scholarly journals Effect on Ocean Noise: Nyepi, a Balinese Day of Silence

2018 ◽  
Author(s):  
Rob Williams ◽  
Christine Erbe ◽  
I Made Iwan Dewantama ◽  
I Gede Hendrawan
Keyword(s):  
Coral Reef ◽  
Coral Reef Fish ◽  
Human Activities ◽  
Killer Whale ◽  
Acoustic Noise ◽  
Acoustic Signals ◽  
Shallow Waters ◽  
Noise Levels ◽  
Sonar System ◽  
Ocean Noise

Taking advantage of a religious holiday called Nyepi that curtailed human activities for one day, we recorded acoustic noise levels for one week in shallow waters of a little-trafficked area west of Bali below the Ngurah Rai airport flight path (Figure 1). Sound is as important to many marine organisms as vision is to humans. From the song of the humpback whale to the exquisite sonar system of the killer whale, many marine vertebrates have evolved sophisticated systems for sending and receiving acoustic signals to facilitate vital life functions. Coral reef fish sing in a dawn chorus, much as songbirds do (McCauley and Cato, 2000).

scholarly journals Approaches to reduce noise from ships operating in important killer whale habitats

2018 ◽  
Author(s):  
Rob Williams
Keyword(s):  
Chinook Salmon ◽  
Killer Whale ◽  
Qualitative Description ◽  
Anthropogenic Noise ◽  
Noise Levels ◽  
Critical Habitat ◽  
Ocean Noise ◽  
Acoustic Quality ◽  
Source Level

Shipping is key to global trade, but is also a dominant source of anthropogenic noise in the ocean. Chronic noise from ships can affect acoustic quality of important whale habitats. Noise from ships has been identified as one of three main stressors–in addition to contaminants, and lack of Chinook salmon prey–in the recovery of the endangered southern resident killer whale (SRKW) population. Managers recognize existing noise levels as a threat to the acoustical integrity of SRKW critical habitat. There is an urgent need to identify practical ways to reduce ocean noise given projected increases in shipping in the SRKW's summertime critical habitat in the Salish Sea. We reviewed the literature to provide a qualitative description of mitigation approaches. We use an existing ship source level dataset to quantify how some mitigation approaches could readily reduce noise levels by 3–10 dB.

THE COMPOSITION AND DISTRIBUTION OF BENTHIC FORAMINIFERA AT CORAL REEF ECOSYSTEM IN THOUSANDS ISLAND

2013 ◽  
Vol 5 (1) ◽  
Author(s):  
Lumban Nauli Lumban Toruan ◽  
Dedi Soedharma ◽  
Kresna Tri Dewi
Keyword(s):  
Coral Reef ◽  
Human Activities ◽  
Close Association ◽  
Mesh Size ◽  
Coral Reef Ecosystem ◽  
Composition Distribution ◽  
Benthic Foraminifers ◽  
High Nutrient ◽  
Binocular Microscope ◽  
Reef Ecosystem

Composition and distribution of foraminifers are affected by human activities and have close association with coral reef ecosystem. The aims of this research were to investigate the benthic foraminifers’ composition and distribution in sediment of coral reef ecosystem. Eleven stations of Karang Bongkok, Pramuka, and Onrust Island were observed in this study. The sediments were taken from surface substrate up to 2 cm under the substrate. Samples were washed on sieve with mesh size 0,063 mm, and then dried in oven with 50°C of temperature  for two hours. After separating from the sediment, the foraminifers were laid on foraminiferal slide and indentified using binocular microscope. The highest composition of symbiont-bearing foraminiferal assemblages which associated with reef ecosystem was in East Pramuka (78.17%) and the lowest was in South Onrust (21,83%). The opportunistic type had the highest composition in South Onrust (38.67%) and the lowest was in South Karang Bongkok. In west Pramuka had the highest composition of heterotrophic type (57.17%) and the lowest was in North Onrust (11.33%). Onrust Island was dominated by opportunistic type, indicating high nutrient. The highest amount of foraminifers’ taxa was found in Karang Bongkok with good coral reef coverage, while the lowest in Onrust facing with Jakarta Bay. Keywords: composition, distribution, benthic foraminifers, coral reef.

scholarly journals Year-round high abundances of the world’s smallest marine vertebrate (Schindleria) in the Red Sea and worldwide associations with lunar phases

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Vanessa Robitzch ◽  
Victor Molina-Valdivia ◽  
Jaiber J. Solano-Iguaran ◽  
Mauricio F. Landaeta ◽  
Michael L. Berumen
Keyword(s):  
Coral Reef ◽  
Reef Fish ◽  
Red Sea ◽  
Coral Reef Fish ◽  
Seasonal Temperature ◽  
Global Trends ◽  
Lunar Phases ◽  
Spatial Differences ◽  
New Moon ◽  
Reproductive Cycles

