Tag Archives: Algae

Kelptastrophe! Mystery of the Missing Kelp

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Catalina Island’s kelp forests are a wonder to witness. The amber-green kelp provides a home for countless animals along the California coastline, from gray whales to juvenile invertebrates. Snorkeling underneath giant kelp is like swimming through a kaleidoscope of stained glass windows and finding animals around every corner. Unfortunately, the kelp is in trouble and it has been struggling to grow in Southern California since 2014.

Giant kelp (Macrocystis pyrifera) is the fastest growing organism on the planet. In ideal conditions, Macrocystis can grow up to 2 feet in a single day! Like other brown algae, Macrocystis is an autotroph, meaning that it makes its own food from the sun using photosynthesis. Kelp forests produce as much oxygen using photosynthesis as the Amazon rainforests with 100 times less biomass. Although giant kelp can grow up to 110 feet in length, it prefers to grow in waters shallower than 30 feet. Air bladders along the kelp help float the translucent blades to the surface to collect sunlight while a branching network called a holdfast anchors the algae to hard substrate below. Giant kelp forms canopies on the water’s surface, providing an island for marine birds and a shelter for countless fish, marine mammals, and invertebrates. Furthermore, rotting kelp washing up on beaches provides a moist cover for fish eggs or ready buffet for insectivorous shorebirds.

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Anatomy of typical algae

Image: The Root Stock

Macrocystis also has critical economic importance to California and the Pacific coast. Many fisheries (rockfish, Dungeness crab, Red abalone, Red urchin) rely on the kelp for habitat, and those species are a food source for larger macrofauna like pinnipeds and seabirds. Giant kelp is widely used in cosmetic and food industries as a thickening agent in products like toothpaste, ice cream, and makeup. Its natural beauty makes it a highlight of tourism for the region as divers and snorkelers travel from all over to the world to frolic in the amber blades. Giant kelp is also being targeted as a possible bio-converter into ethanol as a fuel source for cars and boats.

Macrocystis is deeply integrated into coastal ecology. It is a critical food and habitat source for a wide network of sea creatures. It is an ecosystem in itself, supporting a wide network of consumers and producers. Sea otters and the ochre sea star (Pisaster ochraceus) are two keystone species, meaning that their removal has wide-reaching effects that greatly impact coastal populations relative to other animals. In the case of the kelp forest, they both curb the destructive effects sea urchins have on kelp abundance. Sea urchins are kelp’s worst enemy as they nibble on the stipes until the entire algae breaks off from the holdfast. If too many urchins are present then they will essentially mow down the forest until only barrens remain. Scores of animals that relied on the kelp for food or shelter move away from their former home as a result and the ecosystem could collapse.

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Simplified kelp forest food web, typical for Southern CA

Image: Michelle Frantellizzi

The kelp forests of Southern California are currently in the stages of an ecological emergency. In 2003 another species of brown algae, Sargassum horneri, was accidentally brought over to the Port of Long Beach by a cargo ship from Japan. The spores of this plant then traveled to Catalina Island via a recreational vessel and quickly took root in the hard substratum. Sargassum flourishes in a wide range of temperatures (50-75ºF) and is commonly known as “Devil Weed.” It is an annual alga and can self-fertilize, meaning that multiple generations can exist in a single space. This is the ideal time for Sargassum reproduction: winter and early-spring where the waters are colder and currents are stronger.

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Macrocystis struggling to grow among Sargassum

Image: Alyssa Bjorkquist

Scientists and divers began to notice tangled webs of Sargassum invading spaces where Macrocystis used to flourish. Invasive species can be detrimental to an ecosystem because they outcompete other native species for critical food, habitat, and resources. Once Sargassum was present in the environment, it essentially took three strikes to hurt the giant kelp populations:

Strike 1: While Sargassum began to develop its presence in Southern California, a virus infected essentially erased 90% of Pisaster populations. With sea otters absent from the region, giant kelp lost one of its greatest protectors to Sea Star Wasting Disease. Without a top predator curbing population growth, urchins began clearing the way for Sargassum to grow through intense kelp grazing.

Strike 2: A hurricane in 2014 brought powerful waves, currents, and winds to a relatively stable environment. Although Macrocystis is a hardy algae, massive swaths of kelp washed away in the face of the intense storm. Sargassum seized the opportunity for ideal real estate and claimed the land, weaving dense webs that made it impossible for Macrocystis to resettle.

