First record of red-tide in Elba protectorate coast using Sentinel-3 and its impacts on ecosystem

The Egyptian Journal of Remote Sensing and Space Science, Год журнала: 2022, Номер 25(3), С. 803 - 813

Опубликована: Авг. 2, 2022

This study is the first to document an algal bloom caused by Noctiluca scintillans, which was detected using remote sensing techniques and confirmed in field along coast of Elba National Park. scintillans a phytoplankton species that accumulate toxic ammonia endangers various organisms, including fish, birds, mammals, human. Therefore, monitoring red tide essential for water pollution control management. aims evaluate potential recent launch Ocean Land Color Instrument (OLCI) onboard Sentinel-3 satellite identify chlorophyll-a (Chl-a) as proxy event its impacts on ecosystem. To fulfill aim, OLCI images were collected over area from 25th May 13th June 2017. Satellite converted level 1 2 through radiometric atmospheric correction, Chl-a maps produced 3 data during product development standard 4 MERIS (OC4Me) model. The time-series analyses indicated blooms (Red tide) occurred four days at studied sites (7th 10th June). current findings reveal strong relationship between deterioration quality criteria cell counts (×104) /L (0.05 > P ≤ 0.01). strongly urges routine physicochemical characteristics coastal waters early rid detection phenomenon.

Язык: Английский

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The pulsating soft coral Xenia umbellata shows high resistance to warming when nitrate concentrations are low

Scientific Reports, Год журнала: 2022, Номер 12(1)

Опубликована: Окт. 6, 2022

Abstract The resistance of hard corals to warming can be negatively affected by nitrate eutrophication, but related knowledge for soft is scarce. We thus investigated the ecophysiological response pulsating coral Xenia umbellata different levels eutrophication (control = 0.6, medium 6, high 37 μM nitrate) in a laboratory experiment, with additional (27.7 32.8 °C) from days 17 37. High enhanced cellular chlorophyll content Symbiodiniaceae 168%, while it reduced gross photosynthesis 56%. After warming, polyp pulsation rate was 100% both treatments, and loss 7% d −1 total fragment mortality 26% observed treatment. Warming alone did not affect any parameters. These results suggest that X. exhibits which may facilitate ecological dominance over some as ocean temperatures warm, though clear negative physiological occurs when combined eutrophication. This study confirms importance investigating combinations global local factors understand manage changing reefs.

Язык: Английский

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An assessment of Ryukyu Archipelago's coral communities over a wide latitudinal range

Deep Sea Research Part II Topical Studies in Oceanography, Год журнала: 2023, Номер 208, С. 105270 - 105270

Опубликована: Янв. 26, 2023

Язык: Английский

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Nitrogen fixation and denitrification activity differ between coral- and algae-dominated Red Sea reefs

Scientific Reports, Год журнала: 2021, Номер 11(1)

Опубликована: Июнь 3, 2021

Coral reefs experience phase shifts from coral- to algae-dominated benthic communities, which could affect the interplay between processes introducing and removing bioavailable nitrogen. However, magnitude of such processes, i.e., dinitrogen (N2) fixation denitrification levels, their responses remain unknown in coral reefs. We assessed both for dominant species six categories (hard corals, soft turf algae, rubble, biogenic rock, reef sands) accounting > 98% cover a central Red Sea reef. Rates were extrapolated relative studied organisms co-occurring areas same In general, with high N2 exhibited low activity. Extrapolated respective area, algae rubble accounted 90% overall fixation, whereas corals contributed more than half denitrification. Total was twice as algae- compared coral-dominated areas, levels similar. conclude that promote new nitrogen input through enhanced comparatively The subsequent increased availability support net productivity, resulting positive feedback loop increases competitive advantage over experienced shift.

Язык: Английский

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Stylophora under stress: A review of research trends and impacts of stressors on a model coral species

The Science of The Total Environment, Год журнала: 2021, Номер 816, С. 151639 - 151639

Опубликована: Ноя. 13, 2021

Язык: Английский

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Quantifying functional consequences of habitat degradation on a Caribbean coral reef

Biogeosciences, Год журнала: 2021, Номер 18(24), С. 6501 - 6516

Опубликована: Дек. 17, 2021

Abstract. Coral reefs are declining worldwide. The abundance of corals has decreased alongside a rise filter feeders, turf, and algae in response to intensifying human pressures. This shift prevalence functional groups alters the biogeochemical processes tropical water ecosystems, thereby influencing reef functioning. An urgent challenge is understand consequences these shifts develop suitable management strategies that aim at preserving biological functions reefs. Here, we quantify supporting key (i.e. net community calcification (NCC) production (NCP) nutrient recycling) situ for five different benthic assemblages currently dominating shallow degraded Caribbean habitats. To this end, transparent custom-made enclosure was placed over communities dominated by either one – coral, turf macroalgae, bioeroding sponges, cyanobacterial mats, or sand determine chemical fluxes between overlying water, during both day night. account simultaneous influence distinct have on measured variables, rates were then derived solving model consisting differential equations describing contribution each process fluxes. Inferred low compared those known flats Reduced accretion potential recorded, with negative very modest all communities. Net also low, suggesting limited accumulation biomass through photosynthesis remineralisation organic matter night relatively high comparison, resulting heterotrophy survey period most Estimated recycling nitrification denitrification) but did not fully counterbalance release from aerobic mineralisation, rendering substrates sources nitrogen. Results suggest similar directions magnitudes Curaçaoan reef. We infer amount type released abundant algal turfs mats likely enhances heterotroph activity stimulates proliferation less diverse copiotrophic microbial populations, studied heterotrophic drawing “behaviour” closer other.

