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The Great Barrier Reef (GBR) is an internationally recognized and widely studied ecosystem, yet little is known about its sea surface temperature evolution since the Last Glacial Maximum (LGM) (~20 kyr BP). Here, we present the first paleo‐application of Isopora coral‐derived SST calibrations to a suite of 25 previously published fossil Isopora from the central GBR spanning ~25‐11 kyr BP. The resultant multi‐coral Sr/Ca‐ and δ18O‐derived sea surface temperature anomaly (SSTA) histories are placed within the context of published relative sea level, reef sequence and coralgal reef assemblage evolution. Our new calculations indicate SSTs were cooler on average by ~5‐5.5°C at Noggin Pass (~17°S) and ~7‐8°C at Hydrographer's Passage (~20°S) (Sr/Ca‐derived) during the LGM, in line with previous estimates (Felis et al., 2014). We focus on contextualizing the Younger Dryas Chronozone (YDC, ~12.9‐11.7 kyr BP), whose southern hemisphere expression, in particular in Australia, is elusive and poorly constrained. Our record does not indicate cooling during the YDC with near modern temperatures reached during this interval on the GBR, supporting an asymmetric hemispheric presentation of this climate event. Building on a previous study (Felis et al., 2014), these fossil Isopora SSTA data from the GBR provide new insights into the deglacial reef response, with near‐modern warming during the YDC, since the LGM.

The phone rang 30 minutes before my talk. It was a familiar number—my fertility doctor's office—and I picked up, expecting a nurse to tell me that my pills and injections were ready for my next treatment. Instead, the nurse asked me to hold for the doctor, who told me I was pregnant. It should have been joyous news, but he quickly tempered my enthusiasm by telling me that, given the results of other tests, he wasn't sure the pregnancy would go to term. I felt a complicated wave of emotions: relief that our fertility treatment worked, anxiety at the prospect of starting my new job pregnant, worry that I'd have a miscarriage—and stress about my imminent talk. > “It was a macabre preview into parenthood as an academic.” My husband and I had started fertility treatments during my postdoc years, unable to conceive on our own. The process was exhausting. I had to go into the doctor's office a few times per week for blood tests and appointments—all before my hourlong commute to work. The costs stretched our finances. I began to convert every price tag I saw to a portion of a doctor's visit. During the same time period, my professional life had started to fall into place. I completed my postdoc and landed a faculty job in the same city where we were living. When the doctor's office called that day, I was 1 month away from starting my new position and changing my email signature to “Assistant Professor.” Somehow, I managed to give my talk. But as I delivered my practiced monologue, I was having a very different conversation in my mind. I tried to imagine taking maternity leave during my first year as a professor. I also fretted about the viability of the pregnancy. Follow-up doctor's visits didn't yield positive news. The pregnancy would almost certainly end in a miscarriage. I contemplated termination. But because we'd had such a tough time getting pregnant, my husband and I decided to wait to see what happened. Over the next month, my appointments for blood draws and invasive ultrasounds increased to nearly every other day. During one appointment, we heard a heartbeat. My stomach sank all the way down to the stirrups holding my feet. It was painful to hear that heartbeat—because it provided a glimpse into the excitement of pregnancy that I knew would likely be cut short. We left the office still waiting for the supposedly imminent miscarriage. But I wasn't waiting at home. I was waiting during my first faculty meeting. I was waiting in the lab while teaching interns how to prepare samples. I tried my best to silo my personal and professional lives. As time wore on, though, the barrier between “waiting for miscarriage Logan” and “shiny new professor Logan” became less and less distinct. I was worn out physically and emotionally. It was a macabre preview into parenthood as an academic. I found myself constantly struggling to balance my career goals with my personal life, which featured many more doctor's appointments than visits with friends. I missed deadlines and meetings. I had trouble focusing. And I cried in my office, worried that I was already failing as a professor—feelings intensified by hormones that would bear no fruit. Then, roughly 7 weeks into my pregnancy, I went into the doctor's office—and this time there was no heartbeat. I'd never experienced such a visceral combination of sadness and relief. I swallowed two doses of the abortion pill and waited for my pregnancy to be officially over. I dealt with my grief, in part, by speaking openly with trusted colleagues, including my postdoc adviser and others who'd known me for years. And I'd had time to prepare. Difficult as my experience was, I can't imagine how someone feels when a miscarriage catches them totally off guard, or it happens for the second, third, or eighth time. Ten months have passed, and my husband and I are still working with the fertility doctor. It isn't easy to be open about my personal struggles. But I know many academics are in the same boat: starting their first faculty appointment while trying to start a family, and dealing with the conflicting emotions that even a better outcome can bring. I want them to know they're not alone.