Strike 3: Incredibly warm oceans and strong currents during the 2016 El Niño Seasonal Occurrence (ENSO) swept away Macrocystis spores or freshly settled growths. Giant kelp can only grow in a narrow range of temperatures (59-65ºF), and the 2016 ENSO provided the perfect recipe for inhibiting giant kelp growth with a peak water temperature of 80ºF. Sargassum, on the other hand, flourished under the warm waters and used the strong currents to spread to other kelp forests in the region.

With warming oceans and increasing boat traffic throughout the region, it is unknown whether the giant kelp will be returning any time soon. Juvenile Macrocystis have a difficult time settling and growing among the dense webs of Sargassum and those that do settle are quickly torn apart by the invasive algae. Divers conducting surveys of Sargassum have observed that fish and other grazers are not eating the algae. Preliminary research suggests that the algae’s thick stipe, tiny blades, or potential presence of toxins deter animals from grazing.

The Macrocystis kelptastrophe is not hopeless. Many scientists, divers, and citizens who care deeply about Macrocystis are working hard on restoration projects in the region. Many students are using Macrocystis restoration as an opportunity to connect with their coastlines. Scientists and dive companies are collaborating to conduct surveys of where the algae are distributed and how they are changing over time. Nancy Caruso, a marine biologist in Southern California, has been working with local high school students to raise juvenile Macrocystis in their classrooms and then plant the kelp near their local beaches. Regardless of perspective, it is undeniable how much we love our giant kelp and we hope it comes back soon.

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The underwater forests are changing. (Sargassum on left, Macrocystis on right)

Images: Alyssa Bjorkquist

To track the spread of Sargassum or to report a sighting, visit: http://www.marineinvasives.org

To learn more about Nancy Caruso and how you can help the kelp, click here: http://loe.org/shows/segments.html?programID=14-P13-00045&segmentID=5

To learn more about Southern CA fisheries, click here: http://www.pressdemocrat.com/news/5487602-181/collapse-of-kelp-forest-imperils?artslide=0

Written By: Alyssa Bjorkquist


  1. Harbor Seal in kelp forest: http://www.rsmas.miami.edu/assets/w144-overall-KyleMcBurnie.jpg
  2. Kelp anatomy: http://www.therootstock.org/
  3. Kelp forest food web: https://prattf10.wordpress.com/author/michellefrantellizzi/


  1. http://www.pressdemocrat.com/news/5487602-181/collapse-of-kelp-forest-imperils?artslide=0
  2. http://www.eeb.ucsc.edu/pacificrockyintertidal/data-products/invasive-species/Sargassum%20horneri%20Information%20Sheet_8.27.15.pdf
  3. http://californiadiver.com/the-invasion-of-the-devil-weed-sargassum-horneri-invading-california-waters/
  4. https://www.montereybayaquarium.org/animal-guide/plants-and-algae/giant-kelp
  5. https://caseagrant.ucsd.edu/project/the-spread-and-ecological-consequences-of-the-invasive-seaweed-sargassum-horneri

Algae!! In your…toothpaste?

When you think about the word “algae,” what comes to mind? Do you think slimy? Green? Smelly? These are all ways in which we might describe our gooey ocean plant-like friend, however there are so many beneficial uses to this interesting water plant that we may have never imagined!

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Here’s the deal…we as humans rely on algae for a whole ton of things, and not just for 2/3rds of the air we breathe. That’s right, algae plays a huge role in oxygen production and photosynthesis, acting as a primary producer at the base of the ocean food chain. However, that’s only the beginning of this organisms worth, as it’s properties and sliminess provide humans with crucial ingredients for various everyday items!


Do you brush your teeth every morning? Well, we sure hope you do! Do you enjoy a giant scoop of ice cream on a hot summer day? Do you use shampoo to wash your hair? If you answered yes to any of the above, than you are consuming algae! The properties that make up that slimy consistency in algae create emulsifying properties in the products we consume on a daily basis. Red algae contains something called carrageenan, and it exists in more ingredient labels than you think! It can be found in everyday items like your Starbucks coffee, chocolate milk, yogurt, coconut milk, or even packaged turkey meat. Alginate is a property found within brown algae, and is used as a rubber or adhesive alternative.


Besides it’s many healing properties used in spa treatments, humans consume algae for other uses every day. The sushi industry, which generates billions of dollars and feeds people globally, requires a specific form of algae to stay afloat. Nori, a red type of algae, is used in wrapping the mass amounts of sushi rolls we consume around the world.

