Trophic Index Research Articles

Cardiometabolic effects of oxytocin in modeling the diabetic phenotype of chronic heart failure

Background. The combination of heart failure (HF) and type 2 diabetes mellitus (DM2T) is considered one of the most common and unfavorable duets. A promising area of modern research is the development of translational models of the diabetic phenotype of HF and new methods of its treatment. The aim. To study the effect of oxytocin (Oх) on structural and functional changes of the myocardium in modeling the diabetic phenotype of HF. Materials and methods. The study was performed on sexually mature rats of both sexes of the Wistar line (n = 36): 12 animals are intact; 24 — the main group with the diabetic phenotype HF, modeled according to the new method of Starchenko AD, et al. (2024). From the 28th to the 42nd day of the experiment, oxytocin was administered daily to 12 animals of the main group at a dose of 0.5 U/kg of body weight intramuscularly, glucose levels, NTproBNP in blood serum, left ventricular ejection fraction (LV) were assessed according to echocardiography. The material (heart, LV myocardium) was taken on the 42nd day after the animals were removed from the experiment, followed by histological examination (microscopy, morphometry). Results. It was found that the administration of Ox led to a decrease in the level of glycemia and NTproBNP in animals of both sexes with the diabetic phenotype of HF. A more significant effect of Ox on the structural reorganization of the LV myocardium in the group of females with DM2T and HF was determined: a decrease in the volume density (VD) of the stroma, an increase in VD capillaries and trophic index. Conclusion. Hypoglycemic and cardioprotective effects of Ox (improvement of trophic and inhibition of myocardial fibrosis) in diabetic phenotype of experimental HF have been demonstrated.

Environmental Assessment Using Phytoplankton Diversity, Nutrients, Chlorophyll-a, and Trophic Status Along Southern Coast of Jeddah, Red Sea

The objective of this study is to better identify the state of eutrophication of coastal waters along the southern coast of the city of Jeddah in the Red Sea. Thirty-six samples from surface seawater were collected during the spring and autumn of 2021. Water temperature, pH, salinity, dissolved oxygen (DO), nutrients, and chlorophyll-a (Chl-a) content were examined as a guide of water quality indicators. The present data revealed low levels of Chl-a content (in the range of 0.11–0.24 µg L−1). The average concentrations of DIN (dissolved inorganic nitrogen) forms follow the order NO3-N > NH4-N ~ NO2-N (representing about 11.4–29.4% of the total nitrogen). To investigate the trophic status and water quality, numerical indicators were applied to the results of the analysis of chemical variables (NH4-N, NO3-N, and PO4-P) and the biological analysis (Chl-a) in the aqueous environment within the study area. These indicators are simplified based on the specialist, the non-specialist, the decision-maker, and the one responsible for managing the coastal areas. We also obtain through this method a single numerical value that expresses the state of the coastal waters. According to the analysis of phosphorus and nitrogen data and a trophic index (TRIX), the study area’s trophic status was determined as oligotrophic, due to low nutrient concentrations in the seawater. The current study identified a total of 58 species of phytoplankton comprised four classes in the investigated areas; Bacillariophyceae was the dominant algal class (Diatoms 30 species), followed by Chlorophyceae (9 species), Dinophyceae (11 species), and Cyanophyceae (8 species). Seasonally, spring recorded the highest value of total phytoplankton, recording a value of 251 × 103 cells/L with a percentage of 61%, while autumn recorded the lowest value of 186 × 103 cells/L with a percentage of 39%. Phytoplankton classes can be arranged in order of prevalence as follows: Bacillariophyceae >> Dinophyceae > Chlorophyceae > Cyanophyceae.

