marine ecosystem
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2023 ◽  
Vol 83 ◽  
Guntur ◽  
O.M. Luthfi ◽  
M. A. Asadi

Abstract Crustose coralline algae (Corallinophycideae) are red algae that produced calcium carbonate and are well recognized as foundation species in the epipelagic zone of the marine ecosystem. These algae induced settlement juvenile of coral by released chemical cues from bacterial communities on the surface of their colonies. Their extracellular calcium carbonate also can stabilize reef structure that influencing many invertebrate attaches and growth in the seabed. Crustose coralline algae (CCA) have obtained attention because of their distribution and health compromise to increasing seawater temperature, ocean acidification, and pollutant. As a cryptic species in the ecosystem, the presence of CCA recruit sometimes doesn’t have attention, especially on their capability to occupy the empty space. This study aimed to document coverage and number of CCA recruit in two different recruitment tile’s material. The highest CCA percentage of the cover was showed inside surface than others surface in all stations. Light intensity and low sedimentation were suggested as a key factor of success of high coverage. Overall, station higher CCA recruits have shown from Tiga Warna. Low sedimentation and protection from aerial exposure became the main reason for it. No significant difference number of CCA recruits between marble and sandstone in this study. Successful CCA recruitment in this study can give a wide picture that natural recruitment of coral and other reef biodiversity in Southern Malang might be will succeed because of the abundance of coralline algae that support their life history stage.

2022 ◽  
Vol 5 (1) ◽  
Jia-Zhen Sun ◽  
Tifeng Wang ◽  
Ruiping Huang ◽  
Xiangqi Yi ◽  
Di Zhang ◽  

AbstractMany marine organisms are exposed to decreasing O2 levels due to warming-induced expansion of hypoxic zones and ocean deoxygenation (DeO2). Nevertheless, effects of DeO2 on phytoplankton have been neglected due to technical bottlenecks on examining O2 effects on O2-producing organisms. Here we show that lowered O2 levels increased primary productivity of a coastal phytoplankton assemblage, and enhanced photosynthesis and growth in the coastal diatom Thalassiosira weissflogii. Mechanistically, reduced O2 suppressed mitochondrial respiration and photorespiration of T. weissflogii, but increased the efficiency of their CO2 concentrating mechanisms (CCMs), effective quantum yield and improved light use efficiency, which was apparent under both ambient and elevated CO2 concentrations leading to ocean acidification (OA). While the elevated CO2 treatment partially counteracted the effect of low O2 in terms of CCMs activity, reduced levels of O2 still strongly enhanced phytoplankton primary productivity. This implies that decreased availability of O2 with progressive DeO2 could boost re-oxygenation by diatom-dominated phytoplankton communities, especially in hypoxic areas, with potentially profound consequences for marine ecosystem services in coastal and pelagic oceans.

2022 ◽  
Vol 10 (1) ◽  
pp. 156
Loredana Stabili ◽  
Margherita Licciano ◽  
Adriana Giangrande ◽  
Carmela Caroppo

Harmful algal blooms (HABs) are extreme biological events representing a major issue in marine, brackish, and freshwater systems worldwide. Their proliferation is certainly a problem from both ecological and socioeconomic contexts, as harmful algae can affect human health and activities, the marine ecosystem functioning, and the economy of coastal areas. Once HABs establish, valuable and environmentally friendly control actions are needed to reduce their negative impacts. In this study, the influence exerted by the filter-feeding activity of the two sabellid polychaetes Branchiomma luctuosum (Grube) and Sabella spallanzanii (Gmelin) on a harmful dinoflagellate was investigated. Clearance rates (C) and retention efficiencies were estimated by employing the microalga Amphidinium carterae Hulburt. The Cmax was 1.15 ± 0.204 L h−1 g−1 DW for B. luctuosum and 0.936 ± 0.151 L h−1 g−1 DW for S. spallanzanii. The retention efficiency was 72% for B. luctuosum and 68% for S. spallanzanii. Maximum retention was recorded after 30 min for both species. The obtained results contribute to the knowledge of the two polychaetes’ filtration activity and to characterize the filtration process on harmful microalgae in light of the protection of water resources and human health. Both species, indeed, were extremely efficient in removing A. carterae from seawater, thus suggesting their employment as a new tool in mitigation technologies for the control of harmful algae in marine environments, as well as in the aquaculture facilities where HABs are one of the most critical threats.