For all these reasons listed above and many, many more, we can easily determine how important algae is in our every day lives. So next time you wrinkle your nose at the smell of some beached algae, remember to thank that slimy stuff for all it does for you, and your chocolate milk!

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Sargassum is it a Weed?

What makes a weed a weed? It grows fast, it takes up resources of other native species thereby reducing diversity, and it causes ecological problems because it is so abundant – sometimes called a “monoculture”. Did you know there are “weeds” in the ocean, too? 

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Sargassum horneri, or as it is not-so-fondly known by some California divers, “devil-weed”, is an invasive algae from Asia that has been steadily taking over Catalina since 2006, when it was discovered by divers who began a citizen science project to document its abundance. In some places, including our coves here on the leeward side of the island, it is outcompeting our native algae, including the giant brown kelp that once formed dense forests home to a diverse abundance of invertebrates and fish.

Invasive species traverse the world’s oceans by many means. The most common is through shipping channels. A ship’s hull can hold thousands of species, accumulating them in one port and depositing them thousands of miles away. Ships also hold and empty water called ballast, used to counteract the weight of offloaded cargo to keep the vessel balanced. Sargassum likes shallow, temperate rocky reef habitats, and as of today can be found as far north as and as far South as Baja California, Mexico. and as ocean temperatures rise, it is predicted to continue to expand its range. Sargassum grows ten feet tall and forms “fields” on the ocean floor, and thick carpets on the water’s surface when its holdfasts, root-like structures that keep it anchored to the rocky bottom, break free. While sargassum is displacing kelp populations, it is also increasing fish abundance.

Kelp: The Floating Forests

What has the world’s fastest linear growth, contains remedies for everything from heartburn to wrinkles, and might be in your t-shirt right now and in the PB&J you had for lunch?

If you said giant brown kelp, Macrocystis pyrifera, you’re right!

Tree of life
Algae is different from land plants because it lacks a root system that sucks up water and nutrients from the soil, instead using a root-like system called a holdfast, a cone-shaped network of branches called haptera, to anchor to its substrate. However, its growth is so successful because the more mature blades near the water’s surface can efficiently transfer excess sugars through passageways called sieve tubes down to the younger blades below that cannot yet provide all the energy they need through photosynthesis.

Kelp plantImage from KelpWatch, found at http://www.geol.utas.edu.au/kelpwatch/facts_b.html

Giant brown kelp is part of the phylum Ochrophyta, named for the ochre-colored pigments in its blades (or “lamina”). Instead of chlorophyll, this phylum uses a brown pigment called fucoxanthin in photosynthesis, giving it the brown color that makes it part of the class phaeophyta, the brown algae. Brown algae is the most diverse of the three classes of algae (brown, red, and green) — it comes in all shapes and sizes, and includes the world’s largest algae, like Macrocystis pyrifera!

Sequoia of the sea
Macrocystis pyrifera is the world’s largest seaweed, reaching 50-60 meters in length and 100 kg in weight, with blades up to 70 cm long. In ideal conditions (shallow rocks or coarse sand in cool, nitrogen-rich waters) it can grow 50-60 cm in a single day – that’s almost two feet – and 45 m in a single growing season – that’s as tall as the Statue of Liberty! Giant brown kelp is perennial, which means that it often dies back to its holdfast in winter, losing up to three quarters of its mass before regrowth in warmer season. Kelp can live up to five to eight years, and its massive size has given it the nickname “sequoia of the sea.”

kelp cartoonImage from Tours de Jours comic strip, Catalina Islander, found at MicrobeWiki.Kenyon.edu

Lay it on thick
Alginate, algin, or alginic acid, is a thickener found in many household products that is derived from the cell walls of brown algae. Sodium alginate is the main gum extracted from giant brown kelp, but other forms of this gel-like substance include potassium alginate and calcium alginate.
These products are used in manufacturing paper and fabric, in dyes, for waterproofing and fireproofing, and as a thickener for drinks, ice cream, creamy or gel-like foods (such as jelly or Velveeta cheese) and cosmetics, and even as an alternative wound dressing.

Extract from giant brown kelp, which is rich and vitamins and minerals including iodine, is also taken as a dietary supplement to promote healthy hair, skin, and nails. Rich in vitamins C and E, it has anti-inflammatory and antioxidant properties. It has also been proven to enhance natural collagen and elastin, proteins in skin that keep it firm and strong, and has been proven to reverse sun damage and prevent wrinkles.