Geospatial Assessment of Trophic Status From a Dam Under Significant Agricultural Drainage at the Mid-Anatolia, Türkiye

The population of Anatolia is continuously growing and developing and it is under the deep influence of global warming. It is increasingly evident that more fresh water will be needed for drinking, irrigation and domestic use. This study aims to assess the water quality and trophic status of a dam (Bayramhacılı dam lake) under excessive agricultural irrigation threat using spatial and multivariate statistical analysis. In the study, the periodic changes in the eutrophic state of the dam lake were determined using global index categories, Carlson Trophic Status Index (CTSI = 66.7), Burns Trophic Level Index (BTLI = 6.4), and Shu Trophic State Index (STSI = 65.6). The two periodical averages of total phosphorus (TP), total nitrogen (TN), biological oxygen demand (BOD), (chemical oxygen demand (COD) and chlorophyll a (Chl_a) concentrations, which serve as an indicator of anthropogenic nutrient input, were determined to be 0.23, 31.28, 1.83, 8.99 and 48.1 µg/L, respectively. Trophic index distribution maps demonstrate that the dam’s surface water displays considerable alterations, particularly during the dry season. This evidence supports the implementation of a local management model that addresses the issue of eutrophication. It is therefore imperative that on-site measures are taken without delay.

Assessing Temperature Change Impact in the Wake of Ongoing Land Use Change: A Case Study at Lake Dianshan

Climate change exerts both direct and indirect influences on the eutrophication of surface water ecosystems in various ways. This study aimed to evaluate the impact of temperature fluctuations on trophic levels through various interdisciplinary coupling analysis methods after land use change, which including water and sediment sample analysis, hydraulic model, remote sensing, and historic data analysis. For the historical analysis, six satellite images of Lake Dianshan were examined to assess algal bloom occurrences and the coverage of Eichhornia crassipes from 2013 to 2023. The correlation between trophic indicators and temperature was analyzed using statistical methods. For the monthly analysis, a total of 27 sediment samples and 54 water samples collected from Lake Dianshan were assessed to determine how seasonal temperature variations influence eutrophication status. The trophic indicators have higher concentration at inlet sampling sites compared to outlet sites, which validated the potential external pollution source. The trophic level of Lake Dianshan is influenced not only by climate change but also significantly by urban human activities. The management of eutrophication has substantially improved the water quality of Lake Dianshan over the past few decades. Furthermore, increasing temperatures demonstrate a positive correlation with the proliferation of cyanobacteria, particularly in urban areas.

Assessment of the ecological status of Cala Iris Bay (Northern Morocco): First characterization and classification according to a multiparametric approach

This study reflects the characteristic features of the coastal regions in Cala Iris Bay and the impacts of human activities through a multiparametric approach. The eutrophication status of coastal zones was assessed using various tools, including the trophic index (TRIX), eutrophication index (EI), and the Redfield ratio. The TRIX index ranged from 3.53 to 5.49, indicating oligotrophic to eutrophic conditions. EI values ranged from 0.22 to 1.4, indicating good to poor seawater quality. The Redfield ratio consistently showed N/P values below 16, indicating nitrogen limitation. Variation in microbial indicators (fecal coliforms, fecal streptococci, and Escherichia coli) revealed higher values in autumn and winter and lower values in summer, with distribution governed by water temperature, salinity, and ammonium. These results provide a scientific basis for developing better management strategies to ensure sustainable aquaculture development in Cala Iris Bay and along the Moroccan Mediterranean coast.

SNIPEFISH (MACRORAMPHOSUS SPP.) ABUNDANCE AND TROPHIC DYNAMICS IN RESPONSE TO UPWELLING REGIME IN THE ATLANTIC REGION FROM CAPE BLANC TO CAPE BOUJDOR (20°50 N TO 26°00 N)

Purpose: The objective of this study is to to deepen the understanding of the trophic behavior of the snipefish through an analysis of its diet in relation to the pelagic ecosystem's parameters. Theoretical Framework: Two sympatric species of snipefish have shown significant population increases on the continental shelf of the northern sub-region of the Canary Current upwelling system during intermittent periods in the 1970s, 1990s, and again over the past five years. Method: Between 2018 and 2021, we collected samples to analyze the stomach contents of snipefish and measure zooplankton size. Trophic indices were calculated to characterize the feeding habits of the species. To examine potential affinities between hydrological and biological parameters in snipefish distribution areas, we applied Principal Component Analysis (PCA), a statistical method that clarifies relationships between these two data matrices. Results and Discussion: The results obtained reveal a significant correlation between the range of engulfed prey through the snout of the snipefish and the size of zooplankton available and accessible on the continental shelf. The trophic strategy of the snipefish seems attesting to a case of a species responding to a marine ecosystem subject to hydrological disturbances generated by the level of the upwelling’s intensity. Research Implications: this research will contribute to the current understanding regarding the resurgence of snipefish in the northern sub-region of the Canary Current upwelling ecosystem. Originality/Value: This study contributes to understanding the snipefish's trophic strategy and its responses within a marine ecosystem affected by hydrological disturbances caused by the intensity of upwelling.

