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Wyświetlanie 1-6 z 6
Tytuł:
Diseases prevalence of Acropora corals: Study on Semak Daun Island, Seribu Islands, Jakarta
Autorzy:
Harahap, Syawaludin A.
Fadhil, Farid
Sunarto, Sunarto
Powiązania:
https://bibliotekanauki.pl/articles/1031291.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Acropora
Semak Daun Island
compromised health
coral disease
corallivorous
prevalence
Opis:
Coral reefs have undergone significant degradation as a result of the impact of human disturbance and natural factors on biodiversity and ecosystem function. The impacts ranged from an increase in the appearance of coral bleaching, coral disease, to coral death. Especially for coral disease, it is confirmed that it has contributed to the reduction of live coral cover and the productivity of coral reef ecosystems. The coral disease can be epidemic due to environmental pressures, both anthropogenic and natural, as well as infection from pathogenic microbes. Recently in several places, including Semak Daun Island, Seribu Islands-Jakarta, it was reported that the condition of coral reef cover had increased. However, a high percent of coral cover can increase disease prevalence and abundance. Acropora coral is a type of coral that is commonly found on Semak Daun Island. However, these corals are very susceptible to stress so that the threat of disease is high. So it is necessary to conduct a study that aims to determine the type and prevalence of diseases that disturb Acropora coral in Semak Daun Island, Seribu Islands, Jakarta. The field survey was carried out for coral observation using the line transect method at four stations. Coral disease identification refers to the Coral Disease Handbook and Underwater Cards for Assessing Coral Health. Observation objects, both coral species, and signs of disease were documented using underwater cameras. The study results indicate that 15 types of Acropora corals were dominated by A. humilis. Meanwhile, two groups of diseases were found, namely Tissue loss - Predation caused by the COTS and Drupella, while those from the Compromised Health group included RFA, SD, and Sponges.
Źródło:
World News of Natural Sciences; 2021, 34; 113-126
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variability in fish catch rates associated with Sea Surface Temperature Anomaly (Niño 3.4 index) in the West of Java Sea
Autorzy:
Syamsuddin, Mega
Sunarto, Sunarto
Yuliadi, Lintang
Harahap, Syawaludin
Powiązania:
https://bibliotekanauki.pl/articles/1076099.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Catch rates
El Niño
Java Sea
La Niña
oceanographic conditions
Opis:
The remotely derived oceanographic variables included sea surface height anomaly (SSHA), sea surface temperature (SST), chlorophyll-a (Chl a) and fish catches are used as a combined dataset to understand the ocean climate variability and further addresses their relations with the fish catches in the West-Java Sea. Fish catches and remotely sensed data are analyzed for the 5 years datasets from 2010-2014 and emphasized the differences of climate conditions during El Niño Southern Oscillation (ENSO) events. Here, we demonstrate the prominent annual variation of two species small pelagic fish catches (Euthynus affinis and Scomberomorus commerson) and one demersal species (Netuma thallasina) as representative of dominant catch in the region. Small pelagic catches had significant increment during El Niño compared to during La Niña events. Changes in oceanographic conditions during ENSO events resulted in perceivable variations in catches, with an average catches of 839.6 t (E. affinis) and 273,7 t (S. commerson) during El Niño. During La Niña event catch rates were reduced with an average catches of 602.6 t (E. affinis) and 210.3 t (S. commerson). During the La Niña event was less favorable for small pelagic catches. In contrast, N. thallasina does not seem to be directly affected by the ENSO. The average catches of N. thallasina during El Niño (182.17 t) lower than during La Niña (250.14 t). This inferred that different climate events might cause different oceanographic conditions that related to fish biodiversity. Our results would benefit the fish biodiversity-management to reduce risks due to climate regimes.
Źródło:
World Scientific News; 2019, 117; 175-182
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spatial characteristics of the Hawksbill (Eretmochelys imbricate Linnaeus, 1766) nesting beach on Kepayang Island, Belitung - Indonesia
Autorzy:
Harahap, Syawaludin A.
Prihadi, Donny J.
Virando, Gravito E.
Powiązania:
https://bibliotekanauki.pl/articles/1031644.pdf
Data publikacji:
2020
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eretmochelys imbricate
Kepayang Island
habitat characteristics
hawksbill
nesting beach
Opis:
Hawksbill sea turtles are scattered in Indonesia, especially on small uninhabited islands and are the only species of turtle most bound to tropical waters. The hawksbill has experienced a drastic decline in population mainly due to bycatch in fishing activities and disturbance of the nesting habitats due to anthropogenic presence. Kepayang Island in Belitung is one of the areas used as hawksbill as a habitat for nesting to laying eggs. To get information about hawksbill on this island, a study was conducted to find out the characteristics of hawksbill nesting beaches on Kepayang Island, Belitung. The survey was carried out in July 2014 and successfully identified 12 nests as an observation sample. Observations show that the coast of Kepayang Island where nesting turtles have a narrow beach width of less than 20 m with a slope of between 10° to 16° and an average intertidal area as wide as 11.5 meters. The texture of sand in the nest is coarse to fine sand which is dominated by fine and medium sand and has a temperature of around 27.7 °C to 30.2 °C measured at the bottom of the nest. The range of sand pH distribution on Kepayang Island is between 6 to 8 with a moisture content of 3.1 to 6.6%. The coastal vegetation formation in Kepayang Island is dominated by Barringtonia and Pescaprae with vegetation in the form of screwpine (Pandanus tectorius), railroad vine (Ipomoea pescaprae) and Barringtonia (Barringtonia asiatica). However, there are predators of turtle eggs and hatchlings, especially water monitor lizards (Varanus salvator), sea birds e.g. brahminy kite (Haliastur indus) and gulls (Chlidonias leucopterus). In general, Kepayang Island has characteristics suitable for hawksbill nesting sites.
