Orientation to
Marine Science
Welcome to South Africa's newest matric subject. By the end of this topic you'll know what Marine Sciences actually is, what its four strands cover, and where it can take you after school.
You have probably read that humans have explored only 5% of the ocean. That number is wrong — and why it is wrong is the most useful thing on this page.
The problem is the word "explored". It hides three completely different questions, and they have three completely different answers. NOAA — the American ocean agency — now refuses to give one number, and publishes these instead:
🛰️ The whole seafloor has been mapped from satellites — but only roughly. It gives you shape, and it misses seamounts and shipwrecks entirely.
🚢 28.7% has been mapped properly, by sonar at modern resolution (April 2026). Ten years ago that figure was around 6%.
👁️ Less than 0.001% of the deep seafloor has actually been seen by human or robot eyes. Everything ever looked at adds up to about the size of a small country.
So "5%" is not so much inaccurate as incoherent — it mashes mapping, seeing and understanding into one word. 📌 A map shows you the shape of a place. It cannot tell you a single species that lives there.
Why is it so hard? The deep ocean is one of the hardest places to reach in the solar system. Pressure crushes equipment. Sunlight stops at about 200 m. Salt water destroys electronics. And the ocean is vast.
That is why Marine Sciences exists as a subject — and there is one more twist worth knowing. Of every deep-sea dive ever recorded, about two-thirds happened in the waters of just three wealthy countries. So what humanity "knows" about the deep sea is not a fair sample of the deep sea. African waters, including ours, are barely in the record at all.
What is Marine Sciences?
It's not just one subject. It's four sciences woven together.
Marine Sciences is an interdisciplinary subject — meaning it borrows from many fields and weaves them into one. You'll touch geography, chemistry, physics, biology, ecology, history, and even ethics. The thing they all share is a focus on the ocean — its workings, the life inside it, and our complicated relationship with it.
Across Grade 10, 11, and 12, you'll cover over 80 topics organised into four big strands. Every term, you'll spend time in each strand.
CAPS names twelve fields that feed into it: Geology, Geography, Physics, Chemistry, Geophysics, Meteorology, Botany, Zoology, Ecology, Conservation Biology, Engineering Sciences, and Natural & Environmental Resource Management. Notice that Botany — the study of plants — sits in that list beside Zoology. That is deliberate, and the next paragraph explains why it matters.
A warning your own textbook makes, on its first page
Marine Sciences has a habit of quietly collapsing into Ocean Zoology — all sharks, whales and octopus — because most teachers of the subject arrive from a Zoology background and teach what they know. Your book says so directly, and asks that Humans & the Ocean and Marine Ecology are not allowed to be squeezed out.
Worth knowing early, because it tells you what this subject is actually for. Animals are one strand of four. The chemistry of seawater, the movement of a current, the law governing a fishing quota and the economics of a harbour are all Marine Sciences too — and 📌 two of the four strands are not about animals at all.
Interdisciplinary, and trans-disciplinary
You will meet both words, and they are not quite the same. Interdisciplinary describes the subject: several fields brought side by side to study one thing. Trans-disciplinary — the word CAPS itself uses — describes what happens to you: a skill you build in one field crossing over and working in another.
When you calculate the volume of water a plankton net filtered, that is Maths doing Biology's job. When you explain why the sea breeze turns at midday, that is Physics doing Geography's job. 📌 The crossing over is the point of the subject, which is why CAPS says every marine discipline integrates with the others.
The Four Strands
Tap each strand below to see what it covers. These are the four pillars of the subject — together they tell the full story of the ocean.
Seven Things Everyone Should Know About the Ocean
These seven have a name: the Essential Principles of Ocean Literacy. Marine educators worldwide — the effort is facilitated by the National Marine Educators Association of North America, with input from South Africa — agree they describe what every person, scientist or not, should understand about the ocean. We'll come back to them throughout the course.
📌 Why a subject bothers with a list like this. Your own textbook explains it bluntly: people now make decisions about the sea while social media feeds them false information and misinformation about oceans and climate. Ocean Literacy is the counter-move — an agreed floor of what is actually true, so that an argument can start from facts.
One ocean, many features
- The "five oceans" are really one connected body of water with different regions, currents, and depths.