The condition status index for doline lakes in urban areas

Karst represents approximately 15% of the planet’s surface, hundreds of millions of people live on and rely on these aquifers for water supply and agricultural irrigation. In karstic landscapes, groundwater is exposed in sinkholes, inundated caves, and artesian wells, which are two-way communication spots. When the phreatic level is exposed, the groundwater can change substantially as a result of anthropogenic impacts, modifying the water quality and the environmental integrity by incoming excess nutrients, contaminants, pathogens, and other hazardous substances such as metals and microplastics. In this paper, we develop and test a multimetric index to evaluate the condition status of dolines located within urban areas, including seven indicators: trophic index, fecal bacteria, fecal viruses, microplastics, heavy metals, zooplankton biodiversity, and fish biodiversity. Lastly, we made a proof of concept for the index in the dolines on the island of Cozumel (Mexico), resulting in evaluations from fair to good. The index is powerful due to its sensitivity to pathogens and exotic invasive species. This additive weighted index allows to assess the condition status of dolines in urban areas anywhere in the world; if required, modifications are possible.

Spatial and Temporal Dynamics of Marine Trophic Status Using the Trophic Index in Bone Bay, Indonesia

Spatial and Temporal Dynamics of Marine Trophic Status Using the Trophic Index in Bone Bay, Indonesia

Ecological index analysis in the coastal and estuarine waters of the tropical Amazon Region

The Brazilian Amazon Coastal Zone holds the largest estuarine area in the world, located in the Amazon Continental Shelf (ACS). Additionally, it encompasses numerous estuaries and channels, such as Furo do Muriá (FM) and Furo da Laura (FL), which make up the local landscape and favor the primary productivity of water. The objective of this study was using the trophic index (TRIX) and O'Boyle index to determine the trophic state in the ACS area, FL, and FM, compare the results, and relate them to seasonality and river discharge in the sites. In the three estuaries, the applied methodology was the same: temperature, salinity, pH, dissolved oxygen, and saturation rate of dissolved oxygen data were obtained in situ, and the samples were filtered for the analysis of nitrite, nitrate, ammonia, phosphate, and chlorophyll a. The highest TRIX values were found in FL (3.89–3.12) and ACS (4.43–4.44), while for the O'Boyle index, the highest values were found in FL (16.73–100) and FM (43.3–100). Comparing the indices, it was observed that their classification was similar only in the ACS during the period of maximum discharge of the Amazon River (eutrophic), varying slightly in the minimum discharge period (potentially eutrophic for O'Boyle and eutrophicated for TRIX). This difference can be explained by the additional variables considered by the TRIX, such as nutrients and chlorophyll a. The scenario was completely different for FM and FL, where the TRIX showed greater variation owing to the presence of dissolved inorganic nutrients. Both indices can be used to simply and directly reflect the eutrophication conditions of estuarine areas: the joint and multiparametric approach of the indices provides complementary information regarding the dynamics of studied environments through their trophic status.

