scholarly journals Physical connectivity simulations reveal dynamic linkages between coral reefs in the southern Red Sea and the Indian Ocean

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Yixin Wang ◽  
Dionysios E. Raitsos ◽  
George Krokos ◽  
John A. Gittings ◽  
Peng Zhan ◽  
...  
Keyword(s):  
Coral Reef ◽  
Indian Ocean ◽  
Coral Reefs ◽  
Red Sea ◽  
Hot Spots ◽  
Conservation Strategies ◽  
Substantial Impact ◽  
Coral Reef Ecosystems ◽  
The Indian Ocean

Abstract The southern Red Sea is genetically distinct from the rest of the basin; yet the reasons responsible for this genetic separation remain unclear. Connectivity is a vital process for the exchange of individuals and genes among geographically separated populations, and is necessary for maintaining biodiversity and resilience in coral reef ecosystems. Here, using long-term, high-resolution, 3-D backward particle tracking simulations, we investigate the physical connectivity of coral reefs in the southern Red Sea with neighbouring regions. Overall, the simulation results reveal that the southern Red Sea coral reefs are more physically connected with regions in the Indian Ocean (e.g., the Gulf of Aden) than with the northern part of the basin. The identified connectivity exhibits a distinct monsoon-related seasonality. Though beyond the country boundaries, relatively remote regions of the Indian Ocean may have a substantial impact on the southern Red Sea coral reef regions, and this should be taken into consideration when establishing conservation strategies for these vulnerable biodiversity hot-spots.

Passage Through the Strait of Bab Al-Mandeb

1978 ◽  
Vol 13 (2) ◽  
pp. 180-193
Author(s):  
Ruth Lapidoth
Keyword(s):  
Indian Ocean ◽  
Coral Reefs ◽  
Red Sea ◽  
Democratic Republic ◽  
Gulf Of Aden ◽  
Eastern Shore ◽  
The West ◽  
The Indian Ocean ◽  
The Republic ◽  
Yemen Arab Republic

The strait of Bab al-Mandeb, “the gate of tears” or “the gate of the wailing yard”, joins the high seas of the Gulf of Aden and the Indian Ocean to those of the Red Sea. The name is primarily used by geographers to designate the narrowest part of the passage, between Ras Bab al-Mandeb on the Asian shore and Ras Siyan in Africa. At this point it is bordered on the east by the Yemen Arab Republic (Northern Yemen) and the People's Democratic Republic of Yemen (Southern Yemen), and in the west by the Republic of Djibouti (formerly the French Territory of the Afars and Issas). About 14 miles farther north, where the Red Sea (or, for that matter, the strait) is nearly 20 miles wide, lies the coast of Ethiopia (the province of Eritrea). All the riparians claim a territorial sea of 12 miles, and the Yemen Arab Republic, as well as the People's Democratic Republic of Yemen, also claim jurisdiction for certain purposes in an additional zone of 6 miles.On the eastern shore of the strait of Bab al-Mandeb lies the peninsula of Ras Bab al-Mandeb, which is about 6–10 km. wide. It consists of rocky, volcanic plains with several hills of 200–300 m. The coast of Ras Bab al-Mandeb is surrounded by coral reefs of a width of up to 1500 m. The border between North Yemen and South Yemen passes down the middle of Ras Bab al-Mandeb.

scholarly journals The Extraordinary Importance of Coral-Associated Fauna

Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 357
Author(s):  
Simone Montano
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Intimate Relationships ◽  
Species Interactions ◽  
Associated Fauna ◽  
External Disturbances ◽  
Term Survival ◽  
Symbiotic Relationships ◽  
Coral Reef Ecosystems

