Marine on EARTH Magazine

Free swimmers came back first after Great Dying

Thu, 17 Jan 2019 13:23:48 -0500

In the Early Triassic, following the end-Permian extinction, nektonic marine life recovered fastest, according to new research, resulting in a reversed functional pyramid. Percentages represent the proportion of marine genera belonging to each class of organisms. Credit: courtesy of Haijun Song.

About 252 million years ago, at the boundary between the Permian and Triassic periods, the vast majority of marine and terrestrial life died out in the most devastating extinction event in Earth’s history. Earth’s ecosystems eventually recovered, but not in the way — or as quickly as — scientists thought. In a new study looking at how marine species reemerged in the Triassic, researchers report a surprising trend of recovery from the top of the food chain down.

Marine animals have been migrating for millions of years

Tue, 16 Oct 2018 09:46:47 -0400

Marine organisms like corals, sponges and snails have been migrating for millions of years, mostly driven by temperature changes. Credit: Carl Reddin.

Scientists have suspected that ancient animals migrated in response to changing global temperatures, but until now, there was no documentation of this across extensive time periods. In a new study, researchers found that, for millions of years, marine organisms like corals, sponges and snails, have shifted their ranges in response to climate change.

Globe-trotting kelp set new world record

Fri, 12 Oct 2018 13:03:55 -0400

Kelp grows in underwater forests in shallow regions of temperate, tropical and polar oceans. Air bladders in the leaves enable the seaweed to travel vast distances on currents across oceans. Credit: public domain.

When marine biologist Erasmo Macaya, from University of Concepción in Chile, found a piece of kelp washed up on a beach in Antarctica, he suspected the scrap of seaweed had come a long way.

Oldest blood cells found in Early Jurassic ichthyosaur

Fri, 23 Feb 2018 11:23:23 -0500

The oldest preserved red blood cells, white blood cells and platelets have been found in the remains of a 183-million-year-old ichthyosaur vertebra. Ichthyosaurs were formidable marine predators in Mesozoic seas. Credit: Curtin University.

Since 2005, a steady trickle of reports detailing proteins and other soft tissues preserved in fossils of dinosaurs and other ancient animals has gradually worn down the disbelief that such tissues can last through geologic time. In a new study in Scientific Reports, scientists have now reported the oldest preserved red blood cells, white blood cells and platelets, found in the remains of an ancient marine reptile.

Predators may have spurred evolution of ancient brittle stars

Thu, 14 Dec 2017 18:07:42 -0500

Fossils of roughly 275-million-year-old brittle stars were found in Western Australia. Credit: Kenneth McNamara.

Threats to species can encourage evolution, leading to animals with harder shells or other defensive adaptations. In a recent study in the Journal of Systematic Palaeontology, researchers found that while some ancient brittle stars — relatives of starfish with long, whip-like arms — evolved in the face of threats, some adapted a different approach: they moved.

Marine megafaunal extinction discovered

Thu, 09 Nov 2017 15:07:39 -0500

Fossils from Pliocene megafauna: sharks' teeth from Carchahinus leucas (left) and Negaprion (right). Credit: University of Zurich.

Extinctions of large land animals during the Pleistocene are well documented. In a new study, scientists report that marine megafauna also suffered severe losses several million years ago, around the time that the first hominid ancestors were emerging in Africa.

Nineteenth-century cows muddied Southern California continental shelf

Wed, 19 Jul 2017 11:44:14 -0400

When offshore ecosystems deteriorate, scientists often look at changing ocean conditions, urban runoff or fishing as potential explanations. Cows usually don’t come to mind. But new research investigating the seafloor off the coast of Los Angeles suggests that 19th-century cattle, despite their terrestrial lifestyle, left a lasting impact on the underwater habitat there.

Robotic mussels track temperature change

Thu, 19 Jan 2017 13:36:16 -0500

Researchers deployed fake mussels equipped with internal thermometers to record temperatures in living mussel beds. Credit: Brian Helmuth.

Among the crashing waves of rocky shorelines, tiny robotic mussels are providing scientists with insight into climate change impacts on marine life. The battery-powered “biomimics” hide among real mussels, with internal thermometers to estimate temperatures of their nearby living neighbors. Mussels’ body temperatures are changing with solar radiation, cloud cover and wind speed, says Brian Helmuth, a marine ecologist from Northeastern University in Boston. Because of this, the mussels’ body temperatures are generally much higher than the temperature of the surrounding air during exposure at low tide.