Źródło:
World Scientific News; 2020, 146; 152-169
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trend of Coastline Change for Twenty Years (1994-2014) in Cirebon, Indonesia
Autorzy:
Harahap, Syawaludin A.
Purba, Noir P.
Syamsuddin, Mega L.
Powiązania:
https://bibliotekanauki.pl/articles/1046538.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Cirebon
Landsat imagery
MNDWI
West Java
coastline change
erosion
sedimentation
Opis:
There are many factors lead to coastline change, and coastal erosion by the sea-water can lead to the reduction of land areas. Meanwhile, with sedimentation, there will be an increase in landmass. Cirebon, which is part of the northern coastal area of West Java Province, is located on lowland with a dense population and rapid urban development. Several studies have been conducted during the past decade in the coastal areas of Cirebon with research results indicating that most of the coastal areas in Cirebon are subject to landslides at various scales ranging from vulnerable to bad conditions. Based on this, it is necessary to do a study aimed to know the time series trend of coastline change in Cirebon, Indonesia. This study is expected to provide valuable information on the latest conditions of coastal areas in Cirebon, and can be used as a basis for land use and coastal management planning, as areas of potential loss to erosion can be identified and future mitigation of the coastal areas can be undertaken. The configuration of changes in coastline was determined using remotely sensed data of Landsat 7 TM/ETM+ satellite. Imagery data was processed using MNDWI. Accordingly, Cirebon has for twenty years (1994-2014), experienced a significant shift in the coastline. The average value of the coastline advancing toward the sea is 643 meters and coastline setback is 343 meters, or there has been an average shift of the coastline of approximately 986 meters. Meanwhile, over the past twenty years, the length of the coastline has increased by around 2.2 kilometers. The value of coastline onward that is greater than the setback indicates that changes in the coastline in Cirebon tend to experience accretion. Conclusively, Cirebon’s coastline changes show an increasing trend in length and domination by the accretion (sedimentation) process.
Źródło:
World Scientific News; 2019, 138, 2; 79-92
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Surficial Sedimentary at the Bottom in Waters Surrounding the Arisen Land of Putri Island, Karawang - Indonesia
Autorzy:
Harahap, Syawaludin A.
Yuliadi, Lintang P. S.
Sinulingga, John N.
Powiązania:
https://bibliotekanauki.pl/articles/1031415.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Arisen land
Cikiong Beach
Putri Island
deltaber
grain size
kummod-sel
phi (φ) scale
sedimentation
surficial sedimentary
Opis:
This study was conducted in July 2016 around Putri Island and Cikiong Beach, Batujaya District, Karawang Regency, West Java - Indonesia to know the types of surficial sedimentary that makeup Putri Island. Field survey activities were carried out to collect sediment samples using a 1-meter long piston core. The sampling locations were carried out at five stations by considering representativeness and ease of accessibility. Sediment analysis using the sieve or granulometric method to produce grain size information on the phi (φ) scale. Sediment types were classified based on grain size using the Wentworth scale and followed by the Folk’s ternary diagram. The study results show that the sediment covering the bottom of the waters around Putri Island is composed of seven types of sediment, namely gravel, very coarse sand, coarse sand, medium sand, fine sand, very fine sand, and silt. It can be seen that sand dominates the sediment fraction which reaches 94% followed by 4% mud and 2% gravel. If classified based on the main component of the Folk’s ternary diagram, the seabed of this area has three types of sediment textures, namely slightly gravelly sand [(g) S], Sand [S], and gravelly sand [gS]. Judging from the constituent elements of the sediment, it can be said that the sedimentation that occurs in the study location is composed of alluvial deposits. The formation of this sediment is dominated by material carried by the river flow through fluvial and tidal processes.
Źródło:
World Scientific News; 2021, 151; 95-109
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The patterns of changes in coral reef coverage (1994-2006) in the Seribu Islands National Park, Jakarta, Indonesia
Autorzy:
Harahap, Syawaludin A.
Shabrina, Nikita A.
Purba, Noir P.
Syamsuddin, Mega L.
Powiązania:
https://bibliotekanauki.pl/articles/1839867.pdf
Data publikacji:
2021
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Change analysis
Coral reef
CVA
Landsat Imagery
Lyzenga
TNKpS
Seribu Islands National Park
Opis:
Coral reef ecosystems are unique ecosystems that can live and reproduce well in the tropics. Corals that makeup reefs are a very important component of ecosystems on the earth's surface. These ecosystems are habitats for a large number of diverse organisms in the oceans. However, in recent years coral reefs have experienced significant degradation as a result of the impact of human disturbances and natural factors on biodiversity and ecosystem functions. It is known that 90% of coral reef damage comes from human activities and 10% comes from climate change (natural events). In addition to natural events, such as waves, storms, and rising sea surface temperatures, the use of island land and the increasing population and utilization of coral reef resources around the island, including those that may cause a decrease in coral cover, can indirectly change the morphology of the island. To find out about the pattern of changes in coral reef cover area based on zoning in TNKpS, it is necessary to conduct a quick and effective study by utilizing digital processing of satellite imagery. The data used are Landsat images (1994, 2000, and 2006) with change detection method using CVA technique. The results of the analysis showed that there was a change in the increase in coral reef cover over 12 years (1994-2006). The pattern of changes that occur is dominated towards the Northeast and Northwest in the area 1, meanwhile, for area 2 it varies in all directions.
Źródło:
World News of Natural Sciences; 2021, 38; 120-138
2543-5426
Pojawia się w:
World News of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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