Coral reefs are one of the most diverse marine ecosystems on Earth and one of the richest in terms of species interactions. Scleractinian corals are usually the most likely to provide numerous different habitats and to support many symbiotic relationships. However, many other invertebrate groups, such as sponges, bryozoans, and other cnidarians, establish strict symbiotic relationships with other marine organisms. Despite the nature of these relationships—as well as the factors that drive their establishment—being unclear in most cases, a few studies have already shown that some associations may increase the resistance of their hosts to external disturbances. Thus, the potential ability of each member of these diverse symbiotic assemblages to influence the fitness and long-term survival of their hosts bring the coral-associated fauna to the top of the list of coral reef studies. Unfortunately, the widespread degradation of coral reef ecosystems may threaten the existence of the intimate relationships that may go unrecognized complicating our understanding of the intricate networks connecting the fates of reef species. Therefore, this unprecedented loss of biodiversity calls for synergic conservation and monitoring actions aimed at significantly increasing our efforts to search for and describe as much of the diversity of coral-associated organisms as possible, shedding new light on the complex, elusive mechanisms controlling coral reef functioning.

scholarly journals Analysis of Drought-Sensitive Areas and Evolution Patterns through Statistical Simulations of the Indian Ocean Dipole Mode

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1302 ◽  
Author(s):  
Qing-Gang Gao ◽  
Vonevilay Sombutmounvong ◽  
Lihua Xiong ◽  
Joo-Heon Lee ◽  
Jong-Suk Kim
Keyword(s):  
Indian Ocean ◽  
Indian Ocean Dipole ◽  
Diagnostic Techniques ◽  
Eastern Coast ◽  
Indochina Peninsula ◽  
Indian Ocean Dipole Mode ◽  
Sensitive Areas ◽  
The Indian Ocean ◽  
Long Term Trend

In this study, we investigated extreme droughts in the Indochina peninsula and their relationship with the Indian Ocean Dipole (IOD) mode. Areas most vulnerable to drought were analyzed via statistical simulations of the IOD based on historical observations. Results of the long-term trend analysis indicate that areas with increasing spring (March–May) rainfall are mainly distributed along the eastern coast (Vietnam) and the northwestern portions of the Indochina Peninsula (ICP), while Central and Northern Laos and Northern Cambodia have witnessed a reduction in spring rainfall over the past few decades. This trend is similar to that of extreme drought. During positive IOD years, the frequency of extreme droughts was reduced throughout Vietnam and in the southwestern parts of China, while increased drought was observed in Cambodia, Central Laos, and along the coastline adjacent to the Myanmar Sea. Results for negative IOD years were similar to changes observed for positive IOD years; however, the eastern and northern parts of the ICP experienced reduced droughts. In addition, the results of the statistical simulations proposed in this study successfully simulate drought-sensitive areas and evolution patterns of various IOD changes. The results of this study can help improve diagnostic techniques for extreme droughts in the ICP.

Impacts of human activities on coral reef ecosystems of southern Taiwan: A long-term study

2012 ◽  
Vol 64 (6) ◽  
pp. 1129-1135 ◽  
Author(s):  
Pi-Jen Liu ◽  
Pei-Jie Meng ◽  
Li-Lian Liu ◽  
Jih-Terng Wang ◽  
Ming-Yih Leu
Keyword(s):  
Coral Reef ◽  
Human Activities ◽  
Term Study ◽  
Long Term Study ◽  
Coral Reef Ecosystems ◽  
Southern Taiwan

scholarly journals Measuring Sound at a Cold-Water Coral Reef to Assess the Impact of COVID-19 on Noise Pollution

2021 ◽  
Vol 8 ◽  
Author(s):  
Laurence H. De Clippele ◽  
Denise Risch
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Sea Level ◽  
Cold Water ◽  
Noise Pollution ◽  
Ecosystem Functions ◽  
Noise Levels ◽  
Level Height ◽  
Water Coral

