THE COAST OF CENTRAL CHILE HAS MULTIPLE RIVERS WITH A MARKED SEASONAL DISCHARGE VARIABILITY. FEW STUDIES HAVE ADDRESSED PRIMARILY THE SEASONAL VARIABILITY OF RIVER PLUME EXTENSION AND VERTICAL STRUCTURE. HERE, WE HAVE ANALYZED THE EFFECTS OF MULTIPLE RIVER OUTFLOWS ON THE HYDROGRAPHY (SALINITY AND DENSITY) AND MERIDIONAL TRANSPORTS OFF CENTRAL CHILE. THIS STUDY IS FOCUSED ON SYNOPTIC AND INTRASEASONAL SCALES OF VARIABILITY USING EIGHT YEARS OF SEMI-REALISTIC MODEL OUTPUTS. OUR RESULTS REVEAL THAT THE PLUME SPREADING IS MUCH BROADER DURING WINTER THAN SPRING. WIND-DRIVEN CHANGES IN PLUME SHAPES MODULATE THE GEOSTROPHIC COMPONENT OF THE FLOW FIELD OFF BIOBÍO AND ITATA RIVERS IN WINTER (SPRING) AFTER DOWNWELLING (UPWELLING) FAVORABLE WINDS. THE GEOSTROPHIC FLOW WAS IMPORTANT OFF MATAQUITO AND MAULE RIVERS AFTER UPWELLING-FAVORABLE WINDS, PRIMARILY IN SPRING. THE STRATIFICATION IN WINTER WAS MOSTLY ASSOCIATED WITH THE FRESHWATER CONTENT IN ALL COASTAL REGIONS AND SHOWED A RAPID RESPONSE TO THE WIND STRESS FORCING. THE MIXING THROUGH WIND STRESS DECREASED IN SPRING, MODIFYING THE STRATIFICATION AND UNCOUPLING THE WINTERTIME VARIABILITY BETWEEN STRATIFICATION AND FRESHWATER.

ESTUARIES AND SALTMARSHES PLAY A FUNDAMENTAL ROLE IN THE LIFE CYCLE OF MANY CRAB SPECIES. DIVERSE STUDIES SHOW THAT TEMPERATURE AND SALINITY MODULATE ABUNDANCE, SIZE FREQUENCY DISTRIBUTION (SFD), SEX RATIO AND GROWTH IN CRUSTACEANS. THESE POPULATION PARAMETERS ARE USUALLY CHALLENGING TO ESTIMATE DUE TO THE HIGH ENVIRONMENTAL VARIABILITY OF ESTUARIES. MONTHLY SAMPLES OF THE ESTUARINE CRAB HEMIGRAPSUS CRENULATUS WERE TAKEN FROM OCTOBER 2003 TO OCTOBER 2004 (EXCEPT JULY 2004) IN THE TUBUL ESTUARY, CENTRAL CHILE. WE QUANTIFIED TEMPORAL CHANGES IN ABUNDANCE, SIZE DISTRIBUTION, SEX RATIO AND MONTHLY GROWTH THROUGH THE ANNUAL CYCLE. A TOTAL OF 1025 INDIVIDUALS WERE COLLECTED. SIZES RANGED FROM 7.72?33.51 MM CARAPACE LENGTH (CL) WITH A GROWTH RATE RANGING BETWEEN 2.13?30.5% MM CL MO?1. SIZE AND GROWTH RATES WERE GREATER IN SPRING-SUMMER, SUGGESTING A FASTER GROWTH OF YOUNGER CRABS CORRELATED WITH INCREASING SEA TEMPERATURES IN THE AUSTRAL SUMMER. OVERALL, SEX RATIO WAS 1.75:1 IN FAVOUR OF MALES. MODAL ANALYSIS IDENTIFIED AT LEAST SEVEN COHORTS COHABITING THROUGHOUT THE ANNUAL CYCLE. GROWTH PARAMETERS FOR MALES AND FEMALES WERE THE FOLLOWING, RESPECTIVELY: L? = 33.6 AND 29.6, K = 0.69 AND 0.91, T0 = ?0.39 AND ?0.28. CHANGES IN SIZE DISTRIBUTION SUGGESTED A RECRUITMENT PERIOD DURING AUTUMN AND WINTER SEASONS WHEN THERE ARE LOWER SALINITIES AND TEMPERATURE FLUCTUATIONS STRESSES. GENERALIZED LINEAR MODELS INDICATED THAT SEA TEMPERATURE, SALINITY AND CHLOROPHYLL WERE THE ENVIRONMENTAL VARIABLES THAT BETTER PREDICTED THE ANNUAL PATTERNS IN THE POPULATION STRUCTURE.

