PeerJ:Biosphere Interactionshttps://peerj.com/articles/index.atom?journal=peerj&subject=1403Biosphere Interactions articles published in PeerJRaised water temperature enhances benthopelagic links via intensified bioturbation and benthos-mediated nutrient cyclinghttps://peerj.com/articles/170472024-02-282024-02-28Eilish M. FarrellAndreas NeumannJan BeermannAlexa Wrede
Sediment reworking by benthic infauna, namely bioturbation, is of pivotal importance in expansive soft-sediment environments such as the Wadden Sea. Bioturbating fauna facilitate ecosystem functions such as bentho-pelagic coupling and sediment nutrient remineralization capacities. Yet, these benthic fauna are expected to be profoundly affected by current observed rising sea temperatures. In order to predict future changes in ecosystem functioning in soft-sediment environments like the Wadden Sea, knowledge on the underlying processes such as sediment reworking, is crucial. Here, we tested how temperature affects bioturbation and its associated ecosystem processes, such as benthic nutrient fluxes and sediment oxygen consumption, using luminophore tracers and sediment incubation cores. We used a controlled mesocosm experiment set-up with key Wadden Sea benthos species: the burrowing polychaetes Arenicola marina and Hediste diversicolor, the bivalve Cerastoderma edule, and the tube-building polychaete Lanice conchilega. The highest bioturbation rates were observed from A. marina, reaching up to 375 cm2yr−1; followed by H. diversicolor, with 124 cm2yr−1 being the peak bioturbation rate for the ragworm. Additionally, the sediment reworking activity of A. marina facilitated nearly double the amount of silicate efflux compared to any other species. Arenicola marina and H. diversicolor accordingly facilitated stronger nutrient effluxes under a warmer temperature than L. conchilega and C. edule. The oxygen uptake of A. marina and H. diversicolor within the sediment incubation cores was correspondingly enhanced with a higher temperature. Thus, increases in sea temperatures may initially be beneficial to ecosystem functioning in the Wadden Sea as faunal bioturbation is definitely expedited, leading to a tighter coupling between the sediment and overlying water column. The enhanced bioturbation activity, oxygen consumption, and facilitated nutrient effluxes from these invertebrates themselves, will aid in the ongoing high levels of primary productivity and organic matter production.
Sediment reworking by benthic infauna, namely bioturbation, is of pivotal importance in expansive soft-sediment environments such as the Wadden Sea. Bioturbating fauna facilitate ecosystem functions such as bentho-pelagic coupling and sediment nutrient remineralization capacities. Yet, these benthic fauna are expected to be profoundly affected by current observed rising sea temperatures. In order to predict future changes in ecosystem functioning in soft-sediment environments like the Wadden Sea, knowledge on the underlying processes such as sediment reworking, is crucial. Here, we tested how temperature affects bioturbation and its associated ecosystem processes, such as benthic nutrient fluxes and sediment oxygen consumption, using luminophore tracers and sediment incubation cores. We used a controlled mesocosm experiment set-up with key Wadden Sea benthos species: the burrowing polychaetes Arenicola marina and Hediste diversicolor, the bivalve Cerastoderma edule, and the tube-building polychaete Lanice conchilega. The highest bioturbation rates were observed from A. marina, reaching up to 375 cm2yr−1; followed by H. diversicolor, with 124 cm2yr−1 being the peak bioturbation rate for the ragworm. Additionally, the sediment reworking activity of A. marina facilitated nearly double the amount of silicate efflux compared to any other species. Arenicola marina and H. diversicolor accordingly facilitated stronger nutrient effluxes under a warmer temperature than L. conchilega and C. edule. The oxygen uptake of A. marina and H. diversicolor within the sediment incubation cores was correspondingly enhanced with a higher temperature. Thus, increases in sea temperatures may initially be beneficial to ecosystem functioning in the Wadden Sea as faunal bioturbation is definitely expedited, leading to a tighter coupling between the sediment and overlying water column. The enhanced bioturbation activity, oxygen consumption, and facilitated nutrient effluxes from these invertebrates themselves, will aid in the ongoing high levels of primary productivity and organic matter production.A multi-sensor array for detecting and analyzing nocturnal avian migrationhttps://peerj.com/articles/156222023-08-302023-08-30Alva I. StrandEli S. BridgeJeffrey F. KellyPhillip M. StepanianDavid J. BodineJames R. Soto
Avian migration has fascinated humans for centuries. Insights into the lives of migrant birds are often elusive; however, recent, standalone technological innovations have revolutionized our understanding of this complex biological phenomenon. A future challenge for following these highly mobile animals is the necessity of bringing multiple technologies together to capture a more complete understanding of their movements. Here, we designed a proof-of-concept multi-sensor array consisting of two weather surveillance radars (WSRs), one local and one regional, an autonomous moon-watching sensor capable of detecting birds flying in front of the moon, and an autonomous recording unit (ARU) capable of recording avian nocturnal flight calls. We deployed this array at a field site in central Oklahoma on select nights in March, April, and May of 2021 and integrated data from this array with wind data corresponding to this site to examine the influence of wind on the movements of spring migrants aloft across these spring nights. We found that regional avian migration intensity is statistically significantly negatively correlated with wind velocity, in line with previous research. Furthermore, we found evidence suggesting that when faced with strong, southerly winds, migrants take advantage of these conditions by adjusting their flight direction by drifting. Importantly, we found that most of the migration intensities detected by the sensors were intercorrelated, except when this correlation could not be ascertained because we lacked the sample size to do so. This study demonstrates the potential for multi-sensor arrays to reveal the detailed ways in which avian migrants move in response to changing atmospheric conditions while in flight.
