Our Latest researchThey can also survive low levels oxygen.
This is a surprising result because sponges are rarely exposed to low oxygen levels in modern waters.
We propose that their tolerance is due their long evolutionary history, as well as their exposure to variable oxygen concentrations over geological time.
Sponges are more likely to be able survive in low-oxygen environments than other organisms that live on the sea.
There are approximately 8000+ species of sponges living in the oceans. They are multicellular organisms and have a body that is built around a system water canals, pores, and channels which allow water to flow through them.
Their specialized pumping and feeding cells, known as choanocytes (or choanocytes), are highly efficient. Sponges can pump the equivalent to their body volume in just seconds.
Sponges are an important part of modern oceans. most abundant organismsThey thrive in rocky reef environments. They fulfill Important ecological functionsAs part of bottom-dwelling (benthic), communities around the world.
Sponges play many important roles in marine ecosystems. Water-processing efficiency and abilityBecause it links the seafloor and the water column, the best spot for capturing small particles is spotges Sponges support diverse seafloor communities. Transforming carbon.
Some sponge species have been shown very resilient to climate change stressors such as changes in temperature or acidity (measured as pH). This could make sponges more resilient to climate change stressors. Future winnersIn changing oceans
Sponges found in the past oceans
Although sponges are an ancient organism, we have only recently discovered their existence. 890-million year-old fossilsOur understanding of evolution has been turned on its head.
The period known as the “The Beginning” is when most major animal groups, including arthropods, first appear in fossil records. Cambrian explosion540 million year ago. But if the newly-described fossils are indeed sponges, they would have existed nearly 300 million years earlier, significantly pushing back the date of Earth’s earliest known animals.
If the ancestors modern sponges are around 900million years old, they would have evolved during the last 900 million years. Marinoan glaciation657-645 millions years ago, when the oceans had extremely low levels of oxygen.
They would also have likely experienced large fluctuations in other environmental conditions, such as pH, temperature, and salinity over evolutionary time.
Low oxygen tolerance in sponges
Recent developments Environmental tolerance experimentsThis scenario is supported by evidence that they are quite tolerant to low levels oxygen.
We conducted laboratory experiments on four species of sponges from the northeast Atlantic, and the southwest Pacific to assess their response to low-oxygen events. Over seven to 12 days, sponges were exposed five low oxygen treatments with increasing severity (40%, 20% and 6% respectively).
We found that sponges are generally very adaptable to hypoxia. Only one species survived the extreme conditions. The species that died at the lowest oxygen level was the only one. In most experiments, hypoxic conditions did not significantly affect the sponges’ respiration rates, which suggests they can take up oxygen at very low concentrations in the surrounding environment.
Sponges developed a variety of shapes and structural changes in response to low oxygen levels. This likely increased their ability to absorb oxygen at low levels.
Sponges for future oceans
Warmer ocean waters hold less oxygen. ocean deoxygenationClimate change has many major consequences.
Warmer water is also more buoyant than cool water. This reduces the mixing between surface oxygenated water and deeper layers that naturally contain less oxygen. Warmer temperatures also increase oxygen demand as organisms’ metabolic rates rise and stress responses are initiated.
Anthropocene Reef Ecosystems: The Rise of Sponges
The ocean’s oxygen levels are expected to be only a few hundredths of those in the atmosphere. Average fall of 4%These effects are likely more extreme in certain regions and on all oceans. A process known as “climate-driven ocean deoxygenation” can be worsened in coastal waters. EutrophicationThis is essentially an increase of nutrients. This fuels plankton growth, and when bacteria breaks down the dead phytoplankton they use all the oxygen.
These areas are the most at risk because the land is the main source of excess nutrients. These are areas where the sponges dominate rocky coral reefs, especially below the depth of light penetration (typically between 20-30m).
Our findings support the idea that sponges will survive if the oceans continue to heat.