THE COASTAL REGION OFF CHILEAN PATAGONIA HAS BEEN POORLY STUDIED DUE TO THE LACK OF AVAILABLE OBSERVATIONS. HERE WE ANALYZED, BY THE VERY FIRST TIME, BIOGEOCHEMICAL (BGC) DATA TO ELUCIDATE THE ROLE THAT BIOLOGICAL AND PHYSICAL PROCESSES PLAY ON NITRATE, OXYGEN, PH AND HYDROGRAPHIC VARIABLES, ALONG A SALINITY GRADIENT OFF CENTRAL PATAGONIA. ARGO FLOAT PROFILES COVERING THE UPPER OCEAN FROM DECEMBER 2015 TO JULY 2019 REVEAL THAT OFFSHORE WATERS ARE CHARACTERIZED BY LOW TEMPERATURES AND HIGH SALINITIES RELATED TO HIGH OXYGEN AND MEDIUM-HIGH VALUES OF PH AND NITRATE. AS THE ARGO FLOAT DRIFTED ONSHORE, FRESHWATER INFLUENCES THE UPPER 50?100 M WITH LOW SALINITY AND HIGH TEMPERATURE. WATERS UNDER THE INFLUENCE OF THE CONTINENTAL RUNOFF WERE CHARACTERIZED BY MEDIUM-TO-HIGH OXYGEN AND PH LEVELS, AND THE LOWEST NITRATE CONCENTRATIONS. INTERESTINGLY, OXYGEN-DEFICIENT WATERS LOCATED BENEATH THE FRESHWATER-MODIFIED LAYER SHOWED THE LOWEST PH AND HIGHEST NITRATE. A COMPREHENSIVE ANALYSIS OF THE TEMPORAL AND VERTICAL VARIABILITY OF THE OXYGEN:NITRATE RATIO, IN CONJUNCTION WITH BIOLOGICAL-RELATED AND PHYSICAL PARAMETERS, INDICATES THAT THE BGC VARIABILITY SEEMS TO BE THE RESULT OF A SYNERGISTIC INTERACTION BETWEEN PHYSICAL AND BIOLOGICAL PROCESSES, WHERE THE STRATIFICATION SETS UP THE ENVIRONMENT AND PROMOTES THE BIOLOGICAL RESPONSE THAT, IN TURN, IS AUTO-REGULATED BY MODIFYING THE CHEMICAL COMPOSITION IN THE FRESHWATER-INFLUENCED ZONE. THE ARRIVAL OF FUTURE FLOATS WITH ADDITIONAL SENSORS (CHLOROPHYLL/FLUORESCENCE, PHOTOSYNTHETICALLY ACTIVE RADIATION, BACKSCATTER, ETC.) WILL ADD NEW BGC PROPERTIES THAT IMPROVE OUR UNDERSTANDING OF THE COASTAL MARINE RESPONSE TO THE INCREASING FRESHWATER INPUT OFF WESTERN PATAGONIA IN THE CONTEXT OF CLIMATE CHANGE.

THE INCREASING SHELLFISH AQUACULTURE REQUIRES KNOWLEDGE ABOUT NEARSHORE ENVIRONMENTAL VARIABILITY TO MANAGE SUSTAINABLY AND CREATE CLIMATE CHANGE ADAPTATION STRATEGIES. WE USED DATA FROM MOORING TIME SERIES AND IN SITU SAMPLING TO CHARACTERIZE OCEANOGRAPHIC AND CARBONATE SYSTEM VARIABILITY IN THREE BIVALVE AQUACULTURE AREAS LOCATED ALONG A LATITUDINAL GRADIENT OFF THE HUMBOLDT CURRENT SYSTEM. OUR RESULTS SHOWED PHT

COLORED DISSOLVED ORGANIC MATTER (CDOM) IS AN INDICATOR AND OPTICAL PROXY OF TERRESTRIAL PROCESSES SUCH AS LAND USE WITH ALLOCHTHONOUS MATERIAL FLUXES, BIOGEOCHEMICAL CYCLES, AND WATER QUALITY IN COASTAL ZONES INFLUENCED BY RIVERS. HOWEVER, THE ROLE OF LAND USE CHANGES ON THE SPATIAL AND TEMPORAL AVAILABILITY OF CDOM HAS BEEN POORLY EXPLORED IN CHILE. HERE, WE STUDIED TWO WATERSHEDS WITH SIMILAR CLIMATES AND CONTRASTING LAND USE PATTERNS IN NORTHERN PATAGONIA CONSIDERING THE SAMPLING OF CDOM IN THEIR ESTUARINE AND ADJACENT COASTAL OCEAN. AN EMPIRICAL ALGORITHM WITH THE COEFFICIENTS ADJUSTED TO OUR STUDY AREAS TO ESTIMATE CDOM WAS APPLIED TO LANDSAT 7 AND 8 IMAGES TO EXAMINE TEMPORAL VARIABILITY OF CDOMEST FROM 2001 TO 2011 AND 2013-2020. OUR RESULTS SHOWED AN INCREASING TREND OF CDOMEST IN BOTH AREAS. DIFFERENT TRENDS IN LAND USE PATTERNS BETWEEN THE TWO WATERSHEDS SHOWED A SIGNIFICANT CORRELATION WITH CDOMEST AND CONTRASTING ASSOCIATIONS WITH ENVIRONMENTAL VARIABLES. HIGHER HUMIFICATION WAS FOUND IN YALDAD IN COMPARISON WITH COLU. IN BOTH AREAS, ALLOCHTHONOUS MATERIALS PREDOMINATED, ESPECIALLY DURING AUSTRAL SPRING ACCORDING TO THE LOW VALUES OF THE FLUORESCENCE INDEX (FI). OUR RESULTS HIGHLIGHT THE POTENTIAL OF CDOMEST TO PARAMETERIZE BIOGEOCHEMICAL CYCLING MODELS AND TO FURTHER UNDERSTAND THE DYNAMICS OF CDOM IN COASTAL ECOSYSTEMS.

