The Vina del Mar - Concón Coastal strip is well known for its urban beaches, which play an essential role in the national economy. With extreme urban development, these beaches have become more polluted by litter. This paper evaluates the abundance, spatio-temporal distribution, typology, and sources of beach litter in 14 sectors located inside this coastal strip. A total of 19,886 litter items were collected and grouped into 50 different categories (11 litter typologies). Overall average litter abundance was 0.21 items/m2 while during the fall and winter averages were 0.25 items/m2 and 0.17 items/m2. Values changed along the area and between seasons. Plastics, cigarette butts and paper-cardboard typologies dominated the samples with 42% (0.088 items/m2), 25.4% (0.053 items/m2) and 20.8% (0.043 items/m2).

Along the Viña del Mar - Concón coastal strip 11,894 litter items were collected, and grouped into 48 different categories (11 litter typologies). The average litter abundance was 0.25 items/m2, plastic items, and cigarette butts being the most common. Hazardous litter can be found along the entire study area, reaching 28.9% (3438 items of 11,894 total items collected distributed in 14 different categories), and an average of 0.071 items/m2. The application of environmental evaluation indices based on litter data, allows categorizing the study area as a clean-moderate coastal strip with some presence of hazardous litter items, and unsatisfactory environmental conditions. Studied sectors were statistically grouped into three specific types that ranged from sectors in optimal environmental conditions (Group A) to sectors in adverse environmental conditions (Group C). The typology and magnitudes of litter found along the study area suggest a combination of sources that mainly include direct activities on the beach (recreational and smoking-related) as well dumping. In the same way, sanitary waste, ocean/waterway items, and items related to surfing activities were observed. Strategies for litter management and environmental quality improvement need to be developed and enforced.

The digestion efficiency of liquid industrial wastes increases when using bioreactors colonized by microbial biofilms. High concentrations of proteins derived from the fish processing industry lead to the production of ammonia, which inhibits methane production. Two bioreactors were constructed to compare methanogenic activity: one enriched with mMPA (methylaminotrofic methane production archaea) consortia (control bioreactor), and the second with NH3tolerant consortia (treatment bioreactor). Ammonia tolerant activity was assessed by applying an ammonia shock (755 mg NH3/L). Methane production, consumption of total organic carbon (TOC) and the taxonomic composition of bacteria and archaea was evaluated using 16S rDNA in the acclimatization, ammonia shock, and recovery phases.The ammonia shock significantly affected both methane production and the consumption of TOC in the control reactor (p< 0.05) and taxonomical composition of the microbial consortia (OTU). These values remained constant in the treatment reactor. The analysis of biofilm composition showed a predominance of Methanosarcinaceae (Methanomethylovoranssp., and probably two different species ofMethanosarcinasp.) in bioreactors. These results demonstrate that using acclimated biofilms enriched with ammonia tolerant methanogens control the inhibitory effect of ammonia on methanogenesis.

Seven oceanographic expeditions were conducted between the years 2013 and 2018 to determine the horizontal and vertical distribution schemes in the epipelagic and mesopelagic copepod community structure of the Caribbean Oceanic ecoregion (CAO) and the oceanographic variables that regulate it. Four indicator species are suggested for the North Equatorial Current and the Caribbean Surface Water (CSW) mass (Clausocalanus furcatus, Oncaea venusta, Temora stylifera and T. turbinate) and two indicator species for deep-water masses such as the Western North Atlantic Central Water (NACW) and the Antarctic Intermediate Water (AAIW) (Mormonilla phasma and Conaea rapax). The copepod assemblage responds to local oceanographic patterns that are regulated (24%) by the variability of dissolved oxygen and temperature in the water column. The horizontal structure of the copepod assemblage in offshore waters presented a spatial sectorization. Three zones were differentiated: (1) oceanic Colombian zone; (2) influence of the Magdalena River zone; and (3) offshore north-east zone. Water mass mixing processes and migration mechanisms favour the homogeneity of the vertical assemblage of copepods in the CAO ecoregion. This study provides relevant information on the structure and density of copepod species, providing key information to describe the ecological processes and the different responses to the oceanographic factors that modulate them.