Avian migration has fascinated humans for centuries. Insights into the lives of migrant birds are often elusive; however, recent, standalone technological innovations have revolutionized our understanding of this complex biological phenomenon. A future challenge for following these highly mobile animals is the necessity of bringing multiple technologies together to capture a more complete understanding of their movements. Here, we designed a proof-of-concept multi-sensor array consisting of two weather surveillance radars (WSRs), one local and one regional, an autonomous moon-watching sensor capable of detecting birds flying in front of the moon, and an autonomous recording unit (ARU) capable of recording avian nocturnal flight calls. We deployed this array at a field site in central Oklahoma on select nights in March, April, and May of 2021 and integrated data from this array with wind data corresponding to this site to examine the influence of wind on the movements of spring migrants aloft across these spring nights. We found that regional avian migration intensity is statistically significantly negatively correlated with wind velocity, in line with previous research. Furthermore, we found evidence suggesting that when faced with strong, southerly winds, migrants take advantage of these conditions by adjusting their flight direction by drifting. Importantly, we found that most of the migration intensities detected by the sensors were intercorrelated, except when this correlation could not be ascertained because we lacked the sample size to do so. This study demonstrates the potential for multi-sensor arrays to reveal the detailed ways in which avian migrants move in response to changing atmospheric conditions while in flight.Particulate matter resuspension from simulated urban green floors using a wind tunnel-mounted closed chamberhttps://peerj.com/articles/146742023-02-082023-02-08Inhye SeoChan Ryul ParkGayoung Yoo
Background
Green areas are thought to reduce particulate matter (PM) concentrations in urban environments. Plants are the key to PM reduction via various mechanisms, although most mechanisms do not lead to the complete removal of PM. Ultimately, PM falls into the soil via wind and rainfall. However, the fallen PM can re-entrain the atmosphere, which can affect plants capacity to reduce PM. In this study, we simulated an urban green floor and measured the resuspension of PM from the surface using a new experimental system, a wind tunnel-mounted closed chamber.
Methods
The developed system is capable of quantifying the resuspension rate at the millimeter scale, which is measured by using the 1 mm node chain. This is adequate for simulating in situ green floors, including fallen branches and leaves. This addressed limitations from previous studies which focused on micrometer-scale surfaces. In this study, the surfaces consisted of three types: bare sand soil, broadleaves, and coniferous leaves. The resuspended PM was measured using a light-scattering dust detector.
Results
The resuspension rate was highest of 14.45×10−4 s−1 on broad-leaved surfaces and lowest on coniferous surfaces of 5.35×10−4 s−1 (p < 0.05) and was not proportional to the millimeter-scale surface roughness measured by the roller chain method. This might be due to the lower roughness density of the broad-leaved surface, which can cause more turbulence for PM resuspension. Moreover, the size distribution of the resuspended PM indicated that the particles tended to agglomerate at 2.5 µm after resuspension.
Conclusion
Our findings suggest that the management of fallen leaves on the urban green floor is important in controlling PM concentrations and that the coniferous floor is more effective than the broadleaved floor in reducing PM resuspension. Future studies using the new system can be expanded to derive PM management strategies by diversifying the PM types, surfaces, and atmospheric conditions.
