There are large accumulations of plastics in the ocean, even outside so-called garbage patch

Neuston net towed on the side of the German RV SONNE, collecting surface-floating plastic samples when crossing the North Pacific Ocean.
Photo Credit: Philipp Klöckner / UFZ

When plastic ends up in the ocean, it gradually weathers and disintegrates into small particles. If marine animals ingest these particles, their health can be severely affected. Large accumulations of plastic can therefore disrupt the biological balance of marine ecosystems. But which areas are particularly affected? In a recent study, a research team from the Helmholtz Centre for Environmental Research (UFZ), in collaboration with the Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research (AWI), has found large quantities of plastic waste and microplastics in a remote marine protected area in the Pacific Ocean. These quantities were similar to those found in one of the world’s largest known garbage patches. The researchers highlight that plastics are distributed much more widely than expected. The entire ocean ecosystem is threatened. They therefore call for the global emissions of plastics into the ocean to be stopped as quickly as possible. The study has been published in Environmental Science & Technology.

Marine heat waves disrupt the ocean food web in the northeast Pacific Ocean

Pyrosomes.
Photo Credit: Mark Farley, Hatfield Marine Science Center, Oregon State University.

Marine heat waves in the northeast Pacific Ocean create ongoing and complex disruptions of the ocean food web that may benefit some species but threaten the future of many others, a new study has shown.

The study, just published in the journal Nature Communications, is the first of its kind to examine the impacts of marine heat waves on the entire ocean ecosystem in the northern California Current, the span of waters along the West Coast from Washington to Northern California.

The researchers found that the biggest beneficiary of marine heat waves is gelatinous zooplankton – predominantly cylindrical-shaped pyrosomes that explode in numbers following a marine heat wave and shift how energy moves throughout the food web, said lead author Dylan Gomes, who worked on the study as a postdoctoral scholar with Oregon State University’s Marine Mammal Institute.

“If you look at single species interactions, you’re likely to miss a lot,” Gomes said. “The natural effects of a disturbance are not necessarily going to be straightforward and linear. What this showed us is that these heat waves impact every predator and prey in the ecosystem through direct and indirect pathways.”

The project was a collaboration by Oregon State University and the National Oceanic and Atmospheric Administration. Joshua Stewart, an assistant professor with the Marine Mammal Institute, mentored Gomes and co-authored the paper.

Range-shifting fishes are climate-change losers, according to new research

Pouting (Trisopterus luscus)
Photo Credit: Diego Delso
(CC BY-SA 4.0 DEED)

The warming of the Earth’s oceans due to climate change is affecting where the world’s fishes live, eat and spawn — and often in ways that can negatively impact their populations. That’s according to a new paper in the journal Nature Ecology and Evolution.

The researchers write that populations that experience rapid-range shift decline noticeably, up to 50 per cent over a decade. The populations affected most are those living on the northern poleward edges of their species’ range.

“There is a conventional wisdom among many climate-change biologists that species that shift their ranges quickly by moving northward should provide a mechanism to sustain healthy populations — that shifting species should be climate-change winners. Our results show the exact opposite,” says paper co-author Jean-Philippe Lessard, a professor in the Department of Biology.

“Species that are shifting their range quickly experience little change in their population size in their core range. But some of them experience a major collapse in their populations at the northern edges.

“In fact, the population collapse is mostly driven by the northern poleward populations,” he adds. “We were expecting that many individuals from the core of the range would be moving up north due to climate change and maintain these northern populations. But the northern-edge populations are the ones most likely to collapse.”

History repeats as Coral Bay faces mass loss of coral and fish life

Photo Credit: Nico Smit

A perfect storm of environmental factors has seen a monumental loss of fish and coral life at a popular area of Ningaloo Reef in Western Australia’s Gascoyne region — however Curtin University research into the event shows there is hope it will recover.

In March 2022, during the annual coral spawning event, calm weather and limited tidal movement combined to trap the coral’s eggs within Bills Bay, at the town of Coral Bay.