WIND-DRIVEN UPWELLING PROMOTES THE ONSHORE TRANSPORT OF DENSE SLOPE WATERS ONTO THE CONTINENTAL SHELF. NEW OBSERVATIONAL EVIDENCE SUGGESTS THAT THE PROPAGATION OF COASTAL TRAPPED WAVES (CTWS) OVER A SUBMARINE CANYON CAN ALSO CAUSE UPWELLING WITHIN THE CANYON, INDEPENDENT OF THE WIND FORCING. HERE, WE USE IDEALIZED NUMERICAL EXPERIMENTS TO ASSESS THE ROLE OF CTWS IN PROMOTING THE ONSHORE TRANSPORT OF DEEPER WATERS ONTO THE CONTINENTAL SHELF. THE EXPERIMENTS ARE FORCED WITH A 7-DAYS PERIOD CTW. OVERALL, THERE IS ACCUMULATED UPWELLED WATER IN TIME WITH INCREASED ONSHORE TRANSPORT DURING THE LOW SEA LEVEL PHASE OF THE CTWS. MOST OF THE ONSHORE FLOW IS SPREAD OVER THE UPWAVE SIDE OF THE CANYON DURING THE LOW SEA LEVEL PHASE, BUT IT IS ADVECTED FURTHER DOWNWAVE DURING THE SUBSEQUENT HIGH SEA LEVEL PHASE. AS A RESULT, A DENSE POOL OF UPWELLED WATER IS SPREAD OVER THE SHELF EXTENDING PRIMARILY IN THE DOWNWAVE DIRECTION.

USING 19 YEARS OF REMOTELY SENSED ENHANCED VEGETATION INDEX (EVI), WE EXAMINED THE EFFECTS OF CLIMATIC VARIABILITY ON TERRESTRIAL VEGETATION OF SIX PROTECTED AREAS ALONG SOUTHWESTERN SOUTH AMERICA, FROM THE SEMIARID EDGE OF THE ATACAMA DESERT TO SOUTHERN PATAGONIA (30?S?51?S). THE RELATIONSHIP BETWEEN SATELLITE PHENOLOGY AND CLIMATE INDICES, NAMELY MEI (MULTIVARIATE ENSO INDEX), PDO (PACIFIC DECADAL OSCILLATION) AND SAM (SOUTHERN ANNULAR MODE) WERE ESTABLISHED USING STATISTICAL ANALYSES FOR NON-STATIONARY PATTERNS. THE ANNUAL MODE OF PHENOLOGICAL ACTIVITY FLUCTUATED IN STRENGTH THROUGH TIME FROM THE SEMIARID REGION TO THE BORDER OF SOUTHERN PATAGONIA. CONCOMITANTLY, ENHANCED SYNCHRONY BETWEEN EVI AND CLIMATIC OSCILLATIONS APPEARED OVER INTERANNUAL CYCLES. CROSS CORRELATIONS REVEALED THAT VARIABILITY IN MEI WAS THE LEAD PREDICTOR OF EVI FLUCTUATIONS OVER SCALES SHORTER THAN 4 MONTHS AT LOWER LATITUDES AND FOR THE MOST POLEWARD STUDY SITE. THE PDO WAS CORRELATED WITH EVI OVER LAGS LONGER THAN 4 MONTHS AT LOW LATITUDE SITES, WHILE THE SAM SHOWED RELATIONSHIPS WITH EVI ONLY FOR SITES LOCATED AROUND 40?S. OUR RESULTS INDICATE THAT THE LONG-TERM PHENOLOGICAL VARIABILITY OF THE VEGETATION WITHIN PROTECTED AREAS ALONG SOUTHWESTERN SOUTH AMERICA IS CONTROLLED BY PROCESSES LINKED TO CLIMATE INDICES AND THAT THEIR INFLUENCE VARIES LATITUDINALLY. FURTHER STUDIES OVER LONGER TIME SCALES WILL BE NEEDED TO IMPROVE OUR UNDERSTANDING THE IMPACTS OF CLIMATE CHANGE ON VEGETATION CONDITION AND ITS EFFECT OVER PHENOLOGICAL VARIABILITY.

RIVER-INFLUENCED COASTAL AREAS ARE IMPORTANT ECOSYSTEMS DUE TO THE CRITICAL INFLUENCE OF RIVER RUNOFF ON NUTRIENTS AND THE STRUCTURE OF PLANKTONIC AND BENTHIC COMMUNITIES. MANY STUDIES HAVE FOCUSED ON THE INTERACTION AMONG RIVER RUNOFF, WIND, TIDES AND RIVER PLUME CHARACTERISTICS, AND BASED ON OBSERVATIONS AND MODELING RESULTS. THIS STUDY AIMS TO IMPROVE OUR UNDERSTANDING ABOUT THE CIRCULATION AND SEASONAL PATTERN OF RIVER PLUMES OFF CENTRAL CHILE, USING CLIMATOLOGICAL SIMULATIONS IN THE REGIONAL OCEAN MODELING SYSTEM (ROMS). RESULTS WERE IN REASONABLE AGREEMENT WITH SATELLITE (MODIS) OBSERVATIONS. THE PLUMES EXHIBIT A MINIMAL AREA COVER DURING SUMMER-FALL, WITH A NORTHWEST ORIENTATION AS RESULT OF DOMINANT SOUTHWESTERLY WINDS AND LOW RIVER DISCHARGES. A LARGER PLUME AREA IS DEVELOPED DURING JUNE?SEPTEMBER, AS RESULT OF HIGHER WINTER PRECIPITATIONS. THE ORIENTATION OF THE PLUMES DURING WINTER IS WESTWARD, DRIVEN BY HIGHER RIVER DISCHARGES AND WINDS BLOWING IN THE SOUTHEAST DIRECTION. AN INTERESTING FEATURE REPRODUCED BY THE MODEL WAS THE TREND TO COALESCE AS OBSERVED IN PREVIOUS STUDIES USING SATELLITE IMAGERY.