Background
Green areas are thought to reduce particulate matter (PM) concentrations in urban environments. Plants are the key to PM reduction via various mechanisms, although most mechanisms do not lead to the complete removal of PM. Ultimately, PM falls into the soil via wind and rainfall. However, the fallen PM can re-entrain the atmosphere, which can affect plants capacity to reduce PM. In this study, we simulated an urban green floor and measured the resuspension of PM from the surface using a new experimental system, a wind tunnel-mounted closed chamber.
Methods
The developed system is capable of quantifying the resuspension rate at the millimeter scale, which is measured by using the 1 mm node chain. This is adequate for simulating in situ green floors, including fallen branches and leaves. This addressed limitations from previous studies which focused on micrometer-scale surfaces. In this study, the surfaces consisted of three types: bare sand soil, broadleaves, and coniferous leaves. The resuspended PM was measured using a light-scattering dust detector.
Results
The resuspension rate was highest of 14.45×10−4 s−1 on broad-leaved surfaces and lowest on coniferous surfaces of 5.35×10−4 s−1 (p < 0.05) and was not proportional to the millimeter-scale surface roughness measured by the roller chain method. This might be due to the lower roughness density of the broad-leaved surface, which can cause more turbulence for PM resuspension. Moreover, the size distribution of the resuspended PM indicated that the particles tended to agglomerate at 2.5 µm after resuspension.
Conclusion
Our findings suggest that the management of fallen leaves on the urban green floor is important in controlling PM concentrations and that the coniferous floor is more effective than the broadleaved floor in reducing PM resuspension. Future studies using the new system can be expanded to derive PM management strategies by diversifying the PM types, surfaces, and atmospheric conditions.Wildlife overpass structure size, distribution, effectiveness, and adherence to expert design recommendationshttps://peerj.com/articles/143712022-12-122022-12-12Liam BrennanEmily ChowClayton Lamb
It is now well evidenced that wildlife crossing structures paired with exclusion fencing reduce wildlife vehicles collisions while facilitating wildlife connectivity across roadways. Managing animal mortality and subpopulation connectivity is crucial to successful species and landscape stewardship. Highway mitigation projects are large economic investments that remain on the landscape for many decades. Governments and planning agents thus strive to balance cost and benefit to build cost-effective structures with the greatest positive impact on local wildlife and motorists. Ideal dimensions of overpasses and underpasses vary by species, but scientists generally suggest that overpasses for large mammals should be approximately 50 m wide. Optimal width also depends on structure length, with longer structures requiring additional width. Accordingly, experts have suggested a width to length ratio of 0.8. We sought to assess how these recommendations manifested in practice—where agencies use this information to design and build structures while also balancing cost and logistical challenges—and the degree to which built structures conform to current recommendations. We identified 120 wildlife overpasses across the world that were constructed to reduce the negative impacts of roads. Using a novel measurement technique, we analyzed the dimensions of these 120 overpasses located in North America, Europe, Asia, and Oceania. The average width of the wildlife overpasses was 34 m. Most wildlife overpasses located in North America and Europe did not meet their respective dimensional expert guidelines. We investigate reasons explaining the non-compliance and provide recommendations for future overpass designs. Building on previous evidence showing that wider overpasses have increased crossing rates, we examined crossing rates for multiple large mammal species across 12 overpasses located in western North America. We qualitatively observed that wider North American overpasses (40–60 m), in or near compliance with expert guidelines, were associated with a more diverse set of species use and had nearly twice the average crossing rates when compared to non-compliant, narrow North American overpasses. In reviewing various studies from around the world, we conclude that wide overpasses (~50 m) continue to present ecologically sound and cost-effective solutions for decreasing the barrier of roadways, especially when targeting width-sensitive species and large assemblages of mammals. Future studies, however, are encouraged to further explore the specific instances when underpasses and narrower overpasses present more cost-effective ecological solutions, or how these structures can complement wide overpasses in successful wildlife crossing systems.