Current marine extinction unprecedented

Tue, 27 Dec 2016 16:41:59 -0500

Humpback whales in singing position. Credit: NOAA.

In today’s ocean, larger-bodied animals are more likely to become extinct than smaller creatures, according to a new study in Science. This is contrary to extinction patterns seen during other mass extinction events in Earth’s history, during which smaller species were hit the hardest.

Nutrient deficiency delayed life after mass extinction

Tue, 15 Nov 2016 18:16:07 -0500

Stephen Grasby collects samples from an outcrop on northern Ellesmere Island in the Canadian High Arctic. Credit: John Spear, Colorado School of Mines.

After Earth’s most severe mass extinction, life took up to 9 million years to recover — millions of years longer than after other extinction events. New research published in Geology suggests that a collapse in the ocean’s productivity might have been the cause.

Hammerhead herbivore pioneered vegetarianism in Triassic seas

Tue, 13 Sep 2016 14:01:53 -0400

A model of the head of the hammerhead vegetarian Atopodentatus unicus beside a fossil of the Triassic marine reptile. Credit: ©Nick Fraser.

New fossils found in southern China hint that the earliest herbivorous marine reptiles got off to a bizarre start: Atopodentatus unicus, which lived about 244 million years ago and sported a unique hammerhead-like snout for grazing underwater plants, sheds light on how the earliest marine reptiles began experimenting with herbivory after the Permian mass extinction, which killed off 96 percent of marine organisms about 252 million years ago. This “Great Dying” event left vast holes in the ecology of the Early Triassic, and a diversity of new feeding styles evolved to occupy the open niches.

Subseafloor biosphere extended to greatest depth yet

Tue, 15 Dec 2015 10:38:45 -0500

Microbes cultured from a coal seam buried 2 kilometers below the seafloor off Japan are seen in this scanning electron microscope image at 5,000-times magnification. Credit: Hiroyuki Imachi, JAMSTEC.

Scientists studying sediments collected from the deepest scientific borehole ever drilled have found microorganisms living at astounding depths beneath the seafloor. Recent studies have previously found bacteria and archaea scratching out meager livings in marine sediments buried as deep as 1.9 kilometers, but the new find extends the known biosphere even farther down.

Ancient marine reptiles born alive and ready to hunt

Fri, 21 Aug 2015 11:36:28 -0400

An artist's interpretation of an adult mosasaur giving birth to live young. Credit: Julius T. Csotonyi.

Mosasaurs, giant marine reptiles found in all the world’s oceans during the Late Cretaceous, may have reached up to 18 meters in length, and they were fearsome predators. Little is known, however, about newborn, or neonate, mosasaurs because very few have been found. Now, new research describing a rare fossil find from Kansas reveals that mosasaurs likely gave birth to live young that were born swimming and able to survive alongside the adults.

How the school of rock came to be

Fri, 20 Jul 2012 15:51:55 -0400

The JOIDES Resolution. John Van Hoesen

In the late 1950s, a growing interest in better understanding the structure and composition of Earth resulted in the creation of the controversial Project Mohole. Although the name may sound better suited for an Isaac Asimov novel, it was indeed a real, albeit short-lived, attempt to drill through the boundary between the crust and mantle, called the Mohorovičić (Moho) discontinuity — an engineering feat yet to be achieved. The project led to the modern-day Integrated Ocean Drilling Program (IODP) — and eventually the School of Rock.

Sea sprawl: Into the blue frontier of ocean development

Thu, 05 Jan 2012 06:41:58 -0500

Picture it: Dozens of kilometers off the coast of Texas, a giant polygon-shaped cage constructed of steel ribs and mesh netting floats 30 or so meters beneath the waves. The cage, moored to the seafloor, is filled with tens of thousands of teeming, silvery fish. Several kilometers away, offshore wind turbines sprout from the sea surface in a curving line, their spindly white arms churning the atmosphere. Still farther along the horizon, a massive oil platform squats heavily on four stumpy legs over its parcel of ocean, pipes plunging 11 kilometers into deep reservoirs within the seafloor. In the open waters between these industries, tankers and commercial fishermen follow snaking shipping lanes that lead them toward the coast.