What’s all the fuss about foundations?

What do kelp forests, mussel beds, seagrass meadows and coral reefs have in common? They are all given their name by the foundation species that creates them.

But what does being a foundation species entail?

Great Barrier Reef, Australia

Just as the foundations of your house provide structural stability keeping you house strong and stable, so too does a foundation species within an ecosystem. Because of this they are vitally important in structuring the community and maintaining a healthy ecosystem.

With the growing influence and uncertainty of human activity and environmental change the stability of the world’s ecosystems is questionable. It is therefore imperative that we understand what keeps ecosystems stable.

We know that foundation species are pivotal in ensuring ecosystem stability; but few have quantified it. Fortuitously nearly two decades worth of data and observations exists courtesy of the Santa Barbara Coastal Long-Term Ecological Research Project. Using this data researchers at the UC Santa Barbara’s Marine Science Institute posed the question:

‘Does a stable giant kelp forest result in a more stable understory community?´

MBNMS - Anemone in Kelp

Anemone in Kelp, Monterey Bay National Marine Sanctuary, USA

Well it turns out it does. Just as stable foundations ensure your house stays up, so too does a stable forest of kelp help in maintaining the stability of the under-story community of plants and animal.

Unfortunately in the face of climate change the stability of kelp is likely to change in the future. This could have devastating effects of all the plants and animals that rely on the kelp forest. Not only this, but this new research suggests that all habitats reliant on foundations species may also face such similar problems. Without the important species providing a foundation for all the other plants and animals, we could see devastating changes to these iconic habitats.

So the take home note:

Just as you have to take care of the foundations of your house to prevent it collapsing, so too do we have to take care of the foundations of our ecosystems or face calamitous consequences.

Scorpionfish In Seagrass

Scorpionfish in Seagrass, NOAA Florida Keys National Marine Sanctuary, USA

If you want to read more about this research check out this link or article below:

https://www.news.ucsb.edu/2020/019772/strong-foundation

Lamy, T., Koenigs, C., Holbrook, S.J., Miller, R.J., Stier, A.C. and Reed, D.C., 2020. Foundation species promote community stability by increasing diversity in a giant kelp forest. Ecology, p.e02987.

The demise of Baltic Sea wrack?

Another post about climate change, but this time closer to home. Climate change has been identified as one of the largest contributors to environmental change within the Baltic Sea. It is predicted that Baltic waters will heat by some 2–4°C and become up to 50% fresher by the end of the twenty-first century (Meier 2015).

Coastlines of the Southern Baltic Sea

Coastline of the Southern Baltic Sea

But how will Baltic wracks fair under these new conditions?

Unfortunately the future doesn’t look good for bladderwrack. Research by Antti Takolander and colleges at the University of Helsinki indicated that warming waters and increased freshness pose real threats to bladderwrack. The once abundant brown seaweed may struggle to cope with these new environmental conditions and consequently be lost from much of the Baltic Sea.

Bladder wrack peeking up above the water 4

Bladderwrack – Brofjorden, Sweden

Climate change looks bad for bladderwrack, but is that the case for all wracks of the Baltic Sea?

It seems that the future may not be as bleak for all the Baltic Sea wracks after all. Narrow wrack, having evolved within the Baltic Sea from bladderwrack, can be found nowhere else in the world. As a unique seaweed to the Baltic you might expect that the dramatically changing conditions predicted pose an even greater threat to this sister of bladderwrack. Yet a study by Luca Rugiu and colleges at the University of Turku indicates that this is in fact not the case. By subjecting narrow wrack to higher temperatures and fresher conditions replicating predicted future conditions they assumed that narrow wrack would fair as poorly as bladderwrack; however their results were surprising. Though the predicted future conditions did lead to higher mortality, those individuals that did survive were larger and grew faster.

Bladderwrack (Fucus vesiculosus) and Narrow wrack (Fucus radicans) living side by side – SW Gulf of Bothnia (northern Baltic Sea) [From Pereyra et al., 2009; CC BY 2.0]

Does this mean that narrow wrack may benefit from climate change?

