Seawater Chemistry, Biogeochemical Cycles and Ecology - Ocean Sciences - Engineering Sciences Previous Year Questions

1

2017 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2017

Burning of fossil fuel is increasing the concentration of CO₂ in the atmosphere. A consequence of this is

A

Ocean water which is presently basic will drift towards pH neutral

B

Ocean water which is presently acidic will become more acidic

C

No effect on ocean pH

D

Ocean water which is presently slightly basic will become more basic

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2

2019 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2019

Oxygen minimum zones in the ocean are formed in the layers where

A

Photosynthesis is dominant

B

Sunlight is maximum

C

Decomposition of organic matter is dominant

D

Iron availability is maximum

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3

2019 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2019

The most abundant ions in seawater are

A

Sodium and chloride ions

B

Magnesium and chloride ions

C

Calcium and chloride ions

D

Magnesium and sulphide ions

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4

2020 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2020

Anthropogenic emission of ______ is the main contributor to the ongoing ocean acidification.

A

Methane

B

Carbon dioxide

C

Nitrous oxide

D

Sulphuric acid

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5

2021 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2021

The figure shows vertical variation of two chemicals P and Q measured in the Pacific Ocean. Identify the correct combination showing (P, Q) pair from the list below.

A

Oxygen, Nitrate

B

Oxygen, Neon

C

Nitrate, Oxygen

D

Neon, Nitrate

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6

2022 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2022

Which of the following statement(s) is/are true regarding biogeochemical cycle in the ocean?

A

Shutdown of the biological pump in the ocean would have resulted in higher CO₂ concentration in the atmosphere compared to present-day.

B

If atmospheric CO₂ concentration increases, solubility pump would lead to a decrease in dissolved inorganic carbon in the ocean.

C

All carbon sequestered by marine photosynthesis settles down on the ocean floor as organic matter.

D

Calcification (the process of making shells and skeletons) by marine organisms in the surface ocean layer would lead to an increase in the surface ocean CO₂.

Check answer

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7

2022 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2022

Consider an atmosphere where the mole fractions of N₂, Ar and CO₂ are 7.81×10⁻¹, 9.34×10⁻³ and 4.05×10⁻⁴, respectively. This atmosphere exchanges gases with sea water below having temperature and salinity of 20 °C and 35 psu, respectively. In the absence of biological and chemical activity, relative concentrations of dissolved gases in the surface sea water at equilibrium are ordered as

A

[N₂] > [Ar] > [CO₂]

B

[CO₂] > [N₂] > [Ar]

C

[N₂] > [CO₂] > [Ar]

D

[Ar] > [CO₂] > [N₂]

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8

2023 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2023

Consider the following options and pick out the right choice. The solubility of a gas in sea water increases with __________.

A

the increase of temperature, salinity and pressure

B

the decrease of temperature, salinity and pressure

C

the increase of temperature, and the decrease of salinity and pressure

D

the decrease of temperature and salinity, and the increase of pressure

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9

2023 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2023

From the list given below, identify the organism type in the biological pump that takes up carbon dioxide from the atmosphere into the ocean.

A

Zooplankton

B

Fish

C

Phytoplankton

D

Radiolarians

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10

2023 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2023

The amount of CO₂ that can be absorbed ______ when the temperature of seawater decreases.

A

Remains the same

B

Increases

C

Decreases

D

Can either increase or decrease

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11

2024 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2024

pH of the water in the oceans is/are directly affected by:

A

water temperature

B

water salinity

C

total alkalinity

D

water pressure

Check answer

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12

2025 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2025

The vertical (depth) profiles for three parameters P1, P2, and P3 in the northern Indian Ocean are given in the figure below. The values along the x-axis are the normalized values of the parameters and y-axis is the depth (m).

Identify the parameters P1, P2, and P3 from the options given below.

A

P1: Dissolved Oxygen; P2: Nitrate; P3: Chlorophyll

B

P1: Nitrate; P2: Chlorophyll; P3: Dissolved Oxygen

C

P1: Dissolved Oxygen; P2: Chlorophyll; P3: Nitrate

D

P1: Chlorophyll; P2: Nitrate; P3: Dissolved Oxygen

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13

2026 · Engineering Sciences · Ocean Sciences · Seawater Chemistry, Biogeochemical Cycles and Ecology

Engineering Sciences (XE) 2026

What is the approximate value of annual-mean pH of seawater at the surface in the northern Indian Ocean?

A

4.5

B

5.0

C

8.0

D

11.0

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