Marine hotspots under dual threat from climate change and fishing

A beautiful split image of a school of yellow butterfly fishes and the blue sky in French Polynesia

A beautiful split image of a school of yellow butterfly fishes and the blue sky in French Polynesia. Credit: Global_Pics/iStock/Getty Images.

GR: Nature rarely forms straight lines or even distributions. Global warming, just like biodiversity, is not even. The study reported below suggests areas that need our greatest conservation efforts. However, we have to try to save more than just the best areas. We also need to save some of the intervening regions.

The parts of the world’s oceans with the most varied mix of species are seeing the biggest impacts from a warming climate and commercial fishing, a new study warns.

“The research, published in Science Advances, identifies six marine “hotspots” of “exceptional biodiversity” in the tropical Pacific, southwestern Atlantic, and western Indian Oceans.

“Warming sea temperatures, weakening ocean currents and industrial fishing means these areas are at particular risk of losing many of their species, the researchers say.

Species richness

“From the cold depths of the Arctic waters to the colourful reefs of the tropics and subtropics, the oceans play host to tens of thousands of different species. But they are not evenly spread across the world.

“Using data on 1,729 types of fish, 124 marine mammals and 330 seabirds, the new study estimates how varied the species are in each part of the oceans. They call this the species “richness”.

“You can see this in the map from the study below. It shows an index of species richness, from the lowest (dark blue) to the highest (red).

marine-hotspots

Map of global marine biodiversity, using an index from zero (no species present, shaded dark blue) up to one (largest species richness, shaded red) representing 2,183 marine species. Map also shows the six marine “hotspots” identified in the study. Source: Ramírez et al. (2017)

“From this process, the researchers identified six hotspots where the number and mix of species is exceptionally high. These are outlined in the map above.

“The six hotspots are predominantly in the southern hemisphere. Three are closely packed together around southeast Asia (4), southern Australia and New Zealand (5), and the central Pacific Ocean (6). The other three are more spread out, covering Africa’s southeastern coastline and Madagascar (3), the Pacific waters of Peru and the Galapagos Islands (1), and the southwestern Atlantic ocean off the coast of Uruguay and Argentina (2).” –Robert McSweeney (Continue reading:  Marine hotspots under dual threat from climate change and fishing.)

Species Introductions Are Accelerating

GR:  Invasive plants and animals are destroying native ecosystems. Some species that we take from their homes and release in other regions explode across the new habitat. Free from their natural competitors and diseases, the species are like Superman freed from Krypton’s light. Local species cannot compete and are replaced.  I’ve studied some of the plant species that do this. You can read what I’ve learned here.

My work focuses on invasive plants, but animals can be equally destructive. The Eurasian Wild Boar is a good example of the hundreds of species impacting North American ecosystems. Here’s a brief review of the history of its introduction and spread in the U. S.

Feral Eurasian Wild Boar

Feral Eurasian Wild Boar

Invasive species are second only to complete habitat destruction by roads and buildings as destroyers of nature. Global warming will take their place over the next few decades, but that doesn’t mean that we can ignore invasives. Protecting nature requires that we tend to all our destructive behaviors. My articles include suggestions and references to other resources for invasive plant control.

The article below from the National Geographic Society Blog reports that the invasive species problem is growing. Humans really began spreading species 500 years ago when they began crossing the oceans. It surprises me that we’ve left anything behind, but apparently we left enough invasive species behind to continue and even accelerate this form of the human impact.

“A study released this month has illustrated that the rate of species introductions to locations outside their native range is increasing faster than ever. Hanno Seebens and many others used the date of first records of introductions to plot the total number of new non-native species records every year since 1500. They show that this is not only increasing, but accelerating, with no signs of saturation. The increase was particularly marked since the 1800s. This global exchange of species is not good news, as although it increases species richness at the regional scale, globally the species richness of our planet declines as species go extinct.