This led to an excess of nutrients in the water which consumed more oxygen than usual — causing massive numbers of fish and corals to die from asphyxiation.

Study lead Associate Professor Zoe Richards, from Curtin’s School of Molecular and Life Sciences, said a lack of oxygen is a well-known risk for tropical coral reefs.

“Severely low oxygen levels in the ocean can create ‘dead zones’ where almost nothing can live, causing a lot of harm to nature and, in tourist areas such as Coral Bay, this can also impact the economy and community,” Associate Professor Richards said.

Unprecedented heatwaves revealed by marine lab’s historic data

Photo Credit: Courtesy of University of Auckland

A unique record at the University of Auckland's Leigh marine lab shows dramatic change in the Hauraki Gulf.

A thermometer dipped in a bucket of sea water on New Year’s Day in 1967 began a unique record which shows the dramatic intensification of warming in the Hauraki Gulf.

Sea-surface readings at the Leigh Marine Laboratory north of Auckland since that time indicate the “unprecedented nature of recent marine heatwaves,” according to Dr Nick Shears of the University of Auckland, Waipapa Taumata Rau.

The number of marine heatwave days and their cumulative intensity has increased sharply since 2012, Shears and his co-authors write in a paper published in the New Zealand Journal of Marine and Freshwater Research.

In past decades, some years had no heatwaves, but that hasn’t happened since 2012. Sponges `melting,’ becoming detached from rocks and dying, along with seaweed and kelp die-offs, are among temperature effects.

Especially warm autumns and winters have likely facilitated an increase in subtropical and tropical species such as the long-spined sea urchin Centrostephanus rodgersii, a voracious herbivore which can lay waste to deep reef environments.

Halloween toy among plastics swallowed by sea turtles

A rubber witches' finger found inside a dead sea turtle.
Photo Credit: University-of-Exeter

A Halloween toy was among hundreds of plastic items found in the guts of dead sea turtles in the Mediterranean, a new study reveals.

Researchers examined 135 loggerhead turtles either washed up or killed as “bycatch” (accidentally caught) in fishing nets off northern Cyprus.

More than 40% of the turtles contained “macroplastics” (pieces larger than 5mm), including bottle tops and the Halloween toy – a rubber witch’s finger.

The research team, led by the University of Exeter and the North Cyprus Society for the Protection of Turtles (SPOT), say loggerheads are a potential “bioindicator” species that could help them understand the scale and impact of plastic pollution.

“The journey of that Halloween toy – from a child’s costume to the inside of a sea turtle – is a fascinating glimpse into the life cycle of plastic,” said Dr Emily Duncan, from Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.

“These turtles feed on gelatinous prey such as jellyfish and seabed prey such as crustaceans, and it’s easy to see how this item might have looked like a crab claw.”

Loss of nature costs more than previously estimated

Photo Credit: Christian Heitz

Researchers propose that governments apply a new method for calculating the benefits that arise from conserving biodiversity and nature for future generations.

The method can be used by governments in cost-benefit analyses for public infrastructure projects, in which the loss of animal and plant species and ‘ecosystem services’ – such as filtering air or water, pollinating crops or the recreational value of a space – are converted into a current monetary value.

This process is designed to make biodiversity loss and the benefits of nature conservation more visible in political decision-making.

However, the international research team says current methods for calculating the values of ecosystem services “fall short” and have devised a new approach, which they believe could easily be deployed in Treasury analysis underpinning future Budget statements.

Their approach, published in the journal Science, takes into consideration the increase in monetary value of nature over time as human income increases, as well as the likely deterioration in biodiversity, making it more of a scarce resource.

A Larger Area of Arctic Seafloor is Exposed to Sunlight

Photo Credit: © Ignacio Garrido

Most of the sunlight reaching the Arctic Ocean is reflected by sea ice, shielding ocean ecosystems from light. As Arctic sea ice continues to melt, larger areas of the ocean and seafloor become exposed to sunlight, potentially allowing more photosynthesis to occur and making the Arctic Ocean more productive. However, this does not seem to be occurring uniformly across the Arctic Ocean.

