NEWS 21Populationsof sharksand rays are
disappearing from theworld’s oceans atan
“alarming” rate,anew report haswarned.
Since 1970,numbershave fallenby more
than 70%,adeclinethat has left three-
quartersof shark species facing extinct ion.
“For everyten sharks youhadinthe open
ocean in the1970s,you wouldhave three
today,across these species,on average,”
Dr RichardSherley of the Universityof
Exetertoldthe BBC. Theinternational
study–based onprevious studies andcatch
data –concluded thatoverfishing wasthe
principal causeofthe decline;and its
authorsnoted that hadthey had records
going back further than 1970,the declinewould probablyhave looked even steeper,
as it wasinthe 1950s that mass industrialisedfishingbegan in earnest.
The reportalsonotedthat, owing todifferingpolicies on fishin gmanagement,the
declines areworse in some areas thanothers: in the Atlantic,for instance, populations
started to stabilise in the 2000s,thankstoconservationefforts; butnumbers of sharks
and rays continue to plummet in theIndia nOcean.Health &Science6February2021 THE WEEKGrowingwoodinthelaboratory
Foryears,scientistshavebeendeveloping
lab-grownmeats,sothat peoplecaneat
steakwithouttheneedforcattle.Now
ateamattheMassachusettsInstituteof
Technologyisgrowingwoodinthelab,
sothatpeoplecanhavewoodenfurniture
withouttheneedtochopdowntrees.
Althoughitisinitsearlystages,researchers
hopetheirworkwilleventuallyhelpslow
deforestation,andmakeitpossiblefor
woodtobeproducedrapidly,anywherein
theworld.Thatwouldreducetheamount
ofenergythatiscurrentlyusedtoharvest
andtransporttimber;and,intheory,give
manufacturersaccesstolimitlesssupplies
ofamaterialthatisbothversatileand
biodegradable.Usinglivecellsextracted
fromtheleavesofthezinniaplant,anda
gelinfusedwithplanthormones,theteam
hassofarmanagedtoproducetiny
wood-likestructures,indoorsandwithout
soilorsunlight.Thehormonesinthegel
encouragethecellsto producelignin–the
substancethatgiveswood itsfirmness; and
thegelisformed intoascaffold, which the
wood grows in.Thisscaffold can be
created inanyshape.“So yes, you could
theoreticallygrow atabledirectly–fully
assembled,”mechanical engineerand lead
authorAshley Beckwith told TheTimes.
Pollution linked to sight loss
Peoplewho liveinareaswithhighlevelsof
airpollutionare more likely tosuffer age-
relatedmacular degeneration(AMD)–a
common form ofsight loss thatisprogres-
sive andirreversible–astudyhasshown.
“Even relativelylow exposureappearsto
impactthe risk ofAMD,suggestingthat
airpollutionisanimportantmodifiable
factorforavery large number ofpeople,”
saidProf PaulFoster,who ledthe research
at UniversityCollegeLondon.Histeam
lookedatdataonalmost116,00 0 people
intheUKBiobank,whowereagedfrom
40 to69,and whohad noeyeproblems in
2006.Theywerefollowedfor11 years,
andaskedtoreportonanydiagnosesof
AMD;some alsohadtheireyesexamined.
The researchersthenlookedat separate
data setstoworkouttheaveragepollution
levelsaround theirhomes.Theyfound
thata1.07mcg increaseinaverage
concentrationsofparticulatematter
(PM2.5)was associated with an 8% greater
risk ofapersonhavin gAMD.AMD is the
leading cause of irreversibleblindness
among theover-50sinhigh-income
countries;aroundthe world,some 200
millionpeople have thecondition.Ice melting is accelerating
Earthlost 28 trilliontonnes ofice between
1994 and2017 –and th erateofmelti ng
is accele rating,accordingtoanewstudy.
It foundthat icewas melting atarate of0.8trillion tonnes peryearatt he start of
thatperiod; whereasin 2017, 1.3trillion
tonnes disappeared. The totalamount of
ice lost is equivalent toasheet 100metres
thick, cove ring thewhol eoft he U K;
and therate of lossis in linewiththe
worst-case scenarios envisagedbythe
Intergovernmental Panel onClim ate
Change, says thepaper in the journal
The Cryosphere. Theimpact ofthemelt
willbef eltall overthe world–and soon,
accordingtolead authorDrThom as Slater
of Leeds University.“Sea-levelrise on this
scale willhave very seriousimpacts on
coastalcommunitiesthiscentury,” he said.
Thepapernotes that the greatest losses
were offloa ting icein the polar regions –
whichrisks creat ing afeedback loop:white
icereflects solar radiationbackintospace,
butwhen it m elts, it opens updark water
which absorbsheat, speeding up warming.
The next biggest losses came fromglaciers.The beneficial effect ofanap
Nappinginthe afternoon–even foras
little as fiveminutes –may boostmental
agility andimpr ovethe memory,astudy
published in theBMJ has found. The
research, byateamin Chi na,found that
people whoregularlyhad arestafter
lunch (definedassleeping foraminimum
of five minutesand amaximumof two
hours)tended to have better verbal
fluencythanthose thatdidnot;they also
had better working memories, and better
location awareness. The studywasbased
on 2,214peopleagedover60, who lived
in various Chinese cities. Around1,500
of themregularlynapped; the rest did
not. In both groups, theyslept, on
average,for 6. 5hours per night. Butthe
ones in thenapping groupperfor med
“significantlybetter”incognitive
assessments, saythe study’s authors.1.3 trillion tonnes of ice disappeared in 2017Changes to the tongue’s appearance
could be another symptom of the
coronavirus, it was reported last week. A
British researcher who is tracking Covid-
19 warning signs recently reported more
cases of people complaining of unusual
changes to their tongues. And Prof Tim
Spector’s tweet about “Covid tongue”
has since been backed byastudy in
Spain: it found that more thanatenth of
the 666 Covid patients it examined had
had “oral cavity” issues, including the
inflammation of the small bumps on
the surface of the tongue, “patchy”
areas and ulcers. However, the Spanish
researchers found that an even more
prevalent apparent symptom related
to the hands and feet: 18% of patients
had experienced burning, hives, skin
peeling or redness on the palms of
their hands and the soles of their feet,
according the report, in the British
Journal of Dermatology.CovidtonguewarningManyspecies of shark face extinctionWhat the scientists are saying...Sharks and raysare disappearingfast