AIM WE ASSESS THE SPATIAL DISTRIBUTION OF A SUITE OF COASTAL BIOPHYSICAL CHARACTERISTICS AND HOW THEIR VARIABILITY IS RELATED TO THE DISTRIBUTION AND GEOGRAPHIC RANGE OF A DIVERSE ASSEMBLAGE OF COASTAL BENTHIC SPECIES WITH DIFFERENT LARVAL DISPERSAL STRATEGIES. LOCATION SOUTH-EASTERN PACIFIC (SEP) COAST BETWEEN 18°20S AND 42°35S. METHODS BIOPHYSICAL VARIABILITY WAS ASSESSED USING CHLOROPHYLL-A CONCENTRATION, SEA SURFACE TEMPERATURE AND THE SIGNAL OF TURBID RIVER PLUMES DERIVED FROM MODIS ONBOARD THE AQUA SATELLITE. WE ESTABLISHED THE DOMINANT SPATIAL COMPONENTS USING WAVELET AND COHERENCE ANALYSIS, AND EVALUATED THE BIOGEOGRAPHIC STRUCTURE OF 51 ROCKY INTERTIDAL SPECIES SAMPLED OVER ~2,600 KM ALONG THE SEP USING MULTIVARIATE CLASSIFICATION AND REGRESSION TREES. RESULTS BIOGEOGRAPHIC BREAKS DETECTED HERE WERE CONSISTENT WITH RECENT BIOGEOGRAPHIC CLASSIFICATION SCHEMES. DISTRIBUTION BREAKPOINTS FOR SPECIES WITH LECITHOTROPHIC LARVAE CLUSTERED AROUND 30°S. WE OBSERVED A PREVIOUSLY UNREPORTED BREAK IN THE DISTRIBUTION OF SPECIES WITH PLANKTOTROPHIC LARVAL DISPERSAL STRATEGIES AROUND 35°S. THESE BREAKS ARE RELATED TO COHERENCE IN THE SPATIAL STRUCTURE OF SEA SURFACE TEMPERATURE, CHLOROPHYLL-A AND RIVER OUTFLOW OVER DIFFERENT TEMPORAL SCALES. REGIONS WITH SIMILAR BIOPHYSICAL CHARACTERISTICS, AND THE BREAKS THE SEPARATE THEM, ARE IN STRIKING AGREEMENT WITH THE BIOGEOGRAPHIC PATTERNS REVEALED BY THE MULTIVARIATE CLASSIFICATION TREES. MAIN CONCLUSIONS OUR RESULTS RECONCILE PATTERNS OF BIOGEOGRAPHIC STRUCTURE REPORTED FOR OTHER GROUPS OF SPECIES ALONG THE SEP COAST. WE SUGGEST THAT RIVER OUTFLOW, A POORLY STUDIED COASTAL ENVIRONMENTAL FORCING, MAY PLAY AN IMPORTANT ROLE IN DETERMINING THE GEOGRAPHIC DISTRIBUTION OF ROCKY SHORE SPECIES, PROBABLY THROUGH ITS EFFECTS ON LARVAL DISPERSAL PATTERNS.

HARMFUL ALGAL BLOOMS (HAB) POSE A SEVERE SOCIO-ECONOMIC PROBLEM WORLDWIDE. THE DINOFLAGELLATE SPECIES ALEXANDRIUM CATENELLA PRODUCES POTENT NEUROTOXINS CALLED SAXITOXINS (STXS) AND ITS BLOOMS ARE ASSOCIATED WITH THE HUMAN INTOXICATION NAMED PARALYTIC SHELLFISH POISONING (PSP). KNOWING WHERE AND HOW THESE BLOOMS ORIGINATE IS CRUCIAL TO PREDICT BLOOMS. MOST STUDIES IN THE CHILEAN PATAGONIA, WERE FOCUSED ON COASTAL AREAS, CONSIDERING THAT BLOOMS FROM THE ADJACENT OCEANIC REGION ARE ALMOST NON-EXISTENT. USING A COMBINATION OF FIELD STUDIES AND MODELLING APPROACHES, WE FIRST EVALUATED THE ROLE OF THE CONTINENTAL SHELF OFF NORTHERN CHILEAN PATAGONIA AS A SOURCE OF A. CATENELLA RESTING CYSTS, WHICH MAY ACT AS INOCULUM FOR THEIR TOXIC COASTAL BLOOMS. THIS AREA IS CHARACTERIZED BY A SEASONAL UPWELLING SYSTEM WITH POSITIVE EKMAN PUMPING DURING SPRING-SUMMER, AND BY THE PRESENCE OF SIX MAJOR SUBMARINE CANYONS. WE FOUND OUT THAT THESE SUBMARINE CANYONS INCREASE THE VERTICAL ADVECTION OF BOTTOM WATERS, AND THUS, SIGNIFICANTLY ENHANCE THE PROCESS OF COASTAL UPWELLING. THIS IS A PREVIOUSLY UNREPORTED FACTOR, AMONG THOSE INVOLVED IN BLOOM INITIATION. THIS FINDING PUT THIS OFFSHORE AREA AT HIGH RISK OF RESUSPENSION OF RESTING CYSTS OF A. CATENELLA. HERE, WE DISCUSS IN DETAIL THE PHYSICAL PROCESSES PROMOTING THIS RESUSPENSION.