It is now well evidenced that wildlife crossing structures paired with exclusion fencing reduce wildlife vehicles collisions while facilitating wildlife connectivity across roadways. Managing animal mortality and subpopulation connectivity is crucial to successful species and landscape stewardship. Highway mitigation projects are large economic investments that remain on the landscape for many decades. Governments and planning agents thus strive to balance cost and benefit to build cost-effective structures with the greatest positive impact on local wildlife and motorists. Ideal dimensions of overpasses and underpasses vary by species, but scientists generally suggest that overpasses for large mammals should be approximately 50 m wide. Optimal width also depends on structure length, with longer structures requiring additional width. Accordingly, experts have suggested a width to length ratio of 0.8. We sought to assess how these recommendations manifested in practice—where agencies use this information to design and build structures while also balancing cost and logistical challenges—and the degree to which built structures conform to current recommendations. We identified 120 wildlife overpasses across the world that were constructed to reduce the negative impacts of roads. Using a novel measurement technique, we analyzed the dimensions of these 120 overpasses located in North America, Europe, Asia, and Oceania. The average width of the wildlife overpasses was 34 m. Most wildlife overpasses located in North America and Europe did not meet their respective dimensional expert guidelines. We investigate reasons explaining the non-compliance and provide recommendations for future overpass designs. Building on previous evidence showing that wider overpasses have increased crossing rates, we examined crossing rates for multiple large mammal species across 12 overpasses located in western North America. We qualitatively observed that wider North American overpasses (40–60 m), in or near compliance with expert guidelines, were associated with a more diverse set of species use and had nearly twice the average crossing rates when compared to non-compliant, narrow North American overpasses. In reviewing various studies from around the world, we conclude that wide overpasses (~50 m) continue to present ecologically sound and cost-effective solutions for decreasing the barrier of roadways, especially when targeting width-sensitive species and large assemblages of mammals. Future studies, however, are encouraged to further explore the specific instances when underpasses and narrower overpasses present more cost-effective ecological solutions, or how these structures can complement wide overpasses in successful wildlife crossing systems.Fuel trait effects on flammability of native and invasive alien shrubs in coastal fynbos and thicket (Cape Floristic Region)https://peerj.com/articles/137652022-07-282022-07-28Tineke KraaijSamukelisiwe T. MsweliAlastair J. Potts
In June 2017, extreme fires along the southern Cape coast of South Africa burnt native fynbos and thicket vegetation and caused extensive damage to plantations and residential properties. Invasive alien plants (IAPs) occur commonly in the area and were thought to have changed the behaviour of these fires through their modification of fuel properties relative to that of native vegetation. This study experimentally compared various measures of flammability across groups of native and alien invasive shrub species in relation to their fuel traits. Live plant shoots of 30 species (10 species each of native fynbos, native thicket, and IAPs) were sampled to measure live fuel moisture, dry biomass, fuel bed porosity and the proportions of fine-, coarse- and dead fuels. These shoots were burnt experimentally, and flammability measured in terms of maximum temperature (combustibility), completeness of burn (consumability), and time-to-ignition (ignitability). Multiple regression models were used to assess the relationships between flammability responses and fuel traits, while the Kruskal-Wallis H test was used to establish if differences existed in flammability measures and fuel traits among the vegetation groups. Dry biomass significantly enhanced, while live fuel moisture significantly reduced, maximum temperature, whereas the proportion of fine fuels significantly increased completeness of burn. Unlike other similar studies, the proportion of dead fuels and fuel bed porosity were not retained by any of the models to account for variation in flammability. Species of fynbos and IAPs generally exhibited greater flammability in the form of higher completeness of burn and more rapid ignition than species of thicket. Little distinction in flammability and fuel traits could be made between species of fynbos and IAPs, except that fynbos species had a greater proportion of fine fuels. Thicket species had higher proportions of coarse fuels and greater dry biomass (~fuel loading) than species of fynbos and IAPs. Live fuel moisture did not differ among the vegetation groups, contrary to the literature often ascribing variation in flammability to fuel moisture differences. The fuel traits investigated only explained 21–53% of the variation in flammability and large variation was evident among species within vegetation groups suggesting that species-specific and in situ community-level investigations are warranted, particularly in regard fuel moisture and chemical contents.
