scholarly journals Bioecology of coral reef in Panjang Island of Central Java Indonesia

2021 ◽  
Vol 26 (2) ◽  
pp. 125-134
Author(s):  
Suryono Suryono ◽  
Ambariyanto Ambariyanto ◽  
Munasik Munasik ◽  
Diah Permata Wijayanti ◽  
Raden Ario ◽  
...  

Coral reefs currently are suffered from natural factors along with increasing anthropogenic activity. Panjang Island, a small reef island located in Jepara Regency, may also be experiencing such conditions. Therefore, this work was aimed to observe the condition of the coral cover of Panjang Island. Line intercept transect was applied to survey the coral cover and mortality index from fourteen stations. Insitu data consisted of the bottom substrate composition of the reefs and the physical parameters of the sea. The secondary data, i.e. coral reef area maps from 2001 to 2019 were taken from Landsat Image 7 and 8, data of wind were obtained from www.ogimet.com, while tidal data were collected from BMKG. The bathymetry was determined from the Geospatial Information Agency data, salinity global analysis forecast Phy 001.024 (CMEMS). Sea surface temperature (SST), and chlorophyll-a distribution were analyzed using ENVI software. The result showed that Panjang Island has a poor to the moderate condition of hard coral.  Two out of six categories of abiotic and dead coral were found to be high. The mortality index of coral was in the high category (average 0.52). During research periods the sea waters were characterized by high sea surface temperature (29.34-30.94°C), chlorophyll-a was also tended to be high (0-2.65 mg.m-3), and an average of salinity was high 32 ‰. The weak currents came to all sides of the island, therefore the coral reef was not exposed to extreme currents. The waves came from the east, then the energy decreases after being blocked by coral reefs on the eastern side of the island, so that coral reefs in the northeast and south sides were safer to be exposed. The results suggest that hydrodynamic ecology directly or indirectly affected the percentage of coral cover and mortality index at the reefs of Panjang Island.

2021 ◽  
Vol 14 (9) ◽  
pp. 1-7
Author(s):  
N.D. Hung ◽  
L.T.H. Thuy ◽  
T.V. Hang ◽  
T.N. Luan

The coral reef ecosystem in Cu Lao Cham, Vietnam is part of the central zone of the Cu Lao Cham -Hoi An, a biosphere reserve and it is strictly protected. However, the impacts of natural disasters - tropical cyclones (TCs) go beyond human protection. The characteristic feature of TCs is strong winds and the consequences of strong winds are high waves. High waves caused by strong TCs (i.e. level 13 or more) cause decline in coral cover in the seas around Cu Lao Cham. Based on the relationship between sea surface temperature (SST) and the maximum potential intensity (MPI) of TCs, this research determines the number of strong TCs in Cu Lao Cham in the future. Using results from a regional climate change model, the risk is that the number of strong TCs in the period 2021-2060 under the RCP4.5 scenario, will be 3.7 times greater than in the period 1980-2019 and under the RCP 8.5 scenario it will be 5.2 times greater than in the period 1980-2019. We conclude that increases in SST in the context of climate change risks will increase the number and intensity of TCs and so the risk of their mechanical impact on coral reefs will be higher leading to degradation of this internationally important site.


OSEANA ◽  
2020 ◽  
Vol 45 (2) ◽  
pp. 13-22
Author(s):  
Qinthan Azzahra Aulia ◽  
Ni Wayan Purnama Sari

Coral reef ecosystem is one of the coastal marine ecosystems in tropical waters. Coral reef ecosystems are vulnerable to damage mainly due to environmental factors. A fairly popular event of coral reef damage is coral bleaching. Mass coral bleaching is generally caused by changes in Sea Surface Temperature (SST). The condition of corals that have bleaching is different from the condition of corals that have died. The recovery process from coral bleaching phenomena can be effectively carried out if the surrounding environment is supportive and sea surface temperature return stable. The phenomenon of coral bleaching is a real indicator of the environmental stresses that occur on coral reefs. This paper will explain about coral bleaching, the factors that cause coral bleaching, and whether the bleaching coral reefs mean alive or dead.


