Coral Reefs

The Double Threats to Coral Restoration: Disease and Poor Water Quality

Coral diseases, particularly in the Caribbean, have caused major declines in coral populations, especially affecting staghorn (Acropora cervicornis) and Elkhorn (A. palmata) corals, which play a crucial role in reef ecosystems. Despite efforts to identify the pathogens that cause diseases like White Band Disease (WBD), and Stony Coral Tissue Loss Disease (SCTLD), the specific agents remain largely unknown. Coral restoration programs aim to restore these once abundant coral species, but the effectiveness is threatened by multiple stressors, including increases in disease frequency and nutrient pollution caused from runoff from land-based activities.

Published

1 month ago

March 29, 2025

Édouard P

The health of our planet’s coral reefs is facing a double threat: disease and poor water quality. In recent years, coral diseases have caused significant declines in coral populations, especially affecting staghorn (Acropora cervicornis) and Elkhorn (A. palmata) corals that play a crucial role in reef ecosystems.

Despite efforts to identify the pathogens responsible for diseases like White Band Disease (WBD) and Stony Coral Tissue Loss Disease (SCTLD), the specific agents remain largely unknown. This lack of knowledge makes it challenging to develop effective strategies for coral restoration programs, which aim to restore these once-abundant coral species.

A recent study conducted by scientists at the University of Miami NOAA Cooperative Institute for Marine and Atmospheric Studies (CIMAS) and the Atlantic Oceanographic and Meteorological Laboratory (AOML) has shed light on how different coral genotypes respond to environmental stressors. The researchers examined 10 genotypes commonly used in coral restoration in South Florida, exposing them to two nutrient conditions: normal (ambient) or high ammonium levels.

The study’s key findings include:

• Coral genotypes that previously showed disease resistance did not necessarily maintain that resistance in this experiment, suggesting disease susceptibility may change based on disease cause, environment, or route of infection.
• Elevated dissolved inorganic nitrogen, in the form of ammonium, reduced coral survival – even in the absence of disease – highlighting poor water quality as a significant threat.
• When exposed to disease under normal conditions, four genotypes suffered complete mortality, while others showed varying degrees of resilience.
• When both stressors were combined, all genotypes experienced mortality rates ranging from 30 to 100 percent.

The researchers emphasize the urgent need for improving water quality by limiting runoff to support coral conservation efforts. Since coral disease outbreaks often coincide with pollution-related stress, reducing nutrient pollution is critical to enhancing coral resilience and increasing the success of restoration projects.

“If water quality issues are not addressed, it will be difficult for both wild and restored coral colonies in Florida to survive,” said Ana Palacio, the lead author of the study and a research scientist at CIMAS. “Our findings highlight the importance of selecting coral genotypes that are resilient to local stressors and ensuring improved water conditions before restoration efforts.”

Coral reefs provide essential ecosystem services, including coastal protection, marine biodiversity, and economic benefits to fisheries and tourism. This study underscores the importance of science-driven policymaking and conservation strategies to safeguard these vital ecosystems for the future.

Funding for the study was provided to Ana M Palacio-Castro through the National Academy of Sciences’ National Research Council (NRC) Postdoctoral Fellowship and the Coral Reef Conservation Program (Grant 31250).

Source:University of Miami Rosenstiel School of Marine, Atmospheric, and Earth Science

Original Link:https://www.sciencedaily.com/releases/2025/03/250326221529.htm

Related Topics:Coral Reefs Earth & Climate Ecology Ecology Research Fish Marine Biology Plants & Animals Pollution Sea Life Water

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Animals

Feral Cats Exposed as Primary Predators in Native Animal Deaths

Feral cats have long been suspects in killing native species reintroduced into Australian conservation areas. DNA testing of the carcasses puts felines firmly in the frame.

Published

2 months ago

March 11, 2025

Édouard P

Feral cats have long been suspected of being a major contributor to the decline and extinction of native animals in Australia. However, a recent study published in the Australian Mammalogy journal has provided conclusive evidence that feral cats are indeed the primary predators responsible for the deaths of reintroduced native animals at two conservation sites in South Australia.

Researchers from UNSW Sydney and the University of Adelaide used DNA technology to identify feral cats as the culprits in killing 74 out of 389 released animals, with a staggering 96% of these confirmed by DNA analysis. This finding fits in with previous research that suggests feral cats have killed more native animals than any other feral predator in Australia.

The study’s lead author, Professor Katherine Moseby, notes that determining the cause of death of native animals and attributing it to the right predator has always been a challenge. “In past releases, we’d be radio tracking animals after release, and if we found dead animals, it would be difficult to determine what caused their death,” she says.

The researchers used DNA swabs from carcasses and compared them with evidence in the field, such as animal spoor, carcass remains, or bite marks on collars. They found that field evidence was not a reliable indicator of predation by feral cats, and that DNA and necropsy were needed to confirm cat predation.

At one site, researchers released 148 brush-tailed possums and 110 western quolls between 2014 and 2016, while at the other site, they released 42 greater bilbies and 89 bettongs in 2017. Unfortunately, three out of the four species released still managed to survive in reduced numbers, with the bettongs being no match for feral cats.

The study’s findings have significant implications for conservation efforts, highlighting that there are more cat killings than previously thought. As Professor Moseby notes, “Until we develop genetic tools or other broadscale methods targeted at feral cats, we can only rely on intensely managing them as best we can.”

The researchers hope that their research will encourage more conservationists to use DNA and necropsy to identify the cause of death of animals in wildlife reintroductions, and to increase cat control even if no obvious evidence of cat predation is present.