UCN-CEAZA
Nest building by a small mesograzer limits blade size of the giant kelp Macrocystis pyrifera
Poore, A., Gutow, L., Lörz, A., & Thiel, M.
Small herbivores are abundant on large marine macrophytes, but their impact on their hosts is poorly understood relative to large grazers such as urchins and fish. To limit the risks of predation, many marine mesograzers live within nests or burrows, potentially causing more damage to plants than predicted from consumption alone. To test whether the growth of large primary producers can be affected by modification of plant structures by small herbivores, we quantified the effect of the nest-building amphipod Pseudopleonexes lessoniae on blades of the giant kelp, Macrocystis pyrifera in New Zealand. Amphipods create their nests by rolling the blade margin in close proximity to the meristem. Blades with nests were 40% shorter than blades lacking nests and reduced in area by 55%. We examined the composition of amphipods inhabiting each nest to assess the temporal persistence of grazer aggregations. Nests were occupied by a single female or male–female pairs, and their newly hatched offspring. Analysis of offspring size distributions suggested that offspring dispersed from the maternal nest and did not remain to breed themselves. By concentrating physical damage and feeding on valuable tissues, these results indicate that even low numbers of small herbivores can cause localized impacts on the morphology and size of fast-growing algal blades. Predicting the consequences of this damage on larger scales will require understanding the spatial and temporal distribution of amphipod nests on giant kelp.
Año: 2018
Palabras claves:
Referencia APA: Poore, A., Gutow, L., Lörz, A., & Thiel, M. (2018). Nest building by a small mesograzer limits blade size of the giant kelp Macrocystis pyrifera. Marine Biology, 165(12). doi: 10.1007/s00227-018-3444-6
Plastic Pirates sample litter at rivers in Germany – Riverside litter and litter sources estimated by schoolchildren
Kiessling, T., Knickmeier, K., Kruse, K., Brennecke, D., Nauendorf, A., & Thiel, M.
Rivers are an important source of marine anthropogenic litter, but the particular origins of riverine litter itself have not been well established. Here we used a citizen science approach where schoolchildren examined litter at riversides and identified possible sources at over 250 sampling spots along large and small rivers in Germany, during autumn 2016 and spring 2017. Litter densities have an overall median of 0.14, interquartile range 0–0.57 items m−2 and an overall average (±standard deviation) of 0.54 ± 1.20 litter items m−2. Litter quantities differed only little by sampling year. The principal litter types found were plastics and cigarette butts (31% and 20%, respectively), followed by glass, paper, and metal items, indicating recreational visitors as the principal litter source. At many sites (85%), accumulations of litter, consisting principally of cigarettes and food packaging, have been found. At almost all sampling sites (89%), litter potentially hazardous to human health has been observed, including broken glass, sharp metal objects, used personal hygiene articles and items containing chemicals. In the search for litter sources, the schoolchildren identified mainly people who use the rivers as recreational areas (in contrast to residents living in the vicinity, illegal dumping, or the river itself depositing litter from upstream sources). These results indicate the urgent need for better education and policy measures in order to protect riparian environments and reduce input of riverine litter to the marine environment.
Año: 2018
Palabras claves: Plastic litter, Macrolitter, Freshwater, Source identification, Citizen science
Referencia APA: Kiessling, T., Knickmeier, K., Kruse, K., Brennecke, D., Nauendorf, A., & Thiel, M. (2019). Plastic Pirates sample litter at rivers in Germany – Riverside litter and litter sources estimated by schoolchildren. Environmental Pollution, 245, 545-557. doi: 10.1016/j.envpol.2018.11.025
First insight into the heritable variation and potential response to selection of phototaxis and locomotion behavior associated to the light/dark stimuli in the abalone Haliotis discus hannai
Defranchi, Y., Winkler, F., Farías, W., Herbinger, C., & Brokordt, K.