Over the past 25 years, the amount of summer Arctic sea ice has diminished by more than 1 million square kilometers. As a result, vast areas of the Arctic Ocean are now, on average, ice free in summer. Scientists are closely monitoring how this impacts sunlight availability and marine ecosystems in the far north.

Many questions arise when such large areas become ice-free and can receive sunlight. A prevailing paradigm suggests that the Arctic Ocean is rapidly becoming more productive as sunlight becomes more abundant in the marine environment. However, it is unclear how ecosystems will evolve in response to increasing sunlight availability and how different parts of the marine ecosystem will be affected, says Karl Attard, a marine scientist and Associate Professor at the Department of Biology.

Attard has led an international research team investigating sunlight availability and photosynthetic production on the understudied Arctic seafloor. Their study has been published in the scientific journal Proceedings of the National Academy of Sciences (PNAS).

Lake Ecosystems: Nitrogen has been underestimated

Algae growth in shallow lakes around the world is affected not only by phosphorus but also by nitrogen
Photo Credit: Liz Harrell

An ecological imbalance in a lake can usually be attributed to increased nutrient inputs. The result: increased phytoplankton growth, oxygen deficiency, toxic cyanobacterial blooms and fish kills. Until now, controls in lake management have focused primarily on phosphorus inputs to counteract this effect. Now, this dogma is shaken by a study performed by the Helmholtz Centre for Environmental Research (UFZ) in collaboration with the University of Aarhus (Denmark) and the University of Life Sciences (Estonia) and published in Nature Communications. The researchers show that nitrogen is also a critical driver for phytoplankton growth in lakes worldwide. 

The input of phosphorus and nitrogen from agricultural sources and sewage treatment plants can have a strong effect on phytoplankton growth in rivers and lakes. "However, it was previously assumed that phytoplankton growth in lakes is mostly limited and driven by the availability of phosphorus," says lead author Dr. Daniel Graeber from the UFZ. The underlying theory: If only small quantities of phosphorus are available in a lake, phytoplankton growth is correspondingly limited. In contrast, large quantities of phosphorus will massively drive phytoplankton growth. "In this explanatory model, nitrogen plays no role," says Graeber. "This is based on the fact that specific cyanobacteria in the water can bind the nitrogen contained in the air and introduce it into the lake. This would therefore preclude a long-term nitrogen deficiency in lakes." Nor could an excess supply of nitrogen promote phytoplankton growth - and therefore could not ultimately give rise to eutrophication. "This model forms the basis for lake management worldwide, where the emphasis has been on controlling phosphorus inputs to counteract lake eutrophication," explains Dr. Thomas A. Davidson, limnologist at Aarhus University and last author of the study. "Reducing phosphorus inputs repeatedly fails to prevent eutrophication. This therefore gave rise to the question of whether the water equation included yet another unknown." In its present study, the research team has now clearly identified nitrogen as such a factor, and is thus indicating new directions for inland water science (limnology) and lake management. 

Oregon State University researchers are first to see at-risk bat flying over open ocean

Hoary bat at sea.
Photo Credit: Courtesy of Will Kennerley / the MOSAIC Project.

On a research cruise focused on marine mammals and seabirds, Oregon State University scientists earned an unexpected bonus: The first-ever documented sighting of a hoary bat flying over the open ocean.

The bat was seen in the Humboldt Wind Energy Area about 30 miles off the northern California coast; the Humboldt area has been leased for potential offshore energy development, and the hoary bat is the species of bat most frequently found dead at wind power facilities on land.

OSU faculty research assistant Will Kennerley, the first to see the bat, and colleagues documented the sighting with a paper in the Journal of North American Bat Research. The bat was spotted just after 1 p.m. on Oct. 3, 2022, in observing conditions rated as excellent.

“I have spent a lot of time at sea in all oceans of the world, and I’ve seen a lot of amazing things,” said Lisa Ballance, director of OSU’s Marine Mammal Institute. “A hoary bat was a first for all of us. It’s a reminder of the wonder of nature, and of its vulnerability.”