In short: Yes. Those narrow wrack individuals that can withstand the predicted future conditions will benefit from the increased growth and gain a competitive advantage over those that cannot. Since where each wrack can be found is largely affected by competition between the species the future looks even worse for bladderwrack. Both wracks frequently grow side by side and if narrow wrack profit and bladderwrack lose out from future climate conditions bladderwrack may be lost from these areas and instead replaced with narrow wrack.

The future looks bleak for bladderwrack; we may end up losing vast swathes of bladderwrack forest in the Baltic. Though there is the small silver-lining that narrow wrack appears somewhat tolerant to climate change. So the future may not be all bad. We won’t see the disappearance of all the wracks from the Baltic Sea; though we will see a very different Baltic then we see today.


Sources:

Meier HEM (2015) The BACC II Author Team, Second Assessment of Climate Change for the Baltic Sea Basin, Regional Climate Studies, DOI 10.1007/978-3-319-16006-1_13

Takolander, A., Leskinen, E. and Cabeza, M., 2017. Synergistic effects of extreme temperature and low salinity on foundational macroalga Fucus vesiculosus in the northern Baltic Sea. Journal of Experimental Marine Biology and Ecology495, pp.110-118.

Rugiu, L., Manninen, I., Rothäusler, E. and Jormalainen, V., 2018. Tolerance to climate change of the clonally reproducing endemic Baltic seaweed, Fucus radicans: is phenotypic plasticity enough?. Journal of phycology54(6), pp.888-898.

The unsung hero in the fight against climate change

Buzzword of the day: Climate Change

You will have needed to be living under a rock to have not heard all about the controversial topic of climate change.

Human-induced climate change is having a dramatic effect around the world. In 2017 human-induced warming reached approximately 1°C above pre-industrial levels, with 20–40% of the global human population living in regions that have already experienced warming of more than 1.5°C above pre-industrial in at least one season (IPCC, 2018).

But why should we worry that the world is warming?

Human-induced global warming has already caused multiple observed changes in the climate including more frequent land and marine heatwaves, increases in the frequency, intensity and/or amount of heavy precipitation events, and an increased risk of droughts (IPCC 2018).

So what is causing this problem?

The answer: Greenhouse gases.

The most infamous culprit being carbon dioxide (CO2). At Mauna Loa observatory, a remote research facility located on the slope of Mauna Loa volcano [Hawaii], scientists have been recording atmospheric CO2 levels for the past 60 years and the trends are quite disturbing. Atmospheric CO2 has increased dramatically since recording first began, from 317ppm in 1960 to a high of 415 ppm in May 2019 (NOAA, 2019).

Monthly mean atmospheric carbon dioxide measured at Mauna Loa Observatory, Hawaii

Well maybe seaweed can help..

It is well publicised that trees can remove CO2 from the atmosphere by incorporating the carbon into plant material. But did you know that marine plants can help with storing CO2 from the atmosphere too? Just as with land plants, carbon can be incorporated into marine plants directly or stored in the surrounding sediment. Surprisingly marine plants can even contribute to the long-term storage of carbon in the deep ocean.

Yet it had been assumed that seaweed had little influence in storing CO2 from the atmosphere. In fact seaweed isn’t even included within the Blue Carbon initiative; a global program aiming to lessen climate change through coastal ecosystem management; whereas seagrasses, saltmarshes, and mangroves are. However a recent study published in Nature geoscience challenges this perception. Marine scientists from KAUST have confirmed the importance of seaweed in contributing to deep ocean carbon storage.

Seaweed community at Penguin Island [AU]

Unlike rooted seagrasses and mangroves, the majority of seaweed are rootless and do not remain fixed indefinitely but instead can drift on the currents and tides. This has made estimating their contribution to locking carbon away challenging. However using some cool molecular techniques this study shows that seaweed can be found regularly at depths greater than 1000m. We know that below this depth the carbon is unlikely to return to the atmosphere, and therefore can no longer contribute to the atmospheric CO2.

So it turns out seaweed could have a very important role in helping us fight climate change.