Abalones are especially susceptible to environmental lighting conditions. This factor greatly affects crucial biological process such as feeding rates, energy balance, physiological stress status, and consequently, growth and survival of farmed abalone. Most of these effects have been studied in the economically valuable abalone Haliotis discus hannai. The use of specific photoperiods, and/or light qualities and intensities, have been proposed as managing strategies to increase its production; however, for extensive off-shore or in intensive land-based farming systems, lighting conditions are not likely to be easily managed. Despite the great importance of the biological responses to the light/dark stimuli for abalone farming production, to the best of our knowledge the genetic control upon the variation associated behavioral traits have not been studied. Therefore, the aim of this study was to estimate the heritable variation and potential responses to selection for the phototaxis [i.e., displacement towards (positive) or against (negative) the light source] and locomotion behaviors associated to the intensity of the response (i.e., crawling speed and displacement distance) to the light/dark stimuli in juvenile H. discus hannai. Genetic and phenotypic correlations between these traits were also estimated. Results showed moderate but significant heritable variations for phototaxis (h2 = 0.15) and locomotion responses (h2 = 0.18–0.37); and significant positive genetic correlations among them. Expected gain responses to selection per generation (with a selection intensity of 2.06, i.e., selecting 5% of the individuals from a population) were moderate for phototaxis variation (16%) and high for locomotion responses variation (33–67 or 36–73%, depending on the model used for the estimations). As a consequence, the potential for reducing (or incrementing, depending on the breeding goal) the reactivity or the sensibility to the light stimulus by selective breeding is good, and can be an attractive way of indirectly improving growth, survival and general welfare of farmed H. discus hannai.
Año: 2018
Palabras claves: Abalone phototaxis, Locomotion to light/dark, Phototaxis heritability, Abalone farming, Selective breeding, Haliotis discus hannai
Referencia APA: Defranchi, Y., Winkler, F., Farías, W., Herbinger, C., & Brokordt, K. (2019). First insight into the heritable variation and potential response to selection of phototaxis and locomotion behavior associated to the light/dark stimuli in the abalone Haliotis discus hannai. Aquaculture, 500, 645-650. doi: 10.1016/j.aquaculture.2018.10.065
Travelling light: Fouling biota on macroplastics arriving on beaches of remote Rapa Nui (Easter Island) in the South Pacific Subtropical Gyre
Rech, S., Thiel, M., Borrell Pichs, Y., & García-Vazquez, E.
Marine anthropogenic debris was sampled from two beaches on the remote South Pacific island Rapa Nui (Easter Island). Abundance, composition, and the attached fouling assemblages on stranded litter were analysed. Most litter (n = 172 items found) was composed of plastic material, and 34% of all litter items were fouled. The main fouling species was the encrusting bryozoan Jellyella eburnea. Transporting vectors were exclusively made from plastics and were mainly small items and fragments, probably stemming from the South Pacific Subtropical Gyre. We present the first report of Planes major, Halobates sericeus, and Pocillopora sp. on anthropogenic litter in the South Pacific.
Año: 2018
Palabras claves: Non-indigenous species, Fouling assembly, Long-distance rafting, Marine anthropogenic litter, South Pacific Subtropical Gyre, Oceanic islands
Referencia APA: Rech, S., Thiel, M., Borrell Pichs, Y., & García-Vazquez, E. (2018). Travelling light: Fouling biota on macroplastics arriving on beaches of remote Rapa Nui (Easter Island) in the South Pacific Subtropical Gyre. Marine Pollution Bulletin, 137, 119-128. doi: 10.1016/j.marpolbul.2018.10.015
Asymmetric competitive effects during species range expansion: An experimental assessment of interaction strength between “equivalent” grazer species in their range overlap
Aguilera, M., Valdivia, N., Jenkins, S., Navarrete, S., & Broitman, B.
Biotic interactions are central to the development of theory and concepts in community ecology; experimental evidence has shown their strong effects on patterns of population and community organization and dynamics over local spatial scales. The role of competition in determining range limits and preventing invasions at biogeographic scales is more controversial, partly because of the complexity of processes involved in species colonization of novel habitats and the difficulties in performing appropriate manipulations and controls.
We examined experimentally whether competition is likely to affect poleward range expansion hindering or facilitating the establishment of the limpet Scurria viridula along the south‐eastern Pacific rocky shore (30°S, Chile) in the region occupied by the congeneric S. zebrina. We also assessed whether competition with the “invader” or range‐expanding species could reduce individual performance of the “native” S. zebrina and depress local populations Geographic field surveys were conducted to characterize the abundance and identity of limpets along the south‐eastern Pacific coast from 18°S to 41°S, and the micro‐scale (few cm) spatial distribution across the range overlap of the two species. Field‐based competition experiments were conducted at the southern leading edge of the range of S. viridula (33°S) and at the northern limit of S. zebrina (30°S).