A plant in San Diego operated for 76 years and until its closure in 2005 was the largest kelp harvesting facility in the world. Today, M. pyrifera is still harvested by large barges with spinning blades underneath them that act like marine lawnmowers, for these industrial uses as well as feed in abalone aquaculture.

Floating forests
Kelp is a key organism in shallow ecosystems because it provides plentiful food and shelter for otters, urchins, and many sessile invertebrate species. Macrocystis is the most widely distributed genus of kelp in the world, forming large, dense forests from Australia and New Zealand to South Africa all the way up the western coasts of the Americas. A study off San Clemente found that just as in a terrestrial rainforest, giant brown kelp outcompetes smaller understory kelp, opening up ample space for sessile invertebrates on the bottom. Often, the top layers of a kelp canopy will break off to form a kelp raft, a floating community rich in biodiversity. This is key in both the life cycle of the kelp and of its inhabitants, allowing reproductive spores to travel 1,000 km or more to start new colonies. Some small invertebrates even complete an entire life cycle including a planktonic larval phase, adult phase, and new generation before a kelp raft sinks or floats ashore.

To learn more about giant brown kelp, check out the Seaweed Industry Association website or this page in the Encyclopedia of Life. To see some awesome photos of kelp being harvested off the California coast, check out this collection.

Kelp Rafts

Kelp is anchored in the ocean by a root-like structure called a holdfast. During storms, or when large waves or strong currents come through, kelp can detach from its underlying substrate and begin to drift in the ocean. As the kelp floats along it often becomes entangled and forms a buoyant configuration of algae that we refer to as a kelp raft, or kelp paddy. While still anchored, kelp provides protection for fish and a is a habitat for many invertebrates such as snails, sea stars, and crabs. After the organism is uprooted, kelp rafts attract many new species adrift, while original dwellers often continue to call it home.

kelpAs kelp rafts drift into the open ocean, they become an important resource for pelagic species of fish. Living in the open ocean, these fish can take advantage of the kelp raft as a possible food source where invertebrates and high densities of plankton may be trapped. Baitfish often school under kelp rafts for protection, and clusters of juvenile fish use this drifting habitat as a nursery. Even our largest bony fish, the mola mola, or ocean sunfish, will come to the surface where a kelp raft is present to solicit the help of cleaner fish and birds that are looking for a tasty meal to rid the massive fish of its parasites.

These rafts can drift for miles across the ocean, and have even been regarded as a way for marine invertebrates and different species of algae to find new homes on nearby islands or drift to different countries. You never know what types of animals you will find in or under a kelp raft, so take a peak next time and see who made this floating ecosystem its home!

Written by: Jaclyn Lucas

The Nitrogen Cycle

The Nitrogen Cycle is an essential building block of life. Living organisms need nitrogen to develop the proteins that form the structures of their cells. Nitrogen is also all around us, with nitrogen gas making up nearly 80% of the Earth’s atmosphere. However, most organisms are unable to directly use nitrogen in its pure, gaseous form, so other processes must come into play that help convert the nitrogen in the air into a form that organisms are able to use.


In the ocean, nitrogen gas is dissolved and taken up by nitrogen-fixing microbes, which convert the nitrogen into compounds that allow other organisms to consume it and incorporate it into their cells. Algae is one of these organisms, using the nitrogen to help build chlorophyll-binding proteins that help the algae harvest light.

IMG_6573Ammonia is a nitrogen compound found in the feces and urine of animals that algae is able to readily absorb. Bird poop in particular has high levels of ammonia in it. Rocks that are surrounded by water, like Ship Rock, are favorite resting grounds for birds because their isolation protects the birds from predators. As dense numbers of birds congregate on the rocks, they become covered in poop. Algae then starts to grow around the rock to take advantage of the consistent supply of nitrogen the poop supplies. This in turn brings lots of fish towards the rock who want to live off of the algae. And what do the birds eat? Fish! So the birds continue to stay and poop on the rock because they have a nearby food source readily available to them. This cycle continues, with every organism contributing something important to their ecosystem. And the unlikely powerhouse that keeps this cycle moving is the underrated (and often even despised) substance we call poop.


Holdfast: The Anchor of Algae

Kelp and algae are like the trees and shrubs of the aquatic world except for one important factor, THEY’RE NOT PLANTS!  Kelp is in fact in the Kingdom Protista meaning that among other things it does not use roots to absorb nutrients nor does it have a vascular system to transport those nutrients to its various structures. The part of kelp most similar in appearance and location to the roots of plants is called the holdfast. This spaghetti like structure has a primary function of securing the organism to the sea floor; holding it “fast” in all but the most turbulent conditions.