HUMAN ACTIVITIES HAVE LED TO AN INCREASE IN LAND USE CHANGE, WITH EFFECTS ON THE STRUCTURE AND FUNCTIONING OF ECOSYSTEMS. THE IMPACT OF CONTRASTING LAND USES ALONG RIVER BASINS ON THE CONCENTRATION OF COLORED DISSOLVED ORGANIC MATTER (CDOM) REACHING THE COASTAL ZONE, AND ITS RELATIONSHIP WITH THE CARBONATE SYSTEM OF THE ADJACENT COASTAL OCEAN, IS POORLY KNOWN. TO UNDERSTAND THE RELATIONSHIP BETWEEN LAND USE CHANGE, CDOM AND ITS INFLUENCE ON THE CARBONATE SYSTEM, TWO WATERSHEDS WITH CONTRASTING LAND USES IN SOUTHERN CHILE WERE STUDIED. THE SAMPLES WERE COLLECTED AT EIGHT STATIONS BETWEEN RIVER AND ADJACENT COASTAL AREAS, DURING THREE SAMPLING CAMPAIGNS IN THE AUSTRAL SUMMER AND SPRING. CHEMICAL AND BIOLOGICAL SAMPLES WERE ANALYZED IN THE LABORATORY ACCORDING TO STANDARD PROTOCOLS. LANDSAT 8 SATELLITE IMAGES OF THE STUDY AREA WERE USED FOR IDENTIFICATION AND SUPERVISED CLASSIFICATION USING REMOTE SENSING TOOLS. THE YALDAD RIVER BASIN SHOWED 82% OF NATIVE FOREST AND THE COLU RIVER BASIN AROUND 38% OF GRASSLAND (AGRICULTURE). LOW TOTAL ALKALINITY (AT) AND DISSOLVED INORGANIC CARBON (DIC), BUT HIGH CDOM PROPORTIONS WERE TYPICALLY OBSERVED IN FRESHWATER. A HIGHER CDOM AND HUMIC-LIKE COMPOUNDS CONCENTRATION WAS OBSERVED ALONG THE RIVER-COASTAL OCEAN CONTINUUM IN THE YALDAD BASIN, CHARACTERIZED BY A PREDOMINANCE OF NATIVE FORESTS. IN CONTRAST, NUTRIENT CONCENTRATIONS, AT AND DIC, WERE HIGHER IN THE COLU AREA. LOW CACO3 SATURATION STATE (?AR < 2) AND EVEN UNDERSATURATION CONDITIONS WERE OBSERVED AT THE COASTAL OCEAN AT YALDAD. A STRONG NEGATIVE CORRELATION BETWEEN AT, DIC AND ?AR WITH CDOM/FDOM, SUGGESTED THE INFLUENCE OF TERRESTRIAL MATERIAL ON THE SEAWATER CARBON CHEMISTRY. OUR RESULTS PROVIDE ROBUST EVIDENCE THAT LAND USES IN RIVER BASINS CAN INFLUENCE CDOM/FDOM PROPORTION AND ITS INFLUENCE ON THE CARBONATE CHEMISTRY OF THE ADJACENT COASTAL, WITH POTENTIAL IMPLICATIONS FOR THE SHELLFISH FARMING ACTIVITY IN THIS REGION.

OVER THE LAST CENTURY, CLIMATE CHANGE HAS IMPACTED THE PHYSIOLOGY, DISTRIBUTION, AND PHENOLOGY OF MARINE AND TERRESTRIAL PRIMARY PRODUCERS WORLDWIDE. THE STUDY OF THESE FLUCTUATIONS HAS BEEN HINDERED DUE TO THE COMPLEX RESPONSE OF PLANTS TO ENVIRONMENTAL FORCING OVER LARGE SPATIAL AND TEMPORAL SCALES. TO BRIDGE THIS GAP, WE INVESTIGATED THE SYNCHRONY IN SEASONAL PHENOLOGICAL ACTIVITY BETWEEN MARINE AND TERRESTRIAL PRIMARY PRODUCERS TO ENVIRONMENTAL AND CLIMATIC VARIABILITY ACROSS NORTHERN PATAGONIA. WE DISENTANGLED THE EFFECTS ON THE BIOLOGICAL ACTIVITY OF LOCAL PROCESSES USING ADVANCED TIME-FREQUENCY ANALYSIS AND PARTIAL WAVELET COHERENCE ON 15 YEARS (2003?2017) OF DATA FROM MODIS (MODERATE RESOLUTION IMAGING SPECTRORADIOMETER) ONBOARD THE TERRA AND AQUA SATELLITES AND GLOBAL CLIMATIC VARIABILITY USING LARGE-SCALE CLIMATE INDICES. OUR RESULTS SHOW THAT PERIODIC VARIATIONS IN BOTH COASTAL OCEAN AND LAND PRODUCTIVITY ARE ASSOCIATED WITH SEA SURFACE TEMPERATURE FORCING OVER SEASONAL SCALES AND WITH CLIMATIC FORCING OVER MULTI-ANNUAL (2?4 YEARS) MODES. THESE COMPLEX RELATIONSHIPS INDICATE THAT LARGE-SCALE CLIMATIC PROCESSES PRIMARILY MODULATE THE SYNCHRONOUS PHENOLOGICAL SEASONAL ACTIVITY ACROSS NORTHERN PATAGONIA, WHICH MAKES THESE UNIQUE ECOSYSTEMS HIGHLY EXPOSED TO FUTURE CLIMATIC CHANGE.

