Kelp, krill and whales: Reflecting on World Oceans Day 2020 this June

The UN World Oceans Day on June 8th each year celebrates the major role that the ocean has in our health and that of our planet. It also draws attention to the impact that human actions have, in turn, on the health of the ocean. The world’s ocean captures about 40% of the carbon dioxide emitted by humans – a critical role to us in the present time.

The 2020 theme is ‘Innovation for a Sustainable Ocean’; as the challenges to the ocean grow, so does the need for novel solutions and the people driving them. Across its expanse there is an endless list of services the oceans provide, but also an increasingly long list of ‘tipping points’ – major ecological disruptions that are pushing the oceans towards potentially irreversible change.

Achieving a collective approach to sustaining our oceans is an example of a ‘wicked problem‘ – the ocean covers about 70% of the world’s surface and half of it falls under the jurisdiction of nation states.  We all have our own connection to, and responsibility in looking after the ocean. From the local, individual decisions and actions we take to the much larger policy and industry drivers that impact ocean ecology and productivity on a national and international scale – it all matters. The positive news is that there is a lot we can do as individuals to play a part – the most simple is being engaged in what’s going on; building on what we know and how we value the ocean. So for this month we have put together a little bit of ‘ocean focused’ news that has caught our attention, to help share information and insight on why ocean health matters!

Super Seaweed …

Seaweed (or algae) is one of the key building blocks of the world’s oceans. As a primary producer they provide a foundation for the ocean’s food chains. In the process of photosynthesis, algae also captures carbon dioxide, and produces oxygen as a by-product. Seaweed, as a human food resource, provides a global commercial value of several billion dollars annually. Basically, seaweed rocks! And in keeping with this years ‘innovation for a sustainable ocean’ theme, here are a few really cool recent innovation ventures focusing on this resource …

Phycologist Dr. Pia Winberg  has been exploring some novel uses for seaweed in global aquaculture at the Shoalhaven Marine and Freshwater Centre in NSW; and as a result of some really exciting research, has developed one of the world’s first on-land seaweed farms. This farm works in partnership with one of Australia’s largest wheat refineries to create a closed-loop waste system. The algae (mostly green group algae) that is grown within the Shoalhaven facility captures the carbon dioxide (from released ethanol) and other waste nutrient products from the wheat refinery.

Ulva laetevirans (Sea Lettuce) – one of the green seaweeds researched and produced at the Shoalhaven facility. Photo: Dr. Pia Winberg.

Due to the algae’s ability to absorb such a vast amount of carbon dioxide, it becomes a highly productive crop. For a comparison, a hectare of wheat yields about five tons of dry weight product. Seaweed in a commercial setting such as  the Shoalhaven farm has been demonstrated to be able to yield up to 100 tons of dry weight in one hectare – without using any fresh water! This also provides an avenue for increasing national and global productivity of algae sustainably – without relying on harvesting seaweed from the ocean.

The green seaweed harvested are rich in nutrients and trace elements, and are comparatively lower in iodine levels than other seaweed groups, which can be toxic in high doses. The dry weight seaweed produced is now being used in some pretty different products like protein bars, cereal, pasta … would you try ‘phukka’ (seaweed-enriched dukkha)? This learning has now been taken further, investigating green seaweed for uses such as  medical fibres and even a biodegradable plastic replacement!

Kelp forests as carbon sinks …

Like the green seaweed used  in Dr. Winberg’s work, kelp (the big brown macroalgae most of us are familiar with seeing often along the beach) has an even more impressive ability to absorb CO2 – they form the forests of the sea! Kelp forests are amongst the most productive ecosystems on earth, and in the process of this productivity absorbs vast amounts of CO2.

Research here in Australia and abroad has been trying to understand how these carbon sinks can be utilised to help tackle global warming. Some researchers are looking at taking the production of kelp an extra step by harvesting farmed kelp as a biofuel, and even livestock feed to reduce methane outputs.

A recent global study has found a very critical piece of information – kelp forests growing in cool, nutrient rich waters absorb up to three times more CO2 than those growing in warmer oceanic regions. With ocean temperatures already rising, maintaining the cool-water wild kelp forests in some areas will be just as important as finding ways to grow more in others.  University of Tasmania research has estimated that more than 95% of eastern Tasmania’s kelp forests has been lost in the face of oceanic temperature rise over recent decades. These emerging bodies of research are highlighting just how important kelp and other seaweeds are in the health of oceans, and the broader implications for our global climate.