2000 ◽  
Vol 203 (15) ◽  
pp. 2311-2322 ◽  
Author(s):  
B. Culik ◽  
J. Hennicke ◽  
T. Martin

We satellite-tracked five Humboldt penguins during the strong 1997/98 El Nino Southern Oscillation (ENSO) from their breeding island Pan de Azucar (26 degrees 09′S, 70 degrees 40′W) in Northern Chile and related their activities at sea to satellite-derived information on sea surface temperature (SST), sea surface temperature anomaly (SSTA), wind direction and speed, chlorophyll a concentrations and statistical data on fishery landings. We found that Humboldt penguins migrated by up to 895 km as marine productivity decreased. The total daily dive duration was highly correlated with SSTA, ranging from 3.1 to 12.5 h when the water was at its warmest (+4 degrees C). Birds travelled between 2 and 116 km every day, travelling further when SSTA was highest. Diving depths (maximum 54 m), however, were not increased with respect to previous years. Two penguins migrated south and, independently of each other, located an area of high chlorophyll a concentration 150 km off the coast. Humboldt penguins seem to use day length, temperature gradients, wind direction and olfaction to adapt to changing environmental conditions and to find suitable feeding grounds. This makes Humboldt penguins biological in situ detectors of highly productive marine areas, with a potential use in the verification of trends detected by remote sensors on board satellites.


Author(s):  
R. Shunmugapandi ◽  
S. Gedam ◽  
A. B. Inamdar

Abstract. Ocean surface phytoplankton responses to the tropical cyclone (TC)/storms have been extensively studied using satellite observations by aggregating the data into a weekly or bi-weekly composite. The reason behind is the significant limitations found in the satellite-based observation is the missing of valid data due to cloud cover, especially at the time of cyclone track passage. The data loss during the cyclone is found to be a significant barrier to efficiently investigate the response of chl-a and SST during cyclone track passage. Therefore it is necessary to rectify the above limitation to effectively study the impact of TC on the chlorophyll-a concentration (chl-a) and the sea surface temperature (SST) to achieve a complete understanding of their response to the TC prevailed in the Arabian Sea. Intending to resolve the limitation mentioned above, this study aims to reconstruct the MODIS-Aqua chl-a, and SST data using Data Interpolating Empirical Orthogonal Function (DINEOF) for all the 31 cyclonic events occurred in the Arabian Sea during 2003-2018 (16 years). Reconstructed satellite retrieved data covering all the cyclonic events were further used to investigate the chl-a and SST dynamics during TC. From the results, the exciting fact has been identified that only two TC over the eastern-AS were able to induce phytoplankton bloom. On investigating this scenario using sea surface temperature, it was disclosed that the availability of nutrients decides the suitable condition for the phytoplankton to proliferate in the surface ocean. Relevant to the precedent criterion, the results witnessed that the 2 TC (Phyan and Ockhi cyclone) prevailed in the eastern AS invoked a suitable condition for phytoplankton bloom. Other TC found to be less provocative either due to less intensity, origination region or the unsuitable condition. Thereby, gap-free reconstructed daily satellite-derived data efficiently investigates the response of bio-geophysical parameters during cyclonic events. Moreover, this study sensitised that though several TC strikes the AS, only two could impact phytoplankton productivity and SST found to highly consistent with the chl-a variability during the cyclone passage.


Author(s):  
Mukti Zainuddin

Skipjack tuna is an important species targeting by pole and line fishery in Bone Bay. The distribution and abundance of this species tended to aggregate to the preferred bio-physical environments. To describe the short term relationship between skipjack tuna and oceanographic conditions and to visualize the predicted high catch areas, remotely sensed satellite based-oceanographic sea surface temperature (SST) and chlorophyll-a together fisheries data were used. Results indicated that the highest skipjack CPUEs were mainly found in coastal areas of Palopo and Kolaka both in 2007 and in 2009 during the period of study. The high tuna concentrations corresponded well with chlorophyll-a of 0.15-0.40 mg mg-3 and SST of 29.0-31.5 °C. The preferred ranges provide a good indicator for initially detecting potential skipjack fishing grounds. This study suggested that thermal and chlorophyll fronts as well as upwelling may important mechanisms in explaining the temporal and spatial dynamics of skipjack tuna distribution and abundance in Bone Bay.Keywords: skipjack tuna, potential fishing grounds, satellite images and fronts


2018 ◽  
Vol 8 (1) ◽  
Author(s):  
Piers K. Dunstan ◽  
Scott D. Foster ◽  
Edward King ◽  
James Risbey ◽  
Terence J. O’Kane ◽  
...  

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