The ocean shapes the Earth
- Waves carve coastlines. Currents move continents' worth of water. Ocean life builds reefs and islands.
Weather and climate
- The ocean drives our weather — heat and moisture move from sea to air, then back again.
It made Earth habitable
- Life began in the ocean. The oxygen we breathe largely comes from microscopic ocean plants.
Huge biodiversity
- The ocean supports more variety of life than anywhere else on Earth — much of it still undiscovered.
Humans + ocean are linked
- We depend on the ocean for food, jobs, transport, and recreation. Our actions also harm it.
And the seventh: the ocean is largely unexplored.
We have detailed maps of the Moon, Mars and Venus — while roughly 71% of our own seafloor has still never been mapped at modern resolution, and almost none of the deep sea has been looked at directly. You could be one of the people who changes that — see the hook at the top of this page for what "explored" really means.
Why South Africa Matters
South Africa is a marine superpower
We have two ocean basins, three coastal regions, and one of the most biodiverse marine zones on the planet. From the southern right whales that calve along the southern Cape to Sodwana's coral reefs, our coastline is a working laboratory.
The South African government's Operation Phakisa initiative is building a "Blue Economy" — making marine industries (fishing, aquaculture, ocean energy, tourism) a major part of our economic future. Marine Scientists are needed to make that work without destroying what we have.
Our coastlines are named after what the sea did to ships
Waves and currents here are powerful enough that people named whole stretches of coast for the wrecks. Namibia's Skeleton Coast. The Eastern Cape's Wild Coast. And the Cape of Storms in the south-western Cape — the name Bartolomeu Dias reportedly gave the peninsula before it was rebranded the Cape of Good Hope for the sake of the shipping trade. 📌 Those names are data. They are centuries of observation about currents, swell and wind, recorded before anyone had an instrument — and the physics behind every one of them is in Topic 6 and Topic 4.
You're studying this from the right place.
Gqeberha sits on Algoa Bay, part of the Warm Temperate region. Bird Island, out in this bay, holds the largest Cape gannet breeding colony on Earth — counts have passed 100 000 breeding pairs, and roughly 70% of all the Cape gannets in the world nest there. Almost everything you'll learn this year you can also see within an hour of your front door.
📌 And read that record the way a scientist would. Putting three-quarters of a species on one small island is not a triumph — it is a fragility. One disease outbreak, one oil spill, one bad season in the wrong place, and the whole species takes the hit at once. The Cape gannet is itself listed as Endangered. A superlative is often a risk assessment in disguise.
The other seabird story here is harder. Until about 2015 the world's largest African penguin colony was on St Croix Island, also in this bay — and it then collapsed by roughly 85–90% in under a decade, as ship-to-ship refuelling moved into Algoa Bay from 2016 and the sardine and anchovy shoals the penguins depend on shifted away. Bird Island's penguins roughly halved over the same period. Neither island holds that title any more, and no colony anywhere is large now: in October 2024 the African penguin became the first of the world's 18 penguin species to be classified Critically Endangered, one rank above Extinct in the Wild.
You are studying a system that is changing while you study it — which is exactly why it needs people who can measure it. In March 2025 a South African court ordered no-fishing zones around six penguin colonies, and two of the six are the islands in your bay.
Where the whales actually are — and a lesson in reading a survey
Southern right whales do pass Algoa Bay, roughly July to October. But South Africa's main nursery grounds are further west — De Hoop and Walker Bay, hundreds of kilometres from here. If you see Algoa Bay described as one of the world's great southern right gatherings, that is an overstatement; the whales are here, but this is the edge of the range, not the centre.
📌 Now the part that is worth more than the fact. The count behind that map is an aerial survey flown every year for over 50 years — one of the longest unbroken whale counts anywhere. It flies between Nature's Valley and Muizenberg. Algoa Bay is not in the flight path at all. So a whale missing from that graph may simply be a whale nobody flew over. "Not in the data" and "not there" are different statements, and telling them apart is most of what makes someone good at this subject. You will meet this idea again as sampling bias in Topic 5.
The Treasure, 2000 — and the 19 500 penguins that were brought to Algoa Bay
On 23 June 2000 the ore carrier MV Treasure sank between Robben Island and Dassen Island, releasing roughly 1 300 tonnes of heavy fuel oil directly between the two largest African penguin colonies then in existence. It became the largest animal rescue in history.
