//
you're reading...

Biology

Diversity and its role in combating the effects of climate change

 

 

Article: Baggini, Cecilia, et al. “Herbivore diversity improves benthic community resilience to ocean acidification.” Journal of Experimental Marine Biology and Ecology 469 (2015): 98-104.

doi:10.1016/j.jembe.2015.04.019

Background:

We’ve talked a lot on this blog about the negative impacts of climate change. But as climate change science progresses, the stories are shifting more and more towards the positive, pointing out that things may not be as bad as they seem.

Many scientific studies shed light onto just how damaging warming waters, pollution, and ocean acidification can be to individual organisms (Fig. 1). Whole ecosystems are even projected to be covered by seaweed, losing critical functions and losing species diversity. But when investigating the effects of climate change, it is important to consider all the species within a community and how they are directly and indirectly connected to one another (Fig. 2). This may indicate whether or not an ecosystem has the built-in ability to mitigate change.

Fig. 1: We've almost accustomed ourselves to photos like this (dgrnewsservice.org)

Fig. 1: We’ve almost accustomed ourselves to photos like this (dgrnewsservice.org)

Fig. 2: Food-web, well, it's not quite this simple. But diversity in an ecosystem could prove helpful.

Fig. 2: Food-web, well, it’s not quite this simple. But diversity in an ecosystem could prove helpful (oceanlifecenter.dk).

 

 

 

 

 

 

 

 

I wrote a piece a few months ago about a study that showed small herbivores were able to help control algal growth and takeover of seagrass habitats in areas of nutrient pollution. By having herbivores around, the ecosystem was able to maintain balance. A recent study coming out of the Mediterranean has found something similar: in ecosystems threatened by ocean acidification, the best way to prevent a seaweed takeover is to have a diverse group of organisms feed on the algae (Fig. 3). How did they find this out?

Fig. 3: Sarpa salpa, an herbivorous fish observed in this study (project aware.org).

Fig. 3: Sarpa salpa, an herbivorous fish observed in this study (project aware.org).

The Study:

There are natural volcanic seeps in the Mediterranean that provide a unique opportunity to study the effects of ocean acidification in the field. Sites near the vent are naturally lower in pH. Researchers wanted to see what kind of role herbivores play in normal coastal systems and ones that are more acidic—sites that represent projected norms for future oceans. To investigate this, the researchers picked two sites: one reference site and one low pH site (Fig. 4). They performed surveys of the sea urchin and fish herbivores present, and their abundance at each site. It was found that two species of sea urchins were the dominant herbivores on the reference site and fish were the dominant herbivores in the low pH site (Fig. 5). This fits with what is known about urchins and acidification. Urchins struggle to calcify and maintain health in acidic waters, whereas fish don’t have it as bad. Fish likely dominate the low pH site because they don’t have to compete with the urchins for food. To summarize: there are two sites, one low pH and one normal pH, with both sites having different herbivores.

Fig. 3: These are the sites used by the researchers. REF indicates the site with normal pH, SEEP indicates the low pH site.

Fig. 4: These are the sites used by the researchers. REF indicates the site with normal pH, SEEP indicates the low pH site.

Researchers set out small tiles in the water at both sites to allow colonization by seaweed. There were three types of tiles: open ones (allowing herbivores to eat), caged ones (preventing herbivores from eating), and cage controls (these are open to eating but test whether having the cage makes a difference). They let these tiles sit for almost a year before pulling them up and checking for algal species present and biomass of the algae.

Fig. 4: Survey results of sea urchins and herbivorous fish at both reference and seep sites. There are way more urchins in the reference site, and a lot more fish at the seep site.

Fig. 5: Survey results of sea urchins and herbivorous fish at both reference and seep sites. There are way more urchins in the reference site, and a lot more fish at the seep site.

They found that by excluding herbivores, both sites saw significantly higher biomass of seaweeds. If they aren’t eaten, they will grow like crazy. But where herbivores were allowed to feed, both sites saw a reduction in algal biomass with almost identical results. No matter what type of herbivore, the seaweed was consumed at the same rate (Fig. 6).

Fig. 6: This figure shows the total biomass of algae at both sites and compares herbivore tile treatments. The white bars show large algal growth when herbivores are excluded. When herbivores are able to eat (black bars) they consume it a a large rate.

Fig. 6: This figure shows the total biomass of algae at both sites and compares herbivore tile treatments. The white bars show large algal growth when herbivores are excluded. When herbivores are able to eat (black bars) they consume it at a large rate.

The Significance:

This study helps show that ecosystems have built-in ways of handling climate change. In this case, in a natural setting, sea urchins thrive and help control the growth and spread of algae. But in low pH environments that stress urchins out, they have been “functionally” replaced by herbivorous fish which have the same ability to control the growth and spread of algae. This shows the importance of having a diverse ecosystem. If an ecosystem has diversity, there are other species that can step into a functional role. This helps to keep an ecosystem balanced. Without this replacement, algae would be able to thrive, ultimately altering the system.