Multiannual oceanographic studies in the coastal area of Karadag Nature Reserve and Koktebel Bay (northern Black Sea) in 2004–2021

The study presents the results of the first multiannual oceanographic monitoring in the coastal area of Karadag Nature Reserve and adjacent water areas in May and September in the period from 2004 to 2021. Significant and unprecedentedly high increasing trends were detected for salinity in May. Increasing trends in nitrate concentration in Koktebel Bay were noted both for May and for September. The five-day biochemical oxygen demand (BOD5), ammonium and phosphate concentrations demonstrated mostly negative trends for the measurements in May and positive trends in September. Significant decreasing trends in phytoplankton biomass were noted in September, which fit in the range of the larger-scale phytoplankton trends reported in the literature. The position of the extrema of nutrients in the long-term-average and trend slope maps was confined to the areas of increased hydrodynamic and anthropogenic activity. Multivariate analysis showed significant negative correlations of the quantitative phytoplankton characteristics with salinity, which were explained by the effect of the freshened and nutrient-enriched Azov plume. The absence of significant correlations with nutrients was attributed to the non-conservative and stochastic character of the nutrient inflow on the yearly scale and time lag between the nutrient supply and the phytoplankton growth. The large percentage of occurrences of low BOD5 values at any station indicates the unpolluted status of the area under research, which is confirmed by the low trophic index values and appearance of probability distributions of the nutrient concentrations.

Assessment of the trophic status and water quality in an urbanised tropical estuary, Brazil.

ABSTRACT The Anil River estuary (ARE), which is crucial for São Luís Island's socioeconomic well-being, faces substantial human pressure due to its urban location, hastening the eutrophication process. This study, which was conducted from 2022 to 2023, aimed to assess trophic levels across the ARE. Using a multiparametric probe, we analysed the pH, temperature, dissolved oxygen, oxygen saturation, salinity, and total dissolved solids quarterly during the rainy and dry seasons at six sampling points. The nutrient analysis included nitrite, nitrate, ammonium ions, phosphate, total nitrogen (TN), and total phosphorus (TP). Trophic index (TRIX) values categorised the ARE as eutrophic (sector 1) or hypereutrophic (sector 2). The dry season exhibited relatively high trophic levels, indicating that the ARE was hypereutrophic. Sector 2, influenced by concentrated nutrients and chlorophyll-a, exhibited increased trophic status from domestic and industrial effluent discharge. Rainy season data at the downstream from the point 3 recorded the maximum DIN:DIP ratio, indicating phosphorus limitation. Monitoring estuarine trophic states is vital for kerbing eutrophication and preserving local biodiversity in the anil river estuary.

Estimation of hydrochemical profile and trophic status of a coastal Ramsar site in south west coast of India

Coastal lakes are confronting a spectrum of threats arising from both natural processes and human activities. This study presents an investigation into the nutrient and trophic status of the Ramsar-designated (Ramsar site No. 1204) Ashtamudi Lake (ASL; area= 56 km2), situated along the southwest coast of India. To establish a comprehensive hydrochemical profile, 50 representative water samples comprising lake, surface and bottom layers were systematically collected from 25 distinct sites during the non-monsoon and monsoon seasons of 2017. Physcio-chemical characteristics were evaluated using standard protocols and procedures. The salinity observations consistently position the majority of the lake's area within the 'polyhaline' condition (18–30 PSU) throughout the year. The evaluation of nutrient ratios (DIN/DIP, DSi/DIN, and DSi/DIP) during the respective seasons highlights a prevalent phosphorus (P) and silicon (Si) limited scenario during non-monsoon period. This condition is marked by elevated dissolved inorganic nitrogen (DIN) concentrations juxtaposed with lower levels of dissolved inorganic phosphorus (DIP) and dissolved silicon (DSi). The computed Trophic Index (TRIX) unequivocally denotes a 'hypertrophic' state within the lake during the non-monsoon season. This characterization is upheld by TRIX values of 7.73±0.61 and 8.06±0.62 for surface and bottom water during non-monsoon. Further insight into the TRIX findings is derived from the supplementary Efficiency Coefficient (EF) index, which accentuates ASL's limited nutrient assimilation in conjunction with a substantial input of DIN. Overall, the sustained condition of occurrence of low dissolved oxygen and elevated DIN/DIP ratios exacerbates the hypertrophic state. This complex interplay heightens ecological strain, thereby imperiling aquatic organisms, particularly valuable fishery resources. Unfortunately, this situation invariably curtails the essential ecosystem services furnished by ASL. Therefore, the adoption of strategic interventions aimed at ameliorating nutrient influx and restoring a balanced trophic equilibrium stands imperative to mitigate ecological degradation and uphold the lake's pivotal contributions to its surrounding environment.