Want to know more? Check out the link below:

or find the published article:

Ortega, A., Geraldi, N.R., Alam, I. et al. Important contribution of macroalgae to oceanic carbon sequestration. Nat. Geosci. 12, 748–754 (2019) doi:10.1038/s41561-019-0421-8

https://rdcu.be/bZzWS


Sources:

IPCC, 2018: Global Warming of 1.5°C. An IPCC Special Report on the impacts of global warming of 1.5°C above pre-industrial levels and related global greenhouse gas emission pathways, in the context of strengthening the global response to the threat of climate change, sustainable development, and efforts to eradicate poverty [Masson-Delmotte, V., P. Zhai, H.-O. Pörtner, D. Roberts, J. Skea, P.R. Shukla, A. Pirani, W. Moufouma-Okia, C. Péan, R. Pidcock, S. Connors, J.B.R. Matthews, Y. Chen, X. Zhou, M.I. Gomis, E. Lonnoy, T. Maycock, M. Tignor, and T. Waterfield (eds.)]. In Press. https://www.ipcc.ch/sr15/

NOAA (National Oceanic and Atmospheric Administration), Earth System Research Laboratory Global Monitoring Division [online], 5/12/19, Date Accessed: 23/12/19. https://www.esrl.noaa.gov/gmd/ccgg/trends/mlo.html

Sea Urchin Ranching – the new restorative fishing practice?

Vast plains of barren emptiness, devoid of life, bar one animal: the purple sea urchin. These barrens used to be some of the most productive habitats on the planet, now they are empty wastelands. 

Urchin Valley

Purple sea urchin barren – San Miguel Island, California, United States

So what happened? 

Like a story from the bible, plagues rained down on this once pleasant land. First came pestilence. The sea stars started wasting away. Next came years of extreme heat, with coastal Californian waters reaching record breaking temperatures. And finally an explosion. An explosion of purple sea urchins. Everywhere you look would be purple sea urchins. These ravenous monsters devoured the plentiful forests, one unfortunate kelp individual at a time, until nothing was left but the barren wasteland we see today. 

Sea Star Wasting Syndrome

Ochre sea star suffering sea star wasting disease – North Beach, Washington, United States

Soon there were terrible consequences for the locals as well. With the loss of kelp forests, commercial shellfisheries collapsed. Red abalones declined by 80% and many livelihoods were shattered.

All is not well on these urchin barrens either, for too much competition leads to empty stomachs. Each urchin, competing against its brothers and sisters, now finds food scarcity a real pressing problem. So many mouths to feed, nowhere near enough kelp to eat.

Purple Sea Urchin - Strongylocentrotus purpuratus

Purple sea urchins – Santa Cruz Island, California, United States

So it seems that no individual is particularly happy after this catastrophic chain of events, not the starving sea urchins, the decimated kelp, or the troubled fishermen. 

But there may be a solution, and one in which may please all involved parties, at least in part. 

The urchins are hungry, so firstly why do we not just feed them? This sounds like such an obvious idea. So let’s take the urchins from their barrens and rehome them in special ranches, where they are provided with plentiful food and allowed to grow plump. This is where the urchin’s story gets a little less happy for them. Unfortunately for them, they are considered quite the delicacy, which conversely is quite pleasing for the fishermen, who can make a good living from fattening up urchins for slaughter. Though the urchin’s eventual fate is not necessarily such a pleasant one, they have at least had a good life eating as much as they please up until the end. And the fishermen make a tasty profit. 

But best of all, the biggest beneficiary from all of this is the kelp itself. Once the ravenous urchins are removed the kelp can grow at an enormous rate, one of the fastest on the planet, and restore the wasteland to its former glory. 

So by choosing Californian sea urchins, you as a consumer can help support perhaps the only restorative fishing practice known today, one bite at a time. 

Ollie, the residential sea otter

Sea otter taking a nap in bull kelp – Race Rocks, British Columbia, Canada

Interested in finding out more? Check out the link below where you can find more info from the authors and the freely available article:

https://www.ucdavis.edu/news/california%E2%80%99s-crashing-kelp-forest/

Free-living Bladderwrack – Why should we care?

