Different kelp species support unique macroinvertebrate assemblages, suggesting the potential community‐wide impacts of kelp harvesting along the Humboldt Current System

Abstract. Carbon dioxide and coupled CO2 and O2-driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log10 pO2pCO2) and the pH-dependent aragonite saturation (Ω) to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100 m to about 300 m depth and supporting elevated pCO2 values. The lowest RI values, associated to aerobic stress, were found at about 200 m depth and decreased towards the Equator. Increased pCO2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42° S and 28° S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO2–driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO2-driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000 m depth. Overall pCO2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

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The Humboldt Current System of Northern and Central Chile

Oceanography and Marine Biology - Oceanography and Marine Biology - An Annual Review ◽

10.1201/9781420050943.ch6 ◽

2007 ◽

pp. 195-344 ◽

Cited By ~ 275

Author(s):

Martin Thiel ◽

Erasmo Macaya ◽

Enzo Acu√±a ◽

Wolf Arntz ◽

Horacio Bastias ◽

...

Keyword(s):

Current System ◽

Humboldt Current ◽

Central Chile ◽

Humboldt Current System

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Modelling the mechanisms and drivers of the spatiotemporal variability of pCO2 and air–sea CO2 fluxes in the Northern Humboldt Current System

Ocean Modelling ◽

10.1016/j.ocemod.2018.10.005 ◽

2018 ◽

Vol 132 ◽

pp. 61-72 ◽

Cited By ~ 4

Author(s):

Rodrigo Mogollón ◽

Paulo H.R. Calil

Keyword(s):

Current System ◽

Spatiotemporal Variability ◽

Co2 Fluxes ◽

Humboldt Current ◽

Humboldt Current System

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Marine heatwaves in the Humboldt current system: from 5-day localized warming to year-long El Niños

Scientific Reports ◽

10.1038/s41598-021-00340-4 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Alice Pietri ◽

François Colas ◽

Rodrigo Mogollon ◽

Jorge Tam ◽

Dimitri Gutierrez

Keyword(s):

Hot Spot ◽

Current System ◽

World Ocean ◽

Temperature Data ◽

Sea Surface ◽

Thermal Impact ◽

Humboldt Current ◽

Coastal System ◽

Long Duration ◽

Humboldt Current System

AbstractDuring the last 4 decades punctual occurrences of extreme ocean temperatures, known as marine heatwaves (MHWs), have been regularly disrupting the coastal ecosystem of the Peru-Chile eastern boundary upwelling system. In fact, this coastal system and biodiversity hot-spot is regularly impacted by El Niño events, whose variability has been related to the longest and most intense MHWs in the world ocean. However the intensively studied El Niños tend to overshadow the MHWs of shorter duration that are significantly more common in the region. Using sea surface temperature data from 1982 to 2019 we investigate the characteristics and evolution of MHWs, distinguishing events by duration. Results show that long duration MHWs (> 100 days) preferentially affect the coastal domain north of 15° S and have decreased in both occurrence and intensity in the last four decades. On the other hand, shorter events, which represent more than 90% of all the observed MHWs, are more common south of 15° S and show an increase in their thermal impact as well as on the number of affected days, particularly those spanning 30–100 days. We also show that long duration MHWs variability in the coastal domain is well correlated with the remote equatorial variability while the onset of short events (< 10 days) generally goes along with a relaxation of the local coastal wind.

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Breeding abundance and population trend of the Peruvian Diving-petrel Pelecanoides garnotii in Chile: Recovery of an endangered seabird?

Bird Conservation International ◽

10.1017/s095927091900039x ◽

2019 ◽

Vol 30 (3) ◽

pp. 423-433

Author(s):

CLAUDIA E. FERNÁNDEZ ◽

MATÍAS PORTFLITT-TORO ◽

DIEGO MIRANDA-URBINA ◽

PAULA PLAZA ◽

NICOLAS LUNA ◽

...

Keyword(s):

Current System ◽

Legal Protection ◽

Breeding Population ◽

Management Plan ◽

Population Trend ◽

Humboldt Current ◽

Breeding Habitats ◽

Large Populations ◽

Humboldt Current System ◽

Diving Petrel

SummaryAs island ecosystems are among the most critical breeding habitats for seabirds, their protection should enhance population viability for many species. The Peruvian Diving-petrel Pelecanoides garnotii breeds only in Chile and Perú, is an endangered seabird with historically large populations of over 100,000 breeding pairs, but fewer than 1,000 remained in the 1980s and it became the first endangered seabird of the Humboldt Current System. In Chile, they breed on five islands, three of which are legally protected, but only two have a management plan. Between 2010 and 2014, we evaluated the density of nests, burrow occupancy, and colony patch sizes on the islands to estimate the breeding population. The population trend was assessed by compiling historical data available in the literature and several unpublished technical reports. The current breeding population size in Chile was ∼12,500 breeding pairs (95% CI: 10,613–14,676 pairs) that is ∼34% of the breeding pairs reported for Peru (∼36,450 pairs). Choros Island, the only island with adequate protection, accounted for ∼95% of the total breeding population of the Peruvian Diving-petrel in Chile. Historical population trends showed a significant increase in breeding pairs during recent years on Choros Island. It seems that the adequate legal protection of Choros Island is leading to the recovery of Peruvian Diving-petrels, demonstrating that protection of breeding colonies remains an essential strategy for the conservation of endemic seabirds.

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Reproduction and feeding of Sagitta enflata in the Humboldt Current system off Chile

ICES Journal of Marine Science ◽

10.1093/icesjms/fsn030 ◽

2008 ◽

Vol 65 (3) ◽

pp. 361-370 ◽

Cited By ~ 21

Author(s):

Ricardo Giesecke ◽

Humberto E. González

Keyword(s):

Feeding Rate ◽

Current System ◽

Zooplankton Abundance ◽

Daily Ration ◽

Ecological Significance ◽

Prey Selectivity ◽

Humboldt Current ◽

The Mean ◽

Humboldt Current System ◽

Paracalanus Parvus

Abstract Giesecke, R., and González, H. E. 2008. Reproduction and feeding of Sagitta enflata in the Humboldt Current system off Chile. – ICES Journal of Marine Science, 65: 361–370. This study is based on 3 years (August 2002–July 2005) of monthly zooplankton sampling at a fixed station located 18 km off Coliumo Bay (36°S), Chile. The reproduction of Sagitta enflata, its feeding rate, specific daily ration, and prey selectivity were analysed and related to several environmental variables: temperature, salinity, dissolved oxygen, chlorophyll a concentrations, and both meso- and micro-zooplankton abundance. The main predatory activity of S. enflata was centred on the copepods Paracalanus parvus, Oithona spp., and Calanus chilensis. These three species were consumed at different rates, depending mainly on the maturity of the S. enflata population. When Stages I and II individuals dominated, predation focused on the small P. parvus and Oithona spp., whereas more mature populations (Stages III and IV) preyed selectively on C. chilensis. The mean specific daily ration of 0.1 d−1 increased to 0.5 d−1 before and during maturation. The reproductive phase of S. enflata was closely coupled with the abundance of nauplii, suggesting that chaetognath reproduction paralleled that of copepods, most likely to diminish the mortality of its offspring resulting from starvation. The relationships between these were included in a conceptual model and their ecological significance is discussed.

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