It’s nice to see that climate related studies are giving us a reason for hope. More studies need to take a community approach to their studies; because we may find that they are not as fragile as we think.

 

Discussion

No comments yet.

Post a Comment

Instagram

  • by oceanbites 5 days ago
    Leveling up - did you know that crabs have a larval phase? These are both porcelain crabs, but the one on the right is the earlier stage. It’s massive spine makes it both difficult to eat and quite conspicuous in
  • by oceanbites 2 weeks ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring Cierra Braga. Cierra works ultraviolet c (UVC) to discover how this light can be used to combat biofouling, or the growth of living things, on the hulls of ships. Here, you
  • by oceanbites 3 weeks ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Elena Gadoutsis  @haysailor  These photos feature her “favorite marine research so far: From surveying tropical coral reefs, photographing dolphins and whales, and growing my own algae to expose it to different
  • by oceanbites 1 month ago
    This week for  #WriterWednesday  on Oceanbites we are featuring Eliza Oldach. According to Ellie, “I study coastal communities, and try to understand the policies and decisions and interactions and adaptations that communities use to navigate an ever-changing world. Most of
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Jiwoon Park with a little photographic help from Ryan Tabata at the University of Hawaii. When asked about her research, Jiwoon wrote “Just like we need vitamins and minerals to stay
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  on  #Oceanbites  we are featuring  @riley_henning  According to Riley, ”I am interested in studying small things that make a big impact in the ocean. Right now for my master's research at the University of San Diego,
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Gabby Stedman. Gabby is interested in interested in understanding how many species of small-bodied animals there are in the deep-sea and where they live so we can better protect them from
  • by oceanbites 2 months ago
    This week for  #WriterWednesday  at  #Oceanbites  we are featuring Shawn Wang! Shawn is “an oceanographer that studies ocean conditions of the past. I use everything from microfossils to complex computer models to understand how climate has changed in the past
  • by oceanbites 3 months ago
    Today we are highlighting some of our awesome new authors for  #WriterWednesday  Today we have Daniel Speer! He says, “I am driven to investigate the interface of biology, chemistry, and physics, asking questions about how organisms or biological systems respond
  • by oceanbites 3 months ago
    Here at Oceanbites we love long-term datasets. So much happens in the ocean that sometimes it can be hard to tell if a trend is a part of a natural cycle or actually an anomaly, but as we gather more
  • by oceanbites 4 months ago
    Have you ever seen a lobster molt? Because lobsters have exoskeletons, every time they grow they have to climb out of their old shell, leaving them soft and vulnerable for a few days until their new shell hardens. Young, small
  • by oceanbites 4 months ago
    A lot of zooplankton are translucent, making it much easier to hide from predators. This juvenile mantis shrimp was almost impossible to spot floating in the water, but under a dissecting scope it’s features really come into view. See the
  • by oceanbites 5 months ago
    This is a clump of Dead Man’s Fingers, scientific name Codium fragile. It’s native to the Pacific Ocean and is invasive where I found it on the east coast of the US. It’s a bit velvety, and the coolest thing
  • by oceanbites 5 months ago
    You’ve probably heard of jellyfish, but have you heard of salps? These gelatinous sea creatures band together to form long chains, but they can also fall apart and will wash up onshore like tiny gemstones that squish. Have you seen
  • by oceanbites 6 months ago
    Check out what’s happening on a cool summer research cruise! On the  #neslter  summer transect cruise, we deployed a tow sled called the In Situ Icthyoplankton Imaging System. This can take pictures of gelatinous zooplankton (like jellyfish) that would be
  • by oceanbites 6 months ago
    Did you know horseshoe crabs have more than just two eyes? In these juveniles you can see another set in the middle of the shell. Check out our website to learn about some awesome horseshoe crab research.  #oceanbites   #plankton   #horseshoecrabs 
  • by oceanbites 7 months ago
    Feeling a bit flattened by the week? So are these summer flounder larvae. Fun fact: flounder larvae start out with their eyes set like normal fish, but as they grow one of their eyes migrates to meet the other and
  • by oceanbites 7 months ago
    Have you seen a remote working setup like this? This is a photo from one of our Oceanbites team members Anne Hartwell. “A view from inside the control can of an underwater robot we used to explore the deep parts
  • by oceanbites 8 months ago
    Today is the day of  #shutdownacademia  and  #shutdownstem  and many of us at the Oceanbites team are taking the day to plan solid actions for how we can make our organization and the institutions we work at a better place
  • by oceanbites 8 months ago
    Black lives matter. The recent murders of Ahmaud Arbery, Breonna Taylor, and George Floyd have once again brought to light the racism in our country. All of us at Oceanbites stand with our Black colleagues, friends, readers, and family. The
WP2Social Auto Publish Powered By : XYZScripts.com