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Weekly Ocean News 
Why dolphins don't experience menopause; a UK town enlists beavers to help with flooding; and more in this week's ocean news.
Posted on July 27, 2018
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Ecosystems and Biodiversity

As far as we know, only four species experience menopause: orcas, pilot whales, false killer whales and humans. So, why did these species evolve this late-stage inability to bear offspring? A study on the nursing habits of bottlenose dolphins, which don’t experience menopause, may give us part of the answer. Older dolphin mothers breed less often, are more likely to lose their calves, and spend an additional year nursing them. Because of the high-energy demands that come with raising a calf, it may be more efficient for older mothers to invest their energy into already existing offspring, rather than continue reproducing. Via Science Magazine

As the Arctic continues to warm, spring weather is arriving earlier. Barnacle geese live in temperate regions, but head to the Arctic for the breeding season. Their migration is triggered by the changing hours of sunlight from season to season, however, this isn’t correlated to temperature. Scientists have found that the geese have learned that if they want to get to their breeding grounds in time, they have to fly faster and harder than normal. Unfortunately, this means they need to rest and refuel before they can breed, and their chicks are missing out on spring foraging opportunities. If they are to flourish, they’ll either have to leave earlier, or learn to breed in their temperate home. Via Phys.org

A study by Fisheries and Oceans Canada (DFO) and industry has looked at the amount of microplastics in British Columbia’s shellfish. Based on previous research they were expecting hundreds of pieces of microplastics per gram, but found an average of less than one piece. While there were plastic microfibers present, analysis by Vancouver Aquarium showed that most of these were cotton or cellulose. The difference in results may result from local variations in concentration, or it may be because previous studies weren’t correctly identifying contaminants. Via Hakai Magazine

Water Quality and Supply

A weakening Gulf Stream might not be climate change’s fault.

Scientists have known for some time that the Gulf Stream, the current that takes warm water from the tropics to Western Europe, is slowing down. New research indicates that this may not be the result of climate change, but rather part of a 60 to 70-year cycle. When the current is fast, larger amounts of warm water melt the northern ice faster, and the resulting fresh water layer stalls the current. As it slows, reduced amounts of warm water slow the rate of melt. The good news is that the circulation may not collapse, but the bad news is that the coming increase in speed will contribute to rising temperatures in the Arctic and Europe. Via BBC

Flooding in the UK has increased in recent years. While flood prevention has mainly focused on infrastructure, the citizens of Lydbrook are trying out a less technological approach: beavers. The government is introducing a pair of Eurasian beavers upstream to create natural ponds and reduce the amount of water flowing into Lydbrook during flood periods. Biologists also anticipate that the beavers will alter the habitat in such a way that historic populations of vole, glow worms, and butterflies may return to the area. Via The Guardian

Cities typically rely on water sources that are rich in minerals, however, this forms mineral deposits on the sides of pipes and can lead to clogging. Water companies respond by adding softening agents that dissolve the deposits.  Unfortunately, new research has shown that these softeners not only promote the growth of biofilms, which spread Legionnaire’s and other bacterial-borne diseases, but they loosen the grip of the biofilms on the pipe causing them to spread faster.  Via EurekAlert!

Radar scans have detected a lake of liquid water far beneath the deeply frozen ice cap of the south pole of Mars. The lake, which lies 1.5 km under the ice and spans 20 km, is probably frigid and full of salts, but it is the first to be found on the Red Planet, although water ice has been observed before.  Similar underground lakes have been observed in Greenland and Antarctica. Via Science Magazine

Government Initiatives

A new Cayman Islands’ initiative that bans fishing fertile adult Nassau groupers has seen sucess: a bounce back in population numbers.

In 2001, fishermen in the Cayman Islands almost wiped out the Nassau Grouper, by catching 70% of the huge predatory fish in a few days during their spawning season. Aided by scientists from California and local fishermen, the Caymanian government studied the reproductive habits of the fish. New laws that ban fishing during the spawning season and otherwise limit the size of fish that can be caught were introduced and the population has grown from one thousand to 8,000 in 15 years. Notably, the laws forbid catching old fish that are more fertile than younger fish. Via Scientific American

We started to use up the planet’s resources at an unsustainable rate in the 1970s, and since then a group of environmentalists has published “Earth Overshoot Day,” the date at which they think we’ve consumed a year’s worth of resources. Thirty years ago, the overshoot was on 15 October, which means we need 1.7 planets to sustain our population. However, individual action is less effective than legislation. For example, if 50% of the planet became vegetarian the date would be pushed back by 5 days but efficiency improvements in building and industry could make a difference of three weeks. A 50% reduction in our carbon footprint would push the date back to November. Via The Guardian

Energy and Power

Wave power has increased by 40% over the last century, and that power is picking up.

Wave generators are designed to produce as much energy as they can extract from their location. Their design is mostly based on historical wave data, but a team of Basque and Irish researchers decided to check the relevance of these designs in the wake of profound changes to climate. A wave generator typically lasts 20 years, so they divided the last century into 5 twenty-year slices and looked at how modern designs would cope. They found that the amount of energy delivered by waves has increased by 40% over the last century and that the effect is accelerating, which has profound implications for anyone designing generators. Via EurekAlert!

Powerful batteries can be dangerous things. They discharge   energy, heat up and, if the load suddenly increases, they can explode or burn. Consequently, they have to be protected by cut-out switches and extinguishers, and need to be re-started once they have cooled. Scientists in Hong Kong have developed a hydrogel electrolyte that changes from its normal fluid state to a solid gel when the temperature gets above a certain point, preventing the migration of electrons. This shuts the battery down safely but becomes effective again once it has cooled down. Via EurekAlert!


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