Anthropogenic iron deposition alters the ecosystem and carbon balance of the Indian Ocean over a centennial timescale

2020 ◽  
Author(s):  
Anh Pham ◽  
Takamitsu Ito
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Ocean Basin ◽  
Ecosystem Dynamics ◽  
Carbon Uptake ◽  
The South ◽  
Nutrient Deposition ◽  
The North ◽  
The Indian Ocean ◽  
The Impact

<p>Phytoplankton growth in the Indian Ocean is generally limited by macronutrients (nitrogen: N and phosphorus: P) in the north and by micronutrient (iron: Fe) in the south. Increasing anthropogenic atmospheric deposition of N and dissolved Fe (dFe) into the ocean can thus lead to significant responses from marine ecosystems in this ocean basin. Previous modeling studies investigated the impacts of anthropogenic nutrient deposition on the ocean, but their results are uncertain due to incomplete representations of Fe cycling. We use a state-of-the-art ocean ecosystem and Fe cycling model to evaluate the transient responses of ocean productivity and carbon uptake in the Indian Ocean, focusing on the centennial time scale. The model incorporates all major external sources and represents a complicated internal cycling process of Fe, thus showing significant improvements in reproducing observations. Sensitivity simulations show that after a century of anthropogenic deposition, increased dFe stimulates diatoms productivity in the southern Indian Ocean poleward of 50⁰S and the southeastern tropics. Diatoms production weakens in the south of the Arabian Sea due to the P limitation, and diatoms are outcompeted there by coccolithophores and picoplankton, which have a lower P demand. These changes in diatoms and coccolithophores productions alter the balance between the organic and carbonate pumps in the Indian Ocean, increasing the carbon uptake in the south of 50⁰S and the southeastern tropics while decreasing it in the Arabian Sea. Our results reveal the important role of ecosystem dynamics in controlling the sensitivity of carbon fluxes in the Indian Ocean under the impact of anthropogenic nutrient deposition over a centennial timescale.</p>

Source regions of oxygen maxima in intermediate depths of the Arabian Sea.

1966 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Structural Features ◽  
The South ◽  
The North ◽  
Source Regions ◽  
South Indian ◽  
Indian Central ◽  
South West Monsoon ◽  
The Indian Ocean

Oxygen maxima, in relation to σt salinity maxima and minima, and other hydrological structural features, have been examined along three meridional sections of the Indian Ocean. These relations have provided a background for the interpretation of the water mass sources of oxygen maxima of the whole Indian Ocean. After grouping these oxygen maxima according to density, their salinities have been used to identify mixing circuits in which the following waters are involved: from the south (1) South Indian Central, (2) Subtropical oxygen maximum, (3) Antarctic Intermediate; from the east (4) Equatorial Frontal water; and from the north (5) Persian Gulf, and (6) Red Sea. The principal routes whereby oxygen-rich mixtures of these waters enter the Arabian Sea, during the south-west monsoon, have been determined. The directions of flow along several of these routes agreed with measured directions of current flow. Where these currents disagreed the measured current was generally very weak.

scholarly journals Art. XXVII.—Notes on Malayalam Literature

1900 ◽  
Vol 32 (4) ◽  
pp. 763-768
Author(s):  
T. K. Krishṇa Menon
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
The South ◽  
The West ◽  
The Third ◽  
The North ◽  
South West ◽  
The Indian Ocean

Malayalam is the language of the south-west of the Madras Presidency. It is the third most important language of the Presidency, the first and the second being Tamil and Telugu respectively. It is spoken in Malabar, Cochin, and Travancore. Out of a total of 5,932,207 inhabitants of these parts, 5,409,350 persons are those who speak Malayalam. These countries, taken as a whole, are bounded on the north, by South Canara, on the east by the far-famed Malaya range of mountains, on the south by the Indian Ocean, and on the west by the Arabian Sea.

scholarly journals The Geology of Portuguese Nyasaland

1922 ◽  
Vol 59 (5) ◽  
pp. 200-212
Author(s):  
Robert R. Walls
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
The South ◽  
The North ◽  
Dark Continent ◽  
The Indian Ocean

Portuguese Nyasaland is the name given to the most northern part of Portuguese East Africa, lying between Lake Nyasa and the Indian Ocean. It is separated from the Tanganyika territory in the north by the River Rovuma and from the Portuguese province of Mozambique in the south by the River Lurio. The territory measures about 400 miles from east to west and 200 miles from north to south and has an area of nearly 90,000 square miles. This territory is now perhaps the least known part of the once Dark Continent, but while the writer was actually engaged in the exploration of this country in 1920–1, the Naval Intelligence Division of the British Admiralty published two handbooks, the Manual of Portuguese East Africa and the Handbook of Portuguese Nyasaland, which with their extensive bibliographies contained practically everything that was known of that country up to that date (1920). These handbooks make it unnecessary in this paper to give detailed accounts of the work of previous explorers.