Panama's extreme hydroclimate seasonality is driven by Intertropical Convergence Zone rainfall and resulting runoff. River discharge (Q) carries terrestrially-derived barium to coastal waters that can be recorded in coral. We present a Ba/Ca record (1996–1917) generated from a Porites coral colony in the Gulf of Chiriqui near Coiba Island (Panama) to understand regional hydroclimate. Here coral Ba/Ca is correlated to instrumental Q (R = 0.67, p

The first groups of young and experienced scientists matched by AGU’s new mentoring program gave it high marks.

In Central America, seasonal and interannual shifts in the position of the Intertropical Convergence Zone (ITCZ) control the hydrologic budget. To better understand long-term changes in regional ITCZ-driven precipitation we re-examined a coral δ 18 O record from a Porites lobata coral head near Secas Island (Core ID: S1) (7°59′ N, 82°3′ W) in the Gulf of Chiriqui on the Pacific side of Panama. Linsley et al., (1994) originally published the 277-year time series and first described the presence of a narrow-band decadal cycle (period near 9–12 years) in δ 18 O. The original study did not present potential drivers for the decadal cycle, although they ruled out the influence of the sun spot cycle. Our re-analysis of this record supports the original interpretation that coral δ 18 O is largely responding to variations in precipitation and associated river discharge, but with a new proposed mechanism to explain the decadal mode. There is no similar decadal cycle in gridded instrumental sea surface temperature from the area, suggesting that the decadal coral δ 18 O signal results from hydrologic changes that influence coastal δ 18 O seawater . The decadal component in S1 δ 18 O is also coherent with a decadal mode embedded in the Pacific Decadal Oscillation (PDO) Index that we suggest has tropical origins. We speculate that the coral's temporary δ 18 O deviation (1900–1930) in the decadal mode from the corresponding bands in rainfall and the PDO can be ascribed to a weak PDO in addition to local Panama gap wind variability and its effect on moisture transport from the Atlantic to the Pacific. Ultimately, the Secas Island coral δ 18 O series records ITCZ-driven precipitation dictated by both the Atlantic and Pacific basins.

Although reef coral skeletal carbon isotopes (δ13C) are routinely measured, interpretation remains controversial. Here we show results of a consistent inverse relationship between coral δ13C and skeletal extension rate over the last several centuries in Porites corals at Fiji, Tonga, Rarotonga and American Samoa in the southwest Pacific. Beginning in the 1950s, this relationship breaks down as the atmospheric 13C Suess effect shifts skeletal δ13C > 1.0‰ lower. We also compiled coral δ13C from a global array of sites and find that mean coral δ13C decreases by −1.4‰ for every 5 m increase in water depth (R = 0.68, p, Rising anthropogenic CO2 levels in the atmosphere are resulting in ocean acidification which may impact coral growth rates. Here, the authors quantify the relationship between water depth and δ13C compositions of South Pacific corals from the pre-industrial era, and their results should lead to improvements in the precision of sea level reconstructions using fossil corals.

The original version of the Source Data associated with this Article included an error, in which the ‘Fiji AB d13C-Suess’ data point and the ‘TNI2 d13C-Suess Effect’ data point for the year ‘1950.5’ where incorrectly omitted from the Figure 3 tab. The missing values are ‘−0.24’ and ‘−0.64’, respectively. The HTML has been updated to include a corrected version of Source Data.

A concerted effort has begun to gather and preserve archives of marine samples and descriptive data, giving scientists ready access to insights on ancient environments.