BESIDES, IF THE WATER TRANSFERRED IS SOURCED FROM HUMAN-INTERVENED RIVER BASINS, IT MAY ALSO CONTAIN TOXIC AND OTHER ELEMENTS WITH NEGATIVE ECOSYSTEM IMPACTS FOR THE RECIPIENT AREA. IN CHILE, THE PULP AND PAPER-MILL INDUSTRIES DISCHARGE THEIR TREATED EFFLUENTS INTO SOME RIVERS, SUCH AS BIOBÍO RIVER IN CENTRAL CHILE, AND STANDARD TREATMENT SYSTEMS WILL NOT PREVENT THE RELEASE OF POLLUTANTS (FOR EXAMPLE, TRACE ELEMENTS4, PESTICIDES, DIOXINS AND FURANS, AND HYDROCARBONS5, OR EVEN THE TRANSPORT OF INVASIVE MICROORGANISMS). MOREOVER, UNDER CLIMATE CHANGE SCENARIOS, PRECIPITATION WITHIN THE PROVIDER BASINS WILL SUBSTANTIALLY DECREASE, WHICH IN TURN COULD LIMIT FRESHWATER ACCESS IN THESE COMMUNITIES AND THEIR CAPACITY TO WATER CROPS FOR AGRICULTURE OR TO USE IT FOR OTHER ACTIVITIES. INDEED, THIS REGION IS A MAJOR PRODUCER AND EXPORTER OF CHERRIES, NUTS, BERRIES AND CHEMICAL PULP (HTTPS://WWW.OECD.ORG/CHILE/).

COASTAL UPWELLING ECOSYSTEMS SUPPORT SOME OF THE MOST PRODUCTIVE FISHERIES OF THE PLANET TOGETHER WITH A LARGE SHELLFISH AQUACULTURE SECTOR THAT DEPENDS ON OCEANOGRAPHIC PROCESSES TO DELIVER PLANKTONIC LARVAE TO REPLENISH AND FEED THE FARMED STOCK. COASTAL SHELLFISH AQUACULTURE OPERATIONS IN CHILE AND PERÚ HAVE EXPERIENCED LARGE INTERANNUAL FLUCTUATIONS IN LARVAL SUPPLY OVER THE PAST DECADE, YET THE DRIVERS OF SUCH VARIABILITY REMAIN UNIDENTIFIED. WE FOCUSED ON THE EFFECTS OF ENVIRONMENTAL VARIABILITY ON LARVAL SUPPLY OF THE FARMED PERUVIAN BAY SCALLOP ARGOPECTEN PURPURATUS IN A BAY IN NORTHERN CHILE (TONGOY BAY, 30?S) THAT ACCOUNTS FOR OVER 90% OF COUNTRYWIDE LANDINGS. WE EXAMINED THE HYPOTHESIS THAT THE ENVIRONMENTAL PROCESSES GOVERNING LARVAL SUPPLY WERE SHARED WITH WILD BENTHIC INVERTEBRATES WITH PLANKTONIC LARVAL DEVELOPMENT AND COMPARED TIME SERIES OF LARVAL ABUNDANCE FOR THE SCALLOP WITH LARVAL SUPPLY RATES TO BENTHIC POPULATIONS OF TWO WELL-STUDIED WILD INTERTIDAL SPECIES: THE CHTHAMALID BARNACLE JEHLIUS CIRRATUS AND THE PURPLE MUSSEL PERUMYTILUS PURPURATUS. TO THIS END, WE EXAMINED THE CROSS-CORRELATION OF LARVAL SUPPLY TO ENVIRONMENTAL VARIABILITY USING MODIS SATELLITE FIELDS OF SEA SURFACE TEMPERATURE (SST) CHLOROPHYLL-A CONCENTRATION (CHL-A) AND FLUORESCENCE LINE HEIGHT (NFLH), TOGETHER WITH THREE CLIMATE INDICES RELEVANT FOR THE SOUTH EAST PACIFIC SECTOR: THE SOUTHERN OSCILLATION INDEX (SOI), THE PACIFIC DECADAL OSCILLATION (PDO) AND THE ANTARCTIC OSCILLATION INDEX (AAO). OUR RESULTS SHOWED THAT OVER THE FIVE-YEAR STUDY PERIOD (2009?2013), PATTERNS OF LARVAL SUPPLY TO THE SCALLOP POPULATION WERE RELATED TO INTER-ANNUAL VARIABILITY IN THE ENVIRONMENTAL PROCESSES AS CAPTURED BY THEIR EMPIRICAL ORTHOGONAL FUNCTIONS (EOFS), LIKELY TO ADULT CONDITION BEFORE SPAWNING. SURPRISINGLY, LARVAL SUPPLY FOR NONE OF THE WILD SPECIES SHOWED A CLEAR ASSOCIATION TO THE EOFS. IN CONTRAST, SCALLOPS AND WILD SPECIES SHOWED SIGNIFICANT ASSOCIATION TO LOWER FREQUENCY CLIMATE