Otolith microchemistry identifies shallow, intertidal-dominated estuaries as important nurseries for sand flounder in New Zealand

Estuaries provide critical habitat, food, and refuge for juvenile fish. Elemental concentrations in otoliths can retrospectively identify estuarine nursery habitats that contribute disproportionately to adult populations, providing valuable information for fisheries and coastal ecosystems. The present study aimed to (1) compare elemental signatures of juvenile (age 0+) sand flounder Rhombosolea plebeia otoliths collected from 9 estuaries in east Otago, New Zealand, and (2) assess the application of otolith microchemistry for identifying the nursery habitats contributing to adult (age 1+) sand flounder from the coastal shelf population. Otoliths from juvenile flounder were collected in November 2020, and adults of the same cohort were collected in the winter/spring of 2022. Laser ablation inductively coupled plasma mass spectrometry quantified 12 element concentrations within the post-settlement region of juvenile and adult otoliths using depth-profiling and ablation transects, respectively. Significant differences in post-settlement elemental concentrations were detected among estuaries. Juvenile and adult sand flounder were classified to their nursery origin using canonical analysis of principal coordinates. Grouping estuaries by the New Zealand Estuary Trophic Index classification scheme improved the overall juvenile classification accuracy from 56.7% (51/90) to 82.2% (74/90). Adult sand flounder (n = 78) were classified to have originated from shallow intertidal dominated estuaries (62%), followed by Otago Harbour (32%) and shallow, short residence time river and tidal river with adjoining lagoon estuaries (6%). The results highlight how otolith microchemistry can provide information on the use of critical estuarine nursery habitats for a commercially important species.

Physio-metabolic alterations in Labeo rohita (Hamilton, 1822) and native predator Chitala chitala (Hamilton, 1822) in presence of an invasive species Piractus brachypomus (G. Cuvier, 1818).

A 60days study was conducted to evaluate the physiological response of indigenous species Labeo rohita (LR) and indigenous predator Chitala chitala (CC) in presence of an invasive species Piaractus brachypomus (PB). Two treatment groups as LR + PB (T1) and LR + PB + CC (T2) with individual control groups as T0LR, T0PB and T0CC were designed in triplicates. Fingerlings of LR, PB and CC were randomly distributed into 15 circular tanks with a stocking ratio of 1:1 and 1:1:0.3 in T1 and T2 group, respectively and 10 nos. each of LR, PB and CC in respective control groups. At first 15min of the experiment, cortisol level was found significantly (P < 0.05) higher in all three experimental fishes in T1 and T2 groups. With the experimental duration, the level of stress hormone (cortisol), oxidative stress enzymes (superoxide dismutase, catalase, and glutathione peroxidase), tissue metabolic enzymes (lactate dehydrogenase and malate dehydrogenase), serum metabolic enzymes (transaminase enzymes) and blood glucose level were significantly (P < 0.05) increased in T1 and T2 groups for LR and CC whereas, no variation (P > 0.05) were observed for PB in both T1 and T2 groups. The total antioxidant capacity (TAC), liver glycogen, total protein, albumin and globulin were found to be significantly (P < 0.05) decreased in LR in the presence of PB and CC. The present study provides a preliminary insight into the biological interaction between native and invasive species and their physiological responses in the presence of native predator with higher trophic index. Thus, the results of the study suggest the superior traits of invasive P. brachypomus try to dominate the other two native species by negatively influencing the native fauna even with a higher trophic index (C. chitala).