About 19 000 oiled penguins were caught and washed by hand. But the decision that makes this a marine science story rather than a rescue story was the other one: teams also caught roughly 19 500 penguins that were not yet oiled, drove them 800 km east, and released them at Port Elizabeth — here, in Algoa Bay.
That was a calculated bet on a piece of biology. African penguins have very strong nest-site fidelity: they go home. Three birds — Peter, Pamela and Percy — carried satellite transmitters so the swim could be tracked. The colony took about 10 to 14 days to arrive back at Dassen Island, and in exactly that window the oil was cleaned up. 📌 The penguins were not saved by being moved. They were saved by being made to swim slowly enough that the clean-up could finish first.
Why it belongs in Topic 1. Every strand of this subject is in it. Physics and chemistry decided where the oil drifted. Biology supplied the nest-site fidelity the plan depended on. Ecology explained why two islands mattered more than 800 km of coast. And Humans & the Ocean is the whole reason there was oil in the water. No single specialist could have made that call.
⚠️ A date to watch. Your textbook dates the Treasure spill to July 2000. The ship sank on 23 June 2000. Use the book's wording if a paper quotes it, but the June date is the correct one.
Where Can This Take You?
Marine Sciences leads to an enormous range of careers — and brand new ones are appearing every year. Here are some of the paths a student of this subject can follow.
Research & Science
- Marine biologist
- Oceanographer
- Marine geologist
- Sedimentologist — reads the story in the layers (Topics 3, 12, 19)
- Fisheries scientist
- Climate scientist
Conservation & Education
- Marine protected area manager
- Coastal zone manager — decides what may be built, dug or harvested where
- Conservation biologist
- Environmental educator
- Nature conservation professional
- Aquarium curator
Engineering & Design
- Ocean engineer — structures used in the sea
- Marine and coastal engineer — harbours, breakwaters, sea walls
- Marine architect and ship designer
- Coastal city and regional planner
- Renewable ocean energy
Food from the Sea
- Aquaculturist — farming fish, abalone, oysters, seaweed
- Seafood specialist
- Fisheries observer
- Stock assessment scientist
Law, Policy & Management
- Maritime / marine lawyer
- Marine policy development
- Environmental impact assessor
- Natural & Environmental Resource Management
Non-consumptive Careers
- Eco-tourism facilitation
- Filming and media coverage of the ocean
- Marine archaeologist — wrecks, harbours, drowned coastlines
- Science journalist / communicator
A growing group — see the panel below for what the word means.
Consumptive and non-consumptive use
Every job on this page sits somewhere on one line. Consumptive use takes something out of the sea and does not put it back: resource extraction — minerals, oil or gas — and fisheries. Non-consumptive use earns a living from the ocean while leaving it in place: whale watching, dive tourism, filming, aquarium and education work.
Both are real economies and both employ people. The difference is what happens if the business succeeds enormously. 📌 A non-consumptive industry can grow without shrinking the thing it depends on; a consumptive one cannot. That single sentence is most of what "sustainable use" means, and it is why CAPS asks you to know the term.
Marine Sciences is not on one side of that line. It guides the sustainable use of both — which is why the same subject produces the person opening the fishery and the person setting its quota.
Tertiary requirements at SA universities
If you want to study Marine Sciences at a South African university, you'll need to take Mathematics and Physical Sciences through to matric. Note that this means Mathematics, not Mathematical Literacy. At university, a BSc usually requires Maths, Physics and Chemistry in the first year — no matter which marine specialisation you eventually choose.
📌 Take that seriously now, because it is the one door that closes early. You can decide in second year at university that you want to be a marine geologist instead of a marine biologist. You cannot decide in Grade 12 to have taken Physical Sciences in Grade 10.
Institutions that offer marine qualifications — this is CAPS's own research task, and the practical sheet has the table to fill in:
- Nelson Mandela University, Gqeberha — your local university, and it has a whole Ocean Sciences Campus in Summerstrand
- University of Cape Town — oceanography and marine biology
- Rhodes University, Makhanda — Ichthyology and Fisheries Science, the department tied to SAIAB next door
- University of KwaZulu-Natal · University of the Western Cape · Stellenbosch University
- CPUT — a diploma route in Marine Sciences and oceanography, which is a different door into the same industry and does not require a Bachelor's pass
⚠️ Entry requirements, APS scores and even programme names change every year. Never trust a list like this one — including this one. Check the current prospectus on each university's own website. Working out that a source can be out of date is itself part of the CAPS investigation.