In order to contribute with more integrative strategies for better identify areas of high conservation priority we study the coupling of physical and biological processes that sustain a deep subpopulation of the most caught sea urchin (Loxechinus albus) worldwide and its associated epibenthic community over a bathymetric depression in southern Chile, which is surrounded by intensive anthropic activities. We used a remotely operated vehicle (ROV) to characterize the epibenthic community (organisms > 15 mm long) and substrate, up to a depth of 112 m in a submarine hole. Additionally, a combination of a towed and a moored Acoustic Doppler current Profiler (ADCP) was used to characterize current patterns. We found evidence that physical mechanisms transport and retain macro and micro material in the bottom of the hollow, and they contribute to homogenizing the habitat along the entire bathymetric gradient. These coupled processes allow i) that several species expand their bathymetric distribution range, ii) the existence of nursery areas for fishes, iii) that characteristic grazers in shallow habitats colonize greater depths, where filter feeders or DOM consumers generally represent the typical epifauna. We hypothesize that coupling of physical and biological processes on this bathymetric depression are key for bring on Loxechinus albus along the entire bathymetric gradient, who in turn is key to the community structure of the hollow. Given that this particular habitat is surrounded by intensive anthropic activities (eg. salmon aquaculture, mussel aquaculture, fishing, port) and a city, we suggest: Firstly, that monitoring should be undertaken in order to observe biodiversity changes in the bathymetric gradient, since it could be an indicator of conservation status. Secondly, that a proposal should be formulated to consider this zone as a Marine Protected Area.

Abstract. Zooplankton are a key component of food webs in upwelling systems. Their distribution is influenced not only by mesoscale and climate dynamics but also by topography and local currents. Submarine canyons that incise the continental shelf can act as conduits, transporting deep, nutrient-rich waters to shallower regions and promoting coastal biological productivity. Consequently, these canyons facilitate the advection and accumulation of zooplankton. We aimed to describe the spatio-temporal variability in zooplankton distribution (using net samples and acoustic data) and their association with local currents in a long, narrow submarine canyon located in the highly productive continental shelf off central Chile. The backscattering strength (Sv), a proxy for zooplankton biomass, was highly variable on both diurnal and spatial scales. Higher Sv and abundances were found at night, following the classic diel vertical migration pattern. Zooplankton were not uniformly distributed within the canyon. In the surface and mid-depth layers, the canyon walls accumulated more zooplankton than the center, particularly during the nighttime. Within the canyon, the currents were asymmetrical and frequently reversed direction. When the positive along-canyon current was stronger on the northern slope, Sv was also higher on that wall. This pattern was especially evident in the section closer to the canyon head. We show that the Biobio Canyon is a highly dynamic environment where oceanographic conditions can rapidly shift. Our findings suggest a feasible mechanism for zooplankton retention driven mainly by along-canyon flow asymmetry and vertical migrations.

Una lista actualizada de las especies de sifonóforos de Colombia fue compilada a partir de registros en tesis publicadas e inéditas, e informes técnicos finales de proyectos del Invemar. El inventario más reciente publicado para las aguas marinas sudamericanas contiene algunos de los registros, pero deja fuera otros que se incluyen en este documento. Existe registro de 63 especies de sifonóforos en aguas marinas colombianas, 45 en el Mar Caribe y 46 en el Océano Pacífico oriental, de las familias Abylidae (9 especies), Diphyidae (30 especies), Hippopodiidae (5 especies), Prayidae (4 especies), Rhizophysidae (3 especies), Physaliidae (1 especie), Agalmatidae (9 especies), Apolemiidae (1 especie) y Physophoridae (1 especie).

Common sardine, Strangomera bentincki, support an important artisanal fishery along the Chilean coast; however, there is lack of knowledge of the early life history traits of this species. Using satellite-derived environmental conditions (sea surface temperature, SST, and chlorophyll-a), and otolith microstructure analysis of larval stages collected in coastal waters of central Chile, larval age, growth rates, and back-calculated yolk-sac absorption date patterns were analyzed for 2010–2013. SST varied from 11 to 20 °C and showed the highest values during austral summer 2013, whereas Chl-a varied between 0.2 and 66 mg m−3. The abundance of larval S. bentincki was similar during 2010 and 2011, decreased in 2012 but increased again in 2013 to similar densities of 2010 to 2011. Similarly, larvae collected during 2012 had the largest otoliths (radius, perimeter, area). Larval growth rates did not vary significantly among years and ranged between 0.32 and 0.42 mm day−1. From 2010 to 2011, a significant decrease occurred in the size-at-age of larval S. bentincki, and then, size-at-age was maintained until 2013. Back-calculated yolk-sac absorption dates differed among years and were delayed from winter to spring during 2012. The latter occurred in a period with significantly warmer waters. Additionally, SST and Chl-a concentration were not linearly related to the mean growth rates of larval S. bentincki.