AbstractVery little is known about the ecology and biology of the smallest marine vertebrates, fishes in the genus Schindleria. Even though over half of named Schindleria species have been identified in the Red Sea, the collection of only very few specimens has been documented. Here, we assessed abundance patterns of nearly two thousand Red Sea long dorsal fin (LDF) adults and found evidence for putative seasonal and spatial differences, likely related to differing habitat and environmental conditions. The highest abundances were outside local seasonal temperature extremes and decoupled from peaks of coral reef fish recruitment. We also found evidence for global trends in abundances related to lunar cycles using our Red Sea data and that from a recently published large collection of specimens from the DANA Expedition (1928–1930). The abundance of adult LDF Schindleria in relation to lunar phases differed significantly, with most Schindleria caught outside the full moon, and mostly during the new moon in the Red Sea and the 3rd quarter moon in the DANA collection. We further suggest that the abundances of Schindleria at coral reefs may be related to reproductive cycles and that these cycles may be timed with the moon as back-calculations of hatch dates from otoliths from the Red Sea significantly resulted after the new moon, making Schindleria the fastest-lived coral reef fish with the shortest generation times. Schindleria could be the most numerous coral reef fish in the world, for which we encourage increased research.

scholarly journals Impact of cyclones on hard coral and metapopulation structure, connectivity and genetic diversity of coral reef fish

Coral Reefs ◽  
2021 ◽  
Author(s):  
Gabriele Gerlach ◽  
Philipp Kraemer ◽  
Peggy Weist ◽  
Laura Eickelmann ◽  
Michael J. Kingsford
Keyword(s):  
Genetic Diversity ◽  
Coral Reef ◽  
Genetic Structure ◽  
Reef Fish ◽  
Coral Reef Fish ◽  
Population Genetic Study ◽  
Hard Coral ◽  
Great Loss ◽  
Metapopulation Structure ◽  
The Impact

AbstractCyclones have one of the greatest effects on the biodiversity of coral reefs and the associated species. But it is unknown how stochastic alterations in habitat structure influence metapopulation structure, connectivity and genetic diversity. From 1993 to 2018, the reefs of the Capricorn Bunker Reef group in the southern part of the Great Barrier Reef were impacted by three tropical cyclones including cyclone Hamish (2009, category 5). This resulted in substantial loss of live habitat-forming coral and coral reef fish communities. Within 6–8 years after cyclones had devastated, live hard corals recovered by 50–60%. We show the relationship between hard coral cover and the abundance of the neon damselfish (Pomacentrus coelestis), the first fish colonizing destroyed reefs. We present the first long-term (2008–2015 years corresponding to 16–24 generations of P. coelestis) population genetic study to understand the impact of cyclones on the meta-population structure, connectivity and genetic diversity of the neon damselfish. After the cyclone, we observed the largest change in the genetic structure at reef populations compared to other years. Simultaneously, allelic richness of genetic microsatellite markers dropped indicating a great loss of genetic diversity, which increased again in subsequent years. Over years, metapopulation dynamics were characterized by high connectivity among fish populations associated with the Capricorn Bunker reefs (2200 km2); however, despite high exchange, genetic patchiness was observed with annual strong genetic divergence between populations among reefs. Some broad similarities in the genetic structure in 2015 could be explained by dispersal from a source reef and the related expansion of local populations. This study has shown that alternating cyclone-driven changes and subsequent recovery phases of coral habitat can greatly influence patterns of reef fish connectivity. The frequency of disturbances determines abundance of fish and genetic diversity within species.

scholarly journals Characterization of Noise Level Inside a Vehicle under Different Conditions

Sensors ◽  
2020 ◽  
Vol 20 (9) ◽  
pp. 2471 ◽  
Author(s):  
Daniel Flor ◽  
Danilo Pena ◽  
Luan Pena ◽  
Vicente A. de Sousa ◽  
Allan Martins
Keyword(s):  
Regression Analysis ◽  
Noise Level ◽  
Acoustic Noise ◽  
Experimental Setup ◽  
Strongly Correlated ◽  
Noise Levels ◽  
Noise Sources ◽  
Statistical Tools ◽  
Window Position

Vehicular acoustic noise evaluations are a concern of researchers due to health and comfort effects on humans and are fundamental for anyone interested in mitigating audio noise. This paper focuses on the evaluation of the noise level inside a vehicle by using statistical tools. First, an experimental setup was developed with microphones and a microcomputer located strategically on the car’s panel, and measurements were carried out with different conditions such as car window position, rain, traffic, and car speed. Regression analysis was performed to evaluate the similarity of the noise level from those conditions. Thus, we were able to discuss the relevance of the variables that contribute to the noise level inside a car. Finally, our results revealed that the car speed is strongly correlated to interior noise levels, suggesting the most relevant noise sources are in the vehicle itself.

Sign in / Sign up

Export Citation Format

Share Document