How the Ocean Is Explored
A career in Marine Sciences usually starts with a simple problem: the thing you want to study is under water, and you are not. Everything in this section is a way around that.
Exploration is not a hobby. It is how a coastline earns a living.
CAPS puts it plainly: "The exploration of the ocean contributes to the sustainable future economic potential of coastal areas and associated employment opportunities." Those opportunities come from extracting resources — living ones like fish, abalone and seaweed, and non-living ones like minerals, oil and gas.
But you cannot manage what you have not measured. You cannot set a fishing quota without knowing how many fish there are; you cannot licence a gas field without knowing what lives above it; you cannot claim a seabed without having mapped it. Exploration is the survey work that has to happen before any of the money exists — and it is why a government pays for ships that catch no fish.
What South African researchers actually use
CAPS asks specifically for the South African answer, and it is a good one — we are a small country with a big ocean and a genuinely serious research fleet.
The ships
- SA Agulhas II — the flagship. A Polar Class 5 icebreaker built in 2012, 134 m long, with eight permanent laboratories plus six lab-in-a-shipping-container units, and a moon pool — a hatch through the hull so instruments go down inside the ship. She resupplies our Antarctic and island bases and does research, because South Africa cannot afford one ship for each.
- RV Ellen Khuzwayo — inshore fisheries research, built in Cape Town, in service since 2007. Wet labs, a dry lab, and a CTD lab.
- RV Algoa — coastal oceanographic surveys. Despite the name she works right around the coast.
- RV Africana — commissioned in 1982, and she still runs the trawl and acoustic surveys that set South Africa's fishing quotas.
The institutions
- DFFE — the government department. Owns the ships, runs fisheries and oceans science.
- SAEON — the South African Environmental Observation Network. Its job is the long record: the same measurement, same place, same method, for decades. Its offshore node is Egagasini (Cape Town), which hosts Argo South Africa.
- SAIAB — the South African Institute for Aquatic Biodiversity, in Makhanda. Over a million preserved fish, an underwater-camera platform, a DNA lab, and multibeam sonar for mapping seabed habitat.
- ACEP — the African Coelacanth Ecosystem Programme. A shared national pool of expensive kit, including an ROV, that any qualifying researcher can apply to borrow instead of buying their own.
Two things CAPS says here that have gone out of date
1. The departments no longer exist under those names. CAPS tells you to visit "DAF or DEA research institutions". In 2019 the Department of Environmental Affairs and the fisheries half of the Department of Agriculture, Forestry and Fisheries were merged into one department: the Department of Forestry, Fisheries and the Environment — DFFE. Learn DFFE; recognise DEA and DAFF when an older paper uses them.
2. The Africana is failing. A ship commissioned in 1982 is now old enough to break down mid-survey, and surveys have been lost to her condition. 📌 This is worth sitting with. If the survey does not sail, the quota for the following season has to be set on weaker evidence — and commercial catch figures alone can mislead, because a fleet that is simply getting better at finding fish looks exactly like a fish stock that is recovering. An ageing ship is not a shipping problem. It is a fisheries-management problem.
The closest working marine research institution to you is not an aquarium
SAEON's Elwandle Coastal Node is in Gqeberha, on Nelson Mandela University's Ocean Sciences Campus in Summerstrand. From there it runs the Algoa Bay Sentinel Site — described as the most comprehensive coastal observation network in South Africa, spanning over 300 km of coastline. It combines seabed moorings, hourly temperature sensors, acoustic receivers listening for tagged animals, and repeated ecological sampling.
Elwandle also manages the Shallow Marine and Coastal Research Infrastructure for the entire country — from Gqeberha.
📌 And in November 2025, South Africa flew its first two ocean gliders — robot submarines named Chappie and Imvubu — on the eastern Agulhas Bank, in Algoa Bay and St Francis Bay. When you read the next section and reach "ocean glider", understand that the country's first ones flew in the water you can see from the shore.