CLIMATOLOGICAL HYDROGRAPHIC DATA FOR THE SOUTHEASTERN PACIFIC FROM THE WORLD OCEAN ATLAS SHOW AN EXTENDED LOW-SALINITY REGION ASSOCIATED WITH HIGH RAINFALL/RIVER RUNOFF ALONG THE CHILEAN PATAGONIA COAST. HOWEVER, THE STRUCTURE AND VARIABILITY OF THIS EXTENSIVE FRESHWATER AREA IS POORLY UNDERSTOOD DUE TO THE LACK OF PERIODIC HYDROGRAPHIC OBSERVATIONS. HERE, WE USE 15?YEARS OF SATELLITE OBSERVATIONS IN COMBINATION WITH HYDROGRAPHIC DATA FROM ARGO PROFILING FLOATS TO INCREASE OUR UNDERSTANDING OF THE FRESHWATER STRUCTURE AND ITS SEASONAL VARIABILITY OFF WESTERN PATAGONIA. SATELLITE-DERIVED SEASONAL FIELDS OF SURFACE SALINITY FROM AQUARIUS/SAC-D AND SMAP (SOIL MOISTURE ACTIVE PASSIVE) SATELLITE MISSIONS REVEAL A PROMINENT COASTAL BAND OF LOW-SALINITY WATER YEAR-ROUND (FRESHER DURING SPRING AND SUMMER). HYDROGRAPHIC PROFILES FROM ARGO FLOATS CONFIRM THIS COASTAL FRESHENING. THE MAJOR CONTENT OF FRESHWATER IS LOCATED OFF CENTRAL PATAGONIA, WHERE THE LOW-SALINITY SURFACE LAYER DOMINATES THE STRATIFICATION OF THE UPPER OCEAN. IN CONTRAST, THE FRESHWATER CONTENT PLAYS A MINOR ROLE IN SETTING UP THE STRATIFICATION OFF NORTHERN AND SOUTHERN PATAGONIA. A WARM SURFACE LAYER GREATLY INCREASES THE STABILITY OF THE UPPER 500?M IN THE NORTHERN SECTOR (ESPECIALLY IN SUMMER AND FALL), WHEREAS COLD TEMPERATURES IN THE SOUTHERN REGION TEND TO DAMP ZONAL DENSITY GRADIENTS AND DECREASE THE STRATIFICATION. FUTURE STUDIES AT INTERANNUAL SCALES ARE SUGGESTED CONSIDERING THE MELTING OF PATAGONIAN ICEFIELDS SINCE THE 1960S.

MASS STRANDING EVENTS OF DIFFERENT TAXONOMIC GROUPS ARE PERIODIC IN CERTAIN COASTAL REGIONS WORLDWIDE, BUT THE UNDERLYING CAUSES FOR THESE OCCURRENCES ARE NOT YET FULLY UNDERSTOOD. IN THE EASTERN PACIFIC OCEAN (EPO), THE MOST FREQUENT AND DOCUMENTED MASS STRANDINGS CORRESPOND TO THE JUMBO SQUID DOSIDICUS GIGAS, BUT THE DIFFERENT HYPOTHESES PROPOSED TO EXPLAIN THIS PHENOMENON FAIL TO PREDICT IT. HERE, WE ASSEMBLED A DATABASE WITH HISTORICAL STRANDING OCCURRENCES FROM THE NINETEENTH CENTURY TO 2022, HIGHLIGHTING THE DRAMATIC INCREASE IN STRANDINGS SINCE THE YEAR 2000 ALONG THE EPO. THE MOST COMMON REGIONS FOR JUMBO SQUID STRANDINGS IN THE NORTHERN HEMISPHERE ARE USA AND MEXICO, WHEREAS IN THE SOUTHERN HEMISPHERE THESE EVENTS HAVE MOSTLY OCCURRED IN CHILE. IN BOTH HEMISPHERES THE STRANDINGS ARE FREQUENT IN SUMMER MONTHS. ALTHOUGH WE ASSESSED DIFFERENT HYPOTHETICAL CAUSES (E.G., POST-SPAWNING MORTALITY, HIGH TEMPERATURES, TOXINS FROM HARMFUL ALGAL BLOOMS, HUMAN DISTURBANCE), WE DID NOT FIND ENOUGH EVIDENCE TO SUPPORT ANY OF THEM. BESIDES, THE NEED TO EXPERIMENTALLY TEST THE PLAUSIBLE CAUSE(S), WE ALSO DISCUSS AN ALTERNATIVE ECOPHYSIOLOGICAL HYPOTHESIS ASSOCIATED WITH UPWELLING SHADOWS AND THE SPECIES? DIEL MIGRATORY BEHAVIOR, HIGHLIGHTING THE IMPORTANCE OF STRANDING EVENTS AS KEY COMPONENTS OF GLOBAL NUTRIENT CYCLES.