In June 2017, extreme fires along the southern Cape coast of South Africa burnt native fynbos and thicket vegetation and caused extensive damage to plantations and residential properties. Invasive alien plants (IAPs) occur commonly in the area and were thought to have changed the behaviour of these fires through their modification of fuel properties relative to that of native vegetation. This study experimentally compared various measures of flammability across groups of native and alien invasive shrub species in relation to their fuel traits. Live plant shoots of 30 species (10 species each of native fynbos, native thicket, and IAPs) were sampled to measure live fuel moisture, dry biomass, fuel bed porosity and the proportions of fine-, coarse- and dead fuels. These shoots were burnt experimentally, and flammability measured in terms of maximum temperature (combustibility), completeness of burn (consumability), and time-to-ignition (ignitability). Multiple regression models were used to assess the relationships between flammability responses and fuel traits, while the Kruskal-Wallis H test was used to establish if differences existed in flammability measures and fuel traits among the vegetation groups. Dry biomass significantly enhanced, while live fuel moisture significantly reduced, maximum temperature, whereas the proportion of fine fuels significantly increased completeness of burn. Unlike other similar studies, the proportion of dead fuels and fuel bed porosity were not retained by any of the models to account for variation in flammability. Species of fynbos and IAPs generally exhibited greater flammability in the form of higher completeness of burn and more rapid ignition than species of thicket. Little distinction in flammability and fuel traits could be made between species of fynbos and IAPs, except that fynbos species had a greater proportion of fine fuels. Thicket species had higher proportions of coarse fuels and greater dry biomass (~fuel loading) than species of fynbos and IAPs. Live fuel moisture did not differ among the vegetation groups, contrary to the literature often ascribing variation in flammability to fuel moisture differences. The fuel traits investigated only explained 21–53% of the variation in flammability and large variation was evident among species within vegetation groups suggesting that species-specific and in situ community-level investigations are warranted, particularly in regard fuel moisture and chemical contents.Sensitivity of soil hydrogen uptake to natural and managed moisture dynamics in a semiarid urban ecosystemhttps://peerj.com/articles/129662022-03-172022-03-17Vanessa BuzzardDana ThorneJuliana Gil-LoaizaAlejandro CuevaLaura K. Meredith
The North American Monsoon season (June–September) in the Sonoran Desert brings thunderstorms and heavy rainfall. These rains bring cooler temperature and account for roughly half of the annual precipitation making them important for biogeochemical processes. The intensity of the monsoon rains also increase flooding in urban areas and rely on green infrastructure (GI) stormwater management techniques such as water harvesting and urban rain gardens to capture runoff. The combination of increased water availability during the monsoon and water management provide a broad moisture regime for testing responses in microbial metabolism to natural and managed soil moisture pulses in drylands. Soil microbes rely on atmospheric hydrogen (H2) as an important energy source in arid and semiarid landscapes with low soil moisture and carbon availability. Unlike mesic ecosystems, transient water availability in arid and semiarid ecosystems has been identified as a key limiting driver of microbe-mediated H2 uptake. We measured soil H2 uptake in rain gardens exposed to three commonly used water harvesting practices during the monsoon season in Tucson AZ, USA. In situ static chamber measurements were used to calculate H2 uptake in each of the three water harvesting treatments passive (stormwater runoff), active (stored rooftop runoff), and greywater (used laundry water) compared to an unaltered control treatment to assess the effects of water management practices on soil microbial activity. In addition, soils were collected from each treatment and brought to the lab for an incubation experiment manipulating the soil moisture to three levels capturing the range observed from field samples. H2 fluxes from all treatments ranged between −0.72 nmol m−2 s−1 and −3.98 nmol m−2 s−1 over the monsoon season. Soil H2 uptake in the greywater treatment was on average 53% greater than the other treatments during pre-monsoon, suggesting that the increased frequency and availability of water in the greywater treatment resulted in higher H2 uptake during the dry season. H2 uptake was significantly correlated with soil moisture (r = −0.393, p = 0.001, df = 62) and temperature (r = 0.345, p = 0.005, df = 62). Our findings suggest that GI managed residential soils can maintain low levels of H2 uptake during dry periods, unlike unmanaged systems. The more continuous H2 uptake associated with GI may help reduce the impacts of drought on H2 cycling in semiarid urban ecosystems.
