scholarly journals A Marine Reservoir Correction for the Houtman-Abrolhos Archipelago, East Indian Ocean, Western Australia

Radiocarbon ◽  
2013 ◽  
Vol 55 (1) ◽  
pp. 103-114 ◽  
Author(s):  
Peter Squire ◽  
Renaud Joannes-Boyau ◽  
Anja M Scheffers ◽  
Luke D Nothdurft ◽  
Quan Hua ◽  
...  
Keyword(s):  
Southern Oscillation ◽  
Global Climate ◽  
Current Source ◽  
Lower Latitude ◽  
East Indian ◽  
Leeuwin Current ◽  
Coral Communities ◽  
Nw Australia ◽  
East Indian Ocean ◽  
Reservoir Age

High-precision analysis using accelerator mass spectrometry (AMS) was performed upon known-age Holocene and modern, pre-bomb coral samples to generate a marine reservoir age correction value (ΔR) for the Houtman-Abrolhos Archipelago (28.7°S, 113.8°E) off the Western Australian coast. The mean ΔR value calculated for the Abrolhos Islands, 54 ± 30 yr (1 σ) agrees well with regional ΔR values for Leeuwin Current source waters (N-NW Australia-Java) of 60 ± 38 yr. The Abrolhos Islands show little variation with ΔR values of the northwestern and north Australian coast, underlining the dominance of the more equilibrated western Pacific-derived waters of the Leeuwin Current over local upwelling. The Abrolhos Islands ΔR values have remained stable over the last 2896 cal yr BP, being also attributed to the Leeuwin Current and the El Niño Southern Oscillation (ENSO) signal during this period. Expected future trends will be a strengthening of the teleconnection of the Abrolhos Islands to the climatic patterns of the equatorial Pacific via enhanced ENSO and global warming activity strengthening the Leeuwin Current. The possible effect upon the trend of future ΔR values may be to maintain similar values and an increase in stability. However, warming trends of global climate change may cause increasing dissimilarity of ΔR values due to the effects of increasing heat stress upon lower-latitude coral communities.

scholarly journals A Marine Reservoir Correction for the Houtman-Abrolhos Archipelago, East Indian Ocean, Western Australia

Radiocarbon ◽  
2013 ◽  
Vol 55 (01) ◽  
pp. 103-114 ◽  
Author(s):  
Peter Squire ◽  
Renaud Joannes-Boyau ◽  
Anja M Scheffers ◽  
Luke D Nothdurft ◽  
Quan Hua ◽  
...  
Keyword(s):  
Southern Oscillation ◽  
Global Climate ◽  
Current Source ◽  
Lower Latitude ◽  
East Indian ◽  
Leeuwin Current ◽  
Coral Communities ◽  
Nw Australia ◽  
East Indian Ocean ◽  
Reservoir Age

High-precision analysis using accelerator mass spectrometry (AMS) was performed upon known-age Holocene and modern, pre-bomb coral samples to generate a marine reservoir age correction value (ΔR) for the Houtman-Abrolhos Archipelago (28.7°S, 113.8°E) off the Western Australian coast. The mean ΔR value calculated for the Abrolhos Islands, 54 ± 30 yr (1 σ) agrees well with regional ΔR values for Leeuwin Current source waters (N-NW Australia-Java) of 60 ± 38 yr. The Abrolhos Islands show little variation with ΔR values of the northwestern and north Australian coast, underlining the dominance of the more equilibrated western Pacific-derived waters of the Leeuwin Current over local upwelling. The Abrolhos Islands ΔR values have remained stable over the last 2896 cal yr BP, being also attributed to the Leeuwin Current and the El Niño Southern Oscillation (ENSO) signal during this period. Expected future trends will be a strengthening of the teleconnection of the Abrolhos Islands to the climatic patterns of the equatorial Pacific via enhanced ENSO and global warming activity strengthening the Leeuwin Current. The possible effect upon the trend of future ΔR values may be to maintain similar values and an increase in stability. However, warming trends of global climate change may cause increasing dissimilarity of ΔR values due to the effects of increasing heat stress upon lower-latitude coral communities.

scholarly journals A Portable Cruising Speed Net: Expanding Global Collection of Sea Surface Plankton Data

2020 ◽  
Vol 7 ◽  
Author(s):  
Ulla von Ammon ◽  
Andrew Jeffs ◽  
Anastasija Zaiko ◽  
Aimee van der Reis ◽  
Deb Goodwin ◽  
...  
Keyword(s):  
Global Climate ◽  
Atmospheric Oxygen ◽  
Field Testing ◽  
Biological Data ◽  
Latitudinal Gradients ◽  
Distribution Data ◽  
East Indian ◽  
Marine Food Chain ◽  
Dna Metabarcoding ◽  
East Indian Ocean

