에 노출된 빠르게 색이 바래지는 경향도 관찰되었다. 반면에...

In this study, we investigate the distribution of calanoid copepod eggs in sediments Masan Bay (South Sea, Korea), which hypoxic conditions occur every summer. August (2011), hypoxia was observed at all stations, while normoxia April (2012). The pH and hydrogen sulphide concentration sediment-water interface inner bay during were 7.7 &gt;20 mol L−1, respectively, there no significant difference between stations April. abundance sediment ranged from 0.69 to 1.49 × 106 m−2 August, 0.59 1.08...

This study investigated the tolerance of resting eggs Eurytemora pacifica to storage under low temperatures, which is particular interest in light recent use nauplii as living food aquaculture, other than conditions experienced also wild during winter cold events Northern Hemisphere. Sediment samples collected August 2020 were used store at two different freezing temperatures (−5 and −20 °C) for five durations (1, 3, 6, 9, 12 months). The mean hatching success rates after one month 85.3 ±...

This study was carried out to elucidate the causes of massive outbreaks Aurelia coerulea in Geoje Bay, Korea, from November 2022 October 2023. Adult medusae consistently spawn with planulae, and populations A. Bay could be categorized into current-year overwintering populations. The population began emergence ephyrae February grew until October, while comprised a mixture surviving additional individuals that joined during warm season. size planulae are significantly larger than annual...

Abstract The grazing impacts of two Acartia species ( omorii and A . steueri ) on size-fractionated phytoplankton biomass were measured in Jangmok Bay, Korea (34°59′37.8" N, 128°40′28.2'' E) from January to May 2015. Total chlorophyll (Chl- a concentrations ranged 0.66 5.18 µg L −1 , micro-phytoplankton (&gt; 20 µm) comprised up 66% (range, 10.5–65.6%) the total pigment. abundance 267 5931 ind. m −3 these copepods accounted for 20.8 88.0% copepod abundance. ingestion rates r 2 = 0.904, P...

We determined the combined effects of salinity (10, 15, 20, 25, 27, 30 and 33 psu) cold storage (4 ± 1°C) for 5, 14, 90 180 days extending lifespan subitaneous eggs calanoid copepod Acartia sinjiensis. The hatching success rate decreased with an increase in period. average proportion viable A. sinjiensis after was >40% except at a 10 psu. Eggs hatched different times depending on salinity. Specifically, >55% stored 14 under salinities 25 psu >45% those hatched. However, some which only...

Gamak Bay is frequently affected by hypoxia in summer. Therefore, this study aimed to examine the effect of on mesozooplankton community region. Mesozooplankton samples were obtained biweekly (28 times) at a hypoxic station (inner bay) and normoxic (middle using conical net (mesh size 200 μm; mouth diameter 30 cm) from April 2020 2021. In inner bay, was observed total five times between early June late September, whereas no instances detected middle bay. During period, abundance higher bay...

Purpose: To investigate the relationship between brain injury patterns on magnetic resonance imaging (MRI) and neurodevelopmental outcomes in neonates with postasphyxial hypoxic ischemic encephalopathy (HIE).Methods: Clinical characteristics MRI findings of 49 term HIE were retrospectively reviewed.Brain classified into five categories, along evaluation posterior limb internal capsule (PLIC).Neurodevelopmental assessed by neurological ex amination combined Bayley Scales Infant Development II...