Looking after the giants of the ocean …

Some of us are very fortunate to get a glimpse of the world’s largest living animal as it makes it’s way across the southern Australian coast – mainly from November to May. Blue Whales migrate to the southern hemisphere to over-winter breeding grounds, constantly feeding within the cooler, nutrient rich waters. In our region, the Bonney Upwelling System is a large and deep-reaching upwelling which brings cold, nutrient-rich water to the ocean surface. This is an important driver of biodiversity and has provided a relatively reliable food source and hot-spot for Blue Whales – a phenomenom that has been studied by the ‘Blue Whale Study’ group since 1998. The not-for-profit group, lead by CEO by Dr. Pete Gill, has been a key contributor to blue whale and ecological marine research – mostly through their undertaking of aerial and boat-based surveys along the continental shelf between Warrnambool (Vic) and Robe (SA), and plotting of distribution of several whale species and their key prey (krill) in the Bonney Upwelling System. By relating these distribution patterns to remotely sensed environmental data (e.g. satellite sea surface temperature data) the group have gained great insight to the behaviour and ecology of the region’s whale species.

A map of the Bonney Upwelling event (dark blue surface plume) within the Blue Whale Study focal area. Photo courtesy of Blue Whale Study.

A significant drop in the number of Blue Whale and krill swarm observations within the Bonney system over the past decade has concerned the group. Most historic whale sightings occur just off the continental shelf that borders the cold up-welled water of the upwelling plume – and corresponds with abundant krill swarms. A lack of funding for maintained survey effort in recent years may be, in part, contributing to low sightings. However, following a seemingly strong upwelling in autumn this year, aerial survey efforts still produced very few (two) sightings and no observations of krill swarms. The two sightings were also uncharacteristic in location – with the whales spotted outside of the continental shelf and away from the usual upwelling plume.

A key component of the Blue Whale Study’s research is aerial surveys for the Blue Whale along the continental shelf of the Bonney Coast between Robe (SA) and Cape Otway (Vic).

The group are currently reviewing and looking for any trends in their data to provide more insight, but suggest the possibility that the upwelling is not supporting abundant krill swarms, and whales are searching for prey away from this area. Interestingly, this reported decrease in Blue Whale activity has coincided with strong numbers within the eastern Great Australian Bight. This research is obviously hugely valuable, and there is much more to learn. Unfortunately a drop in funding support is making it hard for the Blue Whale Group to continue their great work. If you would like more information, you can make contact with the Blue Whale Group on Facebook or email.

Beaches – a glimpse into ocean life …

For those that love to visit beaches – whether its your local, or a favourite holiday spot – no visit is the same. There are often times something new catches your eye, maybe something a bit unexpected!

Along much of our south-eastern coastline there is a diversity of life just off the water’s edge living in intertidal zones or subtidal reefs. Full of colourful, diverse, weird and wacky creatures, there is a never-ending opportunity to learn about marine life. NGT’s Rose spoke about an interesting species she found on the beach at Cape Douglas in the Species of the Month post here.

At Narrawong, recent surges have washed up some pretty cool stuff, including an array of immobile, filter-feeding, colony forming creatures amongst the seaweed, rocks, and shells. Here are just a few photos of what has recently been seen (and yet to be fully identified) …

These include sponges, which are simple organisms that colonise a skeleton – which varies greatly in size, shape and form, depending on the particular habitats they adapt to. Ascidians can similar in feature to sponges, particularly those in early stages of growth, but are more complex organisms (in fact, belonging to the phylum chordata – the same as humans!).

Ascidians have a characteristic soft, jelly-like outer tunic. Both are hugely important to the ecology of the marine environments in which they are found, and are very susceptible to impacts such sea temperature increases, acidification, and turbidity through mechanical dredging. A lot of what is recorded or observed in these groups comes from citizen science – that is, people like you!

There are some great resources and groups you can contact to get more information about what you see (including NGT’s Jess), and also have them recorded, including Museums Victoria, Marine and Freshwater Discovery Center, Redmap, Port Phillip Marine Life, and a great ID brochure by the Department of Environment and Water SA.

… And if you know a bit more about the featured creatures in the photo above, send us an email.  We’d love to hear from you!

Lauren Kivisalu