Zagrejana mora i El Niño: Mladunci morskih lavova na Zapadnoj obali ponovo u opasnosti

Razvijajući El Niño u tropskom Pacifiku mogao bi se pojačati kasnije tokom godine i dodatno podići temperaturu već neuobičajeno toplih voda duž Zapadne obale SAD, što povećava rizik za morske ekosisteme koji se još oporavljaju od nedavnih talasa toplote.

Kako kombinacija faktora ugrožava morske lavove

Naučnici upozoravaju da kombinacija preostalog morskog talasa toplote i jačanja El Niño može poremetiti snabdevanje hranom u Kalifornijskom toku. Toplije vode često pomeraju sardine i inćune dalje od obale ili dublje u vodeni stub, pa dojilje moraju putovati duže da bi našle plen, ostavljajući mladunce na obali duže nego obično.

Posledice za mladunce

Tokom prethodnih godina ekstremnog zagrevanja, neki su mladunci bili prerano odvojeni od majki ili su bili podhranjeni; u najtežim godinama više od 4.000 mladih kalifornijskih morskih lavova pronađeno je nasukano duž plaža Kalifornije, što je preopteretilo centre za rehabilitaciju. NOAA Fisheries je zbog toga kasnije proglasio Unusual Mortality Event za ovu vrstu.

Šta pokazuju naučne procene

Istraživanja ukazuju da i relativno mali porast temperature površine mora ima velike posledice: porast od 1°C može smanjiti rast populacije morskih lavova praktično na nulu, dok porast od ~2°C može dovesti do pada populacije od otprilike 7%, navodi NOAA Fisheries. Trenutni morski talas toplote do sada nije dostigao intenzitet ili trajanje "the Blob" iz 2015. godine, ali određene oblasti beleže neuobičajeno ili rekordno tople temperature.

Mogućnosti ublažavanja i potreba za praćenjem

Snažno obalno podizanje hladne i hranjive vode (upwelling) može lokalno ublažiti posledice i pomoći očuvanju ribe koju jedu morske vrste, prema NOAA Fisheries. Ipak, naučnici ističu da se uslovi mogu brzo promeniti: preklapanje regionalnog morskog talasa toplote i klimatskog fenomena El Niño može pojačati stres na prehrambene mreže i stoga zahteva pažljivo praćenje.

Zaključak: Biološke reakcije zabeležene tokom prošlih događaja daju važne tragove šta se može očekivati — spremnost i brza reakcija nadležnih službi su ključni za ublažavanje efekata na mladunce i vrste osetljive na toplotni stres.

Izvori: NOAA Fisheries, National Park Service, USA TODAY.

A holly tree stands tall in the Sunken Forest at Fire Island National Seashore in Suffolk County, New York.(Provide by Nicole Davi.)

Tree rings from a holly tree under a microscope.(Provide by Caroline Leland.)

Spencer Mitchell, small owner forester for Oregon Department of Forestry, holds the core of a healthy Douglas fir tree on Tuesday, April 21, 2026, in Scio, Oregon.(Kevin Neri/Statesman Journal / USA TODAY NETWORK via Imagn Images)

This increment borer is being used to withdraw a core sample small enough to fit inside a paper straw to study this cottonwood tree's rings.(Derek Schook, U.S. Geological Survey)

Tree ring scientist Nicole Davi works with a specialized auger to take a cross section of growth rings from a red cedar at Sandy Hook, New Jersey, without harming the tree.(Provided by Columbia Climate School, Kevin Krajick/Earth Institute)

Tree scientist Valerie Prouet, shown doing field research, is among a cadre of scientists collecting historical information from tree rings.(Provided by Valerie Prouet)

Peter Fule cores a chihuahua pine that survived Rodeo-Chediski Fire in the Sitgreaves National Forest near Overgaard on April 29, 2022.(Mark Henle/The Republic, USA TODAY NETWORK)

A healthy core of Douglas fir tree on the left versus a stressed one on Tuesday, April 21, 2026, in Scio, Oregon(Kevin Neri/Statesman Journal / USA TODAY NETWORK via Imagn Images)

A tree core under a microscope in the Laboratory of Tree-Ring Research at the University of Arizona in Tucson on Jan. 6, 2026.(Mark Henle/The Republic / USA TODAY NETWORK via Imagn Images)

Jeff Perry, founder of Angel City Lumber, points to tree rings as he seals Eaton Fire-damaged tree logs as part of the Altadena Reciprocity Project on December 4, 2025 in Altadena, California. The project is transforming fire-damaged trees collected from the Eaton Fire burn zone into finish-grade millwork lumber to be made available at below market price for fire survivors to rebuild their homes in Altadena.(Mario Tama, Getty Images)

The rings of this tree, found in a forest in Kimberley, British Columbia, are curved instead of circular which shows that this tree survived and kept growing despite being affected by a wildfire in the past.(Eric Seals / USA TODAY NETWORK)

Tree-ring specimens in the Laboratory of Tree-Ring Research archive at the University of Arizona in Tucson on Jan. 6, 2026.(Mark Henle/The Republic / USA TODAY NETWORK)

A portrait of Director Kevin Anchukaitis in the Laboratory of Tree-Ring Research archive at the University of Arizona in Tucson on Jan. 6, 2026.(Mark Henle/The Republic, USA TODAY Network)

Will West talks about counting the rings of the Douglas fir that was cut down on property off of Old Belfair Highway in Belfair, Wash. on Wednesday, Feb. 2, 2022. A community landmark, the tree was likely between 500 to 1,000 years old, according to arborists.(Meegan M. Reid / USA TODAY NETWORK)

Nicole Davi, a tree ring scientist, and a team of researchers visit a stand of holly trees.(Provided by Columbia Climate School, Kevin Krajick/Earth Institute)

Sea lions relaxing on docks near Pier 39 in Fisherman's Wharf, on Friday, May 22, 2026, in San Francisco, CA.