Classification, density, and spatial distribution of polychaete reefs in the Coorong, South Australia

The cosmopolitan species Ficopomatus enigmaticus is one of the most prominent providers of polychaete reefs in shallow and brackish waters. The effects of polychaete reefs on the environment can be positive or negative subject to their structural complexity and vary with local environmental conditions and over time. The Coorong is a large temperate estuarine and lagoonal system with extensive polychaete reefs built by F. enigmaticus. The aims of this study were to (1) classify polychaete reefs based on size and morphology, (2) quantify reef density, (3) assess their spatial distribution and (4) assess the correlation between reefs (e.g., density, size) with the environmental gradient. Structural morphologies of F. enigmaticus were classified as either halo, circular, irregular, platform or fringing reef types. The largest densities of polychaete reefs were recorded in the vicinity of the mouth of the estuary with 224 reefs per ha compared to the lagoon (62 reefs per ha). The most common reef morphology was circular and largest sizes in the lagoon were positively correlated with salinity, chlorophyll a, TRIX (trophic index) and bicarbonate. The largest reef diameter recorded was 11.3 m, exceeding previously known F. enigmaticus circular reef formations globally. The growth of large circular reefs may have benefitted from low flows and eutrophic conditions in the Coorong during the last two decades. This study serves as an important baseline for future assessments of reef change in a Ramsar listed wetland. Furthermore, this study highlights reef characteristics of F. enigmaticus across an environmental gradient, which can be informative for the management of flow and eutrophication in estuaries and coastal lagoons.

Stable isotope and fatty acid variation of a planktivorous fish among and within large lakes.

Aquatic food webs are spatially complex, potentially contributing to intraspecific variability in production pathway reliance of intermediate trophic level consumers. Variation in trophic reliance may be described by well-established trophic indicators, like stable isotope ratios (δ13C, δ15N), along with emerging trophic indicators, such as fatty acid composition. We evaluated stable isotope ratios and fatty acid profiles of European smelt (Osmerus eperlanus) among and within distinct regions of three large Swedish lakes (Hjälmaren, Mälaren, Vättern) which differed in trophic status. We expected that smelts in more oligotrophic lakes and regions would be characterized by distinct stable isotope signatures and fatty acid profiles, with particularly high polyunsaturated fatty acid (PUFA) relative levels. However, we acknowledge that frequent movement of smelts among regions may serve to spatially integrate their diet and lead to limited within-lake variation in stable isotope ratios and fatty acid composition. As expected, in comparison with more productive lakes (i.e., Hjälmaren and Mälaren), smelts from ultra-oligotrophic Vättern were characterized by low δ15N, high δ13C and high percent of a dominant PUFA, docosahexaenoic acid (DHA). Smelts from different regions of the morphometrically complex Mälaren displayed differential stable isotope ratios and fatty acid relative concentrations, which were consistent with within-lake differences in productivity and water residence times, suggesting that smelts in this lake forage locally within distinct regions. Finally, at the individual smelt level there were particularly strong and consistent associations between a well-established trophic indicator (δ13C) and percent DHA, suggesting that the relative concentration of this fatty acid may be a useful additional trophic indicator for smelt.

Seasonal and Interannual Variability of the Trophic State in the Marano and Grado Lagoon (Adriatic Sea, Italy) during the 2011–2021 Period

The Marano and Grado Lagoon (Adriatic Sea, Italy) is an important transitional environment that furnishes numerous ecosystem services and is under protection as Site of Community Importance. It suffers from an excess of nutrients, especially nitrate (NO3−), and has been designated as a nitrate vulnerable zone. In this work, sixteen water bodies were seasonally monitored for physicochemical parameters and nutrients, to elucidate the trophic state of the lagoon and to check the occurrence of significant temporal trends in a time series from 2011 to 2021. Steep gradients of spatial and seasonal distribution were observed for all parameters with elevated concentration of N-NO3− (up to 360 µM) in the western sector. The whole lagoon was in phosphorous limitation (P-PO43− mean ± s.d. = 0.15 ± 0.22 µM) with a mean Redfield ratio of 1130. The concentration of nutrients was significantly correlated with the degree of both freshwater inputs and precipitation. The calculation of trophic indices shows that the lagoon is in an oligotrophic to hypertrophic condition (i.e., TRIX 1.9–6.8). The analysis of the temporal series showed that despite some significant trends, the time span considered is too short to detect significant changes in the trophic state of this dynamic environment.

