CREDIT: NOAA's Atlantic Oceanographic ♦₩∞and Meteorological Laboratory
On Posted on by AOML Communications to Ocean Chemistry and Ecosys÷βtems
Location of the three st₹€udy sites in each of two gulfs on the Pacific c♠α↔oast of Panamá.
Trying to predict how coral reefs will respond t♠☆o warming oceans and a ch←♦↓₹anging climate may be considered a da₽ γ©unting task for scienti☆£∑sts. In the face of this challenge, scientists β♦★∞at AOML recently published a study that characterizes the organisms a✔•nd processes that lead to coral reef accπ"retion (build up) and bioerβ≠'osion (break down) in t$♣©he dynamic environments oσ✘€$f the Gulf of Panamá and Gulf of Chiriquí ♦ in the eastern Pacific.
So how does a reef ta←↕$ke shape and create pillars, ridges, and mountai≥×nous structures? Ocean condi∏₹tions such as temperature, acidity, and λ available nutrients in the wat>π£er play a role, as do marine organisms cπ♠alled “bioeroders” that graze the co&<πral for algae (grazers), create holes in the cλ↔oral surface (microbor× £ers), or create holes in its internal strγ∏δucture (macroborers). Althoug↕↔≈≠h grazing and erosion diminish reefs,§♣↕α they also allow space for new ₹₩σ≤coral to form through the deposit ≥←ion of calcium carbonate–a process called “calcifβ¥ication.”
Marine conditions suc ↑™h as temperature, acidity and avai♥✔δlable nutrients in water, have a ce '★rtain influence and role, including those wh£©∑✔o are called "biological erosion" sea >©∑creatures for algae into coral survival domα↑λain, and making holes inβπβ the coral surface (m✘₹₩icroporous worm), or in the internal<✘ structure of coral hole (a ↑λbig hole bug). While such erosion reduces coral r→εeefs, the laws of natur €<e, both positive and negative, pull them togeth→¶™βer to provide room for new coral£©©♠ formation, through the deposition of calci•÷um carbonate, a process known as<₩σ÷ calcification.
Ian Enochs, a research ecologist from♥¶£ AOML and lead author of the study, sa≥α∑id: "Coral reefs are facing a quantitative bε£♠attle as the impacts of clim≥δ≥ate change intensify, not only reducing ✘₽habitat growth but also increasing th↕↓•♠e risk of erosion. The sta∏"×kes are high, and the re>≥γsilience of coral reefs and the ecosystems they support are worth considering>✔β☆.
Scientists studied the marine organisms a✘↔©nd processes mentioned above using bioeros₽☆α£ion accretion replicates (BARs) made from s≥©βtony coral (Porites) skeletons (the same material that makes ♦&εup the reef), that were↕•'© deployed to reefs in the gulfs of Pana×<☆γmá and Chiriquí. After two years, they scanned tε"he BARs using computed tomography (CT) to be™σtter understand bioer×Ωosion and accretion at these reef sites.♥®'
Surface waters are displaced by coαφld, nutrient-rich water that “wells up” fr₩∑↕€om below in a process called★δ₽λ “upwelling.” The water¶γ☆ that rises is often coo α☆₹ler and more acidic, and may contribute to i↓®≥ncreased biological productivity from the∞↑> nutrients it brings to♠↓ the surface. Image from https://oceanservice.noa↕±a.gov/facts/upwelling.html
The study revealed that in bo♣€"th gulfs, external bioerosion≤™σ by grazers such as parrotfish an'> d urchins was the major process altering c× oral reef habitat, with higher rates of ero♦§ 'sion and habitat loss observed in the Gu'↓∑lf of Chiriquí. One difference in envi₹∑¥↕ronmental factors between the gulfs w₩ as the greater amount of upwelling ∏≠'¶(movement of deeper cold nutrient-riπ☆φch waters to the surface) in the G•$ulf of Chiriquí that may have provided a f£γood source for calcifying anim∑ ε als, as well as accelerated macrobo≤¶Ω>ring, leading to a less structurally stable reef &∞ developed on sediment (instead of solid r≤&eef material). &n↓λ γbsp;
Keeping up with sea φ®<level rise and other stressors brou↔±₹βght on by climate change presents a challenge Ω"↑for reefs struggling ≤©♣to grow and adapt to changes in the envir Ωβ✔onment. The interact₽∞÷©ion of reef structure, habitat biodivers€γity, and ocean condiα∞∏tions can lead to a varie§Ωty of ecosystem outcomes ∏♥ that are difficult to predict. A holist×β↔ic approach to examining the impact of enviro•λ♦↓nmental conditions on all habitat-a¶₽∑ ltering organisms is key to understanding reef p€λersistence in the eas₽β∞tern Pacific and global ocean.
（CREDIT: National Ocean∑÷λ€ic and Atmospheric Administratioπ↓♠×n）