Global temporal trends in first record rates (dots) for all species (a) and taxonomic groups (b–q) (Source: Nature Communications)

“New Zealand was singled out as one country whose trend was negative compared to the rest of the world. As any traveller to New Zealand will have encountered, the biosecurity importation laws and policing are rigorous and every passenger is screened. In tandem with a ‘white-list’, where only certain non-native species are automatically permitted entry, and all others must be assessed, has clearly assisted in protecting New Zealand’s biodiversity and primary industries from the global trend in accelerating species introductions.” –James Russell (Continue reading:  Species Introductions Accelerating – National Geographic Society (blogs).)

Images of new bleaching on Great Barrier Reef heighten fears of coral death

GR:  An update on the continuing bleaching disaster. It appears to me that the fossil-fuel industry has purchased the Australian government and directing the government to permit for-profit developments harmful to the reef.

“The embattled Great Barrier Reef could face yet more severe coral bleaching in the coming month, with areas badly hit by last year’s event at risk of death.

Newly bleached corals discovered near Palm Island on the Great Barrier Reef. Photograph: Australian Marine Conservation Society

“Images taken by local divers last week and shared exclusively with the Guardian by the Australian Marine Conservation Society show newly bleached corals discovered near Palm Island.

“Most of the Great Barrier Reef has been placed on red alert for coral bleaching for the coming month by the US National Oceanic and Atmospheric Administration (NOAA). Its satellite thermal maps have projected unusually warm waters off eastern Australia after an extreme heatwave just over a week ago saw land temperatures reach above 47C in parts of the country.

Newly bleached coral. Most of the reef has been placed on red alert for coral bleaching for the coming month by the US National Oceanic and Atmospheric Administration. Photograph: Australian Marine Conservation Society

“According to the Great Barrier Reef Marine Park Authority, sea surface temperatures from Cape Tribulation to Townsville have been up to 2C higher than normal for the time of year for more than a month.” –Elle Hunt (Continue reading:  Images of new bleaching on Great Barrier Reef heighten fears of coral death | Environment | The Guardian.)

Scientists have just detected a major change to the Earth’s oceans linked to a warming climate

GR:  Here’s some really bad news. It’s been expected, but it hasn’t been confirmed until now. Global warming is robbing the oceans of the oxygen necessary for life. This is just another extinction threat from global warming.

ocean-dead-zone-in-gom-2013-august

Dead Zones like this one in the Gulf of Mexico are spreading worldwide.

“A large research synthesis, published in one of the world’s most influential scientific journals, has detected a decline in the amount of dissolved oxygen in oceans around the world — a long-predicted result of climate change that could have severe consequences for marine organisms if it continues.The paper, published Wednesday in the journal Nature by oceanographer Sunke Schmidtko and two colleagues from the GEOMAR Helmholtz Centre for Ocean Research in Kiel, Germany, found a decline of more than 2 percent in ocean oxygen content worldwide between 1960 and 2010. The loss, however, showed up in some ocean basins more than others. The largest overall volume of oxygen was lost in the largest ocean — the Pacific — but as a percentage, the decline was sharpest in the Arctic Ocean, a region facing Earth’s most stark climate change.

“The loss of ocean oxygen “has been assumed from models, and there have been lots of regional analysis that have shown local decline, but it has never been shown on the global scale, and never for the deep ocean,” said Schmidtko, who conducted the research with Lothar Stramma and Martin Visbeck, also of GEOMAR.

“Ocean oxygen is vital to marine organisms, but also very delicate — unlike in the atmosphere, where gases mix together thoroughly, in the ocean that is far harder to accomplish, Schmidtko explained. Moreover, he added, just 1 percent of all the Earth’s available oxygen mixes into the ocean; the vast majority remains in the air.” –Chris Mooney (More:  Scientists have just detected a major change to the Earth’s oceans linked to a warming climate – The Washington Post).

Here’s another blog post covering this news.