Turbidity estimation from an acoustic backscatter signal in a tropical coral reef system.

Estuarine Coastal and Shelf Science, Год журнала: 2024, Номер 311, С. 109018 - 109018

Опубликована: Ноя. 7, 2024

Язык: Английский

---

Coming to light: How effective are sediment gravity flows in removing fine suspended carbonate from reefs?

The Depositional Record, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 27, 2024

Abstract Coral reefs are hard calcified structures, mainly found in warm tropical water. These ecosystems serve important roles as, for example, a source of food, shelter and nursery different organisms, coastal protection. Reef‐building organisms have evolved to inhabit narrow ecological niche thus particularly susceptible rapid changes their environment, under predicted climate‐change scenarios. Anthropogenic climate change is widely accepted as the leading cause rising ocean temperatures, sea water acidity sedimentation rate, which all affect coral's productivity, health and, some extent, skeletal strength. High‐energy weather events, such storms hurricanes, can erode reefs, thereby increasing amount suspended sediment consequently turbidity The removal from reef vital producers, natural process that removes gravity flows. A key factor controls ability flows transport cohesion, cohesion determines run‐out distance flow through its rheological properties. This study examines cohesive nature laden with fine‐grained CaCO 3 . mud‐grade calcite compared carrying non‐cohesive, silt‐sized, silica flour, weakly kaolinite clay strongly bentonite clay, by means laboratory experiments. results these experiments show behave more akin silica‐flour reaching maximum mobility at considerably higher volumetric concentrations (47% flour 53% ) than (22% 16% bentonite). Fine therefore be regarded physically high may constitute an effective mechanism removing coral especially locations where slope gradient present, front forereef. However, biological caused ‘sticky’ extracellular polymer substances produced micro‐organisms, render less mobile. present should seen first step towards comprehensive analysis efficiency reefs.

Язык: Английский

---

Sediment mobilization by rain-driven landslides in a subtropical moist, mix-use, and predominantly metamorphic setting

Geomorphology, Год журнала: 2022, Номер 413, С. 108380 - 108380

Опубликована: Июль 25, 2022

Язык: Английский

---

Tracking coral loss in the Spermonde Archipelago of Indonesia: 32 years of satellite monitoring from 1990 to 2022

International Journal of Remote Sensing, Год журнала: 2023, Номер 45(23), С. 8937 - 8967

Опубликована: Окт. 24, 2023

An alarming amount of damage has occurred to coral reefs in Indonesia, with the causes such either from human activities (anthropogenic causes) or natural processes. This study investigated long-term dynamic changes reef habitats eight selected islands Spermonde archipelago, using remote sensing and historical information. A series Landsat images recorded different years (i.e. 1990, 1996, 2002, 2008, 2013, 2016, 2018, 2019, 2022) were used map benthic each island live coral, dead seagrass, sand, rubble, mix bottom). The analysis estimated a total 303.47 hectares 76.26% loss studied since 1990. In contrast, there was substantial increase algae at around 108.63 101.91 hectares, respectively. Strong similar negative coefficient determination between cover both (R2 = 0.96, Y -2.95) rubble 0.94, -2.85) suggested that (e.g. destructive fishing activities, anchors, mining) processes sedimentation, bleaching, diseases, predation) played comparable roles degradation Archipelago. Furthermore, this revealed on regardless it inhabited uninhabited influenced by extent its cover. overall highlighted ongoing factors contributing archipelago. Further research monitoring efforts are necessary understand mechanisms driving decline increases rubble. knowledge will aid developing targeted conservation strategies management plans protect ecosystem Archipelago other affected regions Indonesia.

Язык: Английский

---

Evaluation of Wanggu Watershed Carrying Capacity on Water System Indicators in Southeast Sulawesi, Indonesia

Indonesian Journal of Environmental Management and Sustainability, Год журнала: 2023, Номер 7(2), С. 62 - 73

Опубликована: Июнь 7, 2023

The water system or hydrological indicators determine the good and bad of a watershed’s carrying capacity. include discharge fluctuations, annual flow coefficient, sediment load, flood frequency, use index. purpose this study was to evaluate capacity Wanggu watershed based on indicators. method used is score weight for all indicator data in accordance with evaluation guidelines research sourced from primary secondary data. Primary comes direct observation, while agencies related research. Data analysis using Microsoft Excel monthly by producing tables figures. results indicate that fluctuations regime coefficient River Basin are 96.45 which classified as high, well erosion surface runoff, namely load conditions 19.73 also included high category. While value 0.32, average frequency flooding every year occurs once two years index 0.69. three parameters categorized being middle class. From accumulated weights scores parameters, 111.25 class So has poor management indicator.

Язык: Английский

---

On the hydro-geomorphology of steepland coffee farming: Runoff and surface erosion

Agricultural Water Management, Год журнала: 2023, Номер 289, С. 108568 - 108568

Опубликована: Окт. 21, 2023

Soil compaction and natural vegetation removal associated to agriculture tends promote runoff soil erosion with potentially adverse onsite, downstream, global impacts. Although coffee farming represents a fraction of the world's harvested lands, it is vital crop for many developing nations where frequently cultivated on prone, high-relief, wet tropical landscapes. However, limited empirical data exists farm erosion. This article attends this need by describing results rainfall simulation experiments designed evaluate impact sun-grown coffee-farming precipitation excess, infiltration rates, surface overland flow. Results show that rates coffee-cultivated fields are ∼60 – 80% relative undisturbed forested slopes, cultivation increases one two orders magnitude depending presence or absence mulch weed cover. The suggests land unsustainable from both formation an agricultural productivity point view. Unsurfaced access roads display even greater than surfaces ∼10% soils up four-orders above background grading history slope. Farm-scale annualized ∼3–24 Mg ha-1 yr-1 actively used unpaved road abundance as account ∼99% net Implementing efficient control strategies farms therefore essential reduce their current impacts, but also future given worldwide surge in harvesting areas projected upcoming decades.