Field surveys showed poleward range expansion of S. viridula of ca. 210 km since year 2000, with an expansion rate of 13.1 km/year. No range shift was detected for S. zebrina. The resident S. zebrina had significant negative effects on the growth rate of the invading juvenile S. viridula, while no effect of the latter was found on S. zebrina. Spatial segregation between species was found at the scale of cms.
Our results provide novel evidence of an asymmetric competitive effect of a resident species on an invader, which may hamper further range expansion. No negative effect of the invader on the resident species was detected. This study highlights the complexities of evaluating the role of species interactions in setting range limits of species, but showed how interspecific competition might slow the advance of an invader by reducing individual performance and overall population size at the advancing front.
Año: 2018
Palabras claves: Field experiments, Grazers, Pacific Ocean, Range overlap, Range shift, Transitional zone
Referencia APA: Aguilera, M., Valdivia, N., Jenkins, S., Navarrete, S., & Broitman, B. (2018). Asymmetric competitive effects during species range expansion: An experimental assessment of interaction strength between “equivalent” grazer species in their range overlap. Journal Of Animal Ecology, 88(2), 277-289. doi: 10.1111/1365-2656.12917
The 2017 coastal El Niño
Takahashi, K.; Aliaga-Nestares, V.; Avalos, G.; Bouchon, M.; Castro, A.; Cruzado, L.; Dewitte, B.; Gutiérrez, D.; Lavado-Casimiro, W.; Marengo, J.; Martínez, A. G.; Mosquera-Vásquez, K.; Quispe, N.
The original concept of El Niño consisted of anomalously high sea surface temperature and heavy rainfall along the arid northern coast of Peru (Carranza 1891; Carrillo 1893). The concept evolved into the El Niño–Southern Oscillation (ENSO; Bjerknes 1969), although the original El Niño and the Southern Oscillation do not necessarily have the same variability (Deser and Wallace 1987), and the strong El Niño episode in early 1925 coincided with cold-to-neutral ENSO conditions (Takahashi and Martínez 2017). To distinguish the near-coastal El Niño from the warm ENSO phase, Peru operationally defines the “coastal El Niño” based on the seasonal Niño 1+2 SST anomaly (ENFEN 2012; L’Heureux et al. 2017). While recent attention has been
brought to the concept of ENSO diversity (e.g., “central Pacific” vs “eastern Pacific” events; Capotondi et al. 2015), the coastal El Niño represents another facet of ENSO that requires further study in terms of its mechanisms and predictability.
Año: 2018
Palabras claves:
Referencia APA: Takahashi, K.; Aliaga-Nestares, V.; Avalos, G.; Bouchon, M.; Castro, A.; Cruzado, L.; Dewitte, B.; Gutiérrez, D.; Lavado-Casimiro, W.; Marengo, J.; Martínez, A. G.; Mosquera-Vásquez, K.; Quispe, N. (2018). The 2017 coastal El Niño. Bulletin of the American Meteorological Society. https://doi.org/10.1175/2018BAMSStateoftheClimate.1
Extreme El Niño Events
Dewitte, B., & Takahashi, K.
Every few years the tropical Pacific warms abnormally in association with a relaxation of the trade winds, a phenomenon known as the El Niño–Southern Oscillation (ENSO) that represents the strongest fluctuation of the global climate system. Although the contemporary observational record indicates that all El Niño events are not alike, differing in amplitude, warming pattern, and teleconnection, there is a class of events that stands out in terms of the societal and economical impacts: the extreme El Niño events that have occurred every 15–20 years. In this chapter, we propose an overview of the state of knowledge and of some current lines of research dedicated to extreme El Niño events. Building on the recently proposed concept of ENSO diversity, we further synthesize our current understanding of the nonlinear dynamics of this class of events and their expected evolution in a warmer climate and highlight some challenges in ENSO research.
Año: 2018
Palabras claves: El Niño, ENSO diversity, External forcing, Global warming, Teleconnection.
Referencia APA: Dewitte, B., & Takahashi, K. (2019). Extreme El Niño Events. Tropical Extremes, 165-201. doi: 10.1016/b978-0-12-809248-4.00006-6
Is Precipitation a Good Metric for Model Performance?
Tapiador, F., Roca, R., Del Genio, A., Dewitte, B., Petersen, W., & Zhang, F.