Deep-sea vehicles used elsewhere
CAPS asks you to know about "deep sea exploration vehicles used elsewhere — such as submarine research vessels". There are only three kinds, and the difference between them is simply where the human is, and whether there is a cable.
Human-Occupied Vehicle
- People inside a thick pressure sphere
- Gains: real eyes, peripheral vision, instant judgement
- Gives up: time, money, and safety margin
Remotely Operated Vehicle
- A robot on a cable to the ship
- Gains: unlimited power and live video — it can simply stay
- Gives up: range. The cable is a leash
Autonomous Underwater Vehicle
- A free-swimming robot, no cable
- Gains: freedom to roam and map wide areas
- Gives up: the live picture — radio does not travel through seawater
| Vehicle | Country / operator | What it did |
|---|---|---|
| Trieste (1960) | US Navy | Carried Jacques Piccard and Don Walsh to the bottom of Challenger Deep — the first humans ever. A window cracked on the way down and they got about 20 minutes on the seafloor after a five-hour descent |
| DSV Alvin (1964–) | USA · Woods Hole | Found hydrothermal vents in 1977 — whole ecosystems living on chemical energy, with no sunlight. Explored the Titanic in 1986. Upgraded to 6 500 m in 2022 |
| Shinkai 6500 (1991–) | Japan · JAMSTEC | Crewed research submersible rated to 6 500 m. Its own specification gives the best limitation on this table: even with seven searchlights, you can see about 10 m |
| Jiaolong (2012) | China | Reached 7 062 m in the Mariana Trench — China's first independently built deep submersible |
| ROV Jason / Medea | USA · Woods Hole | A two-body system: Medea hangs on the ship's cable and absorbs the swell so Jason can work steadily below. Over 20 000 hours on the seafloor, and one dive lasting more than nine days |
| DSV Limiting Factor (2018–) | Private · Triton | First submersible certified for repeated dives to full ocean depth. Took the Five Deeps expedition to the deepest point of all five oceans in eight months. Now renamed Bakunawa |
| Nereus (2008–2014) | USA · Woods Hole | A hybrid that could work as ROV or AUV. It imploded at about 10 km depth in 2014 — and its loss removed the only working way to drive around the deepest third of the ocean |
A famous line you should stop repeating
You will hear that "more people have walked on the Moon than have been to the bottom of the ocean." That was true for fifty years — from 1960 to 2012 exactly three people had been to Challenger Deep, against twelve Moonwalkers. But once Limiting Factor began diving routinely in 2019, the number climbed past it. 📌 Attach a date, or do not use it. A statistic that was true when someone wrote it down does not stay true — and noticing that is a scientific skill, not a pedantic one. The pressure at the bottom is still about a thousand times what you feel at the surface, which is why the hull is a sphere: a sphere is the only shape that shares pressure evenly.
The Oceanographer's Toolkit
CAPS names seven instruments here and asks you to discuss them. They look like a random list. They are not — they are seven different answers to one problem, and the fastest way to learn them is to see what each one trades away.
Nothing measures everything. Every tool buys one thing by giving up another.
A ship gives you superb data at one place, on one day — and costs tens of thousands of rands an hour. A satellite gives you the whole planet, every day — and cannot see below the surface skin. Everything else on this list is an attempt to get some of both.
📌 Read the last column of the table below first. If you understand the seven limitations, the seven instruments explain themselves — and "which instrument would you use, and why" is a far more likely exam question than "what does CTD stand for".
