Deforestation and the Maya

The ancient Maya civilization, once believed to have lived in harmony with nature, engaged in widespread deforestation to clear land for agriculture, fuel, and construction. This clearcutting had a profound impact on the region’s soil carbon storage capacity.

Study Findings

A recent study published in Nature Geosciences examined soil samples from the Maya lowlands. Researchers analyzed plant waxes, which indicate the age of soil carbon. Their findings revealed that deforestation led to a significant decrease in the age of plant waxes, indicating a reduced ability of the soil to store carbon over time.

Long-Term Impacts

Despite the regrowth of rainforest in areas cleared by the Maya, the soil’s carbon storage capacity has not fully recovered after 1,100 years. This suggests that deforestation can have long-term impacts on ecosystem functioning, including the ability to mitigate climate change.

Implications for Climate Change

The study’s findings have implications for understanding the effectiveness of reforestation as a climate change mitigation strategy. Previously, it was believed that second growth forests could sequester significant amounts of carbon. However, the study suggests that the carbon storage capacity of these forests may be limited due to the long-term effects of deforestation.

Importance of Old-Growth Forests

The study highlights the importance of protecting remaining old-growth tropical forests, which have a higher carbon storage capacity than second growth forests. This emphasizes the need to prioritize conservation efforts and minimize further deforestation.

Analyzing Other Tropical Forests

The researchers acknowledge that their findings may not be applicable to all tropical forests impacted by deforestation. Future research will investigate the effects of clearcutting and agriculture on carbon storage in other regions.

Studying Permafrost

The same analysis technique used in this study can also be applied to investigate the impact of climate change on permafrost’s ability to store carbon. Permafrost, frozen ground found in cold regions, contains vast amounts of carbon. Understanding how climate change affects permafrost’s carbon storage capacity is crucial for predicting future climate impacts.

New Analysis Techniques

The study demonstrates the potential of new analysis techniques to enhance our understanding of carbon cycling between soil and the atmosphere. These techniques provide valuable insights into the complex interactions between human activities and ecosystem processes.

Conclusion

The ancient Mayan civilization’s deforestation had a lasting impact on soil carbon storage, even after centuries of regrowth. The study highlights the need to protect old-growth forests, consider the limitations of reforestation, and explore the effects of deforestation and climate change on carbon storage in various ecosystems.

Invasive Bloodsuckers

Sea lampreys, parasitic fish native to the Atlantic Ocean, have become a major threat to the Great Lakes ecosystem. They were first introduced to the lakes in the 1800s through shipping canals and have since spread throughout the entire system.

Destructive Impacts

Sea lampreys attach to fish using their suction cup mouths and rasp away at their flesh with their sharp tongues, feeding on their blood and body fluids. A single sea lamprey can kill up to 40 pounds of fish per year. Their voracious feeding habits have devastated fish populations in the Great Lakes, particularly trout and whitefish.

Population Control Challenges

Since 1958, the Great Lakes Fishery Commission has implemented a dedicated control program to combat the sea lamprey population. Lampricide, a pesticide specifically designed to target sea lamprey larvae, has been used along with traps and barriers to reduce their numbers. These efforts have successfully reduced the sea lamprey population by 90-95% in the Great Lakes basin.

Covid-19 Disruption

Travel restrictions during the Covid-19 pandemic hindered the application of lampricide and other control measures, leading to a resurgence in the sea lamprey population. This increase became evident in 2022 due to the two-year lag in the animals’ spawning cycle.

Ongoing Control Efforts

Despite the challenges posed by Covid-19, the Great Lakes Fishery Commission has resumed its aggressive control program in 2022 and 2023. They are hopeful that the recent population spike was a temporary blip and that the control measures will continue to keep the sea lamprey population in check.

Ecological Role in Native Range

In their native Atlantic Ocean habitat, sea lampreys play a beneficial role as keystone species and ecosystem engineers. They support both aquatic and terrestrial ecosystems by providing food for other creatures and creating spawning habitats for fish. Their larvae also help maintain water quality.

Evolutionary Resilience

Sea lampreys have existed on Earth for over 340 million years and have survived four major extinction events. They have remained largely unchanged since they evolved, demonstrating their remarkable evolutionary resilience.

Historical Spread in the Great Lakes

Sea lampreys were first documented in the Great Lakes in 1835 in Lake Ontario. Niagara Falls initially served as a natural barrier to their spread, but improvements to the Welland Canal in 1938 allowed them to bypass the falls and invade the entire system. By the 1960s, sea lampreys had devastated the upper Great Lakes’ trout fishery, reducing the take of lake trout from 15 million pounds to just half a million pounds.

Economic Impacts

The decline in fish populations due to sea lampreys has had a significant economic impact on the Great Lakes fishing industry. The rebuilding of the fishery through control efforts has led to a resurgence in the fishing economy, benefiting both commercial and recreational fishers.

Continuing Vigilance

While the Great Lakes Fishery Commission has made significant progress in controlling the sea lamprey population, continued vigilance is necessary to prevent future outbreaks. The commission is committed to monitoring the population and implementing adaptive control measures as needed to protect the Great Lakes ecosystem and its valuable fisheries.

Apex Predators and the Hierarchy of the Deep

In the vast expanse of the ocean, the great white shark has long been revered as the ultimate predator. However, a recent study has revealed a surprising truth: the great white is not the ocean’s true apex predator. That title belongs to the orca, also known as the killer whale.

Orcas: The Killers of the Seas

Orcas are formidable hunters with a diverse diet that includes seals, dolphins, and even other sharks. Their intelligence and cooperative hunting strategies make them formidable adversaries for even the largest marine predators.

The Landscape of Fear: Orcas’ Impact on Great White Sharks

When orcas enter an area, the great white sharks flee their preferred hunting grounds and avoid returning for up to a year. This phenomenon, known as the “landscape of fear,” is driven by the sharks’ instinct to avoid predators.

Researchers have observed this avoidance behavior through radio-tagging studies. In one instance, 17 great white sharks were tagged near Southeast Farallon Island. When a pod of orcas entered the area, the sharks immediately vacated their hunting grounds and most did not return for the rest of the season.

Why the Fear? Orcas’ Devastating Attacks

The fear of orcas stems from their deadly encounters with great white sharks. In recorded interactions, orcas have been observed killing great whites and eating their calorie-dense livers.

In 1997, a pair of orcas brutally killed a young great white shark that attempted to join them in feeding on a sea lion. The orcas bashed the shark to death and devoured its liver.

In 2017, five great white shark carcasses washed ashore in South Africa with surgically removed livers. These gruesome killings were attributed to orcas, who use their powerful jaws to extract the nutrient-rich liver tissue.

Ecosystem Impacts: The Ripple Effects of Fear

The fear of orcas has far-reaching impacts on ocean ecosystems. When great white sharks avoid areas where orcas are present, it creates opportunities for other predators to thrive.

For example, in years when orcas visit the Southeast Farallon Island area, the number of elephant seals eaten by sharks drops by 62%. This decline in shark predation allows the young seals to feed and grow without the threat of being hunted.

Conclusion

The new understanding of the relationship between great white sharks and orcas challenges our traditional view of the ocean’s predator hierarchy. Orcas, with their intelligence, cooperative hunting strategies, and deadly power, reign supreme as the true apex predators of the ocean. Their presence creates a landscape of fear that shapes the behavior and distribution of other marine species, influencing the delicate balance of ocean ecosystems.