El Yali is a complex wetlands system composed by more than 14 waterbodies, located in central Chile and delimited by two basins of the most important rivers of the region. Among the waterbodies is a coastal lagoon, some estuaries, artificial wetlands, salt mine and inner lagoons that were coastal lagoons in the past but due to tectonic processes have been moved and raised to their current location. The damming of the river that delimits the system to the south in 1968 cutoff the natural the sedimentary supply to the extensive beach and dunes, leaving the wetlands in a situation of vulnerability before climate change and variability, anthropic pressure, ocean swells and tsunamis. In the present chapter is illustrated the degradation that the wetlands system is suffering, by means of the estimation of tendencies of the long term records available in the zone, antecedents about its natural history, anthropic pressure and natural disasters like earthquakes, tsunamis, ocean swells and ENSO, along with field monitoring that has been carried out with the objective of implementing an ecological restoration. These antecedents show a decrease of precipitations and river discharges, an increase of ambient temperature and sea surface temperature, a rising of sea level and a change of the incident waves. El Yali was severely affected by the earthquake and tsunami in 2010, which destroyed 800 ha of beach and coastal dunes that provided natural protection. In many opportunities, El Yali was affected by earthquake and tsunamis, intense ocean swells and ENSO, all phenomena that dissipate energy destroying the natural barrier the dunes represent. However, before the construction of Rapel reservoir, the sedimentary supply allowed a rapid recovery of the beach, sandbar and dunes. When this sediment supply was cutoff, the dunes has enough material to support the equilibrium of the system for some decades, but when tsunami waves destroyed the dunes, there was no sand supply to restore the beach nor the dunes. This generated a substantial change in the system, turning it more vulnerable to tsunamis, even smaller, ocean swells, and sea-level raising associated to ENSO Kelvin waves and climate change. For this reason, the first proposed restoration action is to restore the dunes and plant a vegetal cover with native species that reinforce and maintain the dunes.

Abstract The effects of two contrasting environmental conditions in nearshore waters off central Chile on the diet and morphospace of two cohorts of larval labrisomid blenny Calliclinus geniguttatus were studied using geometric morphometrics and gut content analysis. The two environmental conditions corresponded to (a) a cold period with upwelling‐favourable southwesterly winds and a mixed water column of cooler water and (b) a warm period with calm winds and stratified warmer water. During the cold period, fish larvae had a more hydrodynamic head shape, longer jaws and a higher feeding incidence, suggesting a greater food supply due to upwelling events and a possible increase in encounter rates in the turbulent environment. In contrast, the larvae from the warm period had a more robust head shape with smaller jaws and a lower feeding incidence, which was related to higher water temperatures and lower wind intensities. The present study suggests that larvae have a rapid response to environmental changes on a short time scale ( i.e. , from weeks to months), showing a link between environmental conditions and changes in the phenotypic traits and diet of the larval stages of this cryptobenthic species.

The Chilean coastal zone (CCZ) is subjected to a complex spectrum of anthropogenic, geophysical, biogeochemical, and climate-driven perturbations. Potentially affected variables including atmospheric sea level pressure (Pa), alongshore wind, sea surface temperature (SST), chlorophyll-a, rainfall, river discharge, relative mean sea level (RMSL), and wave climate are studied using in situ and satellite records, hindcasts, and reanalysis datasets. Linear temporal trends and correlations of anomalies are estimated between 18°S and 55°S along the CCZ. The comparison of some of the variables is achieved by means of a strict homogenization procedure on a monthly basis for 35 years. Our findings show that the poleward drift and strengthening of the Southeast Pacific Subtropical Anticyclone (SPSA) partially explains the increase in Pa and reduction in rainfall and river discharge. The enhancement of alongshore winds, also attributable to changes in the SPSA, increases coastal upwelling, which in turn could reduce SST and increase chlorophyll-a. Despite differential latitudinal responses, increasing wave heights and a southward rotation are evidenced. RMSL does not show significant variation as it is presumably affected by seafloor changes during the seismic cycle. Though some correlations are evidenced, the influence of climate variability at decadal scale (PDO, SAM) may be affecting the detected trends due to the short length of available data. Impacts on coastal communities, infrastructure, and ecosystems are discussed, aiming to highlight that coastal vulnerabilities and risk management should be based on the cumulative impacts of these variables.

A Correction to this paper has been published: https://doi.org/10.1007/s10584-020-02952-7

Twelve egg capsules laid in captivity by three females of Dipturus chilensis were incubated in the laboratory. After 252 ± 9.4 days, 10 skates successfully hatched, with a mean total length, disc length, and disc width of 17.2, 7.4, and 11.4 cm, respectively. This is the first report of captive hatching of D. chilensis and its corresponding incubation period.