| Instrument | What it measures | How it works, and how the data gets home | What it cannot do |
|---|---|---|---|
| CTD Conductivity, Temperature, Depth |
Salinity, temperature and depth, continuously, all the way down | Lowered from a ship on a cable, usually inside a rosette ringed with bottles that snap shut at chosen depths. Data runs up the cable live, so scientists watch the profile draw itself | Needs a ship parked on the spot. One vertical line, one moment, at very high cost |
| XBT eXpendable BathyThermograph |
Temperature only, down to roughly 760 m | A throw-away probe trailing hair-thin copper wire, dropped from a moving ship — including cargo ships on ordinary trade routes. Costs under about R2 000 each | 🔴 It has no depth sensor. Depth is calculated from how long the probe has been falling. And it never measures salinity |
| Argo float | Temperature and salinity through the top 2 000 m | A free-drifting robot tube. It parks at 1 000 m for about 9 days, sinks to 2 000 m, then rises measuring as it climbs, surfaces, transmits by satellite, and repeats — a 10-day cycle. It has no propeller: it pumps oil into an external bladder to change its density. About 4 000 are active worldwide | Cannot be steered — the ocean decides where it goes. Stops at 2 000 m, roughly half the average ocean depth. Too widely spaced for coastal water or a narrow current like the Agulhas |
| Ocean glider | Whatever sensors it carries — temperature, salinity, oxygen, chlorophyll, even whale sounds | Same buoyancy trick as an Argo float, but with wings, so each sink and rise becomes forward flight. It saw-tooths through the water for weeks, surfacing to phone home — and can be re-tasked mid-mission | Very slow — slower than walking pace. A strong current can simply carry it away, which matters on our east coast. Usually limited to about 1 000 m |
| Marine animal CTD a CTD-SRDL tag |
Temperature and salinity profiles, wherever the animal chooses to dive | A tag about the size of a matchbox, glued to the fur on a seal's head. It records each dive and transmits when the animal surfaces to breathe. Instrumented seals have returned over 800 000 profiles | You cannot choose where it goes — the seal does. And the satellite link is so narrow that the tag must send a sketch of each profile, not the whole thing |
| Mooring | Many depths at once, continuously, for a year or more | A line held vertical between a heavy seabed anchor and a float, with sensors clamped at fixed known depths. It stays in one spot and measures hour after hour | Superb in time, blind in space — one point only. Needs a ship to service it yearly, and gets fouled by barnacles and damaged by fishing gear |
| Satellite remote sensing | Sea-surface temperature, ocean colour (so chlorophyll, so plankton), sea-surface height, and roughly salinity | Detects radiation: heat the sea emits, sunlight it reflects, or a radar pulse the satellite fires and times. Covers the entire world ocean repeatedly | 🔴 It only ever sees the surface skin — micrometres to about a centimetre deep. Blind to 99.9% of the ocean's volume. This is precisely why the other six exist. |
The best idea hiding in this table
A CTD does not measure salinity, and it does not measure depth. It measures how well the water conducts electricity, how warm it is, and how hard it is being squeezed. Salinity is then calculated from conductivity and temperature together — because warm water conducts better too, so conductivity alone would fool you. Depth is calculated from pressure.
📌 Enormous numbers of scientific "measurements" are actually calculations sitting on top of a different measurement. The XBT is the same idea taken further and more riskily: it times a falling probe and converts that to depth. Get the falling speed slightly wrong and every temperature is filed at the wrong depth — which is a real, live problem in decades of archived ocean data. Always ask what an instrument physically detects, as opposed to what its output claims to be.
Seals that do oceanography
The strangest entry on CAPS's list is the marine animal CTD, and it exists because of a gap nothing else could fill. In polar winter, ships are locked out by sea ice and Argo floats cannot surface to transmit — yet that is exactly where and when the cold dense water forms that drives circulation in every ocean. Elephant seals feed there anyway. So researchers glue a tag to the seal's head, and it collects the data on its own errands. The tag weighs about 545 g in air but only 255 g in seawater, because it displaces water — the same principle that lets the Argo float swim, and the same one you will meet as upthrust in Topic 6. South Africa is one of the member countries of the international programme that pools this seal data.
The Kit in Your Own Hands
CAPS names nine pieces of simple apparatus that a Marine Sciences learner should use regularly — not read about once. Most of them are cheap, several you can make, and every one of them produces a number you can put on a graph.