Язык: Английский

---

Transcriptomic signatures across a critical sedimentation threshold in a major reef-building coral

Frontiers in Physiology, Год журнала: 2024, Номер 15

Опубликована: Июнь 11, 2024

Sedimentation is a major cause of global near-shore coral reef decline. Although the negative impacts sedimentation on community composition have been well-documented, effects metabolism in situ received comparatively little attention. Using transcriptomics, we identified gene expression patterns changing across previously defined threshold that was deemed critical due to changes cover and composition. We genes, pathways, molecular processes associated with this transition may allow corals, such as Porites lobata , tolerate chronic, severe persist turbid environments. Alternative energy generation pathways help P. maintain persistent stress response survive when availability light oxygen diminished. found evidence for genes linked increased environmental sensing cellular communication likely efficiently respond pathogen challenges. Cell damage increases under stress; consequently, apoptosis over-represented sedimentation, consequence damaged cell removal colony integrity. The results presented here provide framework field conditions. Testing its related hypotheses using multi-omics approaches can deepen our understanding metabolic plasticity acclimation potential corals their resilience systems.

Язык: Английский

---

Spatial and temporal patterns of diffuse attenuation coefficient in Guánica, Puerto Rico: 15 years after development of a watershed management plan

Frontiers in Remote Sensing, Год журнала: 2024, Номер 5

Опубликована: Июнь 19, 2024

Decreased water quality in coastal environments due to land alterations by human activities has caused stressed and degraded coral reefs worldwide. The consequences of decreased are not limited but also affect the people’s lives increasing incidence diseases, so areas highly impacted have been prioritized for management. Guánica Bay Watershed Management Plan was developed reduce non-point sources pollution that arrive at bay protect adjacent reefs, however, 15 years passed since its creation management actions evaluated. purpose this study evaluate effectiveness implemented watershed. Therefore, objective describe temporal trends (2002–2008 2016–2022) remotely sensed diffuse attenuation coefficient 490 nm (Kd ), a indicator, one managed (Guánica Bay) three non-managed (Guayanilla Bay, Descalabrado River, Guanajibo River) estuaries Southwestern Puerto Rico. This achieved integrating ocean-color satellite imagery from MERIS-Envisat OLCI-Sentinel-3 sensors were sampled using beyond-Before-After-Control-Impact (beyond-BACI) approach. An additional oceanic site selected continuity between estimates. processed SNAP extract Kd values estuaries. analysis beyond-BACI found significant differences periods (before after) changes unique each location within estuary. lowest variability estuary observed (range 0.05–0.1 m -1 ) highest Guayanilla (0.35 ). southern showed similar trends, all having peak 2018 trough 2020. did decrease after implementation actions, which can be related passage several hurricanes during period. Further should done as new data is available last suggested plan.

Язык: Английский

---

Coral disease prevalence and compromised health in the Sempu Island Nature Reserve, Malang District, Indonesia

Biodiversitas Journal of Biological Diversity, Год журнала: 2024, Номер 25(4)

Опубликована: Апрель 14, 2024

Abstract. Isdianto A, Fewila AR, Rijal SS, Setyanto Fathah AL, Atikawati D, Putri BM, Puspitasari ID, Luthfi OM. 2024. Coral disease prevalence and compromised health in the Sempu Island Nature Reserve, Malang District, Indonesia. Biodiversitas 25: 1404-1412. Since Dutch colonialization era, District's Strait has been designated a natural reserve. Environmental changes human activities have contributed to 14.28% coral cover Strait. This study aims assess detect diseases or conditions. At five stations, data were gathered utilizing Underwater Photo Transect method with 10-meter interval 1x1 meter transect implemented across 100 meters. The average is 14.28%, considered inadequate according categories for determining reef status. Fish Bite, Black Band Disease (BBD), Ulcerative White Spots (UWS), Non-Focal Bleaching (NFBL), Trematodiasis, Pigmentation Response are six of that identified. Sediment damage only condition With an 15.35%, (NFBL) most prevalent disease; (BBD) lowest at 0.8%. insufficient coverage caused by surrounding environmental conditions stress corals point where coral-eating increased.

Язык: Английский

---

Experimental study on the settling motion of coral grains in still water

Journal of Fluid Mechanics, Год журнала: 2024, Номер 990

Опубликована: Июль 10, 2024

Understanding settling motion of coral grains is important in terms protection reef systems and resotoration the associated ecosystems. In this paper, a series laboratory experiments was conducted to investigate motion, using optical microscopy measure shape parameters particle-filtering-based object tracking reconstruct three-dimensional trajectory. Three characteristic descent regimes, namely, tumbling, chaotic fluttering, are classified based on trajectory, spiral radius variation velocity spectrum. It demonstrated that if one randomly picks up grain, then probabilities occurrence three regimes approximately $26\,\%$ , $42\,\%$ $32\,\%$ respectively. We have shown first, dimensionless generally increases with non-dimensional diameter Corey factor second, drag coefficient decreases Reynolds number factor. Based this, applicability existing models predicting for further. Finally, we proposed extended velocity. This study contributes better understanding improves our predictive capacity complex geometry.

Язык: Английский

---