Art. VII.—Notes on Persian Belúchistán. From the Persian of Mirza Mehdy Khán. Published Teheran, July, 1875

1876 ◽  
Vol 9 (1) ◽  
pp. 147-154
Author(s):  
A. H. Schindler
Keyword(s):  
Indian Ocean ◽  
Temperate Climate ◽  
The South ◽  
The West ◽  
The North ◽  
The People ◽  
The Indian Ocean ◽  
The Hill ◽  
Cool Climate

The part of Belúchistán now under Persian rule is bounded upon the north by Seistán, upon the east by Panjgúr and Kej, upon the south by the Indian Ocean, and upon the west by Núrámshír, Rúdbár, and the Báshákerd mountains.This country enjoys a variety of climates; almost unbearable heat exists on the Mekrán coast, we find a temperate climate on the hill slopes and on the slightly raised plains as at Duzek and Bampúr, and a cool climate in the mountainous districts Serhad and Bazmán. The heat at Jálq is said to be so intense in summer that the gazelles lie down exhausted in the plains, and let themselves be taken by the people without any trouble.

scholarly journals The Linear Sensitivity of the North Atlantic Oscillation and Eddy-Driven Jet to SSTs

2019 ◽  
Vol 32 (19) ◽  
pp. 6491-6511 ◽  
Author(s):  
Hugh S. Baker ◽  
Tim Woollings ◽  
Chris E. Forest ◽  
Myles R. Allen
Keyword(s):  
Indian Ocean ◽  
North Atlantic Oscillation ◽  
North Atlantic ◽  
High Sensitivity ◽  
Internal Variability ◽  
The North ◽  
The Indian Ocean ◽  
The North Atlantic ◽  
The North Atlantic Oscillation ◽  
The Impact

Abstract The North Atlantic Oscillation (NAO) and eddy-driven jet contain a forced component arising from sea surface temperature (SST) variations. Due to large amounts of internal variability, it is not trivial to determine where and to what extent SSTs force the NAO and jet. A linear statistical–dynamic method is employed with a large climate ensemble to compute the sensitivities of the winter and summer NAO and jet speed and latitude to the SSTs. Key regions of sensitivity are identified in the Indian and Pacific basins, and the North Atlantic tripole. Using the sensitivity maps and a long observational SST dataset, skillful reconstructions of the NAO and jet time series are made. The ability to skillfully forecast both the winter and summer NAO using only SST anomalies is also demonstrated. The linear approach used here allows precise attribution of model forecast signals to SSTs in particular regions. Skill comes from the Atlantic and Pacific basins on short lead times, while the Indian Ocean SSTs may contribute to the longer-term NAO trend. However, despite the region of high sensitivity in the Indian Ocean, SSTs here do not provide significant skill on interannual time scales, which highlights the limitations of the imposed SST approach. Given the impact of the NAO and jet on Northern Hemisphere weather and climate, these results provide useful information that could be used for improved attribution and forecasting.

Impact of Indo-Pacific Feedback Interactions on ENSO Dynamics Diagnosed Using Ensemble Climate Simulations

2012 ◽  
Vol 25 (21) ◽  
pp. 7743-7763 ◽  
Author(s):  
A. Santoso ◽  
M. H. England ◽  
W. Cai
Keyword(s):  
Indian Ocean ◽  
Climate Model ◽  
Southern Oscillation ◽  
Ocean Basin ◽  
Climate Feedback ◽  
Enso Events ◽  
Thermocline Feedback ◽  
Enso Dynamics ◽  
The Indian Ocean ◽  
The Impact

The impact of Indo-Pacific climate feedback on the dynamics of El Niño–Southern Oscillation (ENSO) is investigated using an ensemble set of Indian Ocean decoupling experiments (DCPL), utilizing a millennial integration of a coupled climate model. It is found that eliminating air–sea interactions over the Indian Ocean results in various degrees of ENSO amplification across DCPL simulations, with a shift in the underlying dynamics toward a more prominent thermocline mode. The DCPL experiments reveal that the net effect of the Indian Ocean in the control runs (CTRL) is a damping of ENSO. The extent of this damping appears to be negatively correlated to the coherence between ENSO and the Indian Ocean dipole (IOD). This type of relationship can arise from the long-lasting ENSO events that the model simulates, such that developing ENSO often coincides with Indian Ocean basin-wide mode (IOBM) anomalies during non-IOD years. As demonstrated via AGCM experiments, the IOBM enhances western Pacific wind anomalies that counteract the ENSO-enhancing winds farther east. In the recharge oscillator framework, this weakens the equatorial Pacific air–sea coupling that governs the ENSO thermocline feedback. Relative to the IOBM, the IOD is more conducive for ENSO growth. The net damping by the Indian Ocean in CTRL is thus dominated by the IOBM effect which is weaker with stronger ENSO–IOD coherence. The stronger ENSO thermocline mode in DCPL is consistent with the absence of any IOBM anomalies. This study supports the notion that the Indian Ocean should be viewed as an integral part of ENSO dynamics.