The North American Monsoon season (June–September) in the Sonoran Desert brings thunderstorms and heavy rainfall. These rains bring cooler temperature and account for roughly half of the annual precipitation making them important for biogeochemical processes. The intensity of the monsoon rains also increase flooding in urban areas and rely on green infrastructure (GI) stormwater management techniques such as water harvesting and urban rain gardens to capture runoff. The combination of increased water availability during the monsoon and water management provide a broad moisture regime for testing responses in microbial metabolism to natural and managed soil moisture pulses in drylands. Soil microbes rely on atmospheric hydrogen (H2) as an important energy source in arid and semiarid landscapes with low soil moisture and carbon availability. Unlike mesic ecosystems, transient water availability in arid and semiarid ecosystems has been identified as a key limiting driver of microbe-mediated H2 uptake. We measured soil H2 uptake in rain gardens exposed to three commonly used water harvesting practices during the monsoon season in Tucson AZ, USA. In situ static chamber measurements were used to calculate H2 uptake in each of the three water harvesting treatments passive (stormwater runoff), active (stored rooftop runoff), and greywater (used laundry water) compared to an unaltered control treatment to assess the effects of water management practices on soil microbial activity. In addition, soils were collected from each treatment and brought to the lab for an incubation experiment manipulating the soil moisture to three levels capturing the range observed from field samples. H2 fluxes from all treatments ranged between −0.72 nmol m−2 s−1 and −3.98 nmol m−2 s−1 over the monsoon season. Soil H2 uptake in the greywater treatment was on average 53% greater than the other treatments during pre-monsoon, suggesting that the increased frequency and availability of water in the greywater treatment resulted in higher H2 uptake during the dry season. H2 uptake was significantly correlated with soil moisture (r = −0.393, p = 0.001, df = 62) and temperature (r = 0.345, p = 0.005, df = 62). Our findings suggest that GI managed residential soils can maintain low levels of H2 uptake during dry periods, unlike unmanaged systems. The more continuous H2 uptake associated with GI may help reduce the impacts of drought on H2 cycling in semiarid urban ecosystems.Reactions of two xeric-congeneric species of Centaurea (Asteraceae) to soils with different pH values and iron availabilityhttps://peerj.com/articles/124172021-11-102021-11-10Mateusz WalaJeremi KołodziejekJanusz MazurAlicja Cienkowska
Centaurea scabiosa L. and C. stoebe Tausch are known to co-exist naturally in two extremely different types of open dry habitats in the temperate zone, alkaline xerothermic grasslands and acidic dry grasslands. However, knowledge about their preferences to edaphic conditions, including soil acidity (pH), and iron (Fe) availability is scarce. Therefore, experimental comparison of soil requirements (acidic Podzol vs alkaline Rendzina) of these species was carried out. The study was designed as a pot experiment and conducted under field conditions. Fe availability was increased by application of Fe-HBED. Reactions of plants to edaphic conditions were determined using growth measurements, leaf morphometric measurements, chlorosis scoring, chlorophyll content and chlorophyll a fluorescence (OJIP) quantification as well as determination of element content (Ca, Mg, Fe, Mn, Zn and Cu). Growth and leaf morphometrical traits of the studied congeneric species were affected similarly by the soil type and differently by the chelate treatment. Increased availability of Fe in Rendzina contrasted the species, as treatment with 25 µmol Fe-HBED kg−1 soil promoted growth only in C. stoebe. Both species turned out to be resistant to Fe-dependent chlorosis which was also reflected in only minor changes in chlorophyll a fluorescence parameters. Both species showed relatively low nutritional demands. Surprisingly, Fe-HBED did not stimulate Fe acquisition in the studied species, nor its translocation along the root:shoot axis. Furthermore, contrary to expectations, C. scabiosa took up less Fe from the acidic than alkaline soil. C. scabiosa not only absorbed more Ca and Zn but also translocated greater amounts of these elements to shoots than C. stoebe. Both species acquired more Mg on Podzol than on Rendzina which suggests adaptation allowing avoidance of aluminum (Al) toxicity on acidic soils. Overall, it seems that C. scabiosa prefers alkaline soils, whilst C. stoebe prefers acidic ones.