| Apparatus | What it measures or collects | Get one? | Its honest limit |
|---|---|---|---|
| Surface sampling bottle | A water sample from the top layer — for salinity, pH, temperature or plankton | 🟢 free a rinsed bottle on a string | Surface only. Tells you nothing about the water a metre down |
| Van Dorn bottle CAPS spells it "Van Doorn" — see the note below |
A water sample from a chosen depth. Open at both ends on the way down, then snapped shut by a weight slid down the rope | 🔴 lab supplied in the practical | One depth per drop, and you must know how much rope is out |
| Thermometer | Water temperature — the single most useful number in oceanography | 🟢 kitchen | One point, one moment. A temperature profile needs many |
| Refractometer | Salinity, by measuring how much light bends entering the water | 🟠 hobby or a hydrometer instead | Needs a drop of clean sample and a temperature correction |
| pH meter | How acidic or alkaline the water is — seawater sits near 8.1 | 🟡 pharmacy strips work, a meter is better | Strips are too coarse to see the change acidification causes |
| Secchi disk | Water clarity — the depth at which a black-and-white disk disappears | 🟢 make it a painted lid and a marked rope | Depends on the sun, the sea state and your own eyes |
| Ekman bottom grab sampler | A bite of the seabed — the sediment and the animals living in it | 🔴 lab supplied in the practical | 🔴 Soft mud only. Its spring-loaded jaws jam on sand, shell or gravel — which is most of Algoa Bay |
| Quadrat | Abundance — a fixed square frame you count everything inside | 🟢 make it four sticks or a wire coat hanger | Where you put it decides your answer, so placement must be random |
| Tape measure, for transects | Change across a distance — how species zone up a shore from low to high tide | 🟢 kitchen | A line is not an area. It shows the pattern, not the total |
A spelling to be careful with — CAPS has it wrong
The CAPS document lists a "Van Doorn bottle". The instrument is properly the Van Dorn bottle, named after W. G. Van Dorn, the Scripps oceanographer who designed it in the 1950s to collect bigger samples than a Nansen bottle could.
📌 Answer as your paper asks. If an exam writes "Van Doorn", write "Van Doorn" — you will not be penalised for matching the paper. But know the real spelling, because every catalogue, supplier and scientific paper you will ever meet uses Van Dorn. This is a good early lesson: a syllabus is written by people, and people make typing errors.
Why the same trick appears twice on this table
The Van Dorn bottle and the Ekman grab are both fired by a messenger — a weight you slide down the rope after the instrument is in position. It falls, hits a trigger, and the device closes. Before electronics, that was the way to tell an instrument at 30 m to do something, and it is the same idea as the Nansen bottle you meet in Topic 8. 📌 Gravity as a signal cable.
This kit is for a project, not a demonstration
CAPS is unusually specific here: "Students should be able to use this equipment for science expo poster projects." The Depth column for this topic says the same thing in different words — "This topic is ideally suited for a project."
So the point of the nine items above is not that you can name them. It is that you can pick two or three, take them somewhere real, and come back with data nobody handed you. That is the whole assessment in Topic 5, and this list is where its apparatus comes from.
CAPS also suggests where: "Practical work can be done at a local Marine Sciences centre such as an Aquarium Education Centre." ⚠️ Check before you travel. Gqeberha's obvious candidate, Bayworld, has its Oceanarium closed to the public and scheduled for demolition as phase one of a redevelopment, with its penguins, seals and turtles being relocated — so the aquarium half of that instruction cannot currently be followed here. Bayworld's museum and snake park sites are separate. The Two Oceans Aquarium education centre in Cape Town does run the full programme. The better local answer is on the next section — a working research institution sits closer to you than any aquarium.
In the Lab — the CAPS Investigations
CAPS block 1 sets four investigations, and the Depth column adds that this topic is "ideally suited for a project". None of them needs a laboratory. One of them needs a painted jar lid and a piece of rope.
What CAPS asks for, word for word
Investigations column, block 1: "Use a structured approach to introduce the equipment used, data received, and how these apply to the scientific method" · "Investigate tertiary institutions that offer Marine Sciences and what subjects are required by each" · "Visit DAF or DEA research institutions such as the various aquariums" · "Equipment and methods used by oceanographers". Resources: "Videos · A range of websites · Brochures from Marine Sciences departments at universities".
📌 And your textbook sets two more. Its "Test your knowledge" asks you to "select three pieces of Marine Sciences equipment and explain how they are used to conduct research", and to produce a poster describing a Marine Sciences career — including where that scientist studied and what subjects they took. Between them, those two are the project CAPS is asking for, so both are on the sheet.
Four investigations · the only thing you have to build is a Secchi disk
- 🟢 make it 🌊 shore Build a Secchi disk and measure water clarity — a painted lid, a weight and a marked rope. Then run it as a real investigation: aim, variables, method, results, conclusion. Supplied Algoa Bay data if you cannot get to the water.