Feeding Habits and Prey Composition of Six Mesopelagic Fish Species from an Isolated Central Mediterranean Basin

Mesopelagic fishes hold an important position in marine food webs, serving as a link between lower trophic levels and top predators and transferring energy from their deep mesopelagic habitat to shallower oceanic layers. Despite their ecological importance, research on mesopelagic fishes’ diet and feeding habits in the Mediterranean Sea is far from thorough. The present work attempts to assess the preying patterns and diet composition of four myctophid (Benthosema glaciale, Ceratoscopelus maderensis, Myctophum punctatum, Notoscopelus elongatus) and two sternoptychid (Argyropelecus hemigymnus, Maurolicus muelleri) species from the Corinthian Gulf (Ionian Sea, Greece), sampled during pelagic trawl surveys in 2018 and 2019. Stomach vacuity was high for myctophids caught during daytime, a pattern which sternoptychids did not follow. Estimated trophic indices revealed high dietary diversity (Shannon’s H’ index) for most investigated species, but a narrow trophic niche breadth (Levins’ normalized Bn index). Copepods and various marine crustaceans were dominant in all diets, classifying them under the zooplanktivorous trophic guild, while A. hemigymnus exhibited high concentrations of particulate organic matter in their stomachs and N. elongatus exhibited consumption of fish. Diet overlap was significant among most studied mesopelagic species, as indicated by Shoener’s S index and confirmed by both the multidimensional scaling ordination and a hierarchical cluster analysis. Information on mesopelagic fishes’ diet composition in this poorly studied part of the Mediterranean is useful in further assessing and parameterizing marine food webs and midwater trophic interactions, as well as in quantifying the ensued energy transfer to top predators of commercial interest or conservation concerns.

Afganistan alg türleri kontrol listesi

This first comprehensive checklist of algae from freshwater and soil in Afghanistan is a significant milestone in understanding the country's biodiversity. It is the result of a collaborative effort by researchers from various institutions. It comprises 398 species belonging to 132 genera and five phyla of algae, with samples collected from 19 regions of Afghanistan. The Nitzschia and Navicula genera have the most significant number of species. The checklist also highlights the sensitivity and threatened status of certain species, such as Achnanthidium gracillimum (F. Meister) Lange-Bertalot, Brachysira serians (Brébisson) Round &amp; D.G. Mann, Diploneis ovalis (Hilse) Cleve, Eunotia praerupta Ehrenberg, Eucocconeis flexella (Kützing) F. Meister. The currently accepted name of species, biological condition gradient of species, the status of species in the Red List of Germany, and trophic weight of some diatom species according to two diatom trophic indices were defined in the checklist. This study is a new start for this field of study and intends to provide the groundwork for further research, which will aid in the work of others interested in this topic.

Combined effects of river hydromorphological disturbances on macroinvertebrate communities: Multispatial scales analysis of central European rivers

Hydro-morphological threats impact the natural physical characteristics of river ecosystems, such as flow regimes, sediment transport, and channel morphology. These negative effects can occur at multiple scales, ranging from local microhabitats to geographic regions. Understanding these interactions can be useful for an integrated conservation approach and is needed for effective freshwater management. The aim of the study was to elucidate the combined effects of hydro-morphological threats on macroinvertebrates at three spatial scales: macroscale, including whole catchments, mesoscale (hydro-morphological changes in individual river sections) and the microscale, describing the microhabitat conditions of European rivers. The diversity and trophic structure of 1120 local macroinvertebrate communities in 28 catchments of various hydro-morphological disturbance levels, ranging from 0 to 2400 m asl, were analyzed. The response of macroinvertebrates to the main disturbance gradient differed between mountain and lowland communities. Random forest analysis indicated that the most important predictor of the ecological, diversity, and trophic indices was described by flow rate reduction. Generalized additive mixed models showed that decreased flow combined with river incision explained most of the variation in macroinvertebrate indices. Our results emphasize that based on multi-spatial scale analysis, hydro-morphological threats are very important factors in invertebrates biodiversity loss. Thus, to implement effective river management, we should pay more attention to the combined effects of geomorphological threats.