Centaurea scabiosa L. and C. stoebe Tausch are known to co-exist naturally in two extremely different types of open dry habitats in the temperate zone, alkaline xerothermic grasslands and acidic dry grasslands. However, knowledge about their preferences to edaphic conditions, including soil acidity (pH), and iron (Fe) availability is scarce. Therefore, experimental comparison of soil requirements (acidic Podzol vs alkaline Rendzina) of these species was carried out. The study was designed as a pot experiment and conducted under field conditions. Fe availability was increased by application of Fe-HBED. Reactions of plants to edaphic conditions were determined using growth measurements, leaf morphometric measurements, chlorosis scoring, chlorophyll content and chlorophyll a fluorescence (OJIP) quantification as well as determination of element content (Ca, Mg, Fe, Mn, Zn and Cu). Growth and leaf morphometrical traits of the studied congeneric species were affected similarly by the soil type and differently by the chelate treatment. Increased availability of Fe in Rendzina contrasted the species, as treatment with 25 µmol Fe-HBED kg−1 soil promoted growth only in C. stoebe. Both species turned out to be resistant to Fe-dependent chlorosis which was also reflected in only minor changes in chlorophyll a fluorescence parameters. Both species showed relatively low nutritional demands. Surprisingly, Fe-HBED did not stimulate Fe acquisition in the studied species, nor its translocation along the root:shoot axis. Furthermore, contrary to expectations, C. scabiosa took up less Fe from the acidic than alkaline soil. C. scabiosa not only absorbed more Ca and Zn but also translocated greater amounts of these elements to shoots than C. stoebe. Both species acquired more Mg on Podzol than on Rendzina which suggests adaptation allowing avoidance of aluminum (Al) toxicity on acidic soils. Overall, it seems that C. scabiosa prefers alkaline soils, whilst C. stoebe prefers acidic ones.Land use changes in Zhangjiakou from 2005 to 2025 and the importance of ecosystem serviceshttps://peerj.com/articles/121222021-09-232021-09-23Kaipeng XuYanyan ChiRongfeng GeXiahui WangSiyang Liu
Changes in local land use affect regional ecological services, development planning, and optimal use of space. We analyzed the effects of changes in land use from 2000 to 2025 on the spatial distribution of ecosystem services using CLUS-S modeling to evaluate ecosystem functions in Zhangjiakou, China. We found that the urban ecosystem area in Zhangjiakou increased and farmland decreased between 2000–2025. Water conservation was relatively high and was concentrated in the nature reserves of southern Zhangjiakou. Soil conservation was mainly distributed in eastern and southern counties. The results of the CLUE-S model showed that the relative operating characteristics of the six land use types were > 0.70, and the logistic regression equation was able to successfully explain the distribution pattern of the different types of land use.
Changes in local land use affect regional ecological services, development planning, and optimal use of space. We analyzed the effects of changes in land use from 2000 to 2025 on the spatial distribution of ecosystem services using CLUS-S modeling to evaluate ecosystem functions in Zhangjiakou, China. We found that the urban ecosystem area in Zhangjiakou increased and farmland decreased between 2000–2025. Water conservation was relatively high and was concentrated in the nature reserves of southern Zhangjiakou. Soil conservation was mainly distributed in eastern and southern counties. The results of the CLUE-S model showed that the relative operating characteristics of the six land use types were > 0.70, and the logistic regression equation was able to successfully explain the distribution pattern of the different types of land use.Peach-Morchella intercropping mode affects soil properties and fungal compositionhttps://peerj.com/articles/117052021-07-122021-07-12Haiyan SongDong ChenShuxia SunJing LiMeiyan TuZihong XuRonggao GongGuoliang Jiang
Objective
This study aims to explore a three-dimensional planting mode in orchards and provide theoretical basis for the efficient peach-Morchella planting and soil management after Morchella cultivation.
Methods
Next-generation sequencing was performed to investigate the variations in soil physicochemical properties, enzyme activities and fungal composition under peach-Morchella intercropping for one year and two years, by using the soil without peach-Morchella intercropping as the control group.
Results
Peach-Morchella intercropping decreased the soil bulk density, and significantly increased the maximum field capacity, non-capillary porosity and total porosity, organic matter, available potassium and available zinc, which together improved soil structure and soil fertility. Besides, the intercropping mode obviously enhanced soil enzyme activities and mineral absorption and transformation in peach orchard soils. The intercropping also resulted in a decline of soil fungal diversity, and the 2-year soil samples were of higher abundance of Zygomycota. More importantly, peach-Morchella intercropping elevated the yields of both peach and Morchella, bringing about obviously higher economic benefits.
Conclusion
Continuous peach-Morchella intercropping improves the soil structure and fertility while decreases soil fungal diversity, which can contribute to greater economic benefits of the peach orchard. Our findings shed new light on the intercropping-fungus-soil relationship, and may facilitate the further development of peach-Morchella intercropping.
Objective
This study aims to explore a three-dimensional planting mode in orchards and provide theoretical basis for the efficient peach-Morchella planting and soil management after Morchella cultivation.