Plankton are central to planetary ecology, generating 50% of Earth’s atmospheric oxygen and forming the largest system of interconnected life at the base of the marine food chain. Yet, current oceanographic models aimed at predicting global climate change lack high-resolution biological data, emphasizing the need for innovative approaches to collect plankton biodiversity and distribution data over larger spatial, temporal, and taxonomic scales. The significant number of boats, ranging from small sailing yachts to large commercial vessels, that ply the world’s oceans every day could help scientists collect thousands of valuable plankton samples. Traditional Plankton Nets (TPN) are not suited to the speed of a recreational craft cruising in the high seas (i.e., at speeds >2 knots). We developed and validated the efficiency of a lightweight, easily deployable Cruising Speed Net (CSN) that enables the collection of ocean surface micro- and mesoplankton at speeds up to 5 knots. Field testing was conducted during two distinct research cruises along coastal and oceanic latitudinal gradients (SSV Robert C. Seamans in New Zealand and RV Investigator in the south-east Indian Ocean). DNA metabarcoding performed on the collected plankton samples showed the TPN and CSN yielded identical sequence-based diversity at low speed, with the CSN also effective at higher speed for characterizing latitudinal distribution of plankton communities. The CSN represents a valuable new tool for expanding the global collection of plankton data.

scholarly journals The Impact of the Madden–Julian Oscillation on High-Latitude Winter Blocking during El Niño–Southern Oscillation Events

2018 ◽  
Vol 31 (13) ◽  
pp. 5293-5318 ◽  
Author(s):  
Stephanie A. Henderson ◽  
Eric D. Maloney
Keyword(s):  
Indian Ocean ◽  
High Latitude ◽  
El Niño ◽  
Rossby Waves ◽  
El Nino ◽  
Southern Oscillation ◽  
Madden Julian Oscillation ◽  
West Pacific ◽  
East Indian ◽  
East Indian Ocean

Wintertime high-latitude blocking is associated with persistent changes in temperature and precipitation over much of the Northern Hemisphere. Studies have shown that the Madden–Julian oscillation (MJO), the primary form of intraseasonal tropical variability, significantly modulates the frequency of high-latitude blocking through large-scale Rossby waves that alter the global circulation. However, the characteristics of MJO teleconnections are altered by El Niño–Southern Oscillation (ENSO), which modifies the global flow on interannual time scales, suggesting that the MJO influence on blocking may depend on the ENSO phase. The characteristics of MJO Rossby waves and blocking during ENSO events are examined using composite analysis and a nonlinear baroclinic model. The ENSO phase-dependent teleconnection patterns are found to significantly impact Pacific and Atlantic high-latitude blocking. During El Niño, a significant persistent increase in Pacific and Atlantic blocking follows the real-time multivariate MJO (RMM) phase 7, characterized by anomalous enhanced tropical convection over the East Indian Ocean and suppressed west Pacific convection. The maximum Atlantic blocking increase is triple the climatological winter mean. Results suggest that the MJO provides the initial dipole anomaly associated with the Atlantic blocking increase, and transient eddy activity aids in its persistence. However, during La Niña significant blocking anomalies are primarily observed during the first half of an MJO event. Significant suppression of Pacific and Atlantic blocking follows RMM phase 3, when east Indian Ocean MJO convection is suppressed and west Pacific convection is enhanced. The physical basis for these results is explained.

Foraging movements of common noddies in the East Indian Ocean are dependent on breeding stage: implications for marine reserve design

2019 ◽  
Vol 25 (2) ◽  
pp. 164
Author(s):  
Jill M. Shephard ◽  
James N. Dunlop ◽  
Willem Bouten
Keyword(s):  
Indian Ocean ◽  
Marine Protected Area ◽  
Marine Reserve ◽  
Enso Event ◽  
Reserve Design ◽  
Breeding Cycle ◽  
Home Ranges ◽  
East Indian ◽  
Leeuwin Current ◽  
East Indian Ocean