First occurrence of the moray eel Gymnothorax prolatus Sasaki & Amaoka, 1991 (Teleostei: Anguilliformes: Muraenidae) from the northern Indian Ocean

2015 ◽  
Vol 8 ◽  
Author(s):  
Anil Mohapatra ◽  
Dipanjan Ray ◽  
David G. Smith
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Western Indian Ocean ◽  
Northern Indian Ocean ◽  
The North ◽  
First Occurrence ◽  
The Indian Ocean ◽  
First Time ◽  
North Western ◽  
Moray Eel

Gymnothorax prolatusis recorded for the first time from the Indian Ocean on the basis of four specimens collected in the Bay of Bengal off India and one from the Arabian Sea off Pakistan. These records extend the range of the species from Taiwan to the north-western Indian Ocean.

Impact of the barotropic tides on the seasonal Indonesian Throughflow 

2021 ◽  
Author(s):  
Oceane Richet ◽  
Bernadette Sloyan ◽  
Bea Pena-Molino ◽  
Maxim Nikurashin
Keyword(s):  
Indian Ocean ◽  
Thermohaline Circulation ◽  
Vertical Mixing ◽  
Warm Pool ◽  
Ocean Basin ◽  
Indonesian Throughflow ◽  
Indonesian Seas ◽  
Pacific Waters ◽  
The Indian Ocean ◽  
The Impact

<p>The Indonesian seas play a fundamental role in the coupled climate system, featuring the only tropical exchange between ocean basins in the global thermohaline circulation. The Indonesian Throughflow (ITF) carries Pacific Ocean warm pool waters through the Indonesian Seas, where they are cooled and freshened. The incoming Pacific waters are strongly modified via vertical mixing driven by numerous ocean processes and ocean-atmosphere fluxes. The result is a unique water mass that can be tracked across the Indian Ocean basin and beyond. With our high-resolution regional model of the Indonesian Seas, designed with the MITgcm, we focus our study on the impact of the barotropic tides on the ITF. In fact, the strong tides coming from the Pacific and Indian Oceans enter in the Indonesian Seas through narrow straits and interact with the complex topography of the region (sills, islands, deep seas). This interaction between the tides and the topography impacts directly the ITF by modifying the transport toward the Indian Ocean.</p>

Hydrology of the Indian Ocean. I. The Water Masses in Intermediate Depths of the South-East Indian Ocean

1961 ◽  
Vol 12 (2) ◽  
pp. 129 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
West Indian ◽  
Water Masses ◽  
The South ◽  
North West ◽  
East Indian ◽  
The North ◽  
The Indian Ocean ◽  
The Antarctic ◽  
East Indian Ocean

Three water masses have been identified from maxima and minima in temperature-salinity diagrams for intermediate depths of the south-east Indian Ocean. (1) The Antarctic Intermediate occurred as a salinity minimum within the density range of 7.00-27.28 σt. (2) The North-West Indian Intermediate was found as a salinity maximum within the σt range 27.20-27.50. (3) The Banda Intermediate, lying below the North-West Indian Intermediate, had the characteristic of a salinity minimum within the σt range of 27.28-27.59. Preformed phosphate has been found useful as a third conservative property for the identification of major paths of spreading. The distribution and paths of spreading of the three water masses are shown in charts of the Indian Ocean east of 90�E.

scholarly journals Anomalies Of Isobaric Fields In The Southwestern Indian Ocean During El Nino Climatic Events

2020 ◽  
Vol 3 (4) ◽  
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Global Climate ◽  
Ocean Basin ◽  
The South ◽  
The North ◽  
South West Indian Ocean ◽  
Climate Event ◽  
West Indian Ocean

The el Nino climate event has produced upheavals in the global climate. Among many others is the prolonged drought in the Sahel. In fact, these upheavals are the direct consequences of changes in the centers of action. Therefore, we are interested in knowing their configuration in the South-West Indian Ocean basin, SWOI, both on the ground and at altitude during the two seasons, summer and winter in the southern hemisphere. It has been observed that there are negative pressure anomalies in the western part of the SWOI and positive ones in its eastern part; moreover the geopotential levels 700hPa and 500hPa include positive anomalies in the north and negative anomalies in the south. These mid-altitude results continue at high altitude, with the tropopause experiencing low anomalies on the equator side and high anomalies on the south pole side. As a result on the other hand, the southern winter experiences more moisture than normal. The significance of the images showing isobaric field anomalies was tested by the Student t-test.

Sign in / Sign up

Export Citation Format

Share Document