Little has been studied of the food metrics of most chondrichthyans, which provide baseline information for the assessment of fishing status to guide the development of ecosystem-based management plans. Therefore, the main goal of this study was to approach the isotopic niche of Dipturus chilensis and Callorhinchus callorynchus in the Bay of Valparaíso (central Chile). The main findings showed that C. callorynchus presented a narrow ellipse (E= 0.79; RC= 4.14; θ= 1.39), meanwhile D. chilensis, presented an ellipse with greater extension (E= 0.95; RC= 8.23; θ=-0.11), therefore a wide isotopic niche.

Abstract Larval growth, age, growth effect and instantaneous mortality were estimated in anchoveta, Engraulis ringens , collected biweekly during the austral winter of 2014 in nearshore waters off Bay of Antofagasta (23°41′W–70°30′S), northern Chile. Through measuring standard length ( SL ) and sagitta microstructure analysis, it was estimated that the growth rate of E. ringens larvae decreased from June (0.85 mm day −1 ) to August (0.50 mm day −1 ). However, the water temperature was homogeneous during the sampling dates (14.6, 15.2, 14.4, and 14.6°C), suggesting that the decelerating larval growth was not linked to changes in sea temperature. Additionally, larvae with slow growth have larger otoliths compared with conspecifics with fast growth (growth effect). Larval mortality rates tended to decrease until the middle of July (0.18 per day) but increased to 0.25 per day in early August, which coincided with lower food availability (i.e., chlorophyll‐a, 2.7–5.6 mg m −3 ) and a high occurrence of smaller larvae (1.58–11.5 mm). Partial least squares analysis indicates low covariance between the biological and oceanographic variables ( PLS : 11.71%), suggesting that other factors, such as parental effects, may explain the abrupt decrease in the larval growth rates.

Patagonian grenadier migrates from the southwest Atlantic and southeast Pacific to reproduce in the northern Chilean Patagonia. Spawning occurs mainly in winter at the continental shelf break (CSB), but eggs and larvae are also collected inshore of the Chilean Patagonian Estuarine System (PES) during winter and spring. In order to evaluate whether the ontogenetic changes in distribution of early life stages was part of the reproductive strategy of Patagonian grenadier, we analyzed the distribution and transport of eggs and larvae in spring and winter in three channels of the PES (Ninualac, Darwin and Pulluche channels). Ichthyoplankton stratified sampling showed the highest abundances of eggs in the deepest strata, whereas larvae were heterogeneously distributed along the entire water column. Residual current velocities obtained from ADCP indicated seaward (westward) fluxes at the surface in all channels, except in Pulluche in winter. At depth (50–100 m) fluxes were eastward (inshore) in the northern 2 channels but seaward in the southernmost channel. These differences in residual velocities, with variations in the distribution of eggs and larvae, resulted in different landward and oceanward flows of eggs and larvae among channels and strata. Estimated net fluxes in winter suggested that eggs within the channels would either enter the PES from the continental shelf, mainly at the subsurface layer of the Darwin channel, or come from a secondary spawning within this same channel. Eggs and small larvae would be retained at the inshore zone of the Darwin channel, and the more advanced developed stages would be exported through the Pulluche channel back to the continental shelf. The inshore high abundance of eggs and larvae of M. magellanicus in winter, along with the reduced primary production and microbial-based plankton community previously reported, suggest that entering the channels in winter is not a major part of the reproductive strategy of the species. The exportation of larvae from the channels to the shelf in winter, instead, might promote better feeding conditions in offshore waters where larger zooplankton occurs.

Abstract Early life history traits of small pelagic fish are usually affected by environmental conditions. Patagonian sprat, Sprattus fuegensis , is a small pelagic fish that inhabits the continental shelf, fjords and channels of Patagonia. Their larvae are usually exposed to large variations in physical and biological conditions. We evaluated the effects of environmental conditions on early life history traits of this key species encompassing over 20 years of information. The characterization of oceanographic features, larval abundance and distribution was carried out in western Patagonia between 1996 and 2019, while the growth and mortality rates were estimated for the austral spring 2019 between 49°54′S and 53°55′S. Larval abundance decreased three to ten times from 1996 to 1997 to the rest of the study period (2008–2010 and 2014–2019), with larger abundances being found over the shelf. In spring 2019, the growth rate was 0.20 ± 0.05 mm d −1 for larvae between 9 and 19 days after hatching. The growth rate was similar in partially stratified (7–50 J m −3 ) and stratified waters (50–100 J m −3 ), but slower in mixed waters (< 7 J m −3 ). GAM modelling showed that the faster larval growth occurred in partially stratified waters with temperatures above 7.5°C. Natural mortality rates were higher in partially stratified waters (24% of daily loss), lower in stratified areas (14%) and the lowest in the mixed water column (12%). Accordingly, larvae living in channels had faster growth rates but higher daily mortality, while those that hatched or were advected to water parcels on the continental shelf had slower growth but lower daily mortality. Finally, these latter traits may be an example of an inverse growth‐selective survival strategy.