To answer this question it helps to look at the bigger picture: Why should we care about the natural environment at all? Though the reasons are many, one of the most obvious is that their functioning directly affects our society. This idea is the basis for the ecosystem services concept.

Ecosystems Services – What are they and why do we need them?

Ecosystem services are the benefits provided by the natural environment to society. They are the foundation of human well-being. These services are numerous and highly varied depending on the ecosystem. In forests and woodlands the production of wood as a raw material for the use in manufacturing is one such service. On a smaller scale, individual species can also provide important services, such as bees acting as pollinators for agricultural plants. These services are invaluable to human existence, and often come with no accompanying monetary cost. Being freely available, many are undervalued and consequently protection for the environments that provide them is frequently limited.

Though ecosystem services are often taken for granted, they are hugely important. Imagine if the continued use of pesticides, most famously neonicatoids, led to the extinction of numerous bee species. Many fruit and seed producing crops would be left unpollinated, leading to crop failure and the consequential food shortages within shops and supermarkets. Hence the ecosystem services we take for granted can have monumental effects on society and our quality of life. It therefore seems necessary to provide protections for these environments so that they can continue to provide the services we rely on.

So now we know what Ecosystem Services are – How does this relate to bladderwrack?

As an underwater environment that many people rarely, if ever, see bladderwrack forests are a hugely underrated environment in terms of their value and the ecosystem services they provide. However bladderwrack forests can be considered similar to giant kelp forests, which are some of the most productive habitats on earth.

Bladderwrack forests are highly productive environments storing large quantities of carbon. Because some of this carbon is sequestered bladderwrack can be considered to provide a service in reducing CO2 within the atmosphere and thus help our society with mitigating climate change.

This is not the only services these underwater forests provide. As an ecosystem engineer; a creature that modifies its environment; bladderwrack also provides the additional benefits of food and shelter for a myriad of different plants and animals, all of which themselves contribute to the ecosystem services provided by this habitat. Notably bladderwrack plays an important part in food production by providing nursery and feeding habitat for juvenile fish of commercial importance including cod, pike and perch. By supporting populations of these important fish species they also provide valuable recreational services including recreational fishing, boating and SCUBA diving.

Plaice resting next to an attached bladderwrack stand

An entirely different service that bladderwrack provides influences people’s health by reducing their contact with harmful environments. Within the Baltic Sea, the enrichment of water bodies with excessive nutrients has led to widespread eutrophication and resulting nuisance blooms of cyanobacteria. These blooms can be detrimental for human health and are monitored by the Finnish Environmental Institute SYKE. Importantly though, bladderwrack forests can act as filters against high nutrient inputs from terrestrial sources, providing a service in reducing excessive load of nutrients and consequently benefiting human health and well-being.

These are just a few of the ecosystem services this fascinating habitat provides, though there are numerous others that have not been listed here. We can therefore conclude that both bladderwrack and the associated community of plants and animals are important for the Baltic Sea ecosystem and many of the services we require.

What about free-living bladderwrack and the associated animal community?

Since free-living bladderwrack fulfils a similar ecological niche to the attached form, albeit generally on soft bottoms rather than rocky substrates, we surmise that it provides similar ecosystem services as well. Both forms support a similar animal community living around and on the seaweed, but the free-living form also supports an additional community living within the sediment below the algal mats. It is likely that this community will provide additional services that benefit us, however what these services are is difficult to tell unless we have a greater understanding of the associated animal communities of the free-living form. Hence this is where our study comes in. In one of our projects we are interested in identifying the animals on and below the surface of the sediment, and how these communities vary from those of bare, soft bottoms. To find out how important these creatures are to our society we will delve below the surface of this barely studied habitat.

Free-living bladderwrack forest

The curious case of free-living Fucus: what is it and where does it come from?

Bladderwrack (Fucus vesiculosus) is a brown algae commonly found within many parts of the Baltic Sea. It forms structurally complex habitats at depths of 0.5-7m, providing shelter and food for many marine invertebrates and fish. It is one of the major foundation species in the Baltic Sea coastal zone. Generally, bladderwrack is considered a rocky shore organism, being most notability found growing attached to rocks, boulders and pebbles. However, interestingly an unattached form can also be found.