- 🟢 desk Choose the right instrument — four real marine questions, and CAPS's seven instruments to choose between. Then read an actual temperature-and-salinity profile and work out what it is telling you.
- 🟢 desk Investigate the tertiary institutions — build the comparison table CAPS asks for. A described prospectus set is supplied so the task works without internet.
- 🟢 desk The research-institution visit, and the career poster — supplied as a described visit, because the local oceanarium is closed. Plus the poster your textbook sets, with its marking rubric.
→ Open the Topic 1 practical sheet — printable, with supplied data for every task.
Key Vocabulary
Tap each card to flip it — the equipment, the institutions, and the words CAPS uses to frame this subject. Your textbook marks four of these as formally examinable definitions — bathythermograph, quadrat, refractometer and Secchi disk. The rest are terms CAPS names in its key concepts, so learn them too.
An instrument used to measure ocean temperature at any depth. Lowered from a research vessel.
A portable square frame used to isolate a standard area of seabed or shoreline for counting species.
Measures how much light bends when entering a liquid — used to test the salinity of seawater.
A black-and-white disk lowered into water to measure how clear (transparent) the water is.
A subject that combines several fields of study — like Marine Sciences combining biology, chemistry, physics, geography.
South Africa's initiative to build a Blue Economy — growing ocean-based industries while protecting the environment.
Conductivity, Temperature, Depth. Lowered from a ship, it records continuously all the way down. It actually detects conductivity, temperature and pressure — salinity and depth are calculated from those.
eXpendable BathyThermograph — a throw-away probe dropped from a moving ship, trailing fine wire. Measures temperature only, and works out depth from falling time, not a sensor.
A free-drifting robot that parks at 1 000 m, dives to 2 000 m, then rises measuring temperature and salinity — every 10 days, for years. It has no propeller; it changes its own density with an oil-filled bladder.
A winged robot submarine that changes buoyancy like an Argo float, but whose wings turn sinking and rising into forward flight. Unlike a float, it can be steered and re-tasked mid-mission. South Africa flew its first two in Algoa Bay in 2025.
A small CTD tag glued to a diving animal — usually a seal — which records a profile on every dive and transmits when the animal surfaces. It reaches polar water under sea ice, where ships and floats cannot go.
An instrument line held upright between a seabed anchor and a float, with sensors clamped at known depths. It stays in one place for a year or more, so any change in the data is a change in time, not in position.
Measuring the ocean from orbit by detecting radiation — heat it emits, sunlight it reflects, or radar pulses timed back. Gives temperature, ocean colour (so plankton) and sea-surface height globally. Its hard limit: it only sees the surface skin.
The three kinds of deep-sea vehicle. ROV — remotely operated, on a cable: unlimited power, live video, but leashed. AUV — autonomous, no cable: free to roam, but no live picture. HOV — human-occupied: real eyes, at great cost and risk.
A tube open at both ends, lowered to a chosen depth and then snapped shut by a messenger weight slid down the rope. Collects a water sample from a known depth. CAPS spells it "Van Doorn"; the correct spelling is Van Dorn.
A spring-jawed box dropped on the seabed to bite out a sample of sediment and the animals living in it, triggered by a messenger weight. Works in soft mud only — sand, shell or gravel jams the jaws.
A measured line laid across a habitat — usually a tape from the low-tide mark up the shore — along which you record what occurs. It shows how communities change across a gradient. A quadrat samples an area; a transect samples a direction.
The South African Environmental Observation Network. Its purpose is the long record — the same measurement, in the same place, by the same method, for decades. Its Elwandle coastal node is in Gqeberha and runs the Algoa Bay Sentinel Site.
The South African Institute for Aquatic Biodiversity, in Makhanda. Over a million preserved fish, a DNA lab, underwater camera platforms and multibeam sonar. Founded as the JLB Smith Institute — the coelacanth man from Topic 8.
Earning a living from the ocean without removing anything from it — whale watching, dive tourism, filming, aquarium and education work. Its opposite is consumptive use: fisheries, and extraction of minerals, oil or gas.
CAPS's own word for this subject. Where interdisciplinary describes fields sitting side by side, trans-disciplinary means a skill learned in one field crossing over and working in another — maths doing biology's job, physics doing geography's.
Quick Check
Question 1
Well done!
Move on to Topic 2 when you're ready.