Язык: Английский

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The widely distributed soft coral Xenia umbellata exhibits high resistance against phosphate enrichment and temperature increase

Scientific Reports, Год журнала: 2022, Номер 12(1)

Опубликована: Дек. 22, 2022

Abstract Both global and local factors affect coral reefs worldwide, sometimes simultaneously. An interplay of these can lead to phase shifts from hard dominance algae or other invertebrates, particularly soft corals. However, most studies have targeted the effects single factors, leaving pronounced knowledge gaps regarding combined on Here, we investigated phosphate enrichment (1, 2, 8 μM) seawater temperature increase (26 32 °C) Xenia umbellata by quantifying oxygen fluxes, protein content, stable isotope signatures in a 5-week laboratory experiment. Findings revealed no significant increase, enrichment, combination both fluxes. regardless treatment, total content carbon ratios decreased significantly 62% 7% under respectively, suggesting an increased assimilation their energy reserves. Therefore, hypothesize that heterotrophic feeding may be important for X. sustain reserves highlighting advantages mixotrophic strategy. Overall, shows high tolerance towards changes which explain competitive advantage observed at many Indo-Pacific reef locations.

Язык: Английский

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Nutrient pollution enhances productivity and framework dissolution in algae- but not in coral-dominated reef communities

Marine Pollution Bulletin, Год журнала: 2021, Номер 168, С. 112444 - 112444

Опубликована: Май 10, 2021

Ecosystem services provided by coral reefs may be susceptible to the combined effects of benthic species shifts and anthropogenic nutrient pollution, but related field studies are scarce. We thus investigated in situ how dissolved inorganic enrichment, maintained for two months, affected community-wide biogeochemical functions intact coral- degraded algae-dominated reef patches central Red Sea. Results from chamber incubations revealed 87% increased gross productivity a shift net calcification dissolution communities after same processes were unaffected nutrients neighboring communities. Both community types changed organic nitrogen sinks sources, increase release was 56% higher Nutrient pollution may, thus, amplify on key ecosystem reefs, possibly leading loss structurally complex habitats with carbonate altered recycling.

Язык: Английский

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Localized effects of offshore aquaculture on water quality in a tropical sea

Marine Pollution Bulletin, Год журнала: 2021, Номер 171, С. 112732 - 112732

Опубликована: Июль 27, 2021

Aquaculture production has increased steadily in many tropical countries over the past few decades, although impact assessments have been frequently neglected. We investigated impacts of an offshore barramundi fish farm on water quality southern-central Red Sea, a traditionally understudied tropical, oligotrophic, and semi-enclosed basin. Inorganic nutrients, particulate matter, chlorophyll-a, heterotrophic bacteria were measured periodically 8 months around farm. Water down-current from had, average, more chlorophyll-a than up-current (11% 34% higher, respectively). Ratios dissolved inorganic nitrogen:phosphorus lower ratios (mean 9.8 vs 16.0, Phosphate, nitrogen, matter showed patterns enrichment associated with after feeding event. Strategies such as feed optimization considering hydrodynamics site selection may improve for future farms Saudi Arabia other countries.

Язык: Английский

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Inter-annual variability patterns of reef cryptobiota in the central Red Sea across a shelf gradient

Scientific Reports, Год журнала: 2022, Номер 12(1)

Опубликована: Окт. 9, 2022

The combination of molecular tools, standard surveying techniques, and long-term monitoring programs are relevant to understanding environmental ecological changes in coral reef communities. Here we studied temporal variability cryptobenthic communities across the continental shelf central Red Sea spanning 6 years (three sampling periods: 2013-2019) including 2015 mass bleaching event. We used a tools (barcoding metabarcoding) assess on Autonomous Reef Monitoring Structures (ARMS) as standardized approach. Community composition associated with ARMS for both methodologies was statistically different reefs (shelf position) time periods. partition beta diversity showed higher turnover lower nestedness between pre-bleaching post-bleaching samples than two periods, revealing community shift from However, slight return observed 2019 suggesting recovery trajectory. Given predictions decreasing events, it is concerning that may not fully recover new characteristics will emerge. high among all implying homogenization cryptobiome did occur cross following It possible dispersal limitations distinct benthic structures present maintained heterogeneity reefs. This study has best our knowledge presented first aspect into analysis encompasses show these can detect cryptic degradation provides support being tools.

Язык: Английский

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