Precipitation has often been used to gauge the performances of numerical weather and climate models, sometimes together with other variables such as temperature, humidity, geopotential, and clouds. Precipitation, however, is singular in that it can present a high spatial variability and probably the sharpest gradients among all meteorological fields. Moreover, its quantitative measurement is plagued with difficulties, and there are even notable differences among different reference datasets. Several additional issues sometimes lead to questions about its usefulness in model validation. This essay discusses the use of precipitation for model verification and validation and the crucial role of highly precise and reliable satellite estimates, such as those from NASA’s Global Precipitation Mission Core Observatory.
Año: 2018
Palabras claves:
Referencia APA: Tapiador, F., Roca, R., Del Genio, A., Dewitte, B., Petersen, W., & Zhang, F. (2019). Is Precipitation a Good Metric for Model Performance?. Bulletin Of The American Meteorological Society, 100(2), 223-233. doi: 10.1175/bams-d-17-0218.1
Chapter 29 – Chile: Environmental Status and Future Perspectives
Aguilera, M., Aburto, J., Bravo, L., Broitman, B., García, R., & Gaymer, C., Gelcich, S., López, B.A., Montecino, V., Pauchard, A., Ramos, M., Rutllant, J.A., Sáez, C.A., Valdivia, N., Thiel, M.
The coast of mainland Chile extends from 18°S to about 56°S, and is about 4200 km long. In the north, the coast is characterized by continuous, regular, and wave-exposed shores, while to south of 40°S it is highly fragmented, with extensive fjords and small archipelagos with many wave-protected zones. The Humboldt Current System (HCS) determines oceanographic and ecological processes in the northern part, with persistent upwelling fronts and episodic “El Niño” events. In the southern part the southward-flowing Magellan Current is important. Coastal upwelling along the HCS sustains a diverse pelagic and benthic food web structure. Rocky coastal habitats are dominated by large kelp forests and filter-feeding species like reef-forming mussels and tunicates.
The main coastal habitats along the coast of Chile are rocky shores, sandy beaches, coastal wetlands, and dunes. The main populated zones are concentrated between 33°S to 35°S in central Chile, with economically important trading ports. Sewage discharges from large cities have the potential to increase nutrients levels in nearshore habitats causing localized eutrophication. Mining activities in northern Chile contaminate coastal waters, while in the south intensive aquaculture affects the fjord ecosystem. Also, subsistence harvesting (of kelps, molluscs, fish) is dramatically reducing the abundance of top consumers or habitat-forming species.
The diverse and productive coastal marine ecosystems are used by different socioeconomic activities and exposed to interventions which are potentially harmful. Ecosystem services should be managed, and necessary interventions carefully planned. Achieving sustainable use of natural marine resources and coastal ecosystem integrity is challenging, and a basic understanding of ecosystem responses to direct human impacts and global climate change require better monitoring strategies. The establishment of a marine reserve “Humboldt Current System” would be a major step toward this goal.
Año: 2019
Palabras claves: Continental Chile, Climate, Coastal Ecology, Human interventions, Humboldt Current System, Oceanography, Southeastern Pacific.
Referencia APA: Aguilera, M., Aburto, J., Bravo, L., Broitman, B., García, R., & Gaymer, C., Gelcich, S., López, B.A., Montecino, V., Pauchard, A., Ramos, M., Rutllant, J.A., Sáez, C.A., Valdivia, N., Thiel, M. (2019). Chile: Environmental Status and Future Perspectives. World Seas: An Environmental Evaluation, 673-702. doi: 10.1016/b978-0-12-805068-2.00046-2
Microplastic: What Are the Solutions?
Eriksen, M., Thiel, M., Prindiville, M., & Kiessling, T.
The plastic that pollutes our waterways and the ocean gyres is a symptom of upstream material mismanagement, resulting in its ubiquity throughout the biosphere in both aquatic and terrestrial environments. While environmental contamination is widespread, there are several reasonable intervention points present as the material flows through society and the environment, from initial production to deep-sea microplastic sedimentation. Plastic passes through the hands of many stakeholders, with responsibility for environmental contamination owned, shared, or rejected by plastic producers, product/packaging manufacturers, government, consumers, and waste handlers.
The contemporary debate about solutions, in a broad sense, largely contrasts the circular economy with the current linear economic model. While there is a wide agreement that improved waste recovery is essential, how that waste is managed is a different story. The subjective positions of stakeholders illuminate their economic philosophy, whether it is to maintain demand for new plastic by incinerating postconsumer material or maintain material efficacy through recycling, regulated design, and producer responsibility; many proposed solutions fall under linear or circular economic models. Recent efforts to bring often unheard stakeholders to the table, including waste pickers in developing countries, have shed new light on the life cycle of plastic in a social justice context, in response to the growing economic and human health concerns.