Methods
Next-generation sequencing was performed to investigate the variations in soil physicochemical properties, enzyme activities and fungal composition under peach-Morchella intercropping for one year and two years, by using the soil without peach-Morchella intercropping as the control group.
Results
Peach-Morchella intercropping decreased the soil bulk density, and significantly increased the maximum field capacity, non-capillary porosity and total porosity, organic matter, available potassium and available zinc, which together improved soil structure and soil fertility. Besides, the intercropping mode obviously enhanced soil enzyme activities and mineral absorption and transformation in peach orchard soils. The intercropping also resulted in a decline of soil fungal diversity, and the 2-year soil samples were of higher abundance of Zygomycota. More importantly, peach-Morchella intercropping elevated the yields of both peach and Morchella, bringing about obviously higher economic benefits.
Conclusion
Continuous peach-Morchella intercropping improves the soil structure and fertility while decreases soil fungal diversity, which can contribute to greater economic benefits of the peach orchard. Our findings shed new light on the intercropping-fungus-soil relationship, and may facilitate the further development of peach-Morchella intercropping.Plastics in Porifera: The occurrence of potential microplastics in marine sponges and seawater from Bocas del Toro, Panamáhttps://peerj.com/articles/116382021-07-082021-07-08Bailey R. FallonChristopher J. Freeman
Microplastics (MP) are now considered ubiquitous across global aquatic environments. The ingestion of MP by fish and other marine vertebrates is well studied, but the ingestion of MP by marine invertebrates is not. Sponges (Phylum Porifera) are particularly understudied when it comes to MP ingestion, even though they are widely distributed across benthic habitats, can process large volumes of seawater, and can retain small particles within their water filtration systems. This study examines the presence of potential MP (PMP) in wild marine sponges and seawater collected in Bocas del Toro, Panamá. Subsurface seawater and tissue from six common Caribbean sponge species was collected in Saigon Bay, a heavily impacted, shallow-water coral reef. Seawater samples were filtered onto glass fiber filters to retain any PMP present and sponge tissue was digested with bleach, heated and filtered. Filters were examined using fluorescence microscopy to quantify PMP. An average of 107 ± 25 PMP L–1 was detected in seawater from Saigon Bay with particles ranging in size between 10 μm and ~3,000 μm. The number of PMP found in sponge tissue ranged between 6 ± 4 and 169 ± 71 PMP g–1 of dry tissue. Most particles found in sponge samples were very small (10–20 μm), but fibers greater than 5,000 μm were detected. Our results indicate that PMP exists within the tissues of the sponges we studied, but future studies should confirm the presence of MP in sponges using chemical analysis. Most importantly, the discrepancy between low levels of PMP in our sponge samples and high levels in the surrounding seawater highlights the potential for sponges to resist and/or egest MP. Finally, we provide a critical evaluation of our methods to improve their use in future MP work with benthic marine organisms.
Microplastics (MP) are now considered ubiquitous across global aquatic environments. The ingestion of MP by fish and other marine vertebrates is well studied, but the ingestion of MP by marine invertebrates is not. Sponges (Phylum Porifera) are particularly understudied when it comes to MP ingestion, even though they are widely distributed across benthic habitats, can process large volumes of seawater, and can retain small particles within their water filtration systems. This study examines the presence of potential MP (PMP) in wild marine sponges and seawater collected in Bocas del Toro, Panamá. Subsurface seawater and tissue from six common Caribbean sponge species was collected in Saigon Bay, a heavily impacted, shallow-water coral reef. Seawater samples were filtered onto glass fiber filters to retain any PMP present and sponge tissue was digested with bleach, heated and filtered. Filters were examined using fluorescence microscopy to quantify PMP. An average of 107 ± 25 PMP L–1 was detected in seawater from Saigon Bay with particles ranging in size between 10 μm and ~3,000 μm. The number of PMP found in sponge tissue ranged between 6 ± 4 and 169 ± 71 PMP g–1 of dry tissue. Most particles found in sponge samples were very small (10–20 μm), but fibers greater than 5,000 μm were detected. Our results indicate that PMP exists within the tissues of the sponges we studied, but future studies should confirm the presence of MP in sponges using chemical analysis. Most importantly, the discrepancy between low levels of PMP in our sponge samples and high levels in the surrounding seawater highlights the potential for sponges to resist and/or egest MP. Finally, we provide a critical evaluation of our methods to improve their use in future MP work with benthic marine organisms.