This study compares the noise levels at the cold-water coral Tisler reef, before and after the closure of the border between Norway and Sweden, which occurred as a direct result of the COVID-19 pandemic. The Tisler reef is a marine protected area located under a ferry “highway” that connects Norway and Sweden. Cold-water coral reefs are recognised as being important hotspots of both biodiversity and biomass, they function as breeding and nursing grounds for commercially important fish and are essential in providing ecosystem functions. Whilst studies have shown that fishery, ocean warming, and acidification threaten them, the effects of noise pollution on cold-water coral reefs remains unstudied. To study the severity of noise pollution at the Tisler reef, a long-term acoustic recorder was deployed from 29 January 2020 until 26 May 2020. From 15 March COVID-19 lockdown measures stopped passenger vessel traffic between Norway and Sweden. This study found that the overall noise levels were significantly lower after border closure, due to reduced ferry traffic, wind speeds, and sea level height. When comparing the median hourly noise levels of before vs. after border closure, this study measured a significant reduction in the 63–125 Hz 1/3 octave band noise levels of 8.94 ± 0.88 (MAD) dB during the day (07:00:00–19:59:59) and 1.94 ± 0.11 (MAD) dB during the night (20:00:00–06:59:59). Since there was no ferry traffic during the night, the drop in noise levels at night was likely driven by seasonal changes, i.e., the reduction in wind speed and sea level height when transitioning from winter to spring. Taking into account this seasonal effect, it can be deduced that the COVID-19 border closure reduced the noise levels in the 63–125 Hz 1/3 octave bands at the Tisler reef by 7.0 ± 0.99 (MAD) dB during the day. While the contribution of, and changes in biological, weather-related and geophysical sound sources remain to be assessed in more detail, understanding the extent of anthropogenic noise pollution at the Tisler cold-water coral reef is critical to guide effective management to ensure the long-term health and conservation of its ecosystem functions.

scholarly journals Experimental reef communities persist under future ocean acidification and warming

2021 ◽  
Author(s):  
Christopher Jury ◽  
Keisha Bahr ◽  
Evan Barba ◽  
Russell Brainard ◽  
Annick Cros ◽  
...  
Keyword(s):  
Experimental Study ◽  
Species Richness ◽  
Coral Reef ◽  
Coral Reefs ◽  
Ocean Acidification ◽  
Community Composition ◽  
Functional State ◽  
Reef Communities ◽  
Paris Climate Agreement

Abstract Coral reefs are among the most sensitive ecosystems affected by ocean acidification and warming, and are predicted to shift from net accreting calcifier-dominated systems to net eroding algal-dominated systems over the coming decades. Here we present a long-term experimental study examining the responses of entire mesocosm coral reef communities to acidification (-0.2 pH units), warming (+ 2°C), and combined future ocean (-0.2 pH, + 2°C) treatments. We show that under future ocean conditions, net calcification rates declined yet remained positive, corals showed reduced abundance yet were not extirpated, and community composition shifted while species richness was maintained. Our results suggest that under Paris Climate Agreement targets, coral reefs could persist in an altered functional state rather than collapse.

scholarly journals INCREASE OF THE THERMOCLINE LAYER DUE TO TSUNAMI 2004 IN NANGRO ACEH DARUSSALAM WATERS

2011 ◽  
Vol 3 (1) ◽  
Author(s):  
Hadikusumah Hadikusumah ◽  
J. D. Lekalete
Keyword(s):  
Indian Ocean ◽  
Light Transmission ◽  
Mixed Layer Depth ◽  
Heat Content ◽  
Annual Variations ◽  
The Indian Ocean ◽  
Local Water ◽  
Straits Of Malacca ◽  
Tsunami Energy

Research of physical oceanographic conditions post-tsunami was carried out and subsequently compared with the pre-tsunami 1998. Measurement of suhu, salinity and light transmission was conducted by CTDSBE911pls Model. Results showed that the flow in the Straits of Malacca flowed into the northwest and turned back into the Strait of Bengal and the next rotation into the flow of waters along the west coast of Nangro Aceh Darusalam (NAD). The mainstream off coast NAD in the Indian Ocean flowed to the northwest. Upper thermocline layer (17 m to 50 m) moved upward in 2005 and 2006 compared with previous data 1998 (90 m to 125 m). The moving upward thermocline in 2006 was allegedly due to the influence of Indian Ocean Dipole (IOD) positive. This requires further verification through long-term data collection to determine the monthly and annual variations, which will be compared with previous research. Light transmission (Tx) in 2005 from the surface to near the bottom (water column) was found lower than the year 1998 and 2006. This result was allegedly caused by resuspension from the seabed by energy turbulent produced by the tsunami. Heat content between 5 to 65 m depth in 2005 was higher than in 1998 and 2006. The higher heat content during the year of 2005 (post tsunami) was caused by friction due to the influence of tsunami energy, which predominantly found in the mixed layer depth. Type of water masses in the study area was a mixing between the local water mass, Malacca Strait Water (MSA), Bay of Bengal Water (BBW) under the influence of Arab Waters (AW), and the Indian Deep Water (IDW).Keywords: current, thermocline, heat content, watermass type, and Nangro Aceh Darusalam