Close Up

Because of the way kelp holdfasts are tangled and tasseled, they make the perfect protected place for young ocean animals to get their start in the world. If you were to find an uprooted holdfast floating at sea or on the beach you would be likely to spot more than a few species of animals. Everything from brittle stars to isopods to tube worms, tiny sea hares, kelp crabs and baby octopus can be found in these miniature nurseries. Scientists believe you could find over one hundred species in a single holdfast!

Some holdfasts like those of the giant brown kelp are expansive and winding while others, like that of the sea palm, are more puck-like and perfectly adapted to cement firmly onto rocks and other hard substrate. This tight grip allows kelp to stay stationary for a long time.  While the blades of kelp only live about a month or two, holdfasts can live and grow for up to ten years or more!

More information on kelp and holdfasts can be found at this link: Additional Kelp and Holdfast Information

Likin’ Lichen

Lichen is the combination of fungi, algae and even bacteria through a symbiotic relationship. It is one of the few organisms we know about that draws upon and spans across multiple kingdoms! Lichen are known as pioneer species: a species that will colonize new ecological systems. An example of this is our own Catalina Island! When Catalina rose from the ocean through the collision of tectonic plates, Catalina was mainly rock, inhabitable by most plants and animals. Through wind and bird dispersion, lichen was brought to Catalina. The lichen is capable of being a pioneer species because it decomposes rocks for their main source of energy. When lichen breaks down rock it slowly will become soil and thus a potential source for new plants and life. However this process is not quick, it is estimated that it takes about 10,000 years to make 1 inch of soil! Lichen is also an extremely slow grower, most lichen only will grow about a millimeter every year.

Here at CIMI lichen covers almost every rock face we have spanning from the beach to the top of our canyon. CIMI, Toyon Bay, instructor Kenny is seen in our video talking about lichen while sporting an old pioneer’s hat. He encourages you to next time stop and appreciate our mostly unnoticeable friends next time you hike! We’re lik’n lichen!

DIY Algae Press in 9 Simple Steps

DIY Algae presses are a fun way for students to take a little piece of CIMI home with them. After learning about the three different types of algae (Chlorophyta, Phaeophyta, and Rhodophyta), each student has an opportunity to design their very own algae art piece. Now if you’re trying to do this at home, you may not have easy access to tons of algae, like us, so feel free to go find some plants or flowers in your neighborhood to use.

Things you’ll need:

  • Something to press, like flowers or leaves (stay away from anything with a large stem, as it won’t press very flat)
  • A piece of cardstock or thick paper cut to about 6 by 9 inches
  • Some wax paper or parchment paper
  • Cardboard cut into small 6 by 9 inch sections or so
  • Rubber bands
  • A few heavy books
  • Two weeks of patience
  1. To start, gather all your plants and decide upon a design that you want to create.
  2. Take your piece of cardstock and carefully place your plants down in the shape you picked out. Try not to overlap pieces of plants, instead try to keep just one plant layer all over your paper.
  3. Do not use glue to stick the plants down; they will change shape and size as they dry.
  4. Once you have positioned your plants as you like, place a sheet of wax paper on top of your creation. This will keep the plants from sticking to the cardboard as they dry.
  5. When you are ready, place the cardstock and wax paper in between two piece of cardboard. Basically making a sandwich.
  6. Then use 4-5 rubber bands in both directions to hold your project together.
  7. Find a few heavy books and place your project in a cool dry place for about 2 weeks.
  8. If you check your press after two weeks and its not completely dry, leave it there for another week.
  9. Once everything is dry you can remove your press from the cardboard and wax paper. If the plants aren’t staying in place, feel free to glue them or get your press laminated, this will protect it from general wear and tear.


We would like to thank you for visiting our blog. Catalina Island Marine Institute is a hands-on marine science program with an emphasis on ocean exploration. Our classes and activities are designed to inspire students toward future success in their academic and personal pursuits. This blog is intended to provide you with up-to-date news and information about our camp programs, as well as current science and ocean happenings. This blog has been created by our staff who have at least a Bachelors Degree usually in marine science or related subjects. We encourage you to also follow us on Facebook, Instagram, Google+, Twitter, and Vine to see even more of our interesting science and ocean information. Feel free to leave comments, questions, or share our blog with others. Please visit www.cimi.org for additional information. Happy Reading!