2022 ◽  
Anita Yadav ◽  
Neerja Kapoor ◽  
Amin Arif ◽  

Abstract Energy Dispersive X-Ray Microanalysis (EDXMA) has been used as the non-invasive technique on Indian helminthes to explore the role of nematode parasites as bioindicators in the marine ecosystem of Central West coast of India for the first time. The investigation incorporates assertions on the possible benefit of such technology to elucidate bioremediating prospects that could be helpful to establish helminth parasites as a tool representing Bioindicators. The accumulation of Sulphur and Iron were analysed from a raphidascaridoid roundworm, Rostellascaris spinicaudatum (Malhotra and Anas) parasitizing marine catfish, Arius maculatus from the Central west coast of India at Goa. Quantitatively, the cuticle on oral armature comprised as much as ten times more Sulphur than iron content in the roundworm under study. However, only Carbon and Oxygen were detected over caudal papillae, where no metals or other elements were recorded.

Diversity ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 43
Carlo Nike Bianchi ◽  
Annalisa Azzola ◽  
Silvia Cocito ◽  
Carla Morri ◽  
Alice Oprandi ◽  

Biodiversity is a portmanteau word to indicate the variety of life at all levels from genes to ecosystems, but it is often simplistically equated to species richness; the word ecodiversity has thus been coined to address habitat variety. Biodiversity represents the core of the natural capital, and as such needs to be quantified and followed over time. Marine Protected Areas (MPAs) are a major tool for biodiversity conservation at sea. Monitoring of both species and habitat diversity in MPAs is therefore mandatory and must include both inventory and periodic surveillance activities. In the case of inventories, the ideal would be to census all species and all habitats, but while the latter goal can be within reach, the former seems unattainable. Species inventory should be commeasured to investigation effort, while habitat inventory should be based on mapping. Both inventories may profit from suitability spatial modelling. Periodic surveillance actions should privilege conspicuous species and priority habitats. Efficient descriptor taxa and ecological indices are recommended to evaluate environmental status. While it seems obvious that surveillance activities should be carried out with regular recurrence, diachronic inventories and mapping are rarely carried out. Time series are of prime importance to detect marine ecosystem change even in the absence of direct human impacts.

2022 ◽  
Vol 3 ◽  
Geir Ottersen ◽  
Andrew J. Constable ◽  
Anne B. Hollowed ◽  
Kirstin K. Holsman ◽  
Jess Melbourne-Thomas ◽  

The Polar Regions chapter of the Intergovernmental Panel on Climate Change's Special Report on the Ocean and Cryosphere in a Changing Climate (SROCC) provides a comprehensive assessment of climate change impacts on polar marine ecosystems and associated consequences for humans. It also includes identification of confidence for major findings based on agreement across studies and weight of evidence. Sources of uncertainty, from the extent of available datasets, to resolution of projection models, to the complexity and understanding of underlying social-ecological linkages and dynamics, can influence confidence. Here we, marine ecosystem scientists all having experience as lead authors of IPCC reports, examine the evolution of confidence in observed and projected climate-linked changes in polar ecosystems since SROCC. Further synthesis of literature on polar marine ecosystems has been undertaken, especially within IPCC's Sixth Assessment Report (AR6) Working Group II; for the Southern Ocean also the Marine Ecosystem Assessment for the Southern Ocean (MEASO). These publications incorporate new scientific findings that address some of the knowledge gaps identified in SROCC. While knowledge gaps have been narrowed, we still find that polar region assessments reflect pronounced geographical skewness in knowledge regarding the responses of marine life to changing climate and associated literature. There is also an imbalance in scientific focus; especially research in Antarctica is dominated by physical oceanography and cryosphere science with highly fragmented approaches and only short-term funding to ecology. There are clear indications that the scientific community has made substantial progress in its ability to project ecosystem responses to future climate change through the development of coupled biophysical models of the region facilitated by increased computer power allowing for improved resolution in space and time. Lastly, we point forward—providing recommendations for future advances for IPCC assessments.