Increasingly, space use by foraging seabirds is being used as an indicator of ocean condition to inform projected planning for climate change, fisheries management and marine protected areas. We tracked foraging common noddies (Anous stolidus) from a colony in the East Indian Ocean using back-mounted solar GPS trackers during incubation and chick rearing to evaluate their suitability as biomonitors of ocean condition, and the overlap of flight tracks with marine protected area boundaries. This is the first study to track this species in its eastern distribution and across different stages of the breeding cycle. Six birds were tracked for 89 days in total, describing 10089km of flight. Birds made significantly longer trips during chick rearing, which may reflect reduced availability of prey. The tracking period coincided with a particularly strong ENSO event, which may have impacted foraging behaviour, but the foraging area was found to be at least 10000km2. Foraging was associated with the end points of outward trips that were generally at the edge of the continental shelf, or within proximity of canyon-like bathymetric features or current structures on the shelf. Birds foraged over the shelf during incubation, suggesting a greater reliance on food web structures associated with Leeuwin Current structures. Home ranges and movement tracks showed limited overlap with proposed marine park boundaries, but are promising as indicators of ocean productivity, suggesting that their role in the design of marine reserve networks in the future should be maximised.

scholarly journals The evolving response of mesopelagic fishes to declining midwater oxygen concentrations in the southern and central California Current

2018 ◽  
Vol 76 (3) ◽  
pp. 626-638 ◽  
Author(s):  
J Anthony Koslow ◽  
Pete Davison ◽  
Erica Ferrer ◽  
S Patricia A Jiménez Rosenberg ◽  
Gerardo Aceves-Medina ◽  
...  
Keyword(s):  
Baja California ◽  
Southern Oscillation ◽  
Global Climate ◽  
California Current ◽  
Deep Ocean ◽  
Near Surface ◽  
Oxygen Minimum Zones ◽  
The North ◽  
The Pacific ◽  
Oxygen Concentrations

Abstract Declining oxygen concentrations in the deep ocean, particularly in areas with pronounced oxygen minimum zones (OMZs), are a growing global concern related to global climate change. Its potential impacts on marine life remain poorly understood. A previous study suggested that the abundance of a diverse suite of mesopelagic fishes off southern California was closely linked to trends in midwater oxygen concentration. This study expands the spatial and temporal scale of that analysis to examine how mesopelagic fishes are responding to declining oxygen levels in the California Current (CC) off central, southern, and Baja California. Several warm-water mesopelagic species, apparently adapted to the shallower, more intense OMZ off Baja California, are shown to be increasing despite declining midwater oxygen concentrations and becoming increasingly dominant, initially off Baja California and subsequently in the CC region to the north. Their increased abundance is associated with warming near-surface ocean temperature, the warm phase of the Pacific Decadal oscillation and Multivariate El Niño-Southern Oscillation Index, and the increased flux of Pacific Equatorial Water into the southern CC.

scholarly journals Spurious North Tropical Atlantic precursors to El Niño

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Wenjun Zhang ◽  
Feng Jiang ◽  
Malte F. Stuecker ◽  
Fei-Fei Jin ◽  
Axel Timmermann
Keyword(s):  
El Niño ◽  
Cross Correlation ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Tropical Atlantic ◽  
The North ◽  
Sst Variability ◽  
Primary Driver ◽  
North Tropical Atlantic

AbstractThe El Niño-Southern Oscillation (ENSO), the primary driver of year-to-year global climate variability, is known to influence the North Tropical Atlantic (NTA) sea surface temperature (SST), especially during boreal spring season. Focusing on statistical lead-lag relationships, previous studies have proposed that interannual NTA SST variability can also feed back on ENSO in a predictable manner. However, these studies did not properly account for ENSO’s autocorrelation and the fact that the SST in the Atlantic and Pacific, as well as their interaction are seasonally modulated. This can lead to misinterpretations of causality and the spurious identification of Atlantic precursors for ENSO. Revisiting this issue under consideration of seasonality, time-varying ENSO frequency, and greenhouse warming, we demonstrate that the cross-correlation characteristics between NTA SST and ENSO, are consistent with a one-way Pacific to Atlantic forcing, even though the interpretation of lead-lag relationships may suggest otherwise.

scholarly journals The El Niño: A Meteorological Risk Factor for Vector-borne Diseases

2021 ◽  
Author(s):  
Avi Patel ◽  
Keyword(s):  
El Niño ◽  
Neglected Tropical Diseases ◽  
El Nino ◽  
Southern Oscillation ◽  
Global Climate ◽  
Economic Loss ◽  
Tropical Diseases ◽  
Vector Borne Diseases ◽  
Vector Borne ◽  
Climate Crisis

The El Niño Southern Oscillation (ENSO) has been ravaging numerous coastal and inland communities with excessive flooding and drought conditions, causing immense economic loss, and the incidence of many neglected tropical diseases. Affecting over 60 million people directly, El Niño remains one of the greatest enigmas to human health, and combined with the ever-escalating global climate crisis, El Niño events are only projected to increase in magnitude in the coming years (WHO, 2016).

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