In this work 10 years of data (1986-1996) from a fixed station located in the northern part of Valparaíso Bay (33º00’S; 71º35’W) were analysed to study the influence of coastal upwelling activity on the temporal variation of micro-phytoplankton (20-200 μm) and their relationship with oceanographic conditions. The upwelling activity at the bay was associated to semi-annual wind regime with an intensification of upwelling-favourable S-SW winds from September to March followed by a decrease and the occurrence of downwelling events from April to August. Oceanographic conditions showed the ascent of cold, nutrient-rich salty water in spring (September-November). However, during summertime under highest upwelling index, thermal stratification conditions were registered. This stratification might be associated to either the solar radiation or the presence of an upwelling shadow area in the bay. The upwelling period had the highest micro-phytoplankton abundance mainly dominated by diatoms. This period was associated with an increase in biomass and richness in the bay. Meanwhile during non-upwelling period —under homogenous conditions of temperature, salinity and nutrients— an increase in diversity (but low abundance and richness) associated to dinoflagellates and silicoflagellates was noted. Therefore, the results suggest the presence of a bi-modal regime of micro-phytoplankton in the bay in response to changes in oceanographic conditions related to local wind forcing and mixing/stratification.

Fjords are sensitive areas affected by climate change and can act as a natural laboratory to study microbial ecological processes. The Chilean Patagonian fjords (41–56°S), belonging to the Subantarctic ecosystem (46–60°S), make up one of the world’s largest fjord systems. In this region, Estuarine Water (EW) strongly influences oceanographic conditions, generating sharp gradients of oxygen, salinity and nutrients, the effects of which on the microbial community structure are poorly understood. During the spring of 2017 we studied the ecological patterns (dispersal and oceanographic factors) underlying the microbial community distribution in a linear span of 450 km along the estuarine-influenced Chilean Patagonian fjords. Our results show that widespread microbial dispersion existed along the fjords where bacterioplankton exhibited dependence on the eukaryotic phytoplankton community composition. This dependence was particularly observed under the low chlorophyll- a conditions of the Baker Channel area, in which a significant relationship was revealed between SAR11 Clade III and the eukaryotic families Pyrenomonadaceae (Cryptophyte) and Coccomyxaceae (Chlorophyta). Furthermore, dissolved oxygen and salinity were revealed as the main drivers influencing the surface marine microbial communities in these fjords. A strong salinity gradient resulted in the segregation of the Baker Channel prokaryotic communities from the rest of the Patagonian fjords. Likewise, Microbacteriaceae, Burkholderiaceae and SAR11 Clade III, commonly found in freshwater, were strongly associated with EW conditions in these fjords. The direct effect of EW on the microbial community structure and diversity of the fjords exemplifies the significance that climate change and, in particular, deglaciation have on this marine region and its productivity.

The inter-annual variability of oceanographic conditions and phytoplankton abundance and biomass was studied using 10 years (1986-1996) of in situ observations at a fixed station in Valparaíso Bay (~33ºS). The time series analysis revealed that strong S-SW winds drive a quasi-permanent upwelling activity that maintain the nutrients availability in the water column to fuel the phytoplankton in the bay. The most important changes in bio-oceanographic conditions were observed during 1987 El Niño event, which was characterized by higher temperatures but lower values for salinity, nitrate, and phosphate concentrations, together with a decrease of phytoplankton biomass compared to 1988 La Niña event when colder, saltier, and nutrient-rich upwelled water were observed. High Aconcagua River discharges were observed during the El Niño conditions (1987-1988 and 1993), which led to a decrease in surface salinity and a high abundance of dinoflagellates. Two periods with differences in bio-oceanographic conditions were observed; 1988-1992 showed lower temperatures but higher nutrients (nitrate), phytoplankton biomass and abundance of diatoms than 1993-1996 period. Throughout the study period, positive trends in upwelling activity was registered accompanied by a fall in phytoplankton biomass and dinoflagellate abundance. This paper provides new evidences concerning the influence of El Niño Southern Oscillation (ENSO) in phytoplankton and oceanographic conditions in the coastal upwelling off central Chile.