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 108
Wang Liu ◽  
Xiaowei Zheng ◽  
Xin Dai ◽  
Zhenfeng Zhang ◽  
Wenyan Zhang ◽  

Viruses are far more abundant than cellular microorganisms in the marine ecosystem. However, very few viruses have so far been isolated from marine sediments, especially hydrothermal vent sediments, hindering the understanding of the biology and ecological functions of these tiny organisms. Here, we report the isolation and characterization of a temperate bacteriophage, named PVJ1, which infects Psychrobacillus from a hydrothermal vent field in Okinawa Trough. PVJ1 belongs to the Myoviridae family of the order Caudovirales. The tailed phage possesses a 53,187 bp linear dsDNA genome, with 84 ORFs encoding structural proteins, genome replication, host lysis, etc. in a modular pattern. The phage genome is integrated into the host chromosome near the 3′-end of deoD, a gene encoding purine nucleoside phosphorylase (PNP). The phage integration does not appear to disrupt the function of PNP. The phage DNA is packaged by the headful mechanism. Release of PVJ1 from the host cell was drastically enhanced by treatment with mitomycin C. Phages encoding an MCP sharing significant similarity (≥70% identical amino acids) with that of PVJ1 are widespread in diverse environments, including marine and freshwater sediments, soils, artificial ecosystems, and animal intestines, and primarily infect Firmicutes. These results are valuable to the understanding of the lifestyle and host interactions of bacterial viruses at the bottom of the ocean.

2022 ◽  
Markus Pfeil ◽  
Thomas Slawig

Abstract. The reduction of the computational effort is desirable for the simulation of marine ecosystem models. Using a marine ecosystem model, the assessment and the validation of annual periodic solutions (i.e., steady annual cycles) against observational data are crucial to identify biogeochemical processes, which, for example, influence the global carbon cycle. For marine ecosystem models, the transport matrix method (TMM) already lowers the runtime of the simulation significantly and enables the application of larger time steps straightforwardly. However, the selection of an appropriate time step is a challenging compromise between accuracy and shortening the runtime. Using an automatic time step adjustment during the computation of a steady annual cycle with the TMM, we present in this paper different algorithms applying either an adaptive step size control or decreasing time steps in order to use the time step always as large as possible without any manual selection. For these methods and a variety of marine ecosystem models of different complexity, the accuracy of the computed steady annual cycle achieved the same accuracy as solutions obtained with a fixed time step. Depending on the complexity of the marine ecosystem model, the application of the methods shortened the runtime significantly. Due to the certain overhead of the adaptive method, the computational effort may be higher in special cases using the adaptive step size control. The presented methods represent computational efficient methods for the simulation of marine ecosystem models using the TMM but without any manual selection of the time step.

Svenja Koepper ◽  
Sri Nuryati ◽  
Harry W. Palm ◽  
Christian Wild ◽  
Irfan Yulianto ◽  

Abstract Despite being an important component of the marine ecosystem and posing health risks to human seafood consumers, fish parasites in Indonesia have yet to be adequately described. Here, we analyzed the diet and metazoan parasite fauna of seven commercial fish species (Alectis indica, Carangoides chrysophrys, Johnius borneensis, Mene maculata, Trichiurus lepturus, Upeneus asymmetricus, U. moluccensis) landed in Java, Indonesia. We isolated 11 endoparasite species, established 22 new host and 14 new locality records, and extended parasitological records of A. indica by 24%, C. chrysophrys by 25%, J. borneensis by 40%, M. maculata by 44%, U. asymmetricus by 100%, and U. moluccensis by 17%. We genetically identified the trematode Stephanostomum cf. uku (of Bray et al. 2005) from Alecta indica for the first time in Indonesia and provided the sequence of its 28S marker. Stomach content analysis revealed seven different prey items, and the examined fish species were grouped into four feeding categories, which differed significantly in their respective endoparasite fauna. All but two examined fish species hosted potentially zoonotic nematodes, which reveal a risk for parasite-borne diseases in Indonesian food fishes and call for more consequent monitoring with regard to seafood safety in this region. With this study, we were able to establish an association between the feeding ecology and the endoparasite fauna of marine fishes which will help to better understand the transmission pathways of (potentially zoonotic) parasites in food fishes in tropical waters.

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