Inadvertent Visitors

When I was a kid in northern California, we used to go to the ocean beaches of Marin County on the weekends. The long, sweeping scythes of Drake’s Beach and Limantour still count among my favorite ocean shorelines. Beachgoers wore swimsuits on warm days, but we could always tell the tourists from the locals because the tourists were the ones trying to swim in those suits instead of wade or sunbathe.

Locals usually considered swimming the Pacific water too cold for our tender hothouse skin, even in summer. Non-neoprened swimmers venturing into the waters for a swim were a rare sight.

Drake's Bay, Point Reyes National Seashore Photo: Richard Blair

Drake’s Bay, Point Reyes National Seashore
Photo: Richard Blair

This year, researchers and fishermen have seen even rarer sights: Several species that would normally be found far south have been observed in northern waters. An endangered green sea turtle, usually at home in the waters of southern Mexico and around the Galapagos Islands. The tiny striated sea butterfly and a Guadalupe fur seal, both of Baja California, Mexico, common dolphins, blue buoy barnacles and purple-striped jellyfish of southern California.

Striated Sea Butterfly (Hyalocylis striata), collected offshore from Bodega Marine Laboratory. Photo: Eric Sanford/UC Davis

Striated Sea Butterfly (Hyalocylis striata), collected offshore from Bodega Marine Laboratory.
Photo: Eric Sanford/UC Davis

It’s an influx of inadvertent tourists, animals that would normally encounter the cold water barrier of the northern Pacific and turn around, much as I used to do on the beach when I waded in above the knee level.

According to several sources, water temperatures are 5-6 degrees Fahrenheit (2-3 °C) higher than average this year, likely due to a slackening of winds from the north that would normally keep warm waters further south. The annual winds would also normally cool and push surface waters down, causing colder water to churn up from below (‘upwelling’).

And what about the local species that like it cold? The krill, the salmon? They are scarce, as are the animals that feed on them, the whales and birds.

It’s a 30-year autumnal anomaly, which most expect to pass and with it, the strange and wondrous visitors.

Inside and Out

Green sea urchins
Photo: R. Wollocombe

Ocean acidification has been studied in relation to marine animals with calcium carbonate shells. Oysters, sea butterflies, shrimp – all are affected by acidification when their outer shells don’t develop properly.

According to this article, ocean acidification has increased by 25-30% since the beginning of the Industrial Revolution.

A new study published in Nature Climate Change looks at a different key species in kelp forests in temperate and subpolar oceans, green sea urchins. But it’s not their shells that are at risk.

In a first demonstration that ocean CO2 levels can affect the digestion of a marine creature, German and Swedish researchers showed that the larval stage of green sea urchins (Strongylocentrotus droebachiensis) have difficulty digesting in water with higher levels of acidity.

Green sea urchin Source: OhDeer

Green sea urchin
Source: OhDeer

The sea urchins compensate by eating 11-33% more, but if additional food is unavailable, their growth, fertility and survival can be compromised.

So while some studies have shown that ocean acidification varying levels of impact on different marine life.

Unlike the effects on oysters and sea butterflies, increased acidity (up to a given threshold) has less of an effect on certain marine animals with substantial shell coverings – like the temperate sea urchin.

Unfortunately, being protected by a thick shell may not be all that’s necessary to survive in an acidified ocean.

Green sea urchin endoskeleton Photo: galewhale/Project Noah

Green sea urchin endoskeleton
Photo: galewhale/Project Noah

Larger Than Life

Limacina Helica IV Artist/Photo: Kavanagh/Bessler

Limacina Helicina IV
Artist/Photo: Kavanagh/Bessler

When one thinks of marine life, especially when it comes to endangered marine life, the mind naturally turns to the poster children of conservation: polar bears, whales, dolphins. The big guys. Maybe some of us think of our favorite fish – tuna, for example, or salmon.

Not many spare a thought for the tiny shelled pteropod Limacina. But Limacina makes up in pure grace what it lacks in cute eyes, haunting songs, bottle-nosed grins or delectability.

Limacina helicina  Photo: Alexander Semenov

Limacina helicina
Photo: Alexander Semenov

Known as sea butterflies, they make up a giant link in the food chain between plankton and larger animals. Tiny as they are, they are also a key part of the global carbonate cycle – their shells make up an estimated 12% of the carbonate flux that determines ocean acidity and helps stabilize carbon levels in the atmosphere.

A report, due to be presented at Conference of the Parties (COP 19) to the 1992 United Nations Framework Convention on Climate Change (UNFCCC) in Warsaw next week states with high confidence that ocean acidification is increasing due to carbon dioxide emissions, and that this acidification will have major ramifications.

Limacina Helica V Artist/Photo: Kavanagh/Bessler

Limacina Helicina V
Artist/Photo: Kavanagh/Bessler

According to this article, “the world needs to prepare for major losses of ecosystem services” and all the benefits to human life and activity which those services provide, from food and clean air to reef protection and economic livelihoods.

The sea butterflies, seen here in sculptures by Corneila Kubler Kavanagh, are losing their shells, which are dissolving in acidic waters. Working together with ocean acidification researcher Gareth Lawson, Kavanagh created aluminium visions of Limacina that magnify the fragile creatures by 400 times their natural size of 1 cm (0.4″).

Maybe that size, combined with the UNFCC meeting, is just about big enough to focus attention on the challenge of ocean acidification.

Limacina Helica II Artist/Photo: Kavanagh/Bessler

Limacina Helicina II
Artist/Photo: Kavanagh/Bessler