scholarly journals Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia

2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Anggita Kartikasari ◽  
TODHI PRISTIANTO ◽  
RIZKI HANINTYO ◽  
EGHBERT ELVAN AMPOU ◽  
TEJA ARIEF WIBAWA ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Habitat Mapping ◽  
Benthic Habitat ◽  
Coral Rubble ◽  
Spatial Coverage ◽  
Coral Reef Ecosystems ◽  
Optical Imagery ◽  
Sentinel 2

Abstract. Kartikasari A, Pristianto T, Hanintyo R, Ampou EE, Wibawa TA, Borneo BB. 2021. Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia. Biodiversitas 22: 4766-4774. Satellite optical imagery datasets integrated with in situ measurements are widely used to derive the spatial distribution of various benthic habitats in coral reef ecosystems. In this study, an approach to estimate spatial coverage of those habitats based on observation derived from Sentinel-2 optical imagery and a field survey, is presented. This study focused on the Lovina coral reef ecosystem of Northern Bali, Indonesia to support deployment of artificial reefs within the Indonesian Coral Reef Garden (ICRG) programme. Three specific locations were explored: Temukus, Tukad Mungga, and Baktiseraga waters. Spatial benthic habitat coverages of these three waters was estimated based on supervised classification techniques using 10m bands of Sentinel-2 imagery and the medium scale approach (MSA) transect method of in situ measurement.The study indicates that total coverage of benthic habitat is 61.34 ha, 25.17 ha, and 27.88 ha for Temukus, Tukad Mungga, and Baktiseraga waters, respectively. The dominant benthic habitat of those three waters consists of sand, seagrass, coral, rubble, reef slope and intertidal zone. The coral reef coverage is 29.48 ha (48%) for Temukus covered by genus Acropora, Isopora, Porites, Montipora, Pocillopora. The coverage for Tukad Mungga is 8.69 ha (35%) covered by genus Acropora, Montipora, Favia, Psammocora, Porites, and the coverage for Baktiseraga is 11.37 ha (41%) covered by genus Montipora sp, Goniastrea, Pavona, Platygyra, Pocillopora, Porites, Acropora, Leptoseris, Acropora, Pocillopora, Fungia. The results are expected to be suitable as supporting data in restoring coral reef ecosystems in the northern part of Bali, especially in Buleleng District.

Coral reef-associated bryozoans of Jamaica

Zootaxa ◽  
2021 ◽  
Vol 4988 (1) ◽  
pp. 1-218
Author(s):  
JUDITH E. WINSTON ◽  
JEREMY B.C. JACKSON
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Rare Species ◽  
Ecological Study ◽  
Microscopy Study

As part of a long-term ecological study of the cryptic comunity of Jamaican coral reefs carried out by Jeremy B.C. Jackson and associates during the 1970s and early 1980s, collections were made of reef bryozoans found at 14 sites around the island. Space occupied by bryozoans on undercoral surfaces is dominated by relatively few species. However, during scanning electrone microscopy study and monograph preparation a diverse assortment of relatively rare species was discovered. Of the 132 species found, 56%, 74 species (70 cheilostomes and 4 cyclostomes) are new, as are one family (Inversiscaphidae) and 5 genera (Planospinella, Caribaria, Spirocoleopora, Gemellitheca, and Palliocella).  

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