A meadow of free-living bladderwrack, resulting in 100% coverage. Image taken in the Askö area (Sweden)

These unattached individuals form free-living populations, that can be quite extensive (10-100m2) occurring year after year at the same sites. They have been observed since the late 19th century (Kjellman, 1890) and are generally described as pieces torn from attached populations and deposited in sheltered locations, with no ecological significance. However with modern molecular techniques; including microsatellites and DNA barcoding; we aim to test this theory.

 

The origins of life?

Firstly we aim to test this long held idea that the free-living populations are solely supplied by the surrounding attached populations. To put it simply, do they rely on supplies of torn off pieces to start and replenish a population or are they fully or partially self-sustaining through their own means? This really is a question of ‘can they reproduce?’, and if so ‘how do they do it?’.

The processes involved in forming and maintaining free-living bladderwrack populations

We surmise that the founding members of any free-living population are supplied by pieces from attached populations, as has been suggested since their first documentation. However this is where the ideas diverge, rather than assuming any replenishment to the population are from supplies of material from the nearby attached population, we view that these free-living populations have some level of self-sustainability.

How do they do this? The current idea is through fragmentation, a method of asexual reproduction where new, smaller, genetically identical individuals are formed through breakage from the main individual. If you ever get your hands on a free-living bladderwrack individual, you will see how easily one individual becomes many with just the simplest of handling. Through splitting into many individuals that continue to grow and eventually break apart once more, soft bottoms can quickly become dominated by many genetically identical plants.

Two distinct morph types from different free-living populations around the Askö area (Sweden)

The level at which this asexual reproduction occurs will be defined by the amount of genetic variation within the population. If populations contain only a few genetically different individuals then we can assume that fragmentation plays a large role in maintaining these free-living populations. If we observe the reverse; many genetically different individuals; then it is likely that either attached populations are largely responsible for supplying these populations, or that the free-living plants can themselves reproduce sexually. The latter seems improbable, in part because few free-living individuals have been observed to form sexual structures known as receptacles.

 

Population connectivity?

Now that we have established the possible mechanisms for forming, maintaining and regenerating free-living populations, we can consider the dispersal of a normally immobile seaweed. It is frequently observed that broken off pieces from attached individuals can be transported by currents over great distances; and since reattachment is incredibly rare; either these free-floating pieces eventually sink becoming loose-lying pieces which eventually decay or they contribute material to free-living populations.

However the question is, are free-living individuals equally as mobile? Can free-living individuals migrate between patches, and do distances and other abiotic factors affect their dispersal?

We currently have little idea as to answering this question, but it seems likely that distance and geological features will be the major influences on the dispersal potential. By identifying the genetic variation; or the level of relatedness; between and among populations we will hope to answer this intriguing question.

 

Ecologically important?

Thirdly, we have little idea of the importance of free-living populations. What function and ecosystem services do they provide in the coastal zone? Through inhabiting soft bottoms, that are normally uninhabitable by the attached form of bladderwrack, they can provide a complex habitat that would normally not be found on this substrate type. Consequently this habitat can support a vast variety of plants and animals that would otherwise not be found in that location. Through environmental surveys and the monitoring of biological measurements we aim to identify the important functions and services that are provided by the free-living populations.

 

The importance of this study

Now comes the most important question: Why do we need to study these questions in the first place? As an integral part of the Baltic Sea ecosystem, free-living bladderwrack is considered an important biotope at risk of damage. As such they are listed on HELCOM Red List of biotopes and habitats as endangered (HELCOM, 2013). This means that policy makers and conservationists need to implement methods to best protect these populations. Without adequate knowledge, including the genetic diversity, of these populations successful management is doubtful. As such, if we wish to maintain the health of these populations and consequently that of the Baltic Sea, we need all the research we can collect.

 

References

HELCOM (2013) Red List of Baltic Sea underwater biotopes, habitats and biotope complexes. Baltic Sea Environmental Proceedings No. 138.

Kjellman FR (1890) Handbok i Skandinaviens hafsalgflora. I. Fucoidae., Stockholm