In this chapter we discuss the main solutions, stakeholder costs, and benefits. We emphasize the role of the “honest broker” in science, to present the best analysis possible to create the most viable solutions to plastic pollution for public and private leadership to utilize.
Año: 2017
Palabras claves: Extended producer responsibility, Marine debris solutions, Microplastic, Plastic marine pollution, Recycling, Reuse.
Referencia APA: Eriksen, M., Thiel, M., Prindiville, M., & Kiessling, T. (2017). Microplastic: What Are the Solutions?. The Handbook Of Environmental Chemistry, 273-298. doi: 10.1007/978-3-319-61615-5_13
The colonial ascidian Diplosoma listerianum enhances the occurrence of the hydrozoan Obelia sp. during early phases of succession
Krüger, I., Lenz, M. and Thiel, M.
Recruitment patterns of sessile species often do not reflect the composition of the local propagule pool. This is, among other processes, attributed to the stimulation or inhibition of settlement by resident species. In an experimental study, we evaluated the effects of different densities of the ascidian Diplosoma listerianum on the settlement of the hydrozoan Obelia sp. For this, we monitored the cover of the dominant fouler Obelia sp. on vertically orientated PVC tiles, which were either bare or pre-seeded with two different densities (sparse or dense) of Diplosoma colonies, over the course of 8 weeks. The settlement tiles were deployed at two study sites in La Herradura Bay, Chile. The presence of D. listerianum enhanced the settlement or the growth or both of the colonial hydrozoan, but this effect disappeared within 4–8 weeks. Furthermore, we tested whether the initial enhancement of Obelia sp. by Diplosoma colonies goes back to the fact that larvae, which reject the ascidian tunic as a settlement substratum after a first contact, colonize nearby surfaces because of their limited mobility. However, we found no support for this assumption. We rather suggest that D. listerianum facilitated colonization indirectly by the accumulation of organic material in its vicinity and/or by its pumping activity. Initial resident-mediated enhancement of the hydrozoan was overridden by processes such as competition between later colonizers within the course of weeks and we could not detect any lasting effects of D. listerianum on the structure of the developing communities.
Año: 2018
Palabras claves: Hard-bottom communities, Settlement, Facilitation, Diplosoma listerianum, Obelia sp.
Referencia APA: Krüger, I., Lenz, M. and Thiel, M. (2018). The colonial ascidian Diplosoma listerianum enhances the occurrence of the hydrozoan Obelia sp. during early phases of succession. Helgoland Marine Research, 72(1). https://doi.org/10.1186/s10152-018-0506-6
Protected areas in Chile: are we managing them?
Petit, I., Campoy, A., Hevia, M., Gaymer, C. and Squeo, F.
Background
Human population growth since the mid-1900s has been accompanied by an unsustainable use of natural resources and a corresponding impact on terrestrial and marine biota. In response, most states have established protected areas as tools to decrease biodiversity loss, being Chile one of the signatories of international conservation agreements such as the Convention on Biological Diversity (CBD) and the 2010 Aichi Targets. This study reviews the Chilean protected areas that have been created to date, with an emphasis on the existence and effectiveness of management plans for all terrestrial and marine protected areas.
Effectiveness was individually evaluated using two filters: 1) the age of the management plan and 2) the first four steps of the Protected Areas Management Effectiveness (PAME) methodology recommended by the IUCN.
Results
We show that 84 out of a total of 145 protected areas (PAs), and only five out of a total of 20 marine protected areas (MPAs), have management plans. Only 12% (N = 16) of PAs are effectively managed; while in the marine realm, no MPA has an effective plan.
Conclusions
Our results show the lack of both the effectiveness of and updates to the management plans for the vast majority of the national territory and raise the following question: is it sustainable to continue adding protected areas to the national system even though it is clear that the existing support is insufficient to meet the minimum requirements for full implementation?
Año: 2018
Palabras claves: AICHI targets, Biodiversity, Conservation, Chile, Effective management, MPA
Referencia APA: Petit, I., Campoy, A., Hevia, M., Gaymer, C. and Squeo, F. (2018). Protected areas in Chile: are we managing them?. Revista Chilena de Historia Natural, 91(1). dx.doi.org/10.1186/s40693-018-0071-z