THIS STUDY ASSESSED NATURAL VARIATION IN THE MACROINVERTEBRATE ASSEMBLAGES (MIB) AND WATER QUALITY IN ONE OF THE MAIN BASINS WITH THE LARGEST AGRICULTURAL ACTIVITIES IN CHILE (ACONCAGUA RIVER BASIN). WE SAMPLED THROUGHOUT THE ANNUAL CYCLE; NINE SAMPLING SITES WERE ESTABLISHED ALONG THE BASIN, CLASSIFYING ACCORDING TO AGRICULTURAL AREA COVERAGE AS LEAST-DISTURBED, INTERMEDIATE, AND MOST-DISTURBED. WE COLLECTED 56 MACROINVERTEBRATE TAXA THROUGHOUT THE ENTIRE STUDY AREA. MULTIVARIATE ANALYSIS SHOWS SIGNIFICANT DIFFERENCES AMONG THE THREE DISTURBANCE CATEGORIES IN DIFFERENT SEASONS, BOTH WATER QUALITY VARIABLES AND THE MIB STRUCTURE. DISTANCE-BASED LINEAR MODEL (DISTLM) ANALYSIS FOR ALL SEASONS EXPLAINED MORE THAN 95.9% OF THE MACROINVERTEBRATE ASSEMBLAGES, BEING SIGNIFICANTLY EXPLAINED BY CHEMICAL OXYGEN DEMAND, PH, TOTAL COLIFORMS, NITRITES, ELEVATION, AND WATER TEMPERATURE. ANOVA TEST REVEALED SIGNIFICANT DIFFERENCES IN THE PROPORTION OF NONINSECT INDIVIDUALS, MACROINVERTEBRATES DENSITY, AND THE NUMBER OF TAXA AMONG THE THREE DISTURBANCE CATEGORIES (P < 0.05). IN GENERAL, WATER TEMPERATURE, CONDUCTIVITY, CHEMICAL OXYGEN DEMAND, AMMONIUM, NITRITES, AND NITRATES INCREASED THEIR VALUES DOWNSTREAM IN THE BASIN. OUR RESULTS INDICATE THAT THE ELEVATION GRADIENT AND INCREMENT IN AGRICULTURAL LAND USE IN THE BASIN HAD A STRONG INFLUENCE ON WATER QUALITY AND MIB. A BETTER UNDERSTANDING OF THESE ECOSYSTEMS COULD HELP CONSERVATION AND INTEGRATED WATERSHED MANAGEMENT.

NORTHERN PATAGONIA IS ONE OF THE LARGEST ESTUARINE SYSTEMS WORLDWIDE. IT IS CHARACTERIZED BY COMPLEX GEOGRAPHY, INCLUDING ISLANDS, PENINSULAS, CHANNELS, AND FJORDS. HERE, THE INNER SEA OF CHILOÉ (ISC) IS THE LARGEST ESTUARINE SYSTEM EXTENDING ABOUT 230 KM IN THE MERIDIONAL DIRECTION. PHYTOPLANKTON?S LONG-TERM DYNAMICS AND THE MAIN PHYSICAL DRIVERS OF THEIR VARIABILITY ARE NOT WELL UNDERSTOOD YET. TIME-SPACE FLUCTUATIONS OF CHLOROPHYLL-A (CHL-A) AND CHLOROPHYLL FLUORESCENCE (NFLH) WITHIN THE ISC AND THEIR ASSOCIATION WITH METEOROLOGICAL AND OCEANOGRAPHIC PROCESSES WERE ANALYZED USING HIGH RESOLUTION (1000 M) SATELLITE DATA (2003?2019). OUR RESULTS REVEALED A MERIDIONAL CHL-A AND NFLH GRADIENT ALONG THE ISC, WITH HIGHER CONCENTRATIONS NORTH OF THE DESERTORES ISLANDS WHERE THE TOPOGRAPHY PROMOTES A SEMI-CLOSED SYSTEM WITH ESTUARINE CHARACTERISTICS YEARLONG. SATELLITE CHL-A AND NFLH WERE CHARACTERIZED BY ASYNCHRONOUS SEASONAL CYCLES (NFLH PEAKS IN FALL) THAT DIFFERED FROM THE SOUTHERN ISC WHERE THE MAXIMUM CHL-A AND NFLH OCCURS IN SPRING-SUMMER. THE ADJACENT COASTAL OCEAN INFLUENCES THE SOUTHERN ISC, AND THUS, THE CHL-A AND NFLH VARIABILITY CORRELATED WELL WITH THE SEASONAL VARIATION OF MERIDIONAL WINDS. THE NORTHERN ISC WAS CLEARLY INFLUENCED BY RIVER DISCHARGES, WHICH CAN BIAS THE CHL-A RETRIEVALS, DECOUPLING THE ANNUAL CYCLES OF CHL-A AND NFLH. IN SITU DATA FROM A BUOY IN SENO RELONCAVÍ REAFFIRMED THIS BIAS IN SATELLITE CHL-A AND A HIGHER CORRELATION WITH NFLH, BY WHICH THE CONSTRUCTION OF A LOCAL CHL-A ALGORITHM FOR NORTHERN PATAGONIA IS ESSENTIAL.