Biodiversity

Biodiversity Status

As on land, biodiversity in the oceans is threatened.

Source: World Ocean Assessment ¹.

Biodiversity ultimately depends on primary producers, which in the ocean is mainly plankton. While there is not yet strong enough data to establish a trend on plankton populations, it is expected that unabated global warming will reduce the amount of ocean plankton in the 21st century, reducing the carrying capacity of all other life ¹.

Whaling

The commercial hunting of whales has decreased dramatically since the 1960s, but has ticked up in recent years.

Source: Our World in Data ².

Major reasons for the decline include the establishment of the International Convention for the Regulation of Whaling in 1946 ³ and the International Whaling Commission's 1986 on commercial whaling ⁴. Following the IWC's Florianópolis Declaration in 2018, Japan withdrew from the IWC and announced a resumption of commercial whaling, which they had previously been conducting under the guise of scientific research ⁵.

Most commercial whaling today is conducted for whale meat ⁶. Historically, whaling was also done for whale oil and spermiceti for lighting, baleen (whalebone) to stiffen corsets and other fashion uses, and ambergris for perfumes. These uses have now mostly disappeared ⁷.

Invasive Species

As on land, invasive species in the oceans cause significant ecosystem harm and threats to human wealth and the economy. Sources of invasive species include attachment to ship ballasts, biofouling, aquaculture, and trade in live specimens ⁸. The International Convention for the Control and Management of Ships' Ballast Water and Sediments, designed to control a major vector of invasive species propagation, entered into force in 2017 ⁹, and it is too early to judge how effective these regulations have been ¹.

Of the sources of invasive species, ship biofouling is estimated to cause 55.5-69.2% of the invasions ¹⁰. Several design modifications to ships and seaports can reduce biofouling ¹⁰.

Noise

The importance of noise for ocean ecosystem health is great and has only recently come to be appreciated ¹.

Source: Hildebrand ¹¹. Energy figures are those estimated to be the total released from the given sources as acoustic energy. Underwater nuclear weapons testing is banned under the Comprehensive Test Ban Treaty; while the treaty is not in force, underwater testing has not occurred since it was signed in 1996. The figure assumes one device is detonated every 20 years, as geopolitical circumstances may evolve toward additional testing in the future.

Although more expensive, marine vibrators to replace airguns for offshore oil and gas exploration, with the coal of reducing noise, are under development ¹². Bubble curtains are a tool to reduce ambient noise from pile driving in underwater construction ¹³.

Biodiversity and Carbon Content

A restored marine ecosystem will sequester carbon, countering the effects of climate change. The possible amount sequestered is not well understood ¹⁴. The potential for seaweed growth has been estimated at 0.6 billion tons of carbon ¹⁵, or the equivalent of about 1.7 billion tons of CO₂, about 4% of annual world emissions today.

Source: NOAA ¹⁶.

Ecosystem restoration could be done by removing the negative pressures on marine ecosystems, including plastic pollution and bottom trawling ¹⁴.