Teichberg
Mirta
Teichberg
Mirta
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ArticleMacroalgal responses to experimental nutrient enrichment in shallow coastal waters : growth, internal nutrient pools, and isotopic signatures(Inter-Research, 2008-09-25) Teichberg, Mirta ; Fox, Sophia E. ; Aguila, Carolina ; Olsen, Ylva S. ; Valiela, IvanIncreased nutrient inputs to temperate coastal waters have led to increased occurrences of macroalgal blooms worldwide. To identify nutrients that are limiting to macroalgae and to determine whether different forms of these nutrients and long-term ambient nutrient conditions affect macroalgal response, we used in situ enrichment methods and tested the response of 2 bloom-forming species of macroalgae, Ulva lactuca and Gracilaria tikvahiae, from shallow estuaries of Waquoit Bay, Massachusetts, USA, that receive different land-derived N inputs. We enriched caged macroalgal fronds with nitrate, ammonium, phosphate, and N + P combinations, and measured growth, nutrient content, and δ15N signatures of fronds after 2 wk of incubation. In these estuaries, P did not limit growth, however, the 2 species differed in growth response to N additions. Growth of U. lactuca was greater in Childs River (CR), the estuary with higher nitrate inputs, than in Sage Lot Pond (SLP); growth in SLP increased with nitrate and ammonium enrichment. In contrast, growth of G. tikvahiae was greater in SLP than in CR, but had no growth response to N enrichment in either site. C and N contents differed initially between species and sites, and after nutrient enrichment. Final tissue % N increased and C:N decreased after nitrate and ammonium enrichment. δ15N values of the macroalgae demonstrated uptake of the experimental fertilizers, and a higher affinity and faster turnover of internal N pools with ammonium than nitrate enrichment in both species. We suggest that U. lactuca blooms in areas with both high nitrate and ammonium water column concentrations, and is more N-limited in oligotrophic waters where DIN levels are too low to sustain high growth rates. G. tikvahiae has a greater N storage capacity than U. lactuca, which may allow it to grow in less nutrient-rich waters.
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ArticleCoupling of estuarine benthic and pelagic food webs to land-derived nitrogen sources in Waquoit Bay, Massachusetts, USA(Inter-Research, 2006-01-24) Martinetto, Paulina ; Teichberg, Mirta ; Valiela, IvanThe fact that land-derived sources of nutrients promote eutrophication in the receiving coastal waters implies coupling between land and marine environments. Increasing nitrogen inputs in the estuaries are followed by major shifts in biota composition and abundances. In the present paper we used N and C isotopic ratios to analyze the coupling of benthic and pelagic components of food webs to estuaries receiving different N loads from their watersheds. We found that primary producers, benthic taxa, and fishes were coupled to the watersheds and estuaries where they were collected. In contrast, zooplankton was uncoupled. Primary consumers and predators feeding on benthic prey within the estuaries were also coupled to the watershed and estuaries, but predators feeding on zooplankton were not. We hypothesized that short water residence time in these estuaries uncoupled plankton from terrestrial influence. Stable isotopic measurements of N in producers, consumers, POM, and sediment in different estuaries of Waquoit Bay, Massachusetts, USA, demonstrate a consistent link between land-use on contributing watersheds and the isotopic ratio in all the benthic components and food webs. The remarkably consistent link suggests that the benthos was tightly coupled to land-derived inputs, and that these components, particularly macrophytes, could be good indicators for monitoring increases in land-derived N inputs. Our results showed that stable isotopes of N and C have the potential for use in basic research and applied monitoring, but need to be applied considering the features of estuaries that might couple or uncouple organisms regarding dependency on land, such as hydrodynamic exchanges.
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ArticleEditorial: seagrasses under times of change(Frontiers Media, 2022-04-28) Winters, Gidon ; Teichberg, Mirta ; Reuter, Hauke ; Viana, Ines G. ; Willette, Demian A.Awareness of the ecological importance of seagrasses is growing due to recent attention to their role in carbon sequestration as a potential blue carbon sink (Fourqurean et al., 2012; Bedulli et al.), as well as their role in nutrient cycling (Romero et al., 2006), sediment stabilization (James et al., 2019), pathogen filtration (Lamb et al., 2017), and the formation of essential habitats for economically important marine species (Jackson et al., 2001; Jones et al.). Despite their importance and the increasing public and scientific awareness of seagrasses, simultaneous global (e.g., ocean warming, increase in frequency and severity of extreme events, introduction and spread of invasive species) and local (e.g., physical disturbances, eutrophication, and sedimentation) anthropogenic stressors continue to be the main causes behind the ongoing global decline of seagrass meadows (Orth et al., 2006; Waycott et al., 2009).
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ArticleBottom-up and top-down control of seagrass overgrazing by the sea urchin Tripneustes gratilla(Wiley, 2023-01-19) Moreira-Saporiti, Agustín ; Hoeijmakers, Dieuwke ; Reuter, Hauke ; Msuya, Flower E. ; Gese, Katrin ; Teichberg, MirtaThe lack of top-down control on Tripneustes gratilla, a sea urchin commonly known to graze on seagrass, and the bottom-up control of its feeding preference, led to the overgrazing of seagrass meadows of the species Thalassodendron ciliatum in Changuu Island (Zanzibar Archipelago). The impact of overgrazing on seagrasses was assessed by mapping the presence of grazed versus non-grazed seagrass patches in the study site, while the top-down control on T. gratilla was assessed by measuring the abundance of its fish predators. The feeding preference and distribution of T. gratilla were characterized by calculating the electivity indexes for each seagrass species and measuring sea urchin density, respectively. Approximately half of the patches of T. ciliatum were overgrazed, while predatory fishes of T. gratilla were absent from the site. The Vanderploeg and Scavia's Relativized Electivity Index indicated that T. gratilla had a feeding preference for T. ciliatum, which was also supported by higher urchin densities within T. ciliatum dominated patches. Bottom-up control of grazing activity was observed by quantifying and analyzing morphological, nutritional, and the chemical defense traits of the seagrass in relation to feeding preference and urchin density. Feeding was positively correlated to the seagrass tissue C:P ratio (? = 0.9), whereas urchin density showed no correlations. The bottom-up control of the feeding preference and agglomeration of T. gratilla in T. ciliatum meadows, together with the lack of evidence of substantial top-down control and the long recovery time of T. ciliatum led to the overgrazing of this species at this site. Overgrazing, therefore, was shown to be the result of multiple factors ranging from the traits of the seagrass and feeding preference of T. gratilla, to the abundance of predators in this area.
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ArticleA trait-based framework for seagrass ecology: trends and prospects(Frontiers Media, 2023-03-20) Moreira-Saporiti, Agustín ; Teichberg, Mirta ; Garnier, Eric ; Cornelissen, J. Hans C. ; Alcoverro, Teresa ; Björk, Mats ; Boström, Christoffer ; Dattolo, Emanuela ; Eklöf, Johan S. ; Hasler-Sheetal, Harald ; Marbà, Nuria ; Marín-Guirao, Lázaro ; Meysick, Lukas ; Olivé, Irene ; Reusch, Thorsten B. H. ; Ruocco, Miriam ; Silva, João ; Sousa, Ana I. ; Procaccini, Gabriele ; Santos, RuiIn the last three decades, quantitative approaches that rely on organism traits instead of taxonomy have advanced different fields of ecological research through establishing the mechanistic links between environmental drivers, functional traits, and ecosystem functions. A research subfield where trait-based approaches have been frequently used but poorly synthesized is the ecology of seagrasses; marine angiosperms that colonized the ocean 100M YA and today make up productive yet threatened coastal ecosystems globally. Here, we compiled a comprehensive trait-based response-effect framework (TBF) which builds on previous concepts and ideas, including the use of traits for the study of community assembly processes, from dispersal and response to abiotic and biotic factors, to ecosystem function and service provision. We then apply this framework to the global seagrass literature, using a systematic review to identify the strengths, gaps, and opportunities of the field. Seagrass trait research has mostly focused on the effect of environmental drivers on traits, i.e., "environmental filtering" (72%), whereas links between traits and functions are less common (26.9%). Despite the richness of trait-based data available, concepts related to TBFs are rare in the seagrass literature (15% of studies), including the relative importance of neutral and niche assembly processes, or the influence of trait dominance or complementarity in ecosystem function provision. These knowledge gaps indicate ample potential for further research, highlighting the need to understand the links between the unique traits of seagrasses and the ecosystem services they provide.
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ArticleEditorial: Current advances in seagrass research(Frontiers Media, 2023-04-17) Papenbrock, Jutta ; Teichberg, MirtaSeagrasses are of great ecological importance, forming large “meadows” in all continents except Antarctica and providing vital ecosystem services including primary production, carbon storage, nutrient cycling, habitat structure, and coastal protection. Seagrasses provide shelter and act as a nursery ground for commercially important small fish and invertebrates. Human activity, however, is having profound impacts on marine ecosystems, including seagrass communities. Over the last few decades anthropogenic changes, including reduced water quality, increased temperature, increased sediment loads, and higher grazing pressure, have caused global declines in seagrass populations and the area coverage of seagrass beds. Due to the valuable ecosystem services that seagrasses provide along coastlines all over the world, strategies to increase recovery of seagrass meadows are being developed; however, further research on seagrass distribution, responses to abiotic and biotic stressors and how that impacts the recovery process, acclimation or adaptation potential, and resilience to environmental change is required to support these strategies. For many regions, the exact distribution and coverage of seagrass are not well known, and simple methods to reliably detect changes in seagrass coverage need to be established for the development of locally successful conservation methods. This Research topic, therefore, aimed to advance seagrass research by bringing together different perspectives on seagrasses that highlight their ecological importance and the effects of anthropogenic pressures, as well as the potential for its recovery and restoration.
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ArticlePredicted warming intensifies the negative effects of nutrient increase on tropical seagrass: a physiological and fatty acid approach(Elsevier, 2022-07-26) Beca-Carretero, Pedro ; Azcárate-García, Tomás ; Teichberg, Mirta ; Patra, Priyanka ; Feroze, Farhan ; González, Maria J. ; Medina, Isabel ; Winters, GidonPredicted warming will favour Halophila stipulacea photosynthetic and growth responses. Nutrients reduced Fv/Fm and seagrass production while favouring algae proliferation.Warming enhanced the detrimental effects of eutrophication on seagrasses.Fatty acids unsaturation and elongation indexes can be used as eco-physiological indicators. Ises in temperature and nutrients reduced the accumulation of omega-3 fatty acids.The Gulf of Aqaba (GoA; northern Red Sea) supports extensive seagrass meadows, dominated by the small tropical seagrass species, Halophila stipulacea. Due to its semi-closed structure, in the GoA, regional nutrient loading and global warming are considered the biggest threats to local seagrass meadows, and their combination can potentially amplify their negative impacts. Using a seagrass-dedicated mesocosm, we exposed two seagrass populations with different local “nutrient history” to control (27 °C) and simulated warming (31 °C), with and without nutrients (20 µM DIN). Following four weeks of these treatments (“stress phase”), all plants were returned to control conditions (“recovery phase”) for another three weeks. Results showed that exposure to only thermal stress favoured growth, compared to exposure to only nutrient increase that reduced Fv/Fm and growth but favoured algae proliferation. Exposure to the combined thermal and nutrient stress, negatively affected seagrass performance resulting in high mortality observed after four weeks of combined exposure. The negative effects of combined stressors were stronger in populations with low “nutrient history”. Additionally, we propose two novel fatty acid (FA) biomarkers, one based on FA unsaturation, 16:3n-3/16:2n-6, and the other on FA elongation processes, 18:2n-6/16:2n-6. Fatty acid analyses showed a significant decrease in 16:3n-3/16:2n-6 and 18:3n-3/18:2n-6 with increases in temperature and nutrients; a more drastic decline was found under the interaction of both stressors. Our results point out that C16 PUFAs, that are synthesized within the “prokaryotic pathway”, are more sensitive to thermal and the combined thermal + nutrients stressors than C18 PUFAs, which are synthesized within the “eukaryotic pathway”. In general, following a month of control conditions, a clear recovery of most of the seagrass descriptors was observed, highlighting the great capability of Halophila stipulacea to recover from stress conditions. Our results have important ecological and management implications to the seagrass meadows in the GoA and elsewhere. For seagrasses to survive climate change, managers must put efforts into limiting other stressors such as eutrophication that would potentially reduce the seagrass resilience to climate change.
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ArticleClimate change and the presence of invasive species will threaten the persistence of the Mediterranean seagrass community(Elsevier, 2023-11-18) Beca-Carretero, Pedro P. ; Winters, Gidon ; Teichberg, Mirta C. ; Procaccini, Gabriele ; Schneekloth, Fabian ; Zambrano, Ramon H. ; Chiquillo, Kelcie L. ; Reuters, HaukeThe Mediterranean Sea has been experiencing rapid increases in temperature and salinity triggering its tropicalization. Additionally, its connection with the Red Sea has been favouring the establishment of non-native species. In this study, we investigated the effects of predicted climate change and the introduction of invasive seagrass species (Halophila stipulacea) on the native Mediterranean seagrass community (Posidonia oceanica and Cymodocea nodosa) by applying a novel ecological and spatial model with different configurations and parameter settings based on a Cellular Automata (CA). The proposed models use a discrete (stepwise) representation of space and time by executing deterministic and probabilistic rules that develop complex dynamic processes. Model applications were run under two climate scenarios (RCP 2.6 and RCP 8.5) projected from 2020 to 2100 in four different regions within the Mediterranean. Results indicate that the slow-growing P. oceanica will be highly vulnerable to climate change, suffering vast declines in its abundance. However, the results also show that western and colder areas of the Mediterranean Sea might represent refuge areas for this species. Cymodocea nodosa has been reported to exhibit resilience to predicted climate scenarios; however, it has shown habitat regression in the warmest predicted regions in the easternmost part of the basin. Our models indicate that H. stipulacea will thrive under projected climate scenarios, facilitating its spread across the basin. Also, H. stipulacea grew at the expense of C. nodosa, limiting the distribution of the latter, and eventually displacing this native species. Additionally, simulations demonstrated that areas from which P. oceanica meadows disappear would be partially covered by C. nodosa and H. stipulacea. These outcomes project that the Mediterranean seagrass community will experience a transition from long-lived, large and slow-growing species to small and fast-growing species as climate change progresses.
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ArticleTropical bloom-forming mesoalgae Cladophoropsis sp. and Laurencia sp.—responses to ammonium enrichment and a simulated heatwave(Phycological Society of America, 2024-02-25) Fricke, Anna ; Bast, Felix ; Moreira-Saporiti, Agustin ; Martins Bussanello, Giovanni ; Msuya, Flower E. ; Teichberg, MirtaAlgal blooms are increasing worldwide, driven by elevated nutrient inputs. However, it is still unknown how tropical benthic algae will respond to heatwaves, which are expected to be more frequent under global warming. In the present study, a multifactorial experiment was carried out to investigate the potential synergistic effects of increased ammonium inputs (25 μM, control at 2.5 μM) and a heatwave (31°C, control at 25°C) on the growth and physiology (e.g., ammonium uptake, nutrient assimilation, photosynthetic performance, and pigment concentrations) of two bloom-forming algal species, Cladophoropsis sp. and Laurencia sp. Both algae positively responded to elevated ammonium concentrations with higher growth and chlorophyll a and lutein concentrations. Increased temperature was generally a less important driver, interacting with elevated ammonium by decreasing the algaes' %N content and N:P ratios. Interestingly, this stress response was not captured by the photosynthetic yield (Fv/Fm) nor by the carbon assimilation (%C), which increased for both algae at higher temperatures. The negative effects of higher temperature were, however, buffered by nutrient inputs, showing an antagonistic response in the combined treatment for the concentration of VAZ (violaxanthin, antheraxanthin, zeaxanthin) and thalli growth. Ammonium uptake was initially higher for Cladophoropsis sp. and increased for Laurencia sp. over experimental time, showing an acclimation capacity even in a short time interval. This experiment shows that both algae benefited from increased ammonium pulses and were able to overcome the otherwise detrimental stress of increasingly emerging temperature anomalies, which provide them a